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   1269315篇
  免费   94965篇
  国内免费   1590篇
耳鼻咽喉   16439篇
儿科学   41162篇
妇产科学   35336篇
基础医学   190071篇
口腔科学   34850篇
临床医学   118226篇
内科学   249053篇
皮肤病学   27462篇
神经病学   102271篇
特种医学   46881篇
外国民族医学   265篇
外科学   179300篇
综合类   25772篇
现状与发展   3篇
一般理论   569篇
预防医学   105020篇
眼科学   28121篇
药学   92841篇
  6篇
中国医学   2043篇
肿瘤学   70179篇
  2018年   13754篇
  2017年   10509篇
  2016年   11431篇
  2015年   13210篇
  2014年   18205篇
  2013年   27708篇
  2012年   37867篇
  2011年   40323篇
  2010年   23265篇
  2009年   22460篇
  2008年   38031篇
  2007年   40717篇
  2006年   40247篇
  2005年   39381篇
  2004年   37777篇
  2003年   36174篇
  2002年   35089篇
  2001年   56186篇
  2000年   57234篇
  1999年   48225篇
  1998年   13443篇
  1997年   12249篇
  1996年   12667篇
  1995年   11934篇
  1994年   11135篇
  1993年   10421篇
  1992年   38277篇
  1991年   37731篇
  1990年   36509篇
  1989年   35309篇
  1988年   32750篇
  1987年   32073篇
  1986年   30558篇
  1985年   28807篇
  1984年   21962篇
  1983年   19206篇
  1982年   11374篇
  1981年   10326篇
  1979年   20954篇
  1978年   15398篇
  1977年   12800篇
  1976年   11853篇
  1975年   12822篇
  1974年   15603篇
  1973年   15373篇
  1972年   14524篇
  1971年   13556篇
  1970年   12790篇
  1969年   12068篇
  1968年   11233篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
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   
53.
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   
54.
55.
56.

Aims

Variations of the anatomy of donor hepatic arteries increase the number of arterial anastomoses during liver transplantation and, possibly, the incidence of hepatic artery thrombosis (HAT). In this study, we describe the arterial anatomic variations in liver grafts procured and transplanted by a single center in Greece, the techniques of arterial anastomosis, and their effect on the incidence of early HAT.

Materials and Methods

From January 2013 to December 2017, the arterial anatomy of 116 grafts procured for liver transplantation were recorded, as well as the technique of arterial anastomosis and the incidence of early hepatic artery thrombosis (HAT <30 days).

Results

A single hepatic artery was recorded in 72.41% of the procured grafts, an aberrant left hepatic artery (accessory or replaced) in 18 grafts (15.52%), and an aberrant right hepatic artery (accessory or replaced) in 17 grafts (14.66%), while other variations were observed in less than 1% of the procured livers. Of the 116 primary liver transplantations, 6 patients (5.17%) developed early HAT <30 days. Two of these patients (1.72%) had 1 anastomosis of the hepatic artery and 4 (3.45%) had 2 anastomoses due to anatomic variations.

Conclusions

Anatomic variations of the hepatic artery in liver grafts is a common finding and increase the incidence of early HAT but not to a degree to make these grafts unusable.  相似文献   
57.
58.
59.

BACKGROUND

Online physician rating websites are increasingly used by patients to evaluate their doctors. The purpose of this investigation was to evaluate factors associated with better spine surgeon ratings.

METHODS

Orthopedic spine surgeons were randomly selected from the North American Spine Society directory utilizing a random number generator. Surgeon profiles on three physician rating websites, namely, www.HealthGrades.com, www.Vitals.com, and www.RateMDs.com, were analyzed to gather qualitative and quantitative data on patients’ perceptions of the surgeons. Independent variables from the websites were analyzed in relation to overall physician or patient satisfaction rating. Comments were coded by subject into following three categories: professional competence, bedside manner, and practice characteristics.

RESULTS

A total of 250 surgeons were evaluated, and 92% (n=230) of these doctors had at least one rating among the three websites. The surgeons with a higher average rating had significantly better trust (p<.01), scheduling (p<.01), staff (p<.01), helpfulness (p<.01), and punctuality (p<.01) scores but significantly less experience (p<.05). A linear regression model for the average rating of each surgeon (R2 value=0.754) yielded only following three significant variables: trustworthiness (p<.01), experience match (p<.05), and the average number of negative comments on surgeon's professional competence (p<.05). Trustworthiness (β=0.749) was the strongest predictor variable of physician rating, followed by the number of negative professional competence comments (β=?0.132) and experience match (β=?0.112).

CONCLUSIONS

This investigation assessed spine surgeon online patient ratings and categorized factors that patients associate with quality care. Trustworthiness was the most significant predictor of positive ratings, whereas ease of scheduling, quality of staff, helpfulness, and punctuality were also associated with higher patient ratings. Understanding what patients value may help optimize care of spine surgery patients.  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