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   7744篇
  免费   698篇
  国内免费   41篇
耳鼻咽喉   80篇
儿科学   191篇
妇产科学   235篇
基础医学   1122篇
口腔科学   158篇
临床医学   808篇
内科学   1275篇
皮肤病学   104篇
神经病学   513篇
特种医学   592篇
外科学   892篇
综合类   137篇
一般理论   3篇
预防医学   747篇
眼科学   220篇
药学   516篇
中国医学   4篇
肿瘤学   886篇
  2021年   105篇
  2020年   46篇
  2019年   108篇
  2018年   120篇
  2017年   95篇
  2016年   84篇
  2015年   110篇
  2014年   174篇
  2013年   227篇
  2012年   303篇
  2011年   314篇
  2010年   217篇
  2009年   174篇
  2008年   303篇
  2007年   325篇
  2006年   336篇
  2005年   294篇
  2004年   319篇
  2003年   322篇
  2002年   281篇
  2001年   257篇
  2000年   253篇
  1999年   267篇
  1998年   144篇
  1997年   148篇
  1996年   141篇
  1995年   106篇
  1994年   94篇
  1993年   92篇
  1992年   155篇
  1991年   181篇
  1990年   179篇
  1989年   180篇
  1988年   173篇
  1987年   172篇
  1986年   153篇
  1985年   185篇
  1984年   108篇
  1983年   103篇
  1982年   65篇
  1981年   65篇
  1980年   68篇
  1979年   91篇
  1978年   61篇
  1977年   67篇
  1976年   56篇
  1975年   63篇
  1974年   57篇
  1973年   67篇
  1972年   55篇
排序方式: 共有8483条查询结果,搜索用时 15 毫秒
51.
We provide 1985 estimates of the work force of epidemiologists in the United States, the number of graduates from training programs in epidemiology, and a projection of the future need for these health professionals. Our methods included a search of mailing lists from professional organizations, mail contact with graduate training programs, telephone interviews with experts, and a review of job announcements in professional journals. The study indicates that the current work force of epidemiologists in the United States is estimated to include 4,600 persons, more than half of whom are physicians; most epidemiologists are located in either a state with a major federal public health agency or one with a large population; and programs in epidemiology graduate an average of 475 persons with one or two years of master's level education and approximately 80 with doctoral-level education each year. After considering the factors that influence the supply of epidemiologists, we project a substantial need for more epidemiologists in the future than current sources will provide.  相似文献   
52.
Hyperoxaluria may result in diffuse deposition of calcium oxalate crystals in multiple organs. A patient with primary hyperoxaluria presented with peripheral ischemia on this basis. Computed tomography clarified the diagnosis and helped to direct the appropriate management.  相似文献   
53.
Preliminary results are presented for a general population-based cancer registry in Setif, Algeria, for 1986-88. Standardised incidence rates for all sites, excluding non-melanoma skin cancer, are 70.1 for men and 59.9 for women: these rates are lower than those reported for most populations. The most frequent cancers are lung, stomach and liver in men, and cervix, liver and breast in women. Nasopharyngeal carcinoma is frequent in both sexes. Incidence of cancers of the gallbladder and extrahepatic bile ducts in women appears particularly high. These results represent the first detailed incidence data for all cancers in an Algerian population.  相似文献   
54.
There have been several reports of unusual skin conditions producing genital lesions that can be mistaken for sexual abuse. We report on another unusual skin condition, well known to dermatologists, that can again lead to potential misdiagnosis of sexual abuse.  相似文献   
55.
Oscillatory motion of the normal cervical spinal cord   总被引:2,自引:0,他引:2  
  相似文献   
56.
Periosteal Ewing sarcoma   总被引:3,自引:0,他引:3  
  相似文献   
57.
58.
59.
In a prospective, randomized study of insemination with donor semen, intracervical insemination by straw was compared with insemination using a cervical cap with an intracervical reservoir. A total of 91 patients completed 486 treatment cycles. There were no significant differences in age, parity, indication for insemination by donor, or method of cycle monitoring between women who became pregnant and those who did not conceive with either insemination method. In 236 standard intracervical insemination cycles, 14 patients became pregnant (5.9% per cycle), whereas 38 patients conceived in 250 cervical cap cycles (15.2% per cycle). Both the crude pregnancy rates and the cumulative pregnancy rates calculated by the Kaplan-Meier life-table method were significantly different (chi(2)-test, P < 0.001, and log-rank test, P < 0.005 respectively). Pregnancy rates in artificial insemination with cryopreserved donor semen may be improved by the use of a cervical cap when compared to cervical insemination by straw. The use of the cervical cap may prolong the exposure of the spermatozoa to the cervical mucus and prevent the backflow of semen into the vagina.   相似文献   
60.
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