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   4493篇
  免费   329篇
  国内免费   76篇
耳鼻咽喉   44篇
儿科学   221篇
妇产科学   67篇
基础医学   579篇
口腔科学   176篇
临床医学   512篇
内科学   944篇
皮肤病学   81篇
神经病学   243篇
特种医学   498篇
外科学   406篇
综合类   159篇
预防医学   324篇
眼科学   181篇
药学   284篇
  2篇
中国医学   1篇
肿瘤学   176篇
  2022年   28篇
  2021年   78篇
  2020年   41篇
  2019年   55篇
  2018年   76篇
  2017年   65篇
  2016年   56篇
  2015年   104篇
  2014年   98篇
  2013年   144篇
  2012年   161篇
  2011年   155篇
  2010年   156篇
  2009年   134篇
  2008年   172篇
  2007年   188篇
  2006年   181篇
  2005年   180篇
  2004年   140篇
  2003年   122篇
  2002年   117篇
  2001年   116篇
  2000年   97篇
  1999年   80篇
  1998年   155篇
  1997年   176篇
  1996年   146篇
  1995年   139篇
  1994年   132篇
  1993年   108篇
  1992年   85篇
  1991年   74篇
  1990年   86篇
  1989年   92篇
  1988年   99篇
  1987年   78篇
  1986年   86篇
  1985年   87篇
  1984年   56篇
  1983年   44篇
  1982年   34篇
  1981年   43篇
  1980年   38篇
  1979年   22篇
  1978年   23篇
  1977年   32篇
  1976年   38篇
  1975年   23篇
  1970年   20篇
  1968年   18篇
排序方式: 共有4898条查询结果,搜索用时 0 毫秒
21.
An exploratory study was undertaken in a three-year nursing diploma program to determine instructor and student perceptions of self-evaluation (SE) and its relationship to clinical evaluation. A cross-section of instructors (n = 9) participated in three rounds of a Delphi survey. From this validated data base a questionnaire was developed and distributed to a stratified sample of 145 students. Combined results were then analyzed and compared. Results indicated that both students and instructors perceive self-evaluation more positively than negatively and they see the main purpose as providing direction for learning. Contrary to the literature and perceptions of surveyed instructors, students did not perceive self-evaluation as a factor in promotion of professional growth. Although students value a participatory role in clinical evaluation, the process of self-evaluation generates anxiety and underrating of performance. The authors conclude that self-evaluation is a developmental skill requiring guidelines and practice, and offer recommendations for its use.  相似文献   
22.
23.
The morphological base for the impaired function of the blood retinal barrier was studied in 50 eyes of 10 insulin dependent and 21 non-insulin dependent patients with various levels of diabetic retinopathy. The permeability of the blood retinal barrier (PBRB) was determined by vitreous fluorophotometry with correction for autofluorescence, lenstransmission and non-protein bound plasma fluorescein concentration. Morphological abnormalities of diabetic retinopathy assessed by fundus photography and fluorescein angiography were individually scored on a decimal scale and related to the PBRB by multiple regression analysis. The Pbrb was not correlated to morphological abnormalities of non-proliferative retinopathy [(1) microaneurysms, (2) hard exudates, (3) soft exudates, (4) intraretinal hemorrhages, (5) fluorescein leakage, and (6) capillary closure, p > 0.3]. The PBRB was correlated to morphological abnormalities of (pre)proliferative retinopathy [(1) intraretinal microvascular abnormalities (Sirma) and (2) new vessels (Sneo): pbrb = A – B.SIRMA – C.Sneo with PBRB in nm/sec, A = 1.5 ± 0.5, B = 0.9 ± 0.2 and C = 1.7 ± 0.4, R2 = 0.65, p < 0.0001]. It can be concluded that the increased blood retinal barrier permeability in diabetic patients is mainly due to (pre)proliferative abnormalities and not to non-proliferative abnormalities.  相似文献   
24.
25.
26.
BACKGROUND: The mainstay of treatment for pemphigus is systemic corticosteroids. Different adjuvants have been used to reduce side-effects of long-term corticotherapy. Gold is an anti-inflammatory drug used in autoimmune diseases, whose use has waned with the advent of new immunosuppressive agents. OBJECTIVE: To study the outcome of the use of intramuscular gold treatment of pemphigus vulgaris refractory to previous therapies. METHODS: Thirteen patients with pemphigus vulgaris who had failed to respond to several prior therapies were treated with aurothiomalate, as a steroid-sparing agent. Patients were monitored to assess disease activity and gold toxicity. RESULTS: Seven patients achieved complete remission. Four patients were able to taper prednisone doses, although pemphigus flared when prednisone was discontinued or reduced. Toxicity was observed in the other two patients. CONCLUSIONS: In 53.4% of the patients, the use of chrysotherapy resulted in the complete clearing of the disease, discontinuation of all systemic therapies and induced a long-term clinical remission. Prednisone doses were able to be reduced in the remaining 46.6%. Any side-effects were reversible with drug discontinuation. Gold therapy showed efficacy as a secondary line treatment in refractory pemphigus vulgaris.  相似文献   
27.
Exposure to nitrous oxide produced concentration-dependent analgesia in the mouse abdominal constriction test. Intracerebroventricular or intrathecal pretreatment with naltrexone or nor-binaltorphimine significantly reduced nitrous oxide analgesia. However, similar pretreatment with beta-funaltrexamine had no appreciable effect. These findings suggest that nitrous oxide analgesia involves spinal and supraspinal kappa-opioid receptors.  相似文献   
28.
29.
30.
BACKGROUND: Equilibration of hemoglobin concentration after transfusion has been estimated to take about 24 hours, but some studies have shown that earlier measurements reflect steady-state values in persons who have not bled recently. This study was aimed at assessing the changes over time in hemoglobin concentration after transfusion in acutely anemic patients because of recent bleeding. STUDY DESIGN AND METHODS: Thirty-two normovolemic patients recovering from an acute bleeding episode who were no longer thought to be bleeding and who received a 2- unit red cell transfusion were studied. At baseline and 15, 30, 60, and 120 minutes and 24 hours after transfusion, hemoglobin concentration and hematocrit values were measured. RESULTS: The administration of 2 units of packed red cells elicited a 24-hour increase of 22.4 +/− 6.8 g per L in hemoglobin concentration. Hemoglobin values were not different at any of the defined posttransfusion times. Hematocrit levels experienced similar changes over time. Agreement between 15-minute and 24-hour values was excellent, as only 6 percent of patients exhibited a clinically significant difference (> 6 g/L) between the hemoglobin measurements. CONCLUSION: Hemoglobin and hematocrit values rapidly equilibrate after transfusion in normovolemic patients who are recovering from an acute bleeding episode. This fact would allow a rapid assessment of the effects of transfusion and of the recurrence of bleeding in patients remaining at risk.  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