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   4097336篇
  免费   328308篇
  国内免费   14102篇
耳鼻咽喉   56083篇
儿科学   129183篇
妇产科学   107434篇
基础医学   633264篇
口腔科学   112877篇
临床医学   374993篇
内科学   733971篇
皮肤病学   104639篇
神经病学   341276篇
特种医学   160520篇
外国民族医学   482篇
外科学   621140篇
综合类   118411篇
现状与发展   24篇
一般理论   2507篇
预防医学   342466篇
眼科学   95323篇
药学   290496篇
  29篇
中国医学   11281篇
肿瘤学   203347篇
  2021年   55691篇
  2020年   35452篇
  2019年   58359篇
  2018年   73013篇
  2017年   55850篇
  2016年   61662篇
  2015年   75224篇
  2014年   109591篇
  2013年   174893篇
  2012年   112089篇
  2011年   115615篇
  2010年   122552篇
  2009年   125104篇
  2008年   102176篇
  2007年   108236篇
  2006年   117157篇
  2005年   112180篇
  2004年   113138篇
  2003年   103589篇
  2002年   92977篇
  2001年   146596篇
  2000年   140934篇
  1999年   131984篇
  1998年   69140篇
  1997年   65873篇
  1996年   64004篇
  1995年   59420篇
  1994年   53450篇
  1993年   49792篇
  1992年   95325篇
  1991年   91394篇
  1990年   87826篇
  1989年   86011篇
  1988年   79265篇
  1987年   77378篇
  1986年   73651篇
  1985年   71835篇
  1984年   61513篇
  1983年   55263篇
  1982年   46028篇
  1981年   42961篇
  1980年   40575篇
  1979年   53071篇
  1978年   43742篇
  1977年   39523篇
  1976年   36003篇
  1975年   36054篇
  1974年   39015篇
  1973年   37834篇
  1972年   35712篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
996.
997.
998.
Theory: Immersive simulation is a common mode of education for medical students. Observation of clinical simulations prior to participation is believed to be beneficial, though this is often a passive process. Active observation may be more beneficial. Hypotheses: The hypothesis tested in this study was that the active use of a simple checklist during observation of an immersive simulation would result in better participant performance in a subsequent scenario compared with passive observation alone. Methods: Medical students were randomized to either passive or active (with checklist) observation of an immersive simulation involving cardiac arrest prior to participating in their own simulation. Performance measures included time to cardiopulmonary resuscitation (CPR) and time to defibrillation and were compared between first and second scenarios as well as between passive and active observers. Results: Seventy-nine simulations involving 232 students were conducted. Mean time to CPR was 18 seconds (SD = 11.6) for those using the checklist and 24 seconds (SD = 15.8) for those who observed passively (M difference = 6 seconds), t(35) = 1.46, p =.153. Time to defibrillation was 94 seconds (SD = 26.4) for those using the checklist and 92 seconds (SD = 23.8) for those who observed passively (M difference = –2 seconds), t(38) =.21, p =.837. Time to CPR was 24 seconds (SD = 15.8) for passive observers and 31 seconds (SD = 21.0; M difference = 7 seconds), t(35) = 1.13, p =.265, for their first scenario counterparts. Time to CPR was 18 seconds (SD = 11.6) for active observers and 36 seconds (SD = 26.2; M difference = 18 seconds), t(24) = 2.81, p =.010, for their first scenario counterparts. Time to defibrillation was 92 seconds (SD = 23.8) for passive observers and 125 seconds (SD = 32.2; M difference = 33 seconds), t(33) = 3.63, p =.001, for their first scenario counterparts. Time to defibrillation was 94 seconds (SD = 26.4) for the active observers and 132 seconds (SD = 52.9; M difference = 38 seconds), t(28) =.46, p =.008, for their first scenario counterparts. Conclusions: Observation alone leads to improved performance in the management of a simulated cardiac arrest. The active use of a simple skills-based checklist during observation did not appear to improve performance over passive observation alone.  相似文献   
999.
Mammalian spermatogenesis is a well-organized process of cell development and differentiation. Meiosis expressed gene 1 (MEIG1) plays an essential role in the regulation of spermiogenesis. To explore potential mechanisms of MEIG1''s action, a yeast two-hybrid screen was conducted, and several potential binding partners were identified; one of them was membrane occupation and recognition nexus repeat containing 3 (MORN3). MORN3 mRNA is only abundant in mouse testis. In the testis, Morn3 mRNA is highly expressed in the spermiogenesis stage. Specific anti-MORN3 polyclonal antibody was generated against N-terminus of the full-length MORN3 protein, and MORN3 expression and localization was examined in vitro and in vivo. In transfected Chinese hamster ovary cells, the antibody specifically crossed-reacted the full-length MORN3 protein, and immunofluorescence staining revealed that MORN3 was localized throughout the cytoplasm. Among multiple mouse tissues, about 25 kDa protein, was identified only in the testis. The protein was highly expressed after day 20 of birth. Immunofluorescence staining on mixed testicular cells isolated from adult wild-type mice demonstrated that MORN3 was expressed in the acrosome in germ cells throughout spermiogenesis. The protein was also present in the manchette of elongating spermatids. The total MORN3 expression and acrosome localization were not changed in the Meig 1-deficient mice. However, its expression in manchette was dramatically reduced in the mutant mice. Our studies suggest that MORN3 is another regulator for spermatogenesis, probably together with MEIG1.  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