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   27239篇
  免费   1887篇
  国内免费   251篇
耳鼻咽喉   424篇
儿科学   442篇
妇产科学   594篇
基础医学   3933篇
口腔科学   700篇
临床医学   2360篇
内科学   5208篇
皮肤病学   597篇
神经病学   2020篇
特种医学   1667篇
外科学   4373篇
综合类   302篇
一般理论   10篇
预防医学   1136篇
眼科学   677篇
药学   2346篇
  1篇
中国医学   271篇
肿瘤学   2316篇
  2023年   167篇
  2022年   391篇
  2021年   715篇
  2020年   399篇
  2019年   671篇
  2018年   725篇
  2017年   601篇
  2016年   697篇
  2015年   1021篇
  2014年   1272篇
  2013年   1439篇
  2012年   2138篇
  2011年   2099篇
  2010年   1302篇
  2009年   1210篇
  2008年   1639篇
  2007年   1564篇
  2006年   1456篇
  2005年   1380篇
  2004年   1243篇
  2003年   1087篇
  2002年   956篇
  2001年   779篇
  2000年   764篇
  1999年   605篇
  1998年   226篇
  1997年   208篇
  1996年   191篇
  1995年   158篇
  1994年   136篇
  1993年   120篇
  1992年   248篇
  1991年   185篇
  1990年   179篇
  1989年   171篇
  1988年   153篇
  1987年   113篇
  1986年   101篇
  1985年   79篇
  1984年   80篇
  1983年   50篇
  1982年   57篇
  1981年   47篇
  1980年   47篇
  1979年   57篇
  1978年   45篇
  1977年   49篇
  1974年   37篇
  1972年   44篇
  1971年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Laparoscopic surgery has several advantages over traditional surgery because it has been shown to be less invasive. The next logical step in the evolution of minimally invasive surgery may be to eliminate all abdominal incisions. The natural orifices provide a port of entry via the gastrointestinal tract to the peritoneal cavity. This approach would require the creation of a perforation, which is considered to be a major complication of endoscopy with significant morbidity and mortality. However, there are several recent studies that have described the technical feasibility and safety of a per‐oral transgastric approach to the peritoneal cavity using conventional endoscopes. Theoretically, this approach could reduce postoperative abdominal wall pain, wound infection, hernia formation, and adhesions. This article aims to summarize the current status of transgastric surgery, currently referred to as natural orifice transluminal endoscopic surgery (NOTES), and to address some of its future challenges.  相似文献   
13.
14.
15.
16.
17.
The objective of this study is to assess the efficacy and safety of herbal medicines (HMs), as a monotherapy or adjunct therapy, compared to placebo or conventional approaches in the treatment of idiopathic Parkinson's disease (PD). We conducted a systematic review of randomized controlled trials from both conventional and alternative medicine sources. Outcome measures were overall improvement, quality of life, reduction of levodopa dose, and adverse events. Nine studies were included, each testing a different HM. Six of the trials had limited internal validity due to major flaws in design, including the lack of proper randomization; insufficient blinding; unclear inclusive criteria in terms of diagnostic criteria, baseline staging, and duration of disease; lack of proper sample size calculation; and insufficient data analysis. Imbalances in gender and ethnicity among the patients in the included trials were observed. No major adverse events emerged, and no specific pattern was detected from the trials describing such data. In addition to major methodological defects, heterogeneity in (1) HM tested, (2) control treatment, and (3) outcome measure hindered in-depth data analysis and synthesis. Current evidence is insufficient to evaluate the efficacy and safety of various HMs. Further studies with improved trial design and reporting, with assessment on cost-effectiveness, quality of life, and qualitative data are warranted.  相似文献   
18.
19.
20.
G Nichol  A Nix  P J Barnes    K F Chung 《Thorax》1990,45(9):694-698
The effect of inhaled prostaglandin (PG) F2 alpha on the response to the inhaled tussive agent capsaicin was investigated in normal subjects. Seven subjects inhaled three breaths of four doses of capsaicin (0.3, 0.6, 1.2, and 2.4 nmol) before and immediately after inhaling PGF2 alpha (0.1 mumol) or placebo (0.15M NaCl) on separate days. The numbers of capsaicin induced coughs were greater after PGF2 alpha (mean 42.3 coughs) than after 0.15M sodium chloride (30.1). Visual analogue scores (0-10 on a 10 cm continuous scale) showed that capsaicin was more irritant after PGF2 alpha than after saline. Total respiratory resistance (Rrs), measured by the forced oscillation technique, was unaltered throughout the study. A double blind, placebo controlled study of the effects of inhaled salbutamol (200 micrograms, 0.6 mumol) and ipratropium bromide (40 micrograms, 0.1 mumol) on cough induced by capsaicin (2.4 nmol) and by PGF2 alpha (0.1 mumol) and on PGF2 alpha augmented, capsaicin induced coughing was performed in seven subjects. Neither drug had any effect on capsaicin induced coughing. Salbutamol reduced coughing due to PGF2 alpha (mean 7.7 coughs after salbutamol, 9.3 after placebo) but ipratropium bromide did not (mean 6.9 coughs after ipratropium bromide, 6.6 after placebo). Salbutamol also inhibited the augmentation of the capsaicin induced cough that followed inhalation of PGF2 alpha (mean augmentation 1.9 coughs after salbutamol, 4.1 after placebo), whereas ipratropium bromide did not (augmentation 1.7 coughs after ipratropium bromide, 2.7 after placebo). No changes in Rrs were seen after PGF2 alpha or either drug. Thus salbutamol reduces PGF2 alpha induced cough and the augmentation of capsaicin induced cough that follows PGF2 alpha.  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