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   178449篇
  免费   6800篇
  国内免费   336篇
耳鼻咽喉   3175篇
儿科学   6538篇
妇产科学   4549篇
基础医学   25252篇
口腔科学   5012篇
临床医学   13377篇
内科学   32395篇
皮肤病学   4874篇
神经病学   16312篇
特种医学   9157篇
外国民族医学   25篇
外科学   29427篇
综合类   1112篇
一般理论   42篇
预防医学   8443篇
眼科学   4779篇
药学   12381篇
中国医学   363篇
肿瘤学   8372篇
  2023年   794篇
  2021年   1360篇
  2020年   1202篇
  2019年   1417篇
  2018年   3070篇
  2017年   2502篇
  2016年   3472篇
  2015年   3814篇
  2014年   4052篇
  2013年   5659篇
  2012年   8823篇
  2011年   8200篇
  2010年   4817篇
  2009年   3870篇
  2008年   8102篇
  2007年   8925篇
  2006年   8953篇
  2005年   9324篇
  2004年   8879篇
  2003年   8733篇
  2002年   8652篇
  2001年   6391篇
  2000年   6492篇
  1999年   5612篇
  1998年   1622篇
  1997年   1331篇
  1996年   1019篇
  1995年   827篇
  1994年   783篇
  1992年   2481篇
  1991年   2403篇
  1990年   2382篇
  1989年   2198篇
  1988年   1938篇
  1987年   1933篇
  1986年   1783篇
  1985年   1736篇
  1984年   1339篇
  1983年   1094篇
  1979年   1455篇
  1978年   1045篇
  1977年   881篇
  1975年   1105篇
  1974年   1145篇
  1973年   1044篇
  1972年   1052篇
  1971年   1020篇
  1970年   917篇
  1969年   859篇
  1968年   826篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Adamantinoma of long bones is one of the rarest of malignant bone tumors; it is commonly located in the middle or lower third of the diaphysis of the tibia. A case with multiple occurrences affecting both the tibia and fibula is presented. En bloc resection with wide operative margins was performed, and a large tibial defect of 23 cm was effectively bridged by a revascularized free fibular flap. At 13 months follow-up, there was no sign of local recurrence or metastasis, and the patient was mobile.  相似文献   
22.
23.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
24.
Abstract Chorea is a rare complication of polycythaemia vera. Polycythaemic chorea occurs predominantly in females and usually in generalised form. We present a 66-year-old woman with acute onset hemichorea-ballism with no vascular pathology in the basal ganglia region. A clear relationship was observed between the onset of chorea and worsening of haematological parameters in the patient. After repeated phlebotomies the patient's clinical status was improved. Polycythaemic chorea must be considered, especially in the elderly, as early diagnosis leads to effective treatment and prevention of complications.  相似文献   
25.
26.

Background  

Patient falls in hospitals are common and may lead to negative outcomes such as injuries, prolonged hospitalization and legal liability. Consequently, various hospital falls prevention programs have been implemented in the last decades. However, most of the programs had no sustained effects on falls reduction over extended periods of time.  相似文献   
27.
Spray coated pellets as carrier system for mucoadhesive drug nanocrystals.   总被引:1,自引:0,他引:1  
High pressure homogenization can be employed to produce drug nanocrystals with a number of advantages, like improved solubility behaviors, better drug targeting or even increased mucoadhesiveness. To obtain a controlled drug delivery system it is necessary to transform the resulting nanosuspension into a solid dosage form. The present study shows the feasibility to use a mucoadhesive nanosuspension of poorly soluble hydrocortisone acetate produced by high pressure homogenization as layering dispersion in a fluidized bed process, followed by the application of an enteric coating to achieve a controlled drug release. To point out the advantages of drug nanocrystals the new fomulation was compared with a formulation containing micronized drug. Both formulations were characterized with regard to their particle size and crystallinity by using laser diffractometry, photon correlation spectroscopy and X-ray diffraction. The pellet morphology was characterized by using the environmental scanning electron microscopy (ESEM). In the in vitro dissolution tests an accelerated dissolution velocity and an increased drug release could be shown for the pellets containing drug nanocrystals.  相似文献   
28.
Both vascular surgery and endovascular interventions traumatise the arterial wall, especially the endothelium. The vessel responds with neointimal hyperplasia and/or constrictive remodelling, and this is still the limiting factor in curative interventions. Stent placement prevents constrictive remodelling but is the main trigger for in-stent restenosis. Hyperproliferation of neointimal tissue is the main response to arterial thrombosis, local inflammation or medio-intimal injury such as occurs, for example, after balloon dilatation in the region of arterial anastomoses or of a thrombectomy (Fogarty-manoeuvre). At present, research on prevention of restenosis is focused on inhibiting neointimal hyperproliferation by using drug-eluting stents, and especially sirolimus- or paclitaxel-eluting stents. In addition, further experimental research work is in progress, with the aim of esablishing new treatment regimens and solving the problem of neointimal formation, thrombosis and constrictive remodelling. These include both local and systemic pharmacological therapy, brachy- and laser therapy, and many genetic treatment options, some of which are currently the subjects of experimental studies and early-stage clinical trials. Gene therapy seems like a promising way of preventing restenosis, but has not yet been tested in clinical trials. In the near future, selective, simultaneous, and perhaps even polyphasic regulation for gene silencing of two or more genes involved in the development of restenosis could improve the long-term patency rate.  相似文献   
29.
Zusammenfassung Dieser Artikel stellt eine Übersetzung der im Jahr 2006 herausgegebenen Empfehlungen zur Behandlung von Patienten mit spontaner intrazerebraler Blutung der Europäischen Schlaganfallinitiative (EUSI) für das Europäische Schlaganfall-Council (ESC), die Europäische Neurologische Gesellschaft (ENS) und die Europäische Förderation Neurologischer Gesellschaften (EFNS) dar.Diese EUSI-Empfehlungen werden von dem European Stroke Council (ESC), der European Neurological Society (ENS) und der European Federation of Neurological Societies (EFNS) unterstützt.  相似文献   
30.
The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males.  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