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   13381篇
  免费   224篇
管理学   1748篇
民族学   54篇
人才学   1篇
人口学   1130篇
丛书文集   80篇
教育普及   2篇
理论方法论   1265篇
综合类   339篇
社会学   6673篇
统计学   2313篇
  2021年   69篇
  2020年   195篇
  2019年   230篇
  2018年   257篇
  2017年   391篇
  2016年   301篇
  2015年   239篇
  2014年   279篇
  2013年   2187篇
  2012年   416篇
  2011年   334篇
  2010年   238篇
  2009年   254篇
  2008年   290篇
  2007年   304篇
  2006年   236篇
  2005年   372篇
  2004年   314篇
  2003年   272篇
  2002年   285篇
  2001年   321篇
  2000年   316篇
  1999年   322篇
  1998年   224篇
  1997年   215篇
  1996年   225篇
  1995年   195篇
  1994年   211篇
  1993年   188篇
  1992年   242篇
  1991年   234篇
  1990年   221篇
  1989年   224篇
  1988年   199篇
  1987年   189篇
  1986年   190篇
  1985年   181篇
  1984年   213篇
  1983年   205篇
  1982年   166篇
  1981年   142篇
  1980年   142篇
  1979年   167篇
  1978年   138篇
  1977年   122篇
  1976年   105篇
  1975年   102篇
  1974年   97篇
  1973年   94篇
  1972年   66篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
Beryllium is the strongest of the lightweight metals. Used primarily in military applications prior to the end of the Cold War, beryllium is finding new applications in many commercial products, including computers, telecommunication equipment, and consumer and automotive electronics. The use of beryllium in nondefense consumer applications is of concern because beryllium is toxic. Inhalation of beryllium dust or vapor causes a chronic lung disease in some individuals at concentrations as low as 0.01 microg/m3 in air. As beryllium enters wider commerce, it is prudent to ask what risks this might present to the general public and to workers downstream of the beryllium materials industry. We address this question by evaluating the potential for beryllium exposure from the manufacturing, use, recycle, and disposal of beryllium-containing products. Combining a market study with a qualitative exposure analysis, we determine which beryllium applications and life cycle phases have the largest exposure potential. Our analysis suggests that use and maintenance of the most common types of beryllium-containing products do not result in any obvious exposures of concern, and that maintenance activities result in greater exposures than product use. Product disposal has potential to present significant individual risks, but uncertainties concerning current and future routes of product disposal make it difficult to be definitive. Overall, additional exposure and dose-response data are needed to evaluate both the health significance of many exposure scenarios, and the adequacy of existing regulations to protect workers and the public. Although public exposures to beryllium and public awareness and concern regarding beryllium risks are currently low, beryllium risks have psychometric qualities that may lead to rapidly heightened public concern.  相似文献   
44.
This paper estimates a simultaneous-equations model with public sector bargaining laws and union membership treated as jointly-determined variables. The extent of public sector unionization has a significant positive influence on the passage of prolabor bargaining legislation and bargaining legislation has strong, independent effects on the extent of public sector unionization. We gratefully acknowledge the research support provided by Minbo Kim and Parisun Chantonahom.  相似文献   
45.
This article explores two problems analysts face in determining how to estimate values for children's health and safety risk reductions. The first addresses the question: Do willingness‐to‐pay estimates for health risk changes differ across children and adults and, if so, how? To answer this question, the article first examines the potential effects of age and risk preferences on willingness to pay. A summary of the literature reporting empirical evidence of differences between willingness to pay for adult health and safety risk reductions and willingness to pay for health and safety risk reductions in children is also provided. The second dimension of the problem is a more fundamental issue: Whose perspective is relevant when valuing children's health effects—society's, children's, adults‐as‐children, or parents'? Each perspective is considered, followed ultimately by the conclusion that adopting a parental perspective through an intrahousehold allocation model seems closest to meeting the needs of the estimation problem at hand. A policy example in which the choice of perspective affects the outcome of a regulatory benefit‐cost analysis rounds out the article and emphasizes the importance of perspective.  相似文献   
46.
College students (20 women, 14 men) seeking career counseling services at a university career center participated in this exploratory investigation. A 2 (DISCOVER treatment) × 2 (counseling treatment) research design was used to evaluate the individual and combined effects of DISCOVER (ACT, 1998) and counseling on participants' career decision‐making self‐efficacy and career decision‐making attributional style. Findings revealed a significant effect of the use of DISCOVER on participants' career decision‐making self‐efficacy and their sense of control over the career decision‐making process. Results are discussed regarding the implications for career counseling and ideas for further research in this domain.  相似文献   
47.
We discuss the issue of using benchmark doses for quantifying (excess) risk associated with exposure to environmental hazards. The paradigm of low-dose risk estimation in dose-response modeling is used as the primary application scenario. Emphasis is placed on making simultaneous inferences on benchmark doses when data are in the form of proportions, although the concepts translate easily to other forms of outcome data.  相似文献   
48.
This study concerned the immunological correlates of stress and work. Self reported stress, emotional state, ego-strength, and defensiveness were examined in relation to measures of cellular immunity (T-cell response to Con A and number of T4 and T8 cells) and humoral immunity (concentrations of immunoglobulins and complement components in plasma) in a group of 96 Norwegian female bank employees. The analyses showed that workload, the stress factor with the highest group mean, was associated with number of T-cells, while strain due to body posture during work was related to concentrations of IgM and C3. Further, depression was significantly correlated with IgM concentration and T-cell number, and anxiety with C3 concentration. T-cell activity was the immunological parameter most consistently associated with psychological well-being, showing positive correlations with defensiveness and ego-strength and negative correlations with anxiety and depression. In conclusion, T-cell number and concentrations of IgM and C3 were sensitive to both work-related stress experience and emotional distress. Coping abilities, indicated by the MMPI Ego-strength scale and emotional distress, were reflected in T-cell activity; insufficient coping was associated with low T-cell activity.  相似文献   
49.
A review of the sociological research about gender and migration shows the substantial ways in which gender fundamentally organizes the social relations and structures influencing the causes and consequences of migration. Yet, although a significant sociological research has emerged on gender and migration in the last three decades, studies are not evenly distributed across the discipline. In this article, we map the recent intellectual history of gender and migration in the field of sociology and then systematically assess the extent to which studies on engendering migration have appeared in four widely read journals of sociology (American Journal of Sociology, American Sociological Review, Demography, and Social Forces). We follow with a discussion of these studies, and in our conclusions, we consider how future gender and migration scholarship in sociology might evolve more equitably.  相似文献   
50.
The Hohokam of southern Arizona are noted for greater duration of settlement than other major agricultural traditions in the archaeological record of the southwestern United States, including the Anasazi and Mogollon. The 40,000 square mile area inhabited by the Hohokam is marked by low elevation desert basins, but encompasses a range of topographic and climatic variability that shaped opportunities for prehistoric farming technologies. Irrigation from rivers was frequently associated with the longterm persistence of individual sites, while floodwater farming along ephemeral drainages was more often correlated with continuous occupation of hydrologically favored zones. Renewal of fields by waterborne nutrients and efficient practices in the use of natural resources countered the limited mobility options afforded by the Hohokam environment.In spite of a restrictive agricultural setting and an essentially static suite of productive technologies over many centuries, relationships among population, settlement, and landuse were redefined in evolving social and economic configurations. An example from the Tucson Basin illustrates differentiated patterns of settlement and agriculture arising in conjunction with increased levels of population and territorial integration in the late prehistoric period. Community organization among interrelated settlements incorporated a diversity of topographic zones and agricultural technologies in this high-risk context for prehistoric cultivators.  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