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   1279049篇
  免费   97819篇
  国内免费   1991篇
耳鼻咽喉   18427篇
儿科学   44367篇
妇产科学   35012篇
基础医学   182215篇
口腔科学   33590篇
临床医学   111295篇
内科学   258288篇
皮肤病学   28020篇
神经病学   100399篇
特种医学   51223篇
外国民族医学   660篇
外科学   196400篇
综合类   27051篇
现状与发展   1篇
一般理论   377篇
预防医学   95738篇
眼科学   27913篇
药学   94782篇
  2篇
中国医学   2422篇
肿瘤学   70677篇
  2018年   13139篇
  2017年   9965篇
  2016年   10908篇
  2015年   12377篇
  2014年   17172篇
  2013年   26220篇
  2012年   36026篇
  2011年   38077篇
  2010年   22811篇
  2009年   21814篇
  2008年   36658篇
  2007年   39261篇
  2006年   39520篇
  2005年   38447篇
  2004年   37600篇
  2003年   36454篇
  2002年   35805篇
  2001年   63998篇
  2000年   66507篇
  1999年   56416篇
  1998年   15131篇
  1997年   13758篇
  1996年   14199篇
  1995年   13454篇
  1994年   12773篇
  1993年   11793篇
  1992年   44564篇
  1991年   43472篇
  1990年   42226篇
  1989年   40114篇
  1988年   36903篇
  1987年   36241篇
  1986年   33623篇
  1985年   32283篇
  1984年   24138篇
  1983年   20272篇
  1982年   11724篇
  1981年   10692篇
  1980年   9516篇
  1979年   21343篇
  1978年   14821篇
  1977年   12536篇
  1976年   11697篇
  1975年   12625篇
  1974年   14662篇
  1973年   14119篇
  1972年   12945篇
  1971年   11729篇
  1970年   11051篇
  1969年   10027篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
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   
12.
13.
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   
14.
The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.  相似文献   
15.
16.
17.
Pharmaceutical Chemistry Journal - Three extracts were produced from the above-ground part of the meadowsweet Filipendula ulmaria (L.) Maxim. using water, 40% ethanol, and 70% ethanol. Comparative...  相似文献   
18.
19.
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   
20.
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