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   34048篇
  免费   2518篇
  国内免费   795篇
耳鼻咽喉   491篇
儿科学   498篇
妇产科学   620篇
基础医学   4332篇
口腔科学   806篇
临床医学   3190篇
内科学   5632篇
皮肤病学   783篇
神经病学   2208篇
特种医学   1902篇
外科学   4913篇
综合类   2138篇
现状与发展   3篇
一般理论   10篇
预防医学   1766篇
眼科学   840篇
药学   3356篇
  17篇
中国医学   1239篇
肿瘤学   2617篇
  2024年   52篇
  2023年   238篇
  2022年   570篇
  2021年   953篇
  2020年   596篇
  2019年   809篇
  2018年   863篇
  2017年   768篇
  2016年   834篇
  2015年   1324篇
  2014年   1598篇
  2013年   1940篇
  2012年   2801篇
  2011年   2770篇
  2010年   1906篇
  2009年   1723篇
  2008年   2279篇
  2007年   2171篇
  2006年   1979篇
  2005年   1804篇
  2004年   1543篇
  2003年   1351篇
  2002年   1109篇
  2001年   927篇
  2000年   861篇
  1999年   633篇
  1998年   221篇
  1997年   208篇
  1996年   181篇
  1995年   151篇
  1994年   132篇
  1993年   104篇
  1992年   245篇
  1991年   184篇
  1990年   178篇
  1989年   173篇
  1988年   146篇
  1987年   107篇
  1986年   96篇
  1985年   70篇
  1984年   79篇
  1983年   51篇
  1982年   52篇
  1981年   44篇
  1980年   44篇
  1979年   56篇
  1978年   44篇
  1977年   47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
1.
2.
3.
4.
5.
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   
6.
7.
8.
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   
9.
A new range of stand magnifiers has been released by the COIL company in the United Kingdom. Examination of these magnifiers reveals that they fail to deliver the rated magnifications labelled prominently on the appliances, as a result of the manufacturer's conformance with the requirements of the German DIN standard and the use of back vertex power (F'v) rather than equivalent dioptric power (Fm) of the magnifier. In this study we provide information on the optometric parameters of these new stand magnifiers that will assist the more accurate specification of improvements in vision expected from their use.  相似文献   
10.
PURPOSE: Gas embolism is a rare but well documented entity during operative hysteroscopy, with an incidence of 10-50%. Catastrophic outcomes occur at a rate of three in 17,000 procedures. The purpose of this report is to present a non-fatal case of gas embolism probably caused by the gaseous products of combustion. CLINICAL FEATURES: A 50-yr-old woman with a history of menorrhagia was scheduled for hysteroscopy and endometrial ablation and polypectomy. Fifteen minutes into the procedure, with the patient in lithotomy position, 20 degree head down tilt, and breathing spontaneously, a sudden oxygen desaturation occurred from 97% to 87%. The patient's end-tidal carbon dioxide dropped from 46 mmHg to 27 mmHg. The patient's breathing pattern remained normal, respiratory rate remained 11-12 breaths x min(-1) but amplitude of the reservoir bag movement was increased. Cardiovascular variables remained stable. She responded rapidly to 100% oxygen and made an uneventful recovery. Having ruled out other possible causes, we concluded gas embolism was responsible for the fall in oxygen saturation and end-tidal CO(2). CONCLUSION: With all the precautions in place to minimize the likelihood of fluid overload and ambient air embolism occurring, we surmised that products of combustion were the cause of the gas embolism. During endometrial ablation, gaseous products of combustion, mainly carbon dioxide, accumulate. The gases may then contribute to the rise in uterine pressure that occurs as irrigation fluid enters the uterus and this rise in pressure in turn encourages passage of gas into the open venous sinuses.  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