全文获取类型
收费全文 | 11112篇 |
免费 | 208篇 |
国内免费 | 2篇 |
专业分类
管理学 | 1529篇 |
民族学 | 64篇 |
人才学 | 3篇 |
人口学 | 992篇 |
丛书文集 | 70篇 |
理论方法论 | 1143篇 |
综合类 | 229篇 |
社会学 | 5684篇 |
统计学 | 1608篇 |
出版年
2023年 | 56篇 |
2020年 | 168篇 |
2019年 | 260篇 |
2018年 | 275篇 |
2017年 | 399篇 |
2016年 | 282篇 |
2015年 | 212篇 |
2014年 | 268篇 |
2013年 | 1789篇 |
2012年 | 369篇 |
2011年 | 353篇 |
2010年 | 283篇 |
2009年 | 272篇 |
2008年 | 258篇 |
2007年 | 307篇 |
2006年 | 265篇 |
2005年 | 272篇 |
2004年 | 256篇 |
2003年 | 188篇 |
2002年 | 220篇 |
2001年 | 282篇 |
2000年 | 236篇 |
1999年 | 213篇 |
1998年 | 175篇 |
1997年 | 161篇 |
1996年 | 157篇 |
1995年 | 144篇 |
1994年 | 153篇 |
1993年 | 152篇 |
1992年 | 152篇 |
1991年 | 149篇 |
1990年 | 152篇 |
1989年 | 149篇 |
1988年 | 135篇 |
1987年 | 149篇 |
1986年 | 120篇 |
1985年 | 150篇 |
1984年 | 158篇 |
1983年 | 148篇 |
1982年 | 126篇 |
1981年 | 90篇 |
1980年 | 111篇 |
1979年 | 114篇 |
1978年 | 102篇 |
1977年 | 86篇 |
1976年 | 88篇 |
1975年 | 99篇 |
1974年 | 94篇 |
1973年 | 69篇 |
1972年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
291.
This study investigated the relation between maternal contingent responsiveness and 4‐ and 5‐month‐old infants' (N = 64) social expectation behavior in a still‐face procedure. Mothers were asked to interact with their infants for 2 min (interactive phase), remain still‐faced for 1 min (still‐face phase), and resume interaction for 2 min. Mother and infant behavior was assessed for the frequency of infant and mother smiles, mother smiles that were contingent to infant smiles and infant smiles were contingent to mother smiles during the interactive phase, and infant social bids to mother during the still‐face phase. Hierarchical regression showed that mother contingent smiles during the interactive phase accounted for unique variance in infant social bids during the still‐face phase beyond that accounted for by the frequency of mother and infant smiles during the interactive phase. These results support the view that young infants' social expectations and sense of self‐efficacy are formed within their interactions with their caregivers. 相似文献
292.
Infants' response to maternal mirroring was investigated in 4‐month‐old infants. Mother–infant dyads participated in the still face and replay tasks. Infants were grouped by those whose mothers did and did not mirror their behavior in the interactive phases of the tasks. In the still face task, infants with maternal mirroring showed more attention, smiling, and positive vocalizations across the phases, although both groups of infants demonstrated the still‐face effect with attention and smiling. Infants' social bidding to the mother during the still‐face phase correlated with mothers' mirroring behavior. In the replay task, infants with maternal mirroring demonstrated carryover effects with smiling; infants without maternal mirroring showed no awareness of change in their mothers' behavior. In both the still face and replay tasks, infants with maternal mirroring were more engaged with their mothers. Results suggest that maternal mirroring of infants' behavior affects infants' detection of, and response to, reciprocal interaction. 相似文献
293.
Stephen E. Bechtold 《决策科学》1988,19(2):353-372
This paper presents a tractable set of integer programming models for the days-off scheduling of a mix of full- and part-time employees working α to β days/week (cycle) in a multiple-objective, multiple-location environment. Previous models were formulated to specifically schedule part-time employees working either two or three days per week. These models were intractable because they required complete employee schedule information. The new models are deemed implicit optimal since they are required to supply only essential information. While the number of variables in previous models is an exponential increasing function of β-α, the size of three of the new models is independent of α and β. The first three models developed here (as in [18]) deal with the trade-offs between idle time, the number of employees required to work at multiple “locations,” and the size of the total labor pool. The inherent flexibility of the implicit modeling approach is illustrated by the presentation of various modifications of the basic models. These modifications permit the use of preference weights on the number of employee work days/week (cycle) or the minimization of payroll costs where differential pay rates exist. These latter models may also be formulated such that idle time is ignored, constrained or minimized. The execution time for the implicit models (on a CDC CYBER 730 computer with commercially available software) averaged well under five seconds on 1200 trial problems for the type of application considered in [18]. A solution was obtained in less than 46 seconds of CPU time for a trial problem which would have required over 1.4 million integer variables with previous models. The availability of optimal solutions was invaluable in the development of two heuristics designed to deal with the trade-offs of [16]. In an experimental analysis a previous heuristic produced results which averaged from 74 to 508 percent above optimum across six experimental conditions. The comparable new heuristic produced results which averaged from 3 to 8 percent above optimum for the same experimental conditions. The paper concludes by developing a framework to integrate the results of this research with the tour scheduling problem and by identifying several other areas for related research. 相似文献
294.
Urbanization is a process that heavily alters marine and terrestrial environments, though terrestrial urban ecosystems have been studied far more intensively. Terrestrial studies suggest that urbanization can facilitate mesopredators by enhancing food and shelter resources and reducing predation pressure from apex consumers. This in turn has considerable consequences for ecological communities. We evaluated spatial distribution patterns and habitat-use of the marine mesopredator, giant Pacific octopus (Enteroctopus dofleini), relative to terrestrial urbanization intensity in Puget Sound, Washington, USA. Using field surveys and citizen-contributed data for E. dofleini, we examined whether: (1) Distribution was related to urbanization, (2) Abundance was related to the extent of benthic anthropogenic debris, and (3) Diet differed as a function of urbanization and den cover. Our results suggest that urbanization impacts may differ with depth. Mixed-effects logistic regression model estimates for the probability of occurrence increased with urbanization in deep-water (> 24 m), and decreased with urbanization in shallow water (< 18 m). Accompanying field surveys indicated that E. dofleini abundance was correlated with the number of benthic anthropogenic debris items, and that E. dofleini diets were not affected by urbanization intensity or den cover. Though E. dofleini may be synanthropic within certain urban environments, the mechanisms driving this pattern likely differ from those affecting common urban mesopredators on land, with den provisioning from man-made structures being more important than altered food resources. 相似文献
295.
Anna L. Hotton Lance Keene Dennis E. Corbin John Schneider Dexter R. Voisin 《Journal of gay & lesbian social services》2018,30(1):64-81
Black gay men must navigate identities and stigmas related to being gay and Black, and report higher HIV incidence relative to their White male counterparts although they report lower rates of drug use and risky sexual behaviors. This study examined whether closeness to the gay or Black community correlated with HIV-related risk and protective behaviors. Data were drawn from uConnect, a population-based cohort study of young Black men who have sex with men (YBMSM) on Chicago's South Side. The sample consists of 618 Black MSM ranging in age from 16 to 29. Cross-sectional measures for this study include Black and gay community closeness, drug use, sexual risk behaviors, HIV testing, and health promotion behaviors. Closeness with the gay community was associated with greater pre-exposure prophylaxis (PrEP) knowledge as well as participating in health promotion programs along with higher rates of transactional sex and having sex under the influence of substances, and increased odds of self-reported HIV seropositivity. Involvement in the Black community was associated with lower odds of reporting being HIV positive. Findings suggest that programs and initiatives are needed to help promote the positive aspects of the Black and gay communities, while minimizing the negative correlates of such involvements. 相似文献
296.
David T. Kryszajtys Tara E. Hahmann Andrée Schuler Sarah Hamilton-Wright Carolyn P. Ziegler Flora I. Matheson 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2018,34(3):893-914
Despite many studies indicating an association between problem gambling and delinquent behaviours among adolescents, there has been no effort to systematically analyze the state of the literature on this relationship. To fill this gap, we conducted a scoping review of the literature published between 2000 and 2016 on problem gambling and delinquent behaviours among adolescents. We searched twelve databases and reviewed reference lists to identify eligible studies. Search terms included a combination of medical subject headings and keywords for gambling, youth, and delinquency, which were combined with the Boolean operator “AND”. 1795 studies were identified through the literature search. Nine studies were eligible for inclusion. All of the studies were conducted in North America, with primarily male participants, and most of the data were cross-sectional. No qualitative studies met the inclusion criteria. Screening tools used to measure problem gambling were inconsistent, making comparisons across studies difficult. We found a consistent moderate to strong association between problem gambling and delinquent behaviour. Only one study presented associations by socio-economic status and none considered gender, sex or ethnic differences. Studies in the review showed that problem gambling is associated with both violent and non-violent behaviours among adolescents. These associations may suggest that problem gambling and delinquent behaviours have common risk factors and reflect a syndrome of risky behaviours best targeted through prevention and treatment that is holistic and considers the context in which the youth is situated. Further research is warranted to better understand the relationship between problem gambling and delinquent behaviours. 相似文献
297.
Nigel E. Turner Tara Elton-Marshall Jing Shi Jamie Wiebe Angela Boak Mark van der Maas Robert E. Mann 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2018,34(2):521-537
This paper reports on the cross validation of the Gambling Problem Severity Subscale of the Canadian Adolescent Gambling Index (CAGI/GPSS). The CAGI/GPSS was included in a large school based drug use and health survey conducted in 2015. Data from students in grades 9–12 (ages 13–20 years) derived from the (N = 3369 students). The CAGI/GPSS produced an alpha of 0.789. A principle component analysis revealed two eigenvalues greater than one. An oblique rotation revealed these components to represent consequences and over involvement. The CAGI/GPSS indicated that 1% of the students fell into the “red” category indicating a severe problem and an additional 3.3% scored in the “yellow” category indicating low to moderate problems. The CAGI/GPSS was shown to be significantly correlated with gambling frequency (r = 0.36), largest expenditure (r = 0.37), sex (more likely to be male) (r = ?0.19), lower school marks (r = ?0.07), hazardous drinking, (r = 0.16), problem video game play (r = 0.16), as well as substance abuse. The CAGI/GPSS was cross validated using a shorted version of the short SOGS, r = 0.48. In addition the CAGI/GPSS and short SOGS produced very similar patterns of correlations results. The results support the validity and reliability of the CAGI/GPSS as a measure of gambling problems among adolescents. 相似文献
298.
ABSTRACTThis article summarizes panel discussions that took place at an international conference on shared parenting (SP) held in May 2017. The panelists were internationally recognized experts on the legal and psychological implications of custody arrangements and parenting plans. Seven broad themes dominated the discussions: whether or not there was persuasive evidence that SP provides real benefits to children whose parents separate; what specific factors make SP beneficial; what symbolic value SP might have; whether there should be a legal presumption in favor of SP, and if so, what factors should make for exceptions; whether high parental conflict, parents’ failure to agree on the parenting plan, or dynamics of parental alienation should preclude SP; and what should happen when a parent wants to relocate away from the other parent. 相似文献
299.
Jessica Krahn Vera Caine Jean Chaw-Kant Ameeta E. Singh 《Journal of Social Distress and the Homeless》2018,27(1):75-88
Family homelessness is a growing problem in North America with most of these families headed by single women. Homeless women also experience high rates of pregnancy and addiction (drugs and alcohol). Housing interventions have been identified as key to addressing the complex needs of pregnant/early parenting, homeless women with addictions. The aim of this systematic review is to determine what housing models and programs for this population yield the best outcomes. We systematically searched 10 databases and retrieved eight articles describing four distinct studies that met the inclusion criteria for this review. Overall, improved outcomes were found for all intervention groups with the most recent and rigorous studies favoring models combining Housing First and case management. However, methodological limitations, study quality, and varied outcomes made comparison across studies difficult. Further research must be done in this area using standardized outcomes and rigorous designs to develop evidence-based best practice guidelines to address the unique needs of this population. 相似文献
300.