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   946019篇
  免费   65807篇
  国内免费   2354篇
耳鼻咽喉   11855篇
儿科学   29441篇
妇产科学   22070篇
基础医学   141759篇
口腔科学   24381篇
临床医学   87917篇
内科学   184907篇
皮肤病学   19361篇
神经病学   72627篇
特种医学   33806篇
外国民族医学   87篇
外科学   140968篇
综合类   18151篇
现状与发展   2篇
一般理论   471篇
预防医学   72072篇
眼科学   22615篇
药学   70287篇
  9篇
中国医学   2698篇
肿瘤学   58696篇
  2021年   10509篇
  2019年   10412篇
  2018年   13458篇
  2017年   10299篇
  2016年   11495篇
  2015年   13027篇
  2014年   18413篇
  2013年   26618篇
  2012年   37491篇
  2011年   39352篇
  2010年   22754篇
  2009年   20907篇
  2008年   35721篇
  2007年   38100篇
  2006年   38397篇
  2005年   36943篇
  2004年   35424篇
  2003年   33302篇
  2002年   31858篇
  2001年   38370篇
  2000年   38488篇
  1999年   32657篇
  1998年   10799篇
  1997年   9112篇
  1996年   9064篇
  1995年   8621篇
  1994年   7775篇
  1993年   7111篇
  1992年   24216篇
  1991年   24048篇
  1990年   23295篇
  1989年   23042篇
  1988年   20978篇
  1987年   20355篇
  1986年   19401篇
  1985年   18244篇
  1984年   13874篇
  1983年   11840篇
  1982年   7241篇
  1981年   6547篇
  1979年   12212篇
  1978年   8875篇
  1977年   7455篇
  1976年   7183篇
  1975年   7729篇
  1974年   8960篇
  1973年   8528篇
  1972年   8008篇
  1971年   7396篇
  1970年   7130篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Although studies have documented underuse of controller medications and overuse of short-acting inhaled ss(2)-agonist among children with persistent asthma in disadvantaged communities, the persistence of oral ss(2)-agonist use in pediatric practice has not been studied since inhaled short-acting ss(2)-agonists became widespread. We describe medications used to treat asthma among children 3 to 5 years of age at 10 Head Start and other subsidized preschool centers in East and Central Harlem, New York City. We interviewed 149 parents/guardians of children who were identified as having probable asthma based on physician's diagnosis, persistent symptoms, hospitalization, and medication use. We classified 86 of the 149 children (58%) as having current persistent asthma. Only 15 of them (17%) were reported to have used controller medications at least 5 days/week in the last 4 weeks-only 2 of whom used inhaled corticosteroids. By contrast, 53 children (62%) used oral ss(2)-agonist in the last 4 weeks, often (72%) in conjunction with nebulized or inhaled short-acting ss(2)-agonist. Use of oral ss(2)-agonist was associated with more severe symptoms. This study documents the continued widespread use of oral ss(2)-agonist for treatment of children in a low-income community with high prevalence of asthma.  相似文献   
22.
23.
24.
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.  相似文献   
25.
Photodynamic therapy (PDT) is based on the selective light activation of an exogenously given drug to patients. PDT acts mainly on cell membranes either of neovascular endothelial cells or of cancer cells leading to cancer cell death. Six drugs are now marketed based on clinical assays in various indications, which showed a clear cost efficiency as compared to other classical procedures. PDT is easy to handle and can be performed in medical installations fitting the conditions of health care in developing countries. Its cost effectiveness could represent an appropriate solution to the increasing number of cancers of various origin. However despite all the clinical results now available, PDT development remains slow. The reasons for this situation include cost of development, intellectual property, and competition between pharmaceutical companies.  相似文献   
26.
27.
OBJECTIVE: Antidepressants are commonly used drugs with potential for numerous drug interactions. This study aims to systematically review the literature on drug interactions with antidepressants. METHODS: We searched MEDLINE (1966 to November 2003) and EMBASE (1980 to 2003), using the heading drug interactions combined with individual antidepressant names. We restricted searches to English-language articles and human studies. We screened drug interaction texts and review articles for relevant studies. We included articles reporting original human data on drug interactions with antidepressants commonly used in North America. Articles were independently evaluated by 2 reviewers on clinical effect, clinical significance, and quality of evidence. Discrepancies were resolved by consensus. RESULTS: There were 904 eligible interactions, involving 9509 patients, for a total of 598 summary interactions. Of these, 439 (73%) demonstrated an interaction, 148 (25%) had no effect, and 11 (2%) had conflicting evidence. For 510 interactions (85%), the quality of evidence was poor. It was fair for 67 (11%) interactions and good for 10 (2%) interactions. There were no interactions with excellent quality of evidence. There were 145 (24%) interactions of major clinical significance. These were predominantly hypertensive emergencies and serotonin syndrome. Most interacting drugs had central nervous system (CNS) activity. As expected, monoamine oxidase inhibitors (MAOIs) appear to be the most problematic family in terms of potential for serious drug interactions. CONCLUSIONS: Drug interactions with antidepressants are an important cause for concern, but this concern is based primarily on poor evidence. We recommend caution when combining antidepressants with other CNS drugs, particularly when coadministering MAOIs with other substances.  相似文献   
28.
29.
30.
Published data devoted to making and characterization of the properties of polymeric wound dressings with proteolytic action are reviewed. These data are indicative of individual dependence of the physicochemical properties, activity, and stability of each particular enzyme on the type of polymer matrix and the method of immobilization. In order to obtain wound dressings, which are active in physiological medium and retain their activity upon sterilization, it is necessary to optimize the composition and characteristics of a polymer matrix and the enzyme included into its structure. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 8, pp. 24–28, August, 2006.  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