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   1613868篇
  免费   130756篇
  国内免费   4098篇
耳鼻咽喉   20760篇
儿科学   52062篇
妇产科学   45019篇
基础医学   227582篇
口腔科学   41638篇
临床医学   146868篇
内科学   326479篇
皮肤病学   36280篇
神经病学   137103篇
特种医学   60679篇
外国民族医学   472篇
外科学   241459篇
综合类   35733篇
现状与发展   3篇
一般理论   783篇
预防医学   127651篇
眼科学   37005篇
药学   112912篇
  5篇
中国医学   3639篇
肿瘤学   94590篇
  2021年   15293篇
  2019年   15990篇
  2018年   21479篇
  2017年   16364篇
  2016年   18319篇
  2015年   20754篇
  2014年   29681篇
  2013年   43240篇
  2012年   60285篇
  2011年   63500篇
  2010年   37003篇
  2009年   34935篇
  2008年   58208篇
  2007年   61507篇
  2006年   61926篇
  2005年   60324篇
  2004年   57386篇
  2003年   54392篇
  2002年   52030篇
  2001年   74750篇
  2000年   75868篇
  1999年   63512篇
  1998年   19560篇
  1997年   17594篇
  1996年   17368篇
  1995年   16532篇
  1994年   14901篇
  1993年   13898篇
  1992年   46793篇
  1991年   44403篇
  1990年   42270篇
  1989年   40326篇
  1988年   36937篇
  1987年   36118篇
  1986年   33614篇
  1985年   32062篇
  1984年   24808篇
  1983年   20911篇
  1982年   13309篇
  1981年   11828篇
  1979年   21246篇
  1978年   15184篇
  1977年   12573篇
  1976年   11792篇
  1975年   11973篇
  1974年   14356篇
  1973年   13844篇
  1972年   12928篇
  1971年   11703篇
  1970年   11090篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.

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   
52.
Metabolism describes the series of chemical reactions that are concerned with the provision of energy to biological systems. They may be divided into reactions involved in energy yield (catabolism: demand exceeds supply), and energy storage (anabolism: supply exceeds demand). Regulation of these pathways is critical for homeostasis, and derangements in metabolism are seen in a wide variety of pathological processes. Understanding metabolism is key to the treatment of many diseases, notably diabetes, as well as underpinning clinical nutritional support.  相似文献   
53.
54.
55.
56.
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   
57.
58.
We report on a child with several café au lait spots in association with a lumbar lipomeningomyelocele as an apparently new association. Cutaneous markers, the identification of which plays a crucial role in the early diagnosis and management of spinal malformations, can accompany occult spinal dysraphism. Herein we report a case of lumbar lipomeningomyelocele associated with an overlying café au lait spot that served as a marker of occult spinal dysraphism. The patient also had segmental café au lait spots on the face, making the association unique.  相似文献   
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