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   19709篇
  免费   560篇
  国内免费   1篇
管理学   2876篇
民族学   77篇
人才学   1篇
人口学   1920篇
丛书文集   76篇
教育普及   2篇
理论方法论   1799篇
现状及发展   1篇
综合类   261篇
社会学   9626篇
统计学   3631篇
  2021年   119篇
  2020年   289篇
  2019年   401篇
  2018年   465篇
  2017年   629篇
  2016年   505篇
  2015年   370篇
  2014年   481篇
  2013年   3081篇
  2012年   655篇
  2011年   646篇
  2010年   469篇
  2009年   391篇
  2008年   467篇
  2007年   490篇
  2006年   474篇
  2005年   459篇
  2004年   425篇
  2003年   397篇
  2002年   436篇
  2001年   532篇
  2000年   543篇
  1999年   468篇
  1998年   349篇
  1997年   314篇
  1996年   329篇
  1995年   313篇
  1994年   285篇
  1993年   298篇
  1992年   347篇
  1991年   318篇
  1990年   291篇
  1989年   293篇
  1988年   290篇
  1987年   253篇
  1986年   249篇
  1985年   279篇
  1984年   269篇
  1983年   251篇
  1982年   219篇
  1981年   181篇
  1980年   164篇
  1979年   195篇
  1978年   177篇
  1977年   161篇
  1976年   135篇
  1975年   159篇
  1974年   118篇
  1973年   115篇
  1972年   93篇
排序方式: 共有10000条查询结果,搜索用时 72 毫秒
181.
182.
Native American drinking: a neglected subject of study and research   总被引:1,自引:0,他引:1  
Although Native Americans are plagued by high rates of alcoholism, violence, suicide and early death, these social and clinical problems are usually given little more than cursory treatment in textbooks. A content analysis of twenty-six textbooks on alcoholism and substance misuse revealed that only four provided a detailed discussion of Native American drinking. Greater attention needs to be given to the cultural, psychological, and biological issues of drinking and drunkenness among this special population.  相似文献   
183.
184.
Although concerns have frequently been raised recently regarding the quality of life of intercollegiate athletes, information is seldom available on which college and university administrators can base policy decisions. Particularly lacking are studies that provide administrators with assessments of their own athletics programs relative to athletics programs at other institutions. We describe here a method we used in conducting a comparative evaluation of the status of student-athletes at a large public university, involving comparisons of student-athletes at this university to student-athletes at a subset of the institutions that participated in the 1987–88 National Study of Intercollegiate Athletes. By utilizing existing data sets to construct comparison samples, relative assessments of the status of student-athletes at a given institution can be performed without the excessive costs of gathering data on student-athletes at comparison institutions. Techniques employed in data collection and analysis are discussed as well as the format of the report in which the findings of the study were presented.  相似文献   
185.
The present study was conducted to assess differences in the behavioral and demographic characteristics of snuff (dip) users as compared to users of chewing tobacco. High School football players (1116) were surveyed concerning their use and perceptions of smokeless tobacco. Adolescent athletes who tried smokeless tobacco were more likely to be white, to use cigarettes, alcohol, and cigars and to have family users than those who never tried. Initial use was highest before the age of fourteen years and was influenced by friends, curiosity and family. Dippers tended to initiate use because of friends, while chewers started because of family users. Users of both dip and chew started primarily because of curiosity. Users of both were more likely to consume greater amounts to alcohol and cigarettes and to smoke cigars and pipes. It appears that the longer smokeless tobacco is consumed, the more likely both dip and chew will be used. Users of smokeless tobacco for more than two years tended to consume more of the product each week, used it for more hours/day, initiated use at an earlier age, and used it more often at school and work than those using it for less than two years. Use of cigars/pipes, consumption of alcohol, and quantity of cigarette consumption increased significantly with longer duration of smokeless tobacco use. Intervention and prevention programs would be helped by understanding differences between users of various smokeless tobacco products and differences related to the duration of use. In addition, further analyses of smokeless tobacco users should study chewers, dippers, and users of both separately.  相似文献   
186.
This report summarizes the proceedings of a conference on quantitative methods for assessing the risks of developmental toxicants. The conference was planned by a subcommittee of the National Research Council's Committee on Risk Assessment Methodology 4 in conjunction with staff from several federal agencies, including the U.S. Environmental Protection Agency, U.S. Food and Drug Administration, U.S. Consumer Products Safety Commission, and Health and Welfare Canada. Issues discussed at the workshop included computerized techniques for hazard identification, use of human and animal data for defining risks in a clinical setting, relationships between end points in developmental toxicity testing, reference dose calculations for developmental toxicology, analysis of quantitative dose-response data, mechanisms of developmental toxicity, physiologically based pharmacokinetic models, and structure-activity relationships. Although a formal consensus was not sought, many participants favored the evolution of quantitative techniques for developmental toxicology risk assessment, including the replacement of lowest observed adverse effect levels (LOAELs) and no observed adverse effect levels (NOAELs) with the benchmark dose methodology.  相似文献   
187.
J. Richard Udry 《Demography》1994,31(4):561-573
I explain a biosocial model of women’s gendered behavior (behavior on which the sexes differ). This model integrates a macro sociological theory with a biological theory derived from primate behavior. The sociological model is designed to explain changes in the relationship between sex and behavior over time or between groups. The biological model is designed to explain individual within-sex variance and between-sex variance in gendered behavior in a cohort. Results from an original study are presented to demonstrate that within-sex variance in women’s gendered behavior is explained well by the primate model. I conclude that human nature is gendered. The implications of this conclusion are explored for demographic and other social science research.  相似文献   
188.
189.
The possibility that carbon dioxide emissions from fossil fuel use might lead to global warming has become a leading environmental concern. Many scientific and environmental organizations have called for immediate action to limit carbon dioxide production. For the most part, however, public debate has focused on a single policy instrument: a carbon tax applied to fossil fuels in proportion to their carbon content. We present a detailed model of the U.S. economy and use it to compare carbon taxes with two other instruments that could achieve the same reduction in carbon dioxide emissions: a tax on the energy content of fossil fuels (a BTU tax) and an ad valorem tax on fuel use. We find that carbon taxes can achieve a given reduction with the least overall effect on the economy, but with a large effect on coal mining. Energy taxes are fairly similar to carbon taxes but have slightly less impact on coal mining and slightly greater overall cost. In contrast, ad valorem taxes fall much more lightly on coal mining but have a much greater effect on the economy as a whole.  相似文献   
190.
The authors consider the issue of map positional error, or the difference between location as represented in a spatial database (i.e., a map) and the corresponding unobservable true location. They propose a fully model‐based approach that incorporates aspects of the map registration process commonly performed by users of geographic informations systems, including rubber‐sheeting. They explain how estimates of positional error can be obtained, hence estimates of true location. They show that with multiple maps of varying accuracy along with ground truthing data, suitable model averaging offers a strategy for using all of the maps to learn about true location.  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