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   2346289篇
  免费   175386篇
  国内免费   5792篇
耳鼻咽喉   32198篇
儿科学   77721篇
妇产科学   66929篇
基础医学   344185篇
口腔科学   65821篇
临床医学   216328篇
内科学   452508篇
皮肤病学   47950篇
神经病学   189866篇
特种医学   87979篇
外国民族医学   696篇
外科学   342636篇
综合类   51388篇
现状与发展   2篇
一般理论   729篇
预防医学   189152篇
眼科学   53375篇
药学   176501篇
  7篇
中国医学   5075篇
肿瘤学   126421篇
  2018年   25287篇
  2017年   19036篇
  2016年   21068篇
  2015年   24142篇
  2014年   33308篇
  2013年   51417篇
  2012年   70486篇
  2011年   75268篇
  2010年   44151篇
  2009年   40977篇
  2008年   70458篇
  2007年   75243篇
  2006年   76039篇
  2005年   74017篇
  2004年   70927篇
  2003年   68043篇
  2002年   66554篇
  2001年   104119篇
  2000年   106736篇
  1999年   90282篇
  1998年   26105篇
  1997年   23566篇
  1996年   23447篇
  1995年   22169篇
  1994年   20910篇
  1993年   19524篇
  1992年   72555篇
  1991年   71479篇
  1990年   69852篇
  1989年   67164篇
  1988年   62357篇
  1987年   60917篇
  1986年   58222篇
  1985年   55695篇
  1984年   41849篇
  1983年   35984篇
  1982年   21722篇
  1981年   19259篇
  1979年   39078篇
  1978年   27687篇
  1977年   23353篇
  1976年   22497篇
  1975年   23889篇
  1974年   28593篇
  1973年   27886篇
  1972年   26170篇
  1971年   24287篇
  1970年   22630篇
  1969年   21303篇
  1968年   20131篇
排序方式: 共有10000条查询结果,搜索用时 250 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