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   235242篇
  免费   14888篇
  国内免费   990篇
耳鼻咽喉   2523篇
儿科学   5993篇
妇产科学   4438篇
基础医学   29301篇
口腔科学   4320篇
临床医学   24065篇
内科学   49579篇
皮肤病学   3229篇
神经病学   23660篇
特种医学   10114篇
外国民族医学   13篇
外科学   37030篇
综合类   2538篇
现状与发展   1篇
一般理论   177篇
预防医学   16532篇
眼科学   5531篇
药学   15483篇
  2篇
中国医学   319篇
肿瘤学   16272篇
  2023年   1337篇
  2022年   2194篇
  2021年   5340篇
  2020年   3046篇
  2019年   5059篇
  2018年   6056篇
  2017年   4449篇
  2016年   4849篇
  2015年   5734篇
  2014年   8354篇
  2013年   11249篇
  2012年   17286篇
  2011年   18013篇
  2010年   10072篇
  2009年   9312篇
  2008年   15867篇
  2007年   16661篇
  2006年   16203篇
  2005年   16059篇
  2004年   15108篇
  2003年   13790篇
  2002年   13187篇
  2001年   1927篇
  2000年   1427篇
  1999年   2004篇
  1998年   2784篇
  1997年   2212篇
  1996年   1923篇
  1995年   1761篇
  1994年   1526篇
  1993年   1492篇
  1992年   977篇
  1991年   924篇
  1990年   783篇
  1989年   742篇
  1988年   677篇
  1987年   612篇
  1986年   636篇
  1985年   678篇
  1984年   909篇
  1983年   786篇
  1982年   1033篇
  1981年   965篇
  1980年   835篇
  1979年   468篇
  1978年   514篇
  1977年   448篇
  1976年   420篇
  1975年   314篇
  1974年   310篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
PURPOSE: Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, increases survival when combined with irinotecan-based chemotherapy in first-line treatment of metastatic colorectal cancer (CRC). This randomized, phase II trial compared bevacizumab plus fluorouracil and leucovorin (FU/LV) versus placebo plus FU/LV as first-line therapy in patients considered nonoptimal candidates for first-line irinotecan. PATIENTS AND METHODS: Patients had metastatic CRC and one of the following characteristics: age > or = 65 years, Eastern Cooperative Oncology Group performance status 1 or 2, serum albumin < or = 3.5 g/dL, or prior abdominal/pelvic radiotherapy. Patients were randomly assigned to FU/LV/placebo (n = 105) or FU/LV/bevacizumab (n = 104). The primary end point was overall survival. Secondary end points were progression-free survival, response rate, response duration, and quality of life. Safety was also assessed. RESULTS: Median survival was 16.6 months for the FU/LV/bevacizumab group and 12.9 months for the FU/LV/placebo group (hazard ratio, 0.79; P = .16). Median progression-free survival was 9.2 months (FU/LV/bevacizumab) and 5.5 months (FU/LV/placebo); hazard ratio was 0.50; P = .0002. Response rates were 26.0% (FU/LV/bevacizumab) and 15.2% (FU/LV/placebo) (P = .055); duration of response was 9.2 months (FU/LV/bevacizumab) and 6.8 months (FU/LV/placebo); hazard ratio was 0.42; P = .088. Grade 3 hypertension was more common with bevacizumab treatment (16% v 3%) but was controlled with oral medication and did not cause study drug discontinuation. CONCLUSION: Addition of bevacizumab to FU/LV as first-line therapy in CRC patients who were not considered optimal candidates for first-line irinotecan treatment provided clinically significant patient benefit, including statistically significant improvement in progression-free survival.  相似文献   
52.
53.
The most important physiological parameter influencing tissue response to heat is blood flow. At mild hyperthermia temperatures blood perfusion increases in many tumours and this effect is heating time-, temperature- and tumour-dependent. These flow increases can improve tumour oxygenation. When heating is terminated, perfusion and oxygenation commonly recover, although how quickly this occurs appears to be tumour-specific. While these effects are unlikely to have any anti-tumour activity they can be exploited to improve the combination of heat with other therapies. However, since similar physiological effects should occur in normal tissues, such combination therapies must be carefully applied. Heating tumours to higher temperatures typically causes a transient increase in perfusion during heating, followed by vascular collapse which if sufficient will increase tumour necrosis. The speed and degree of vascular collapse is dependent on heating time, temperature and tumour model used. Such vascular collapse generally occurs at temperatures that cause a substantial blood flow increase in certain normal tissues, thus preferential anti-tumour effects can be achieved. The tumour vascular supply can also be exploited to improve the response to heat. Decreasing blood flow, using transient physiological modifiers or longer acting vascular disrupting agents prior to the initiation of heating, can both increase the accumulation of physical heat in the tumour, as well as increase heat sensitivity by changing the tumour micro-environmental parameters, primarily an increase in tumour acidity. Such changes are generally not seen in normal tissues, thus resulting in a therapeutic benefit.  相似文献   
54.
55.
56.
57.
58.
59.

Background  

Despite a decreasing incidence of peptic ulcer disease, most previous studies report a stabile incidence of ulcer complications. We wanted to investigate the incidence of peptic ulcer complications in Sweden before and after the introduction of the proton pump inhibitors (PPI) in 1988 and compare these data to the sales of non-steroid anti-inflammatory drugs (NSAID) and acetylsalicylic acid (ASA).  相似文献   
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