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   27828篇
  免费   1347篇
  国内免费   97篇
耳鼻咽喉   322篇
儿科学   687篇
妇产科学   703篇
基础医学   3723篇
口腔科学   1686篇
临床医学   2082篇
内科学   6689篇
皮肤病学   567篇
神经病学   2157篇
特种医学   535篇
外科学   3075篇
综合类   130篇
一般理论   15篇
预防医学   3274篇
眼科学   405篇
药学   1904篇
中国医学   150篇
肿瘤学   1168篇
  2023年   262篇
  2022年   237篇
  2021年   693篇
  2020年   409篇
  2019年   707篇
  2018年   1161篇
  2017年   705篇
  2016年   720篇
  2015年   869篇
  2014年   951篇
  2013年   1281篇
  2012年   2288篇
  2011年   2492篇
  2010年   1140篇
  2009年   785篇
  2008年   1851篇
  2007年   1973篇
  2006年   1744篇
  2005年   1666篇
  2004年   1487篇
  2003年   1359篇
  2002年   1235篇
  2001年   452篇
  2000年   498篇
  1999年   364篇
  1998年   97篇
  1997年   50篇
  1996年   46篇
  1995年   49篇
  1994年   32篇
  1993年   40篇
  1992年   223篇
  1991年   160篇
  1990年   136篇
  1989年   118篇
  1988年   99篇
  1987年   99篇
  1986年   86篇
  1985年   71篇
  1984年   54篇
  1983年   54篇
  1979年   30篇
  1975年   38篇
  1974年   50篇
  1973年   29篇
  1971年   34篇
  1970年   38篇
  1969年   32篇
  1968年   38篇
  1967年   29篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
31.
ObjectiveThis review analyzes the literature concerning gut peptides and bariatric surgery, from 2005 to July 2009. In particular, we are interested in whether, and how, gastrointestinal peptide alterations following surgery interfere with appetite/satiety, and what role they might play in the resolution of comorbidities.Research methods and procedurePubMed/MEDLINE and ISI Web of Knowledge were used to search for human studies concerning gut peptides profiles after any bariatric operation technique.ResultsMost of the studies reviewed had longitudinal design, short follow-up, and low statistical power. The diversity of study results may be partially explained by methodological aspects. Glucagon-like peptide-1, gastric inhibitory peptide, and peptide YY alterations may contribute to the excellent results in glycemic control of diabetics. Results do vary depending on bariatric operation technique; this is particularly evident in the case of ghrelin, which has been much studied in recent years. Ghrelin suppression has been linked to increased satiety, alterations in energy homeostasis, and better glucose metabolism.ConclusionsThere is a lack of long-term data on gastrointestinal hormone profiles after bariatric surgery and the studies have many methodological pitfalls. We still need prospective, long-term, good methodological studies in this area.  相似文献   
32.
33.
OBJECTIVE: To evaluate the dynamics of bacterial contamination of healthcare workers' (HCWs) hands during neonatal care. SETTING: The 20-bed neonatal unit of a large acute care teaching hospital in Geneva, Switzerland. METHODS: Structured observation sessions were conducted. A sequence of care began when the HCW performed hand hygiene and ended when the activity changed or hand hygiene was performed again. Alcohol-based handrub was the standard procedure for hand hygiene. An imprint of the five fingertips of the dominant hand was obtained before and after hand hygiene and at the end of a sequence of care. Regression methods were used to model the final bacterial count according to the type and duration of care and the use of gloves. RESULTS: One hundred forty-nine sequences of care were observed. Commensal skin flora comprised 72.4% of all culture-positive specimens (n = 360). Other microorganisms identified were Enterobacteriaceae (n = 55, 13.8%); Staphylococcus aureus (n = 10, 2.5%); and fungi (n = 7, 1.8%). Skin contact, respiratory care, and diaper change were independently associated with an increased bacterial count; the use of gloves did not fully protect HCWs' hands from bacterial contamination. CONCLUSIONS: These data confirm that hands become progressively contaminated with commensal flora and potential pathogens during neonatal care, and identify activities at higher risk for hand contamination. They also reinforce the need for hand hygiene after a sequence of care, before starting a different task, and after glove removal.  相似文献   
34.

Background  

The justification for Nazi programs involving involuntary euthanasia, forced sterilisation, eugenics and human experimentation were strongly influenced by views about human dignity. The historical development of these views should be examined today because discussions of human worth and value are integral to medical ethics and bioethics. We should learn lessons from how human dignity came to be so distorted to avoid repetition of similar distortions.  相似文献   
35.
This case report demonstrates how extracting a maxillary deciduous canine affects the eruption path of a labially displaced ectopically erupting permanent canine. A long-term follow-up is presented, and the biologic mechanisms are discussed.  相似文献   
36.
Percutaneous embolization of large portosystemic collaterals was performed in three patients following placement of a transjugular intrahepatic portosystemic shunt in order to improve hepatopetal portal flow. Improved hepatic portal perfusion was achieved in these cases, thereby theoretically reducing the risk of chronic hepatic encephalopathy.  相似文献   
37.
Summary Nerve regeneration was studied in a model of centrocentral anastomosis (CCA) performed on the sciatic nerve of the rat. Experimental CCA was made by suturing the proximal end of the peroneal branch on the proximal end of the sural branch, placing between them a peroneal nerve graft (Group I, 20 rats) or a silicone chamber (Group II, 12 rats). Nerve grafts had a length of 5mm and silicone chambers 7 mm. In six silicone chambers an 1 mm nerve graft was placed in the centre of the tube. In group I animals anterograde degeneration was studied by cutting the graft 60 days after surgery. In group II, nerve regeneration was studied 2, 4 and 8 weeks after surgery. Results indicate that in CCA: 1) regenerated axons coming from one nerve end grow into the graft but do not cross the contralateral suture line; 2) regeneration is poorer in silicone chambers than in nerve grafts; and, 3) in silicone chambers regeneration is related to time. The reduction in the regenerative capability in CCA seems to be related to the alteration of nerve sprouts aiming for the peripheral targets.  相似文献   
38.
We have designed a double-lumen inflatable needle for the atraumatic dissection of brain substance. This balloon needle has been successfully used for the ventricular approach in brain grafting procedures to obtain a rounded corticotomy with a diameter of 1.5-2 cm in the treatment of Parkinson's disease.  相似文献   
39.
Nine publications are reviewed concerning blood pressure (BP) levels among Amerindian tribes of the Amazon Basin. The lifestyle of these lowland peoples includes most known protective factors against hypertension, and relative isolation from Western society. The latter, however, is rapidly changing. Sampling, data, and analysis problems make current blood pressure data difficult to interpret, and provide a questionable baseline from which to document pressure change during rapid culture change for these groups. Ethnographic and epidemiological perspectives are offered for future blood pressure and health studies among native Amazonians.  相似文献   
40.
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