首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13840篇
  免费   280篇
  国内免费   15篇
管理学   1677篇
民族学   84篇
人才学   1篇
人口学   1184篇
丛书文集   145篇
理论方法论   1268篇
综合类   704篇
社会学   7286篇
统计学   1786篇
  2023年   72篇
  2021年   109篇
  2020年   216篇
  2019年   262篇
  2018年   354篇
  2017年   496篇
  2016年   344篇
  2015年   277篇
  2014年   331篇
  2013年   2182篇
  2012年   509篇
  2011年   487篇
  2010年   409篇
  2009年   337篇
  2008年   414篇
  2007年   430篇
  2006年   433篇
  2005年   376篇
  2004年   296篇
  2003年   267篇
  2002年   281篇
  2001年   355篇
  2000年   292篇
  1999年   288篇
  1998年   213篇
  1997年   175篇
  1996年   168篇
  1995年   176篇
  1994年   164篇
  1993年   167篇
  1992年   192篇
  1991年   191篇
  1990年   188篇
  1989年   162篇
  1988年   171篇
  1987年   198篇
  1986年   151篇
  1985年   162篇
  1984年   182篇
  1983年   153篇
  1982年   155篇
  1981年   128篇
  1980年   116篇
  1979年   129篇
  1978年   101篇
  1977年   80篇
  1976年   97篇
  1975年   115篇
  1974年   86篇
  1972年   62篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Since 1965 hundreds of articles and books have been published about African American families. Nevertheless, our understanding of these families continues to be limited. There is a tendency to gloss over important within-group differences; thus, monolithic, stereotypic and inaccurance portrayals of Black family life are common. This paper sets aside debates of Black family pathology or viability, focusing instead on these families' essential character. The paper seeks to understand Black families on their own terms, locating them in relevant social, historical, political and cultural contexts. Key empirical patterns and trends reveal dramatic changes in Black family geographic location, headship, quality of life and socioeconomic status since 1950.A complex picture is revealed. There has been gradual but steady overall improvement alongside persistent, extreme racial disparties and pronounced class disparities among Black families. The proposed Black Family Socio-Ecological Context model specifies and connects institutional, interpersonal, environmental, temporal and cultural facts that shape the essential character of Black family life in such a way as to produce characteristics simultaneously shared and idiosyncratic. The model also provides an organized, systematic accounting of research and public policy issues relevant to the study of African American families.An early version co-authored with Richard A. English was presented during the National Council on Family Relations Meetings in Portland, Oregon, October 1980.  相似文献   
72.
Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.  相似文献   
73.
文章根据专业学习和技能培训的关系,设计了本科教学的机械设计技能培训模块,为培养大学生的设计技能提供了一个实践平台。  相似文献   
74.
The government, the market, and the problem of catastrophic loss   总被引:1,自引:0,他引:1  
This article addresses the comparative advantage of the government to the private property/casualty insurance industry for the provision of insurance coverage for catastrophic losses. That the government can play an important role as an insurer of societal losses has been a central public policy principle since at least the New Deal. In addition, our government typically automatically provides forms of specific relief following unusually severe or unexpected disasters, which itself can be viewed as a form of ex post insurance. This article argues that, for systemic reasons, the government is much less effective than the private property/casualty insurance market in providing coverage of losses generally, but especially of losses in contexts of catastrophes.  相似文献   
75.
76.
This paper discusses the employment situation of Chilean migrant workers, their impact on labor markets in Patagonia, Argentina, and the government's past and projected responses to this phenomenon. In 1980, Chilean inhabitants of patagonia comprised 11% of the area's population. Chilean migration to patagonia was closely linked to economic activities that began to flourish in the 20th century, such as livestock raising, fruit and vegetable cultivation, and mining for coal and petroleum. No Chilean migrants work in a wide range of sectors. In Patagonia's southern provinces availability and ability to withstand rigorous climate conditions are the main factors which account for the prevalence of Chilean manpower. Chilean migrants do not in general displace local manpower. Legislation and the permeability of the border ensure that most workers enter the country as tourists. Clandestine migration is not an issue. Illegal migrants have provoked negative reactions for several reasons: 1) they comprise a marginal population without formal citizenship; 2) being employed as clandestine workers, they pay no social security, nor do their employers; 3) being illegal, they are obliged to accept lower wages and inferior working conditions which creates unfair competition within labor markets; and 4) as a result of these conditions, xenophobic and endophobic attitudes in relations with Argentine nationalists are reinforced. The government has attempted to solve these problems through various measures. Beginning in 1934, most foreigners entered Argentina with a tourist visa, becoming illegal when they stayed beyond authorized limits. Several measures over the years provided amnesty to illegal migrants. Currently, the law promotes immigration, monitors the admission of foreigners to the country and stipulates their rights and obligations. The law lists 115 articles on immigration promotion and on regulation of the movements of foreigners. Because of the present economic crisis in Argentina, authorities are investigating the effect of Chilean manpower on Argentine labor markets.  相似文献   
77.
This article examines the origins of physicians and nurses who were admitted as permanent immigrants to the US from 1962-1979. Data are mainly from the Immigration and Naturalization Service. Countries used in the developmental analysis are only those whose population was estimated at 1 million or more as of mid-1979, encompassing 99% of the physicians and 97% of the nurses. Life expectancy at birth is the criterion used to differentiate origin countries by developmental dimension of health status. During the study period, health workers constituted about 30% of immigrants admitted to the US; of these, nurses and physicians constituted 72-82% throughout the study period. The period 1962-1979 has 4 distinct phases, marked by important legislative and/or policy changes; 1) 1962-1965, when the McCarran-Walter Act prevailed; 2) ending in 1968, the 2nd phase covers the transition mandated under the 1965 Immigration Act, which encouraged physician immigration; 3) the 3rd phase, 1969-1976, covers the transition to the 1976 Immigration and Nationality Act amendments; and 4) the 4th stage is 1977-1979. Results show that 1) under the McCarran-Walter Act, North America became the dominant physician source; 2) from 1966-1968, Asia attained dominance as the physician source and became even more predominant after 1968; 3) North America produced relatively few physicians in the early 1970s; 4) Europe produced substantially fewer physicians in the 1970s than in the 1960s; 5) South America, Africa, and Oceania were the lowest contributors of physicians; 6) during the McCarran-Walter years, North America and Europe produced almost 90% of nurses admitted into the US; 7) the 1965 Immigration Act and its aftermath resulted in Asia becoming the dominant source of nurses; 8) prior to the 1965 Immigration Act, Canada generated 20% of the aggregate number of physicians; 9) the Philippines surpassed Canada during the transition and India led after the transition; and 10) Canada supplied 30% of the nurses up through the transition, with the Philippines in the lead 1969-1979. Low health status countries were a relatively minor nurse source. Health status at the origin was a far less significant determinant of physician immigration than that of nurses. English language high and low health status country groups produced substantially more physician and nurse immigrants that their corresponding non-English language counterparts. The US attracted more physicians and nurses from less developed countries than more developed countries after 1968.  相似文献   
78.
Working with a treatment and observing team at the same time, behind the oneway mirror, offers a variety of ways to: (a) generate multiple realities; (b) work with two different models of family therapy simultaneously; and (c) provide feedback on the teams' own roles, rules and group process. The process that 6 trainees and two supervisors used with T and O teams to examine their own coevolution as a therapeutic system using the Milan model of family therapy and Ericksonian hypnotherapy is described. The article concludes with a discussion of the advantages and pitfalls of this type of dual supervision.  相似文献   
79.
It is interesting to note that antidepressants are widely represented in the medications used to treat the anxiety disorders. This has led to speculation about the role of depression, particularly subclinical forms being manifested as anxiety disorders. The specificity of diagnostic categories suggests that, at least for the moment, medications have a very specific and circumscribed role in the treatment of anxiety. This suggests that the difficulties of many anxious patients are not effectively treated with medication or that medication has only a short-term role at best. The next column will review health problems associated with psychotropic treatments for anxiety and discuss strategies for creating a "wedge," ie, introducing adjunct learning experiences along the anxiety gradient in conjunction with pharmacotherapy.  相似文献   
80.
This paper tests some predictions derived from Williamson's transaction cost theory of the organization of work, which holds that the form of the employment relationship is determined largely by the idiosyncrasy of work—that is, the nature of skills and knowledge used in production. It examines the occurrence of theoretically relevant provisions in collective bargaining agreements in the United States and finds they are related to a contract-level proxy for idiosyncrasy (based on bargaining structure) as predicted by the theory. An analysis of an individual-level variable, the difficulty of finding a comparable job, provides some additional support. Finally, several alternative explanations of the results are considered, and it is argued that none are consistent with the evidence. The analysis thus finds strong, if necessarily provisional, support for the theory.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号