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   1686879篇
  免费   121400篇
  国内免费   2540篇
耳鼻咽喉   24074篇
儿科学   55964篇
妇产科学   48827篇
基础医学   253227篇
口腔科学   47761篇
临床医学   143981篇
内科学   325053篇
皮肤病学   36499篇
神经病学   128983篇
特种医学   64789篇
外国民族医学   426篇
外科学   259094篇
综合类   33846篇
现状与发展   1篇
一般理论   414篇
预防医学   124826篇
眼科学   39252篇
药学   129768篇
  1篇
中国医学   3238篇
肿瘤学   90795篇
  2018年   15719篇
  2015年   15225篇
  2014年   20994篇
  2013年   32200篇
  2012年   44045篇
  2011年   47519篇
  2010年   27987篇
  2009年   26392篇
  2008年   45911篇
  2007年   49727篇
  2006年   50519篇
  2005年   49347篇
  2004年   47630篇
  2003年   46080篇
  2002年   45517篇
  2001年   76627篇
  2000年   78979篇
  1999年   66618篇
  1998年   18583篇
  1997年   16515篇
  1996年   17003篇
  1995年   15986篇
  1994年   15098篇
  1993年   14116篇
  1992年   53181篇
  1991年   53077篇
  1990年   52712篇
  1989年   51112篇
  1988年   47609篇
  1987年   46720篇
  1986年   44433篇
  1985年   42457篇
  1984年   31565篇
  1983年   27389篇
  1982年   16011篇
  1981年   14348篇
  1979年   30223篇
  1978年   21457篇
  1977年   18416篇
  1976年   17519篇
  1975年   19396篇
  1974年   22957篇
  1973年   21984篇
  1972年   21010篇
  1971年   19701篇
  1970年   18365篇
  1969年   17726篇
  1968年   16655篇
  1967年   14738篇
  1966年   13480篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
Bulletin of Experimental Biology and Medicine - Ammonium, an end-product of catabolism, in low doses can promote adaptation of metabolic pathways in erythrocytes under conditions of extreme...  相似文献   
23.

Objective

To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.

Methods

This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.

Results

Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).

Conclusions and Implications

Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program.  相似文献   
24.
25.
Erosive pustular dermatosis of the scalp (EPDS) is an uncommon chronic inflammatory response to scalp trauma that usually resolves with cicatricial alopecia. It most commonly affects elderly patients with a history of actinic damage. Herein, we describe a 16‐year‐old girl with acrofacial dysostosis type 1 presenting after surgery with crusting purulent scalp lesions, whose clinical presentation and histopathologic findings were consistent with EPDS. A review of the literature on EPDS in children is also detailed.  相似文献   
26.

Objective

Comparative survival between neoadjuvant chemotherapy and adjuvant chemotherapy for patients with cT2-4N0-1M0 non–small cell lung cancer has not been extensively studied.

Methods

Patients with cT2-4N0-1M0 non–small cell lung cancer who received platinum-based chemotherapy were retrospectively identified. Exclusion criteria included stage IV disease, induction radiotherapy, and targeted therapy. The primary end point was disease-free survival. Secondary end points were overall survival, chemotherapy tolerance, and ability of Response Evaluation Criteria In Solid Tumors response to predict survival. Survival was estimated using the Kaplan–Meier method, compared using the log-rank test and Cox proportional hazards models, and stratified using matched pairs after propensity score matching.

Results

In total, 330 patients met the inclusion criteria (n = 92/group after propensity-score matching; median follow-up, 42 months). Five-year disease-free survival was 49% (95% confidence interval, 39-61) for neoadjuvant chemotherapy versus 48% (95% confidence interval, 38-61) for adjuvant chemotherapy (P = .70). On multivariable analysis, disease-free survival was not associated with neoadjuvant chemotherapy or adjuvant chemotherapy (hazard ratio, 1.1; 95% confidence interval, 0.64-1.90; P = .737), nor was overall survival (hazard ratio, 1.21; 95% confidence interval, 0.63-2.30; P = .572). The neoadjuvant chemotherapy group was more likely to receive full doses and cycles of chemotherapy (P = .014/0.005) and had fewer grade 3 or greater toxicities (P = .001). Response Evaluation Criteria In Solid Tumors response to neoadjuvant chemotherapy was associated with disease-free survival (P = .035); 15% of patients receiving neoadjuvant chemotherapy (14/92) had a major pathologic response.

Conclusions

Timing of chemotherapy, before or after surgery, is not associated with an improvement in overall or disease-free survival among patients with cT2-4N0-1M0 non–small cell lung cancer who undergo complete surgical resection.  相似文献   
27.
28.
29.
30.
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