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   210449篇
  免费   15220篇
  国内免费   749篇
耳鼻咽喉   2291篇
儿科学   5482篇
妇产科学   4310篇
基础医学   27105篇
口腔科学   4512篇
临床医学   20005篇
内科学   44890篇
皮肤病学   2756篇
神经病学   20306篇
特种医学   6954篇
外国民族医学   13篇
外科学   32987篇
综合类   3411篇
现状与发展   2篇
一般理论   291篇
预防医学   19068篇
眼科学   4373篇
药学   14398篇
  1篇
中国医学   374篇
肿瘤学   12889篇
  2023年   843篇
  2022年   1406篇
  2021年   3443篇
  2020年   2106篇
  2019年   3393篇
  2018年   3968篇
  2017年   3213篇
  2016年   3413篇
  2015年   4068篇
  2014年   6096篇
  2013年   8825篇
  2012年   13129篇
  2011年   14329篇
  2010年   8098篇
  2009年   7305篇
  2008年   13592篇
  2007年   14438篇
  2006年   13928篇
  2005年   14396篇
  2004年   13813篇
  2003年   12909篇
  2002年   12438篇
  2001年   1881篇
  2000年   1469篇
  1999年   2055篇
  1998年   2831篇
  1997年   2441篇
  1996年   2207篇
  1995年   1953篇
  1994年   1756篇
  1993年   1658篇
  1992年   1213篇
  1991年   1155篇
  1990年   1061篇
  1989年   958篇
  1988年   1016篇
  1987年   1022篇
  1986年   1001篇
  1985年   1084篇
  1984年   1479篇
  1983年   1467篇
  1982年   1815篇
  1981年   1639篇
  1980年   1559篇
  1979年   816篇
  1978年   960篇
  1977年   933篇
  1976年   832篇
  1975年   683篇
  1974年   667篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
Preventing sports injury has rarely been cited as an appropriate action to respond to the obesity epidemic, and in fact a recent letter has suggested that those playing sport are as responsible for their predicament as those who are obese. This opinion piece argues that it is time for better prevention and management of sports injury to be seen as part of the complex solution to preventing obesity, rather than being a self-inflicted problem that governments should continue to ignore.  相似文献   
83.
84.
85.
OBJECTIVE: To assess the impact of activity restriction (AR) on the incidence of preterm birth in women treated for preterm labor testing negative for fetal fibronectin (fFN). STUDY DESIGN: Women who were diagnosed with preterm labor and tocolyzed with magnesium sulfate were concurrently screened with fFN for the purpose of subsequent management. Included were consenting patients with negative fFN, gestational age 23 0/7-33 6/7 weeks, cervical dilation < or =3 cm, and minimal vaginal bleeding. Patients were randomized to AR or no AR. Primary study outcome was incidence of preterm delivery and interval from randomization to delivery. RESULTS: A total of 73 women with negative fFN were randomized (36 with AR, 37 without AR). The overall preterm birth rate was 40%, with 44.4% of patients with AR and 35.1% of patients without AR delivering preterm, p=0.478. CONCLUSION: Maternal AR did not impact pregnancy outcome. The incidence of preterm birth in symptomatic women testing fFN negative was higher than previously reported.  相似文献   
86.
87.
Pryor  John 《JAMA》2006,296(19):2379
  相似文献   
88.
89.
Event-related brain potentials (ERPs) were recorded during a computerized and modified version of the Digit Span Backwards (DB) task from the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III). The modified DB version (ERP-DB task) was divided into two sections of 2, 4, 6 and 8 digits in length (Group 1) and 3, 5 and 7 digits in length (Group 2). Each trial had a study phase and a test phase. For the study phase, a series of digits was presented sequentially and aurally to 20 participants (10 for each group). For the test phase, a second series of digits was also presented sequentially and aurally that either corresponded to the reverse order of the digits in the study phase (correct condition) or had one digit in the sequence replaced by an incorrect digit (incorrect condition). The traditional DB task of the WAIS-III was also administered for comparison purposes. A prolonged positive slow wave (PSW) peaking between 450 and 750 ms was elicited to incorrect condition trials. For each participant, a derived measure was calculated from the ERP differentiation between correct and incorrect conditions. The derived measure was defined as the mean of the t-values obtained from the correct and incorrect waveform comparison, within the temporal interval that encompassed this component. The strongest statistical correlations between the derived measure and the traditional DB test scores were found at the Pz site (Group 1: r=0.79; Group 2: r=0.59). This statistical approach shows that it is possible to adequately relate an individual's performance on a traditional measure of working memory and ERP patterns. Overall, we believe that this kind of ERP approach holds promise as a technique for assessing quantitatively non-communicative patients.  相似文献   
90.
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