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   4601篇
  免费   129篇
  国内免费   3篇
管理学   541篇
民族学   27篇
人口学   398篇
丛书文集   27篇
理论方法论   350篇
综合类   90篇
社会学   2010篇
统计学   1290篇
  2023年   31篇
  2021年   28篇
  2020年   76篇
  2019年   141篇
  2018年   118篇
  2017年   200篇
  2016年   128篇
  2015年   108篇
  2014年   124篇
  2013年   988篇
  2012年   151篇
  2011年   122篇
  2010年   82篇
  2009年   112篇
  2008年   104篇
  2007年   89篇
  2006年   76篇
  2005年   82篇
  2004年   72篇
  2003年   66篇
  2002年   87篇
  2001年   96篇
  2000年   82篇
  1999年   90篇
  1998年   81篇
  1997年   75篇
  1996年   59篇
  1995年   77篇
  1994年   60篇
  1993年   59篇
  1992年   72篇
  1991年   69篇
  1990年   77篇
  1989年   65篇
  1988年   44篇
  1987年   50篇
  1986年   52篇
  1985年   57篇
  1984年   65篇
  1983年   46篇
  1982年   38篇
  1981年   36篇
  1980年   41篇
  1979年   49篇
  1978年   39篇
  1977年   30篇
  1976年   22篇
  1974年   22篇
  1973年   20篇
  1971年   22篇
排序方式: 共有4733条查询结果,搜索用时 15 毫秒
991.
992.
Abstract

“Usefulness of Screening Chest Roentgenograms in Preoperative Patients,” Lloyd Rucker, Elizabeth B. Frye, Myrlene A. Staten. We proposed that clinical criteria could define a group of patients very unlikely to have abnormal preoperative chest roentgenograms. Nine hundred five surgical admissions were screened for the presence of clinical factors we thought would make those patients more likely to have abnormal preoperative chest roentgenograms. Of these, 368 had no risk factors. One patient (0.3%) of the 368 had an abnormal x-ray film, which did not affect the surgery. No material abnormalities were found in the remainder of the group without risk factors. Five hundred four patients had identifiable risk factors. Of these, 114 (22%) were found to have serious abnormalities on preoperative chest roentgenograms. (Journal of the American Medical Association 1983;250:3209–3211)

“Effect of Treatment Regimens for Neisseria Gonorrhoeae on Simultaneous Infection With Chlamydia Trachomatis,” Walter E. Stamm, et al. We evaluated the effect of treatment for gonorrhea on simultaneous Chlamydia trachomatis infection by randomly assigning 293 heterosexual men and 246 heterosexual women with gonorrhea to receive one of the following treatment regimens: (1) 4.8 million units of aqueous procaine penicillin plus 1 g of probenecid, (2) nine tablets of trimethoprim-sulfamethoxazole daily for three days, or (3) 500 mg of tetracycline four times a day for five days. Among the men, gonococcal infection was cured in 99 per cent given penicillin plus probenecid, 96 per cent given trimethoprim-sulfamethoxazole, and 98 per cent given tetracycline. Among the women, only 90 per cent given tetracycline were cured, in contrast to 97 per cent given penicillin plus probenecid and 99 per cent given trimethoprim-sulfamethoxazole.  相似文献   
993.
Abstract

The responses of 582 male university students attending the UCLA Student Health Service for medical evaluation are presented. Of these students, 37% (215) were freshmen and varsity athletes having pretraining physicals, and 63% (367) were students being evaluated in the SHS primary care clinics. A self-report questionnaire examined the frequency of sexual problems experienced by the respondents and their partners. The most common concerns expressed about themselves were orgasmic difficulties, feeling too interested in sex, and trouble getting and keeping erections. Forty-one percent of the SHS group and 33% of the athletes group had sexual concerns, and, of these, 55% and 40% respectively wanted help with their problems. Specific counseling needs of students were also evaluated.  相似文献   
994.
Data from the 1911 Census of England and Wales are examined for evidence of family limitation early in marriage. It is shown that a substantial number of couples used birth control for ‘spacing’ as well as for ‘stopping’ fertility. Moreover ‘spacing’ of births appears to have been more widespread in districts in which women's employment opportunities were relatively good. In general, the results obtained do not fit with the Princeton view of the European fertility transition with its stress on parity-specific family limitation spreading in response to improvements in contraceptive information and technology.  相似文献   
995.
Life Tables have been calculated by Kuczynski's method for males and females in Ceylon for 1910–12, 1920–2 and 1945–7. The method is described, and the main results are presented.  相似文献   
996.
997.
998.
Since the 1920' sanduntil recently, numerical computation has beena limiting factor in the application of statistical methods to the improvement of product quality. This restriction is be in geliminated by the in troduction of computer tools for statistical quality control.

Both novice and expertusers of statistical methods can ben-efitsubstantially from the availability o intergrated soft ware for computing, graphics, and data management. Theuse of such soft ware in SQC training program senables the student to focus on the under standing of statistical techniques, rather than the irmechanicaldetails. In productionen vironments, properly designedinterfaces facilitated at aent ryand access to statistical soft ware by plant personnel, with out requiring know ledge of a computer language. The sesame tool scan be used by management to retrieve in for mationandob tain summaries and display sofcriti-caldata gatheredover different period softime. Finally, computer tool sprovide the applied statistician with agreater range of advanced methods, includinganalytical and graphical extensions of the traditional She whart control chart.  相似文献   
999.
Objectives. The competitiveness of the 2008 presidential primaries in both the Republican and Democratic parties has prompted a reconsideration of the role of delegate‐selection rules in influencing the strategic behavior of presidential candidates. Using advertising and candidate state‐visit data from the 2004 and 2008 presidential nominating campaigns, we reexamine the strategies presidential candidates use when competing for the nomination of their party. Methods. Using the Wisconsin Advertising Project Data from 2004 and 2008, we estimate several multiple regressions designed to analyze the factors predicting candidate visits and advertising. Results. We find that, to a large extent, the rules of the game help predict where candidates allocate their political advertising and campaign stops; candidates consider whether a contest is a primary or caucus, they pay attention to how many delegates are at stake, and they consider whether a state's delegate‐allocation method is largely proportional or winner take all. Yet we also find some differences in how the rules influence frontrunners and long‐shot candidates, and we discover how other factors, including a candidate's access to financial resources, influence the allocation of ads and visits. Conclusion. Our findings offer some of the first empirical evidence for the idea that a state's delegate‐allocation method influences candidates' resource‐allocation behavior. That these rules matter at all is somewhat of a surprise given that the delegate‐allocation methods used by states have become more homogenous within each party.  相似文献   
1000.
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