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   161791篇
  免费   7540篇
  国内免费   530篇
耳鼻咽喉   2658篇
儿科学   4879篇
妇产科学   3697篇
基础医学   22140篇
口腔科学   5664篇
临床医学   10340篇
内科学   39464篇
皮肤病学   5146篇
神经病学   13338篇
特种医学   3642篇
外国民族医学   2篇
外科学   19281篇
综合类   1009篇
一般理论   43篇
预防医学   15730篇
眼科学   3501篇
药学   11495篇
中国医学   905篇
肿瘤学   6927篇
  2023年   988篇
  2022年   1507篇
  2021年   4404篇
  2020年   2230篇
  2019年   4143篇
  2018年   5885篇
  2017年   3551篇
  2016年   3412篇
  2015年   3832篇
  2014年   5099篇
  2013年   7266篇
  2012年   11421篇
  2011年   12259篇
  2010年   6439篇
  2009年   5029篇
  2008年   9462篇
  2007年   10017篇
  2006年   9283篇
  2005年   9233篇
  2004年   8262篇
  2003年   7648篇
  2002年   7079篇
  2001年   4475篇
  2000年   5024篇
  1999年   3966篇
  1998年   904篇
  1997年   694篇
  1996年   582篇
  1995年   518篇
  1994年   408篇
  1993年   339篇
  1992年   1538篇
  1991年   1276篇
  1990年   1148篇
  1989年   949篇
  1988年   844篇
  1987年   770篇
  1986年   772篇
  1985年   659篇
  1984年   475篇
  1983年   405篇
  1979年   442篇
  1975年   307篇
  1974年   394篇
  1973年   390篇
  1972年   336篇
  1971年   366篇
  1970年   328篇
  1969年   351篇
  1968年   312篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
101.
102.
An important part of fundamental research in catalysis is based on theoretical and modeling foundations which are closely connected with studies of single-crystalline catalyst surfaces. These so-called model catalysts are often prepared in the form of epitaxial thin films, and characterized using advanced material characterization techniques. This concept provides the fundamental understanding and the knowledge base needed to tailor the design of new heterogeneous catalysts with improved catalytic properties. The present contribution is devoted to development of a model catalyst system of CeO2 (ceria) on the Cu(111) substrate. We propose ways to experimentally characterize and control important parameters of the model catalyst—the coverage of the ceria layer, the influence of the Cu substrate, and the density of surface defects on ceria, particularly the density of step edges and the density and the ordering of the oxygen vacancies. The large spectrum of controlled parameters makes ceria on Cu(111) an interesting alternative to a more common model system ceria on Ru(0001) that has served numerous catalysis studies, mainly as a support for metal clusters.  相似文献   
103.
104.
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.  相似文献   
105.
ABSTRACT

This study closely examines 51 breast cancer narratives Latina and Spanish women wrote for other patients to illuminate how they conceptualize their health, with insights for addressing health disparities. Using discourse analysis of the role of language and culture in health care communication, this study focuses on the use of metaphors in the narratives. This provides revelations about the cultural and linguistic aspects of how the writers conceptualize their disease. Building on past research on metaphor use in cancer discourse in the English language, this study reveals the prevalence of metaphors comparing cancer to combat, or more generally, violence (e.g., “my battle against cancer”), or a journey (e.g., “my path with cancer”). Writers used this metaphorical language to offer advice to others with cancer and to mark their membership in a larger community of people with cancer. We also find that Spanish women use metaphors more frequently than Latinas and that they differed in their metaphorical portrayals of cancer. This research uncovers culturally embedded themes that are central to how women with cancer think about the disease, such as the prominence of spirituality in Latinas’ metaphorical constructions, a pattern not evident in Spanish women’s narratives.  相似文献   
106.
107.
108.
ObjectiveSeptic arthritis is a medical emergency and crystal-induced arthritis is a risk factor for its development. If both occur simultaneously, crystal-induced arthritis may mask the diagnosis of infection and delay antibiotic therapy.MethodRetrospective analysis of patients with coexistence of septic and crystal-induced arthritis. We included only patients with isolation of crystals in synovial fluid analysis and positive culture of synovial fluid and/or blood culture.ResultsA total of 25 patients (17 men and 8 women) with a mean age of 67 years. The most commonly affected joint was the knee. In synovial fluid cytological studies, the most frequently identified crystals were monosodium urate. Risk factors included diabetes and chronic renal failure. The most frequently isolated germs were methicillin-sensitive S. aureus (48%), methicillin-resistant S. aureus (12%) and Mycobacterium tuberculosis (12%). In all, 36% of subjects required surgical drainage (excluding those caused by M. tuberculosis). Clinical outcome was favorable in 56%, although intercurrent complications were usual (40%). Mortality was 8%.ConclusionsCoexistence of septic and crystal-induced arthritis represents a diagnostic challenge and requires a high index of suspicion. Gout was the most prevalent crystal-induced arthritis. S. aureus was the most commonly causative pathogen, with a high rate of methicillin-resistant S. aureus infection. If treated early, the outcome is usually favorable, making synovial fluid microbiological study imperative.  相似文献   
109.
110.
Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes.  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