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   2623468篇
  免费   187150篇
  国内免费   7669篇
耳鼻咽喉   34660篇
儿科学   86087篇
妇产科学   72194篇
基础医学   368243篇
口腔科学   70653篇
临床医学   238070篇
内科学   522479篇
皮肤病学   62978篇
神经病学   216891篇
特种医学   101716篇
外国民族医学   747篇
外科学   391622篇
综合类   50850篇
现状与发展   5篇
一般理论   1004篇
预防医学   199326篇
眼科学   57677篇
药学   190210篇
  8篇
中国医学   5389篇
肿瘤学   147478篇
  2021年   20563篇
  2019年   21203篇
  2018年   29961篇
  2017年   23143篇
  2016年   26862篇
  2015年   30237篇
  2014年   41507篇
  2013年   61981篇
  2012年   82497篇
  2011年   86919篇
  2010年   52405篇
  2009年   50403篇
  2008年   81316篇
  2007年   86165篇
  2006年   87892篇
  2005年   83995篇
  2004年   80800篇
  2003年   78115篇
  2002年   75344篇
  2001年   128818篇
  2000年   131700篇
  1999年   110936篇
  1998年   31696篇
  1997年   28272篇
  1996年   28530篇
  1995年   27664篇
  1994年   25304篇
  1993年   23639篇
  1992年   85405篇
  1991年   81782篇
  1990年   78982篇
  1989年   76268篇
  1988年   69657篇
  1987年   68184篇
  1986年   63712篇
  1985年   60712篇
  1984年   45152篇
  1983年   38142篇
  1982年   22682篇
  1981年   20201篇
  1979年   39119篇
  1978年   27606篇
  1977年   23390篇
  1976年   21627篇
  1975年   22948篇
  1974年   26917篇
  1973年   25478篇
  1972年   23852篇
  1971年   22026篇
  1970年   20249篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
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   
103.
104.
105.
Objective:To study the effect of oral administration of dimethyl dimethoxy biphenyl dicarboxylate(DDB) on adjusting angiogeneic/inflammatory mediators and ameliorating the pathology of bones in rats with collagen-induced arthritis(CIA).Methods:Wistar rat model of CIA was set up using bovine collagen type Ⅱ.Fifty rats were divided into five groups randomly:normal,CIA model,DDB treatment,methotrexate(MTX) treatment,and combined DDB+MTX treatment.Ankle joints of rats were imaged with digital X-ray machine to show the destruction of joints.Fore and hind paw and knee joints were removed above the ankle joint then processed for haematoxylin and eosin staining.Plasma levels of vascular endothelial growth factor(VEGF),platelet derived growth factor,interleukin-8(IL-8),IL-4,tumor necrosis factor α(TNF-α),and cyclooxygenase-2(COX-2) were quantified by enzyme-linked immunosorbent assay.Nitric oxide levels were detected by Griess reagent.Results:Compared with the CIA model group,a remarkable reduction in various angiogenic(VEGF and IL-8) and inflammatory mediators(TNF-α,IL-4 and COX-2) after treatment with DDB either alone or combined with MTX(P0.05 or P0.01).Histopathological and X-ray findings were confirmatory to the observed DDB anti-arthritic effect.The DDB-treated group showed amelioration in signs of arthritis which appeared essentially similar to normal.Conclusion:Our data shed light on the therapeutic efficacy of DDB in experimental rheumatoid arthritis(RA) compared with a choice drug(MTX) and it may be offered as a second-line drug in the treatment of RA.  相似文献   
106.
Traditionally, major complications and unanticipated admission/readmission rates were used to assess outcome after day surgery. However, in view of the relative absence of major complications the quality of recovery (QOR) should be considered one of the principal endpoints after day surgery. In our study, the level of QOR is defined by a combination of the Global Surgical Recovery (GSR) Index and the Quality of Life (QOL).The aim of this study was to analyze prevalence and predictors of QOR after day surgery on the fourth postoperative day.Elective patients scheduled for day surgery from November 2008 to April 2010 were enrolled in a prospective cohort study. Outcome parameters were measured by using questionnaire packages at 2 time points: 1 week preoperatively and 4 days postoperatively. Primary outcome parameter is the QOR and is defined as good if the GSR index >80% as well as the postoperative QOL is unchanged or improved as compared with baseline. QOR is defined as poor if both the GSR index ≤80% and if the postoperative QOL is decreased as compared with baseline. QOR is defined as intermediate in all other cases. Three logistic regression analyses were performed to determine predictors for poor QOR after day surgery.A total of 1118 patients were included. A good QOR was noted in 17.3% of patients, an intermediate QOR in 34.8%, and a poor QOR in 47.8% 4 days after day surgery. The best predictor for poor QOR after day surgery was type of surgery. Other predictors were younger age, work status, and longer duration of surgery. A history of previous surgery, expected pain (by the patient) and high long-term surgical fear were significant predictors of poor QOR in only 1 of 3 prediction models.The QOR at home 4 days after day surgery was poor in the majority of patients and showed a significant procedure-specific variation. Patients at risk for poor QOR can be identified during the preoperative period based on type of surgery, age, work status, and the duration of the surgery.  相似文献   
107.
108.
109.
110.
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