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   13920篇
  免费   1204篇
  国内免费   38篇
耳鼻咽喉   90篇
儿科学   520篇
妇产科学   293篇
基础医学   1735篇
口腔科学   196篇
临床医学   1385篇
内科学   2707篇
皮肤病学   142篇
神经病学   1374篇
特种医学   477篇
外科学   1996篇
综合类   383篇
一般理论   11篇
预防医学   1369篇
眼科学   421篇
药学   1049篇
中国医学   50篇
肿瘤学   964篇
  2023年   65篇
  2022年   109篇
  2021年   258篇
  2020年   173篇
  2019年   279篇
  2018年   278篇
  2017年   215篇
  2016年   249篇
  2015年   257篇
  2014年   425篇
  2013年   559篇
  2012年   922篇
  2011年   891篇
  2010年   495篇
  2009年   466篇
  2008年   824篇
  2007年   921篇
  2006年   884篇
  2005年   912篇
  2004年   823篇
  2003年   752篇
  2002年   707篇
  2001年   198篇
  2000年   206篇
  1999年   210篇
  1998年   163篇
  1997年   153篇
  1996年   140篇
  1995年   129篇
  1994年   114篇
  1993年   120篇
  1992年   149篇
  1991年   115篇
  1990年   124篇
  1989年   108篇
  1988年   129篇
  1987年   121篇
  1986年   105篇
  1985年   116篇
  1984年   116篇
  1983年   96篇
  1982年   81篇
  1981年   78篇
  1980年   68篇
  1979年   58篇
  1978年   65篇
  1977年   44篇
  1973年   57篇
  1972年   47篇
  1970年   49篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Sixty Sprague-Dawley rats were pair-fed one of three nutritionally identical diets. One diet contained “low-fiber” (3.8% crude fiber); the others contained “high fiber” (28.7% crude fiber) composed of either cellulose or lignin. Although both “high fiber” diets had similar stool bulking effects, only the cellulose diet was associated with a reduction in 1,2-dimethylhydrazine (DMH)-induced colon neoplasms. The cellulose diet was also associated with distinct changes in the gut bacterial profile and with a lowered serum cholesterol. © 1993 Wiley-Liss, Inc.  相似文献   
32.
The effect of cadmium on the respiration of Ulva lactuca was examined using an oxygen electrode. Discs of U. lactuca thallus in filtered seawater were either incubated in the dark for 24 h or treated with 20 μM 3(3,4-dichlorophenyl) 1,1-dimethylurea to inhibit photosystem II dependent noncyclic electron transfer. In both cases, the addition of cadmium, as sulphate, increased respiration, with maximum stimulation occurring at approximately 15 mM; above this concentration respiration declined and at >21 mM inhibitory effects were significant. Dinitrophenol (DNP, 50 μM) and carbonyl cyanide m-chlorophenylhydrazone (CCCP, 10 μM) also uncoupled respiration of U. lactuca, and when these compounds were used in conjunction with Cd the effects were found to be additive. Oligomycin (12.5 μ mL?1), which inhibits the mitochondrial ATPase, inhibited U. lactuca respiration but subsequent Cd addition (to 6 mM) resulted in a 2.5 × increase in respiration over control values. DNP had a similar effect when used with oligomycin. DNP and CCCP had a negligible effect on the respiration of KCN-treated discs but the addition of Cd restored respiration to control values, probably because of the formation of insoluble Cd(CN)2. These results demonstrate that Cd can act as a respiratory uncoupler in U. lactuca.  相似文献   
33.
A 25 year old woman developed Clostridium difficile colitis following a course of vancomycin and metronidazole prescribed for pelvic inflammatory disease. The condition resolved after treatment with vancomycin given alone. Colitis following this combination of antibiotics has not been described previously.  相似文献   
34.
35.
This article examines the outcomes of participation in mental health Consumer/Survivor Initiatives (CSIs) and identifies helpful qualities of CSIs through a longitudinal, qualitative study that involved in‐depth interviews of people who experienced severe mental health challenges in Ontario, Canada. We used a nonequivalent control group design in which we compared active participants in CSIs ( n = 15) with nonactive participants ( n = 12) at baseline and at 9‐ and 18‐month follow‐up intervals. Compared with non‐CSI participants, CSI participants reported more stable mental health, enhanced social support, sustained work, stable income, and participation in education and training at 9‐ and 18‐month interviews. The helpful qualities of CSIs that participants reported were (1) safe environments that provide a positive, welcoming place to go; (2) social arenas that provide opportunities to meet and talk with peers; (3) an alternative worldview that provides opportunities for members to participate and contribute; and (4) effective facilitators of community integration that provide opportunities to connect members to the community at large. The findings are discussed in terms of previous research in self‐help and consumer‐run organizations in mental health. © 2006 Wiley Periodicals, Inc.  相似文献   
36.
37.
The Childrens Cancer Study Group evaluated daily oral 13-cis-retinoic acid to determine its therapeutic efficacy in 28 children with advanced neuroblastoma refractory to conventional therapy. Cheilitis and fissured lips were the most common side effects; however, fewer than 50% of the patients experienced any toxicity. Two of twenty-two evaluable children demonstrated positive response to therapy. In one case, a child received the drug for 11 months. Seventeen patients demonstrated progressive disease within 28 days of the start of treatment. Three other patients with stable disease, or removed from study at day 28, were considered nonresponsive. Our data demonstrate that, when given as a single daily oral dose of 100 mg/m2, 13-cis-retinoic acid does not have significant activity in children with advanced neuroblastoma. © 1992 Wiley-Liss, Inc.  相似文献   
38.
To assess its reliability as a marker of cardiomegaly in elderly patients, we compared a clinical assessment of heart size with that calculated from chest radiography. In 100 hospitalized subjects of median age 78 years, the apex beat was palpable in only 35% and its palpability declined with increasing age. Even when palpable, the apex beat had low specificity (74%) and sensitivity (69%) as a marker of cardiomegaly and its positive predictive value (69%) and negative predictive value (74%) were poor. The clinical assessment of heart size in elderly hospitalized patients should be interpreted with caution.  相似文献   
39.
Recently it has been suggested that the Australian snake antivenoms made by CSL Ltd. are in fact not truly monovalent and may contain antibodies to other snake venoms because the horses are injected with multiple snake venoms. It is unclear to what extent various monovalent antivenoms can neutralise the effect of other venoms, whether this is due to a mixture of antibodies or true cross-reactivity, and whether this has any clinical significance. We aimed to study the immunological and functional properties of brown snake (Pseudonaja spp.) antivenom (BSAV) and tiger snake (Notechis spp.) antivenom (TSAV) against their respective venoms using enzyme immunoassays (EIA) and in vitro clotting studies. There was significant overlap between the two antivenoms with both TSAV and BSAV being detected by EIA on brown snake venom (BSV)-coated and tiger snake venom (TSV)-coated wells, respectively. In a competition EIA, increasing amounts of immunoaffinity-purified hen anti-brown antibodies (IgYp) mixed with TSAV reduced TSAV measured on TSV-coated wells. Both BSAV and TSAV prevented the clotting activity of both venoms. IgYp also prevented the clotting activity of TSV, suggesting true cross-reactivity. The cross-reactivity of TSAV and BSAV with BSV and TSV, respectively, was likely due to each being a mixture of anti-brown and anti-tiger antibodies, but there was partial cross-reactivity demonstrated by the effect of IgYp. Single-polyvalent antivenom for brown snake and tiger snake may be feasible in the future.  相似文献   
40.
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