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   2475397篇
  免费   177099篇
  国内免费   6149篇
耳鼻咽喉   34107篇
儿科学   82568篇
妇产科学   70981篇
基础医学   360700篇
口腔科学   69303篇
临床医学   225974篇
内科学   474853篇
皮肤病学   51061篇
神经病学   197875篇
特种医学   95784篇
外国民族医学   787篇
外科学   362476篇
综合类   51910篇
现状与发展   2篇
一般理论   730篇
预防医学   199710篇
眼科学   56361篇
药学   185287篇
  9篇
中国医学   5138篇
肿瘤学   133029篇
  2018年   28225篇
  2017年   22326篇
  2016年   23603篇
  2015年   27884篇
  2014年   36479篇
  2013年   53800篇
  2012年   77927篇
  2011年   78540篇
  2010年   45599篇
  2009年   43790篇
  2008年   71742篇
  2007年   76988篇
  2006年   77935篇
  2005年   82786篇
  2004年   81129篇
  2003年   74383篇
  2002年   68679篇
  2001年   106285篇
  2000年   107458篇
  1999年   93273篇
  1998年   26284篇
  1997年   23589篇
  1996年   23572篇
  1995年   22344篇
  1994年   21031篇
  1993年   19586篇
  1992年   76320篇
  1991年   75443篇
  1990年   73865篇
  1989年   71076篇
  1988年   65984篇
  1987年   64479篇
  1986年   61594篇
  1985年   58780篇
  1984年   43939篇
  1983年   37669篇
  1982年   22302篇
  1981年   19675篇
  1979年   41385篇
  1978年   29159篇
  1977年   24420篇
  1976年   23437篇
  1975年   25424篇
  1974年   30561篇
  1973年   29626篇
  1972年   27965篇
  1971年   26031篇
  1970年   24336篇
  1969年   22941篇
  1968年   21618篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.

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   
52.
53.
54.
55.

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   
56.
57.
58.
59.
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