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   7947篇
  免费   378篇
  国内免费   193篇
耳鼻咽喉   13篇
儿科学   48篇
妇产科学   23篇
基础医学   624篇
口腔科学   23篇
临床医学   632篇
内科学   896篇
皮肤病学   26篇
神经病学   1198篇
特种医学   112篇
外科学   579篇
综合类   715篇
预防医学   299篇
眼科学   34篇
药学   2981篇
  2篇
中国医学   149篇
肿瘤学   164篇
  2023年   42篇
  2022年   56篇
  2021年   132篇
  2020年   126篇
  2019年   144篇
  2018年   142篇
  2017年   174篇
  2016年   180篇
  2015年   184篇
  2014年   365篇
  2013年   808篇
  2012年   343篇
  2011年   392篇
  2010年   369篇
  2009年   364篇
  2008年   428篇
  2007年   371篇
  2006年   344篇
  2005年   264篇
  2004年   250篇
  2003年   282篇
  2002年   205篇
  2001年   180篇
  2000年   189篇
  1999年   167篇
  1998年   135篇
  1997年   139篇
  1996年   128篇
  1995年   107篇
  1994年   103篇
  1993年   108篇
  1992年   73篇
  1991年   55篇
  1990年   55篇
  1989年   60篇
  1988年   63篇
  1987年   86篇
  1986年   86篇
  1985年   153篇
  1984年   114篇
  1983年   70篇
  1982年   91篇
  1981年   82篇
  1980年   97篇
  1979年   54篇
  1978年   48篇
  1977年   33篇
  1976年   31篇
  1975年   17篇
  1974年   13篇
排序方式: 共有8518条查询结果,搜索用时 15 毫秒
21.
Summary. The first American programme for chemically dependent medical students at the University of Tennessee, Memphis is described. The goals of the Aid for the Impaired Medical Student (AIMS) Program are to provide confidential treatment for chemically dependent medical students, to assure that recovering students are able to resume their education, and to protect patients and others from the harm that may be caused by impaired students. The Program is administered by the AIMS Council, consisting of medical professionals and elected student representatives. The Council oversees the management of cases, including investigation of students who may be impaired, intervention when chemical dependency is suspected, diagnostic evaluation, treatment and aftercare, and post-recovery advocacy for students. The Program's experience includes 18 cases of suspected chemical dependency, with four self-referrals and 14 students referred by third parties. Eleven students have been diagnosed as chemically dependent and have completed treatment programmes. Nine have maintained recovery and eight have graduated. One student subsequently relapsed and committed suicide. Obstacles in programme implementation have involved absence of perceived need, the view that chemically dependent students should be dismissed from school, and reluctance of students to report classmates. Resources have included highly respected student representatives, a supportive administration, assistance of the impaired physicians programme, and medical insurance and professional courtesy to defray costs. Although the number treated has been modest, the AIMS Program is an important vehicle for training students regarding chemical dependency and their professional obligations toward impaired colleagues.  相似文献   
22.
1. The effects of graded doses of the α2-adrenoceptor agonists clonidine, tizanidine and BHT-920, and the α2-adrenoceptor antagonists yohimbine and idazoxan, on gastrointestinal transit were investigated in mice using the charcoal meal test. 2. The agonists produced significant and dose-dependent decreases in gastrointestinal transit, and the antagonists produced the opposite effect. In affecting the gastrointestinal transit, clonidine (1 mg/kg) was as effective as tizanidine (12 mg/kg) and BHT-920 (40 mg/kg), while yohimbine (2 mg/kg) was as effective as idazoxan (1 mg/kg). 3. Morphine (2, 4 and 8 mg/kg) significantly inhibited gastrointestinal transit. This effect was significantly reversed by the co-administration of yohimbine (2 mg/kg) and idazoxan (1 mg/kg). 4. The acute administration of glucose (5.04 g/kg, i.p.) potentiated the inhibition of gastrointestinal transit produced by clonidine (1 mg/kg) and BHT-920 (40 mg/kg). Glucose treatment, however, had no significant effect on the increase in gastrointestinal transit induced by yohimbine (2 mg/kg) or idazoxan (1 mg/kg). 5. Castor oil (0.25 mL/mouse, orally) induced diarrhoea in saline-treated animals within about 45 min. Clonidine (1 mg/kg), tizanidine (12 mg/kg) and BHT-920 (40 mg/kg) delayed the occurrence of diarrhoea to 2.1, 1.2 and 1.4 h, respectively.  相似文献   
23.
This cross-sectional study used a semi-automated analysis technique to quantify regional brain cerebrospinal fluid (CSF) volumes derived from computed tomography (CT) in 84 healthy men ranging from 21 to 82 years of age and 28 patients meeting Research Diagnostic Criteria for alcohol dependence. The goals were to replicate an earlier CT study of an independent sample of alcoholic and control subjects (Pfefferbaum et al., 1988a; Zipursky et al., 1988) and to compare CT assessments of brain changes with magnetic resonance imaging (MRI) assessments made in the same alcoholic patients (Pfefferbaum et al., 1992). Regional brain changes associated with normal aging were derived by regression analysis, using CT data collected from the healthy control subjects. As in the earlier CT study and in the concurrent MRI study, ventricular and sulcal CSF volumes in alcoholic patients were greater than would be expected for their age. Furthermore, the present CT study replicated the previous CT and MRI findings of a positive relationship between age and CSF volume enlargement in alcoholic patients over and above the normal age-related increase in CSF volume, suggesting greater vulnerability of the aging brain to alcohol. Comparison of CT-and MRI-derived estimates of ventricular and cortical sulcal volume revealed high correlations (>0.80). MRI and CT produced similar absolute ventricular volumes, while MRI produced larger sulcal volume estimates than did CT. The difference in sulcal volume estimate may be due to differences between CT and MRI in slice thickness and sensitivity to partial volume effects.  相似文献   
24.
In the 19th century, investigators recognized that addiction to opiates involves tolerance and dependence. In the United States, the National Academy of Sciences and the Public Health Service initiated systematic investigations into opiate addiction in 1929. Tolerance and dependence to morphine, the prototype for opiate drugs, were the emphasis of human studies for the next fifty years. This presentation highlights salient features of tolerance and dependence learned in these studies and relates these findings to clinical use in treating pain.  相似文献   
25.
2-chloroprocaine antagonism of epidural morphine analgesia   总被引:2,自引:0,他引:2  
Background: 2-chloroprocaine (2-CP) used for lumbar epidural anesthesia (LEA) reportedly decreases the efficacy of epidural morphine (EM) administered for post-cesarean section (CS) analgesia. The amount of supplemental i.v. morphine self-administered by the patient via the patient-controlled analgesia device (PCA) is used to study the interaction between EM and 2-CP.
Methods: Forty-two patients scheduled for elective CS were randomly divided into 3 equal groups, and received 2-CP, 2-CP+epinephrine (Epi, 5 μg ml-1) or 2% lidocaine (Lido) with Epi for LEA. All patients received 5 mg EM and i.v. PCA morphine for postoperative pain. Cumulative amount of i.v. morphine used in the first 24 hours as well as the amount of the drug used during each 2-h period were noted. Nonparametric analysis of variance and Chi-squared analysis were used for statistical comparisons.
Results: The mean cumulative 24-h i.v. PCA morphine requirement in the 2-CP, 2-CP+Epi and Lido+Epi groups respectively was 20.5±24, 33.1.5±27 and 4.07±6.3 (mean±SD). The Lido+Epi group used significantly less morphine ( P = 0.01) compared to either of the 2-CP groups with no significant difference between the 2-CP groups. The maximum i.v. PCA morphine use occurred in the first 4 hours following surgery in all three groups.
Conclusion: Analgesic efficacy of EM is decreased when 2-CP is used for LEA compared to when Lido+Epi is used.  相似文献   
26.
姜树军  胡三觉 《医学争鸣》1994,15(2):112-115
作利用复合致痛剂引起大鼠尾部皮肤多觉型伤害性感受器(PMN)持续性放电模型,经股静脉注入吗啡(4mg/kg),显抑制PMN持续性放电。吗啡抑制PMN放电50%的潜伏期为10±4.5min,抑制时程超过30min。纳络酮1mg/mg iv,可翻转吗啡的抑制作用。在慢性吗啡耐受大鼠,吗啡几乎失去其抑制作用。吗啡引起的PMN放电数变化不呈一致关系。小剂量吗啡(1mg/kg)注入支配感受野皮肢的尾动脉  相似文献   
27.
呋喃唑酮合并认知行为疗法治疗酒依赖对照研究   总被引:3,自引:0,他引:3  
目的:评价呋喃唑酮合并认知行为疗法对酒依赖的治疗效果。方法:将55例酒依赖患者随机分为两组,联合治疗组给予呋喃唑酮合并认知行为治疗,呋喃唑酮组单用呋喃唑酮治疗,应用临床疗效标准及酒依赖严重程度问卷(SADQC)定期评定。疗程6个月。结果:在治疗1、2、4个月和6个月时,联合治疗组疗效显著优于呋喃唑酮组,尤其是对情感性戒断症状疗效更好。结论:呋喃唑酮合并认知行为疗法治疗酒依赖效果优于单用呋喃唑酮治疗。  相似文献   
28.
29.
目的了解海洛因依赖者脱毒时伴发意识障碍与苯二氮  相似文献   
30.
Abstract: The development of a teaching package for nurse educators on drug and alcohol problems is described and the contents of its 16 modules outlined.  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