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   1279173篇
  免费   97927篇
  国内免费   1989篇
耳鼻咽喉   18426篇
儿科学   44362篇
妇产科学   35018篇
基础医学   182249篇
口腔科学   33592篇
临床医学   111339篇
内科学   258322篇
皮肤病学   28025篇
神经病学   100392篇
特种医学   51210篇
外国民族医学   660篇
外科学   196522篇
综合类   27049篇
现状与发展   1篇
一般理论   377篇
预防医学   95749篇
眼科学   27913篇
药学   94785篇
  2篇
中国医学   2422篇
肿瘤学   70674篇
  2018年   13144篇
  2017年   9970篇
  2016年   10903篇
  2015年   12384篇
  2014年   17174篇
  2013年   26228篇
  2012年   36073篇
  2011年   38098篇
  2010年   22830篇
  2009年   21846篇
  2008年   36661篇
  2007年   39268篇
  2006年   39521篇
  2005年   38463篇
  2004年   37605篇
  2003年   36466篇
  2002年   35816篇
  2001年   64009篇
  2000年   66507篇
  1999年   56419篇
  1998年   15129篇
  1997年   13756篇
  1996年   14198篇
  1995年   13456篇
  1994年   12766篇
  1993年   11791篇
  1992年   44561篇
  1991年   43472篇
  1990年   42226篇
  1989年   40117篇
  1988年   36899篇
  1987年   36237篇
  1986年   33630篇
  1985年   32286篇
  1984年   24144篇
  1983年   20269篇
  1982年   11729篇
  1981年   10696篇
  1980年   9517篇
  1979年   21344篇
  1978年   14824篇
  1977年   12535篇
  1976年   11698篇
  1975年   12632篇
  1974年   14664篇
  1973年   14119篇
  1972年   12948篇
  1971年   11732篇
  1970年   11055篇
  1969年   10028篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Dosage form is a mean used for the delivery of drug to a living body. In order to get the desired effect the drug should be delivered to its site of action at such rate and concentration to achieve the maximum therapeutic effect and minimum adverse effect. Since oral route is still widely accepted route but having a common drawback of difficulty in swallowing of tablets and capsules. Therefore a lot of research has been done on novel drug delivery systems. This review is about oral dispersible tablets a novel approach in drug delivery systems that are now a day''s more focused in formulation world, and laid a new path that, helped the patients to build their compliance level with the therapy, also reduced the cost and ease the administration especially in case of pediatrics and geriatrics. Quick absorption, rapid onset of action and reduction in drug loss properties are the basic advantages of this dosage form.  相似文献   
5.
6.
Analyzing functional species’ characteristics (species traits) that represent physiological, life history and morphological characteristics of species help understanding the impacts of various stressors on aquatic communities at field conditions. This research aimed to study the combined effects of pesticides and other environmental factors (temperature, dissolved oxygen, dissolved organic carbon, floating macrophytes cover, phosphate, nitrite, and nitrate) on the trait modality distribution of aquatic macrofauna communities. To this purpose, a field inventory was performed in a flower bulb growing area of the Netherlands with significant variation in pesticides pressures. Macrofauna community composition, water chemistry parameters and pesticide concentrations in ditches next to flower bulb fields were determined. Trait modalities of nine traits (feeding mode, respiration mode, locomotion type, resistance form, reproduction mode, life stage, voltinism, saprobity, maximum body size) likely to indicate pesticides impacts were analyzed. According to a redundancy analysis, phosphate -and not pesticides- constituted the main factor structuring the trait modality distribution of aquatic macrofauna. The functional composition could be ascribed for 2–4 % to pesticides, and for 3–11 % to phosphate. The lack of trait responses to pesticides may indicate that species may have used alternative strategies to adapt to ambient pesticides stress. Biomass of animals exhibiting trait modalities related to feeding by predation and grazing, presence of diapause form or dormancy, reproduction by free clutches and ovoviviparity, life stage of larvae and pupa, was negatively correlated to the concentration of phosphate. Hence, despite the high pesticide pollution in the area, variation in nutrient-related stressors seems to be the dominant driver of the functional composition of aquatic macrofauna assembly in agricultural ditches.  相似文献   
7.
Haemophilia is a common cause of genetically inherited bleeding disorders. Pseudotumours occur in 1–2 % of persons with severe forms of haemophilia. These are a result of repeated haemorrhage into soft tissues, subperiosteum or a site of bone fracture with inadequate resorption of the extravasated blood. There are a number of therapeutic alternatives for this dangerous condition: surgical removal, percutaneous management, irradiation, embolization etc. In this case report, we describe the natural history, clinical course and successful surgical management of a patient with haemophilia who presented with a massive pseudotumour. We also briefly review the relevant literature on the various therapeutic modalities that have been implemented in the management of this rare complication. Though surgeons may be averse to operate on haemophiliacs, primary surgical management as done in our case may prove to be the definitive treatment option for such patients.  相似文献   
8.
9.
As millions of people turn to social media for health information, better understanding the factors that guide health-related judgments and perceptions in this context is imperative. We report on two Web experiments (n > 400 total) examining the power of society’s widespread weight bias and related stereotypes to influence nutrition judgments in social media spaces. In Experiment 1, meals were judged as lower in nutritional quality when the person who recommended them (the source) was depicted as obese rather than of normal weight, an effect mediated by stereotypic beliefs about the source as a generally unhealthy person. Experiment 2 replicated this effect, which—notably—remained significant when controlling for objective nutritional information (calories and fat content). Results highlight spillover effects of weight bias that extend beyond person perception to color impressions of objects (here, food) that are associated with stigmatized attributes. Implications for everyday nutrition judgments and public health are considered.  相似文献   
10.
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