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   337907篇
  免费   46410篇
  国内免费   2071篇
耳鼻咽喉   4957篇
儿科学   8927篇
妇产科学   6759篇
基础医学   34719篇
口腔科学   9361篇
临床医学   49837篇
内科学   75166篇
皮肤病学   6462篇
神经病学   35083篇
特种医学   11698篇
外国民族医学   11篇
外科学   54522篇
综合类   3615篇
现状与发展   40篇
一般理论   318篇
预防医学   33591篇
眼科学   8503篇
药学   17724篇
  6篇
中国医学   365篇
肿瘤学   24724篇
  2024年   613篇
  2023年   5893篇
  2022年   3267篇
  2021年   7785篇
  2020年   8098篇
  2019年   7020篇
  2018年   12303篇
  2017年   11262篇
  2016年   12236篇
  2015年   13259篇
  2014年   18217篇
  2013年   22929篇
  2012年   21142篇
  2011年   21842篇
  2010年   16776篇
  2009年   17751篇
  2008年   19557篇
  2007年   19408篇
  2006年   20376篇
  2005年   18990篇
  2004年   17362篇
  2003年   15942篇
  2002年   14897篇
  2001年   3803篇
  2000年   2652篇
  1999年   3857篇
  1998年   4965篇
  1997年   4334篇
  1996年   3992篇
  1995年   3648篇
  1994年   2742篇
  1993年   2434篇
  1992年   1961篇
  1991年   1749篇
  1990年   1477篇
  1989年   1454篇
  1988年   1441篇
  1987年   1297篇
  1986年   1287篇
  1985年   1243篇
  1984年   1445篇
  1983年   1392篇
  1982年   1580篇
  1981年   1500篇
  1980年   1267篇
  1979年   784篇
  1978年   876篇
  1977年   749篇
  1976年   669篇
  1974年   552篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.

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   
32.
33.
34.
35.
Owing to the frequent incidence of blast-induced traumatic brain injury (bTBI) in recent military conflicts, there is an urgent need to develop effective therapies for bTBI-related pathologies. Blood-brain barrier (BBB) breakdown has been reported to occur after primary blast exposure, making restoration of BBB function and integrity a promising therapeutic target. We tested the hypothesis that treatment with dexamethasone (DEX) after primary blast injury potentiates recovery of an in vitro BBB model consisting of mouse brain endothelial cells (bEnd.3). DEX treatment resulted in complete recovery of transendothelial electrical resistance and hydraulic conductivity 1 day after injury, compared with 3 days for vehicle-treated injured cultures. Administration of RU486 (mifepristone) inhibited effects of DEX, confirming that barrier restoration was mediated by glucocorticoid receptor signaling. Potentiated recovery with DEX treatment was accompanied by stronger zonula occludens (ZO)-1 tight junction immunostaining and expression, suggesting that increased ZO-1 expression was a structural correlate to BBB recovery after blast. Interestingly, augmented ZO-1 protein expression was associated with specific upregulation of the α+ isoform but not the α isoform. This is the first study to provide a mechanistic basis for potentiated functional recovery of an in vitro BBB model because of glucocorticoid treatment after primary blast injury.  相似文献   
36.
37.
38.
39.
40.
The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.  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