全文获取类型
收费全文 | 7942篇 |
免费 | 209篇 |
专业分类
管理学 | 1137篇 |
民族学 | 35篇 |
人才学 | 1篇 |
人口学 | 731篇 |
丛书文集 | 33篇 |
理论方法论 | 711篇 |
综合类 | 284篇 |
社会学 | 3404篇 |
统计学 | 1815篇 |
出版年
2023年 | 41篇 |
2021年 | 52篇 |
2020年 | 91篇 |
2019年 | 135篇 |
2018年 | 170篇 |
2017年 | 248篇 |
2016年 | 204篇 |
2015年 | 149篇 |
2014年 | 177篇 |
2013年 | 1377篇 |
2012年 | 302篇 |
2011年 | 220篇 |
2010年 | 175篇 |
2009年 | 160篇 |
2008年 | 193篇 |
2007年 | 183篇 |
2006年 | 142篇 |
2005年 | 198篇 |
2004年 | 177篇 |
2003年 | 216篇 |
2002年 | 233篇 |
2001年 | 223篇 |
2000年 | 194篇 |
1999年 | 188篇 |
1998年 | 145篇 |
1997年 | 114篇 |
1996年 | 132篇 |
1995年 | 105篇 |
1994年 | 98篇 |
1993年 | 106篇 |
1992年 | 125篇 |
1991年 | 115篇 |
1990年 | 113篇 |
1989年 | 103篇 |
1988年 | 111篇 |
1987年 | 112篇 |
1986年 | 103篇 |
1985年 | 121篇 |
1984年 | 98篇 |
1983年 | 106篇 |
1982年 | 74篇 |
1981年 | 76篇 |
1980年 | 72篇 |
1979年 | 76篇 |
1978年 | 78篇 |
1977年 | 54篇 |
1976年 | 45篇 |
1975年 | 59篇 |
1974年 | 48篇 |
1973年 | 41篇 |
排序方式: 共有8151条查询结果,搜索用时 46 毫秒
321.
Stephen J. Zaccaro Jennifer P. Green Samantha Dubrow MaryJo Kolze 《The Leadership Quarterly》2018,29(1):2-43
In this article, we provide a wide-ranging review of recent research on leader individual differences. The review focuses specifically on the explosion of such research in the last decade. The first purpose of this review is to summarize and integrate various conceptual frameworks describing how leader attributes influence leader emergence and leader effectiveness. The second purpose is to provide a comprehensive review of empirical research on this relationship. Also, most prior reviews primarily examined leader personality traits; this review includes a broader array of leader attributes, including cognitive capacities, personality, motives and values, social skills, and knowledge and expertise. The final broad purpose of this paper is to review and integrate situational and contextual parameters into our conceptual framing of leader individual differences. Few, if any, prior reviews have systematically accounted for the critical role of such parameters in cuing, activating, or delimiting the effects of particular leader attributes. We do so in this article. 相似文献
322.
D. V. Gribanov D. S. Malyshev P. M. Pardalos S. I. Veselov 《Journal of Combinatorial Optimization》2018,36(4):1128-1144
This paper studies a new version of the location problem called the mixed center location problem. Let P be a set of n points in the plane. We first consider the mixed 2-center problem, where one of the centers must be in P, and we solve it in \(O(n^2\log n)\) time. Second, we consider the mixed k-center problem, where m of the centers are in P, and we solve it in \(O(n^{m+O(\sqrt{k-m})})\) time. Motivated by two practical constraints, we propose two variations of the problem. Third, we present a 2-approximation algorithm and three heuristics solving the mixed k-center problem (\(k>2\)). 相似文献
323.
We investigate special cases of the quadratic minimum spanning tree problem (QMSTP) on a graph \(G=(V,E)\) that can be solved as a linear minimum spanning tree problem. We give a characterization of such problems when G is a complete graph, which is the standard case in the QMSTP literature. We extend our characterization to a larger class of graphs that include complete bipartite graphs and cactuses, among others. Our characterization can be verified in \(O(|E|^2)\) time. In the case of complete graphs and when the cost matrix is given in factored form, we show that our characterization can be verified in O(|E|) time. Related open problems are also indicated. 相似文献
324.
Network coding is a generalization of conventional routing methods that allows a network node to code information flows before forwarding them. While it has been theoretically proved that network coding can achieve maximum network throughput, theoretical results usually do not consider the stochastic nature in information processing and transmission, especially when the capacity of each arc becomes stochastic due to failure, attacks, or maintenance. Hence, the reliability measurement of network coding becomes an important issue to evaluate the performance of the network under various system settings. In this paper, we present analytical expressions to measure the reliability of multicast communications in coded networks, where network coding is most promising. We define the probability that a multicast rate can be transmitted through a coded packet network under a total transmission cost constraint as the reliability metric. To do this, we first introduce an exact mathematical formulation to construct multicast connections over coded packet networks under a limited transmission cost. We then propose an algorithm based on minimal paths to calculate the reliability measurement of multicast connections and analyze the complexity of the algorithm. Our results show that the reliability of multicast routing with network coding improved significantly compared to the case of multicast routing without network coding. 相似文献
325.
Many important questions and theories in demography focus on changes over time, and on how those changes differ over geographic
and social space. Space-time analysis has always been important in studying fertility transitions, for example. However, demographers
have seldom used formal statistical methods to describe and analyze time series of maps. One formal method, used widely in
epidemiology, criminology, and public health, is Knox’s space-time interaction test. In this article, we discuss the potential
of the Knox test in demographic research and note some possible pitfalls. We demonstrate how to use familiar proportional
hazards models to adapt the Knox test for demographic applications. These adaptations allow for nonrepeatable events and for
the incorporation of structural variables that change in space and time. We apply the modified test to data on the onset of
fertility decline in Brazil over 1960–2000 and show how the modified method can produce maps indicating where and when diffusion
effects seem strongest, net of covariate effects. 相似文献
326.
The aims of this investigation were (1) to measure the impact of arts-related activities on the perceived quality of life
of a representative sample of British Columbians aged 18 years or more in the spring of 2007, and (2) to compare the findings
of this study with those of a sample of 1,027 adults drawn from five B.C. communities (Comox Valley, Kamloops, Nanaimo, Port
Moody and Prince George) in the fall of 2006. Seven hundred and eight British Columbians responded to a mailed out questionnaire,
and the working data set was weighted by age and education to match the 2006 census statistics for the province, yielding
a fairly representative sample. Speaking quite generally, about 62.0% of the results for the two samples are very similar.
In particular, in both surveys we found that (a) among arts-related activities in which people participate relatively infrequently
(i.e., participation is counted in times per year rather than in hours per week), live theatre is supreme in the strength of its positive correlation with respondents’ perceived quality of life measured
in 7 different ways, and (b) compared to 4 demographic variables (age, education, household income and body mass index), household
income had the highest average, positive correlation with 7 different measures of respondents’ overall life assessments, namely,
self-assessed general health, satisfaction with life as a whole (single item), happiness, satisfaction with the quality of
life, satisfaction with life as a whole (5-item index), contentment with life (5-item index) and subjective wellbeing (4-item
index). Different results were found in the province-wide versus the five-communities survey for the following, among other
things, (a) compared to all 7 life assessment measures, for the province, satisfaction with the quality of life and happiness
had the largest number of significant correlations with arts-related activities measured in hours per week engaged, while for the five communities, the single measure of satisfaction with the quality of life had the largest number
of significant correlations, and (b) For the province, compared to all 7 life assessment measures, satisfaction with the quality
of life had the largest number of significant correlations with arts-related activities measured in times per year engaged; for the five communities, compared to all 7 life assessment measures, self-assessed general health had the largest
number of significant correlations with arts-related activities measured in times per year engaged. 相似文献
327.
This research examines land use change in Israel––an intriguing but understudied setting with regard to population–environment
dynamics. While Israel is fairly unique with regard to its combined high levels of economic prosperity and high population growth, this case study has relevance for developed countries and regions (like the south and southwest regions
of the USA) which must balance population growth and urban development with open space conservation for ecosystem services
and biological diversity. The population–land development relationship is investigated during the period from 1961 to 1995
at three spatial scales: national, regional (six districts), and local (40 localities). There is a positive correlation between
population growth and land development rates at the national scale, and while remaining positive, the strength of the relationship
varies greatly at regional and local scales. The variation in population–land use dynamics across scales is used to garner
insight as to the importance of geography, policy and historical settlement patterns. 相似文献
328.
Katherine Péloquin Audrey Brassard Marie-France Lafontaine Phillip R. Shaver 《Journal of sex research》2014,51(5):561-576
Attachment researchers have proposed that the attachment, caregiving, and sexual behavioral systems are interrelated in adult love relationships (Mikulincer &; Shaver, 2007). This study examined whether aspects of partners’ caregiving (proximity, sensitivity, control, compulsive caregiving) mediated the association between their attachment insecurities (anxiety and avoidance) and each other's sexual satisfaction in two samples of committed couples (Study 1: 126 cohabiting or married couples from the general community; Study 2: 55 clinically distressed couples). Partners completed the Experiences in Close Relationships measure (Brennan, Clark, &; Shaver, 1998), the Caregiving Questionnaire (Kunce &; Shaver, 1994), and the Global Measure of Sexual Satisfaction (Lawrance &; Byers, 1998). Path analyses based on the actor-partner interdependence model (APIM) revealed that caregiving proximity mediated the association between low attachment avoidance and partners’ sexual satisfaction in distressed and nondistressed couples. Sensitivity mediated this association in nondistressed couples only. Control mediated the association between men's insecurities (attachment-related avoidance and anxiety) and their partners’ low sexual satisfaction in nondistressed couples. Attachment anxiety predicted compulsive caregiving, but this caregiving dimension was not a significant mediator. These results are discussed in light of attachment theory and their implications for treating distressed couples. 相似文献
329.
This research compared direct and indirect measures of ambivalence, 2 commonly used strategies for measuring intergenerational ambivalence between older parents and their adult children. Directly and indirectly measured ambivalence, corresponding to felt and potential manifestations of the construct, were contrasted with each other and across generations. Data were derived from 253 older parent–adult child dyads participating in the Longitudinal Study of Generations in 2005. Direct and indirect measures of ambivalence were moderately correlated with each other within each generation. Children expressed greater indirect ambivalence than their parents but were no different than their mothers or fathers in their levels of direct ambivalence. Multivariate regression analyses examining the relationship between each type of ambivalence with individual and relationship characteristics found differences in associations across equations. The results suggest that direct and indirect measures are related but represent 2 distinct conceptions of ambivalence. This research highlights the challenges in understanding the full complexity of intergenerational relations and suggests that both generational perspectives be considered in future research. 相似文献
330.
Robyn L. Fielder Jennifer L. Walsh Kate B. Carey Michael P. Carey 《Journal of sex research》2014,51(2):131-144
“Hookups” are sexual encounters between partners who are not in a romantic relationship and do not expect commitment. We examined the associations between sexual hookup behavior and depression, sexual victimization (SV), and sexually transmitted infections (STIs) among first-year college women. In this longitudinal study, 483 women completed 13 monthly surveys assessing oral and vaginal sex with hookup and romantic partners, depression, SV, and self-reported STIs. Participants also provided biological specimens that were tested for STIs. During the study, 50% of participants reported hookup sex and 62% reported romantic sex. Covariates included previous levels of the outcome, alcohol use, impulsivity, sensation seeking, and romantic sex. Autoregressive cross-lagged models showed that, controlling for covariates, hookup behavior during college was correlated with depression, Bs = .21, ps < .05, and SV, Bs = .19, ps < .05. In addition, precollege hookup behavior predicted SV early in college, B = .62, p < .05. Hookup sex, OR 1.32, p < .05, and romantic sex, OR 1.19, p < .05, were associated with STIs. Overall, sexual hookup behavior among college women was positively correlated with experiencing depression, SV, and STIs, but the nature of these associations remains unclear, and hooking up did not predict future depression. 相似文献