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   1512篇
  免费   88篇
  国内免费   11篇
耳鼻咽喉   8篇
儿科学   100篇
妇产科学   19篇
基础医学   154篇
口腔科学   25篇
临床医学   172篇
内科学   272篇
皮肤病学   20篇
神经病学   93篇
特种医学   312篇
外科学   116篇
综合类   10篇
预防医学   86篇
眼科学   50篇
药学   81篇
肿瘤学   93篇
  2023年   5篇
  2021年   16篇
  2020年   8篇
  2019年   13篇
  2018年   23篇
  2017年   8篇
  2016年   13篇
  2015年   27篇
  2014年   29篇
  2013年   33篇
  2012年   26篇
  2011年   27篇
  2010年   33篇
  2009年   35篇
  2008年   23篇
  2007年   42篇
  2006年   39篇
  2005年   33篇
  2004年   28篇
  2003年   24篇
  2002年   25篇
  2001年   31篇
  2000年   18篇
  1999年   39篇
  1998年   96篇
  1997年   71篇
  1996年   81篇
  1995年   56篇
  1994年   58篇
  1993年   67篇
  1992年   27篇
  1991年   19篇
  1990年   28篇
  1989年   50篇
  1988年   45篇
  1987年   49篇
  1986年   43篇
  1985年   45篇
  1984年   30篇
  1983年   24篇
  1982年   28篇
  1981年   24篇
  1980年   32篇
  1979年   14篇
  1978年   21篇
  1977年   22篇
  1976年   25篇
  1975年   19篇
  1974年   6篇
  1973年   7篇
排序方式: 共有1611条查询结果,搜索用时 93 毫秒
101.
自美国国家骨髓库(NMDP)开展第一例无关供者移植以来,至今已有20年.NMDP目前的库容量已逾700万,已为6大洲提供了30 000多份无关供者造血干细胞.这一辉煌成就是美国国家骨髓库600多名工作人员共同努力的结果,同时也得益于广泛的国际合作,包括171个移植中心,73个供者中心,24个脐血库,97个骨髓采集中心,91个血液净化中心,26个HLA分型实验室和26个合作供者登记处.本文回顾了美国国家骨髓库的历史,阐述了20年来移植病人、移植物来源和预处理方案几方面的主要变化趋势.  相似文献   
102.
Growth hormone therapy for protein catabolism   总被引:5,自引:0,他引:5  
GH and IGF-I have shown remarkable consistency of effect in a wide range of catabolic conditions. Doses of around 10 IU/m2/day of GH and 80 micrograms/kg/day of IGF-I over short periods of time can improve net protein synthesis and preserve lean body mass. Most studies have reported metabolic endpoints, but favorable clinical effects have included decreased hospital stay and mortality in burns, improved respiratory muscle function in COAD, preserved grip strength post- operatively, and improvements in cardiac and bowel failure. Adverse effects of GH treatment are uncommon and usually related to glycaemic control. GH and IGF-I have differential effects on insulin concentrations--increasing or decreasing concentrations, respectively. The hypoglycaemic effects of IGF-I are dependent on route of administration and are avoided by subcutaneous delivery. Occasional patients have needed to discontinue GH treatment due to hyperglycaemia, although the anabolic action of GH may be partially mediated by increased insulin levels. The co-administration of GH and IGF-I has theoretical advantages by both increasing IGF binding-protein concentrations and balancing glycaemic control. An initial study with combination therapy in calorically-restricted volunteers has shown anabolic effects greater than with either agent alone. This approach requires further study in catabolic patients. There is a need for large, well-designed trials with clinical rather than purely metabolic end-points, and some of these are already underway. Should these studies confirm the early findings, financial considerations will become paramount, although it remains possible that treatment may be self-financing if lengths of hospital admissions are shortened.   相似文献   
103.
Two patients are described in whom clinically significant red blood cell alloantibodies could be demonstrated only by in vivo 51chromium (51Cr) survival studies. The first patient had experienced a severe delayed hemolytic transfusion reaction to four units of crossmatch compatible blood. Serial phenotype studies suggested the presence of a serologically undetectable anti-c (hr') antibody. 51Cr survival of c- positive red blood cells was one per cent at 24 hours, while survival of c-negative red blood cells was 80 per cent at 24 hours. The second patient had multiple red blood cell alloantibodies. An anti-c antibody was suspected but could not be convincingly demonstrated by in vitro techniques. 51Cr survival of c-positive red blood cells, however, was 57 per cent at 24 hours and 17 per cent at 48 hours. 51Chromium red blood cell survival studies should be considered whenever an unexplained hemolytic transfusion reaction occurs, or when an expected red blood cell alloantibody cannot be demonstrated by in vitro laboratory studies.  相似文献   
104.
The effect of prestorage irradiation on posttransfusion red cell survival   总被引:1,自引:0,他引:1  
Transfusion-associated graft-versus-host disease (TA-GVHD) may occur whenever immunologically competent allogeneic lymphocytes are transfused to an immunocompromised recipient. Irradiation of blood components eliminates the risk of TA-GVHD but may damage the cellular elements in the transfused component, particularly if the cells are stored for prolonged periods in the irradiated state. To study the effect of irradiation on long-term storage of red cells, AS-1 red cells from eight normal subjects were prepared on two occasions. On one occasion, the units were stored as standard AS-1 red cells for 42 days at 4 degrees C; on the other, they were exposed to 3000 cGy radiation within 4 hours of collection and then were stored as AS-1 red cells for 42 days at 4 degrees C. The donations were at least 12 weeks apart. Irradiated units demonstrated significant elevations in poststorage plasma hemoglobin (Hb) (623 +/- 206 vs. 429 +/- 194 g/dL [6230 +/- 2060 vs. 4290 +/- 1940 g/L], p less than 0.02) and plasma potassium (78 +/- 4 vs. 43 +/- 9 mEq/L [78 +/- 4 vs. 43 +/- 9 mmol/L], p less than 0.01) and significant decreases in red cell ATP (1.9 +/- 0.2 vs. 2.1 +/- 0.3 microM/g Hb, p less than 0.04) and 24-hour posttransfusion red cell recovery (68.5 vs. 78.4%, p less than 0.02), as compared to nonirradiated units. It can be concluded that irradiation with 3000 cGy damages red cells and that long-term storage in the irradiated state may enhance this damage. Red cells should not be stored for 42 days after irradiation with 3000 cGy.  相似文献   
105.
This article reviews the pathophysiology and pharmacology of emesis in relation to migraine pathogenesis. Also, the place of antiemetic and gastrointestinal prokinetic agents in current and future acute migraine treatment strategies is reviewed. The mechanisms of action of current and novel acute migraine therapies are considered with respect to the neurogenic and vascular hypotheses. Control of migraine-associated nausea and vomiting is often achieved with the benzamide dopamine D2 receptor antagonist metoclopramide. This drug also has 5HT3 receptor antagonist activity and reproducibly stimulates gastric motility to increase the availability of orally administered drugs. Other antiemetic and gastroprokinetic agents with potential value for the treatment of migraine-associated nausea and vomiting could speed absorption of oral antimigraine therapies without central nervous system side effects. Domperidone, a dopamine D2 receptor antagonist that does not cross the blood brain barrier is relatively free of the central side-effect liability of metoclopramide. Cisapride, a benzamide 5HT4 receptor agonist gastrointestinal prokinetic drug, lacks dopamine antagonist activity. A controlled comparison of these agents as migraine co-therapies could provide information on the importance of peripheral and central mechanisms in migraine-associated nausea and vomiting and improve antimigraine treatment options.  相似文献   
106.
自美国国家骨髓库(NMDP)开展第一例无关供者移植以来,至今已有20年.NMDP目前的库容量已逾700万,已为6大洲提供了30 000多份无关供者造血干细胞.这一辉煌成就是美国国家骨髓库600多名工作人员共同努力的结果,同时也得益于广泛的国际合作,包括171个移植中心,73个供者中心,24个脐血库,97个骨髓采集中心,91个血液净化中心,26个HLA分型实验室和26个合作供者登记处.本文回顾了美国国家骨髓库的历史,阐述了20年来移植病人、移植物来源和预处理方案几方面的主要变化趋势.  相似文献   
107.
BACKGROUND: Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, is endemic to Latin America and may be transmitted in the United States via blood donated by infected immigrants. Blood- borne pathogens such as T. cruzi require supplemental testing for confirmation of seroreactivity. STUDY DESIGN AND METHODS: A study was undertaken to determine an optimal scheme for confirmation of seroreactivity in repeatedly reactive samples identified by the Chagas antibody enzyme immunoassay (EIA). The procedure for initial confirmation involves three purified antigens coated onto three separate polystyrene beads and uses an EIA format. If the sample is reactive with two of three or three of three antigens, it is confirmed as seroreactive. If none or one of three beads is reactive, the sample is indeterminate and subjected to a radioimmunoprecipitation assay (RIPA). The RIPA must demonstrate characteristic bands at 32, 34, and 90 kDa. RESULTS: When tested with sera from persons with potentially cross-reactive diseases (n = 39) or against a presumed negative population from southeast Wisconsin (n = 289), the confirmatory EIA had a specificity of 100 percent. Sensitivity was 100 percent (28/28) with xenodiagnosis-positive sera and 97.6 percent (80/82) with chagasic sera from Latin America. The RIPA showed a specificity of 100 percent in EIA- nonreactive samples (n = 100) and a sensitivity of 100 percent with both xenodiagnosis-positive (28/28) and chagasic (82/82) sera. CONCLUSION: The confirmatory EIA and the RIPA together provide a highly specific and sensitive means of confirming seroreactivity for antibodies to T. cruzi.  相似文献   
108.
109.
Fragile X syndrome is, after Down's syndrome, the most common form of mental retardation. Women are potential carriers and can have the defective gene on one of their two X chromosomes without developing the complete syndrome. In this paper we examine which psychiatric disturbances may appear or develop in women because they are carriers of the fragile X mutation. Carriers have been found to have a higher frequency of anxiety disorders, affective disorders and schizotypal features.  相似文献   
110.
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