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   383108篇
  免费   15280篇
  国内免费   901篇
耳鼻咽喉   3300篇
儿科学   12030篇
妇产科学   7248篇
基础医学   46450篇
口腔科学   6599篇
临床医学   32179篇
内科学   74708篇
皮肤病学   4431篇
神经病学   36276篇
特种医学   17212篇
外国民族医学   51篇
外科学   58662篇
综合类   4714篇
现状与发展   2篇
一般理论   216篇
预防医学   33222篇
眼科学   6997篇
药学   24124篇
  2篇
中国医学   1029篇
肿瘤学   29837篇
  2023年   996篇
  2022年   1686篇
  2021年   3791篇
  2020年   2562篇
  2019年   3691篇
  2018年   25813篇
  2017年   20274篇
  2016年   22798篇
  2015年   5377篇
  2014年   7020篇
  2013年   9683篇
  2012年   19971篇
  2011年   34244篇
  2010年   26544篇
  2009年   18865篇
  2008年   31494篇
  2007年   34461篇
  2006年   13537篇
  2005年   15237篇
  2004年   15910篇
  2003年   16050篇
  2002年   13738篇
  2001年   3883篇
  2000年   3714篇
  1999年   3696篇
  1998年   3138篇
  1997年   2533篇
  1996年   2116篇
  1995年   2024篇
  1994年   1768篇
  1993年   1747篇
  1992年   2264篇
  1991年   2251篇
  1990年   2065篇
  1989年   1986篇
  1988年   1717篇
  1987年   1708篇
  1986年   1580篇
  1985年   1524篇
  1984年   1347篇
  1983年   1232篇
  1982年   1230篇
  1981年   1145篇
  1980年   1018篇
  1979年   996篇
  1978年   772篇
  1977年   764篇
  1976年   645篇
  1975年   680篇
  1974年   682篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
PURPOSE: Epidermal growth factor receptor is expressed in pediatric malignant solid tumors. We conducted a phase I trial of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in children with refractory solid tumors. PATIENTS AND METHODS: Gefitinib (150, 300, 400, or 500 mg/m2) was administered orally to cohorts of three to six patients once daily continuously until disease progression or significant toxicity. Pharmacokinetic studies were performed during course one (day 1 through 28). RESULTS: Of the 25 enrolled patients, 19 (median age, 15 years) were fully evaluable for toxicity and received 54 courses. Dose-limiting toxicity was rash in two patients treated with 500 mg/m2 and elevated ALT and AST in one patient treated with 400 mg/m2. The maximum-tolerated dose was 400 mg/m2/d. The most frequent non-dose-limiting toxicities were grade 1 or 2 dry skin, anemia, diarrhea, nausea, and vomiting. One patient with Ewing's sarcoma had a partial response. Disease stabilized for 8 to > or = 60 weeks in two patients with Wilms' tumor and two with brainstem glioma (one exophytic). At 400 mg/m2, the median peak gefitinib plasma concentration was 2.2 microg/mL (range, 1.2 to 3.6 microg/mL) and occurred at a median of 2.3 hours (range, 2.0 to 8.3 hours) after drug administration. The median apparent clearance and median half-life were 14.8 L/h/m2 (range, 3.8 to 24.8 L/h/m2) and 11.7 hours (range, 5.6 to 22.8 hours), respectively. Gefitinib systemic exposures were comparable with those associated with antitumor activity in adults. CONCLUSION: Oral gefitinib is well tolerated in children. Development of the drug in combination with cytotoxic chemotherapy will be pursued.  相似文献   
143.
144.
145.

Background  

It is well known that physicians' night-call duty may cause impaired performance and adverse effects on subjective health, but there is limited knowledge about effects on sleep duration and recovery time. In recent years occupational stress and impaired well-being among anaesthesiologists have been frequently reported for in the scientific literature. Given their main focus on handling patients with life-threatening conditions, when on call, one might expect sleep and recovery to be negatively affected by work, especially in this specialist group. The aim of the present study was to examine whether a 16-hour night-call schedule allowed for sufficient recovery in anaesthesiologists compared with other physician specialists handling less life-threatening conditions, when on call.  相似文献   
146.
Associations between street connectivity and active transportation   总被引:1,自引:0,他引:1  

Background  

Past studies of associations between measures of the built environment, particularly street connectivity, and active transportation (AT) or leisure walking/bicycling have largely failed to account for spatial autocorrelation of connectivity variables and have seldom examined both the propensity for AT and its duration in a coherent fashion. Such efforts could improve our understanding of the spatial and behavioral aspects of AT. We analyzed spatially identified data from Los Angeles and San Diego Counties collected as part of the 2001 California Health Interview Survey.  相似文献   
147.

Objective  

To test the effects of the use of a collapsible, portable chair (chair B), as opposed to a ‘standard’ chair (chair A), on the outcome of the timed “Up and Go” (TUG) test.  相似文献   
148.
149.

Background  

Exercise has been recommended for improving global-well being in adults with fibromyalgia. However, no meta-analysis has determined the effects of exercise on global well-being using a single instrument and when analyzed separately according to intention-to-treat and per-protocol analyses. The purpose of this study was to fill that gap.  相似文献   
150.

Background  

Due to marginalization, trafficking violence, conflicts with the police and organic and social psychological problems associated with the drug, crack is one of the most devastating drugs currently in use. However, there is evidence that some users manage to stay alive and active while using crack cocaine for many years, despite the numerous adversities and risks involved with this behavior. In this context, the aim of the present study was to identify the strategies and tactics developed by crack users to deal with the risks associated with the culture of use by examining the survival strategies employed by long-term users.  相似文献   
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