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   33733篇
  免费   3715篇
  国内免费   448篇
耳鼻咽喉   737篇
儿科学   1632篇
妇产科学   387篇
基础医学   2160篇
口腔科学   807篇
临床医学   7027篇
内科学   3157篇
皮肤病学   225篇
神经病学   2226篇
特种医学   643篇
外科学   3083篇
综合类   3671篇
预防医学   5649篇
眼科学   272篇
药学   4238篇
  143篇
中国医学   1065篇
肿瘤学   774篇
  2024年   49篇
  2023年   665篇
  2022年   913篇
  2021年   1616篇
  2020年   2333篇
  2019年   1862篇
  2018年   1697篇
  2017年   1475篇
  2016年   1567篇
  2015年   1539篇
  2014年   2363篇
  2013年   3256篇
  2012年   1693篇
  2011年   1776篇
  2010年   1425篇
  2009年   1515篇
  2008年   1518篇
  2007年   1428篇
  2006年   1209篇
  2005年   986篇
  2004年   839篇
  2003年   714篇
  2002年   577篇
  2001年   536篇
  2000年   548篇
  1999年   421篇
  1998年   363篇
  1997年   340篇
  1996年   234篇
  1995年   203篇
  1994年   171篇
  1993年   186篇
  1992年   174篇
  1991年   113篇
  1990年   140篇
  1989年   107篇
  1988年   116篇
  1987年   122篇
  1986年   87篇
  1985年   155篇
  1984年   133篇
  1983年   75篇
  1982年   100篇
  1981年   100篇
  1980年   102篇
  1979年   74篇
  1978年   68篇
  1977年   58篇
  1976年   59篇
  1975年   33篇
排序方式: 共有10000条查询结果,搜索用时 639 毫秒
101.
Buprenorphine is a mu opioid partial agonist currently used as an analgesic, and being developed for the treatment of opioid dependence. The purpose of this study was to determine the abuse liability of parenteral buprenorphine in volunteers maintained on daily sublingual (SL) buprenorphine (8 mg). In a residential laboratory, eight volunteers underwent pharmacologic challenges two times per week. Medication challenges were 16 h after the daily dose of buprenorphine, and consisted of double-blind IM injections of buprenorphine (4, 8, 16 mg), the prototypic mu opioid agonist hydromorphone (9 and 18 mg), or saline. Assessments consisted of physiologic monitoring, subjects’ self-reports, and a trained observer’s ratings of drug effects, and were collected for 0.5 h before and 2.0 h following injection. Supplemental doses of IM buprenorphine produced opioid agonist-like effects, indicating some abuse potential of parenteral buprenorphine in buprenorphine-maintained patients. There was incomplete cross-tolerance to the effects of hydromorphone, suggesting that higher maintenance doses of buprenorphine may be needed to maximize clinical efficacy. However, there was a lack of graded dose-effects for hydromorphone, suggesting that buprenorphine’s combination of partial agonist effects and high affinity for opioid receptors may limit the magnitude of effects of supplemental full agonists. Finally, participants tolerated cumulative doses of maintenance buprenorphine plus challenge buprenorphine without adverse effects, suggesting higher doses of buprenorphine can be safely administered to opioid dependent patients. Received: 22 February 1996/Final version: 23 August 1996  相似文献   
102.
We report on 7 patients (6 M, 1 F) with Coffin-Lowry syndrome who have a sensorineural hearing deficit in addition to developmental delay and characteristic facial changes. One of the patients also had a history of premature exfoliation of primary teeth. These are previously unappreciated clinical signs that may aid in the early diagnosis of Coffin-Lowry syndrome. Early diagnosis and recognition of a hearing deficit in the patient can lead to the use of hearing aids to help the patient achieve his or her full potential. These “;new”; clinical manifestations expand the phenotype of Coffin-Lowry syndrome and constitute an additional indication of pleiotropy. © 1993 Wiley-Liss, Inc.  相似文献   
103.
We compared nicotine dependence and withdrawal in male alcoholic and control ever-smokers, controlling for relevant demographic and clinical variables. Alcoholics were more likely to meet criteria for moderate or severe nicotine dependence and endorse more nicotine dependence symptoms. Symptoms reported more frequently by alcoholics included: (a) using nicotine in larger amounts or over a longer time than intended; (b) continued use despite problems caused or exacerbated by nicotine; (c) marked tolerance; and (d) experiencing characteristic nicotine withdrawal symptoms. Alcoholics also smoked more heavily. Other than “headaches,” and “decreased heart rate,” alcoholics consistently endorsed nicotine withdrawal symptoms at a higher rate. After controlling for demographic and clinical variables and level of nicotine dependence, only “feel depressed” differed significantly between groups. Our research supports previous findings suggesting that nicotine dependence is more severe in those with a history of alcohol dependence. As a result, alcoholics may experience greater discomfort from nicotine withdrawal upon smoking cessation.  相似文献   
104.
105.
Background.Physical inactivity is recognized as an important public health issue. Yet little is known about doctors' knowledge, attitude, skills, and resources specifically relating to the promotion of physical activity. Our survey assessed the current practice, perceived desirable practice, confidence, and barriers related to the promotion of physical activity in family practice.Methods.A questionnaire was developed and distributed to all 1,228 family practitioners in Perth, Western Australia.Results.We received a 71% response (n= 789). Family practitioners are most likely to recommend walking to sedentary adults to improve fitness and they are aware of the major barriers to patients participating in physical activity. Doctors are less confident at providing specific advice on exercise and may require further skills, knowledge, and experience. Although they promote exercise to patients through verbal advice in the consultation, few use written materials or referral systems.Conclusions.There are significant differences between self-reports of current practice and perceived desirable practice in the promotion of physical activity by doctors. Future strategies need to address the self-efficacy of family physicians and involve resources of proven effectiveness. The potential of referral systems for supporting efforts to increase physical activity by Australians should be explored.  相似文献   
106.
107.
108.
The development of a unifying framework for conceptualizing the commonalities in various forms of substance abuse must encompass the data base focused upon the stimulus functions of drugs. In the first instance, for example, the research on drug self-administration has provided convincing evidence of a remarkable concordance between laboratory animals and human substance abusers in the reinforcing stimulus functions of a range of chemical agents. The recognition of these cross-species and cross-drug generalities has radically changed conceptualizations of substance abuse from a reactive to a more active process and has encouraged the kind of functional analysis of drug-seeking and drug-taking that has proven productive and useful in the study of other behavioral interactions. In this regard as well, recent refinements in the analysis of the discriminative stimulus functions of drugs have provided a more comprehensive basis for characterizing a chemical agent's spectrum of action and evaluating its abuse liability. While the correlation between the discriminative stimulus functions and the reinforcing stimulus functions is remarkably high for some drug classes, there are notable exceptions. Finally, the assessment of abuse liability requires an analysis of the eliciting stimulus functions of drugs as reflected by the physiological and behavioral changes, both acute and chronic, that follow drug administration. The methods used to evaluate both physiological dependence and behavioral toxicity in relationship to sensory and motor effects for a range of abused drugs have depended heavily upon an assessment of the eliciting stimulus functions of such compounds.  相似文献   
109.
Summary UK health policy requires child and adolescent mental health service providers to demonstrate that their services are effective. The FOCUS project has been developed to improve the availability and accessibility of research evidence and innovation, to support purchasers in the effective commissioning of services and to help providers base service provision on evidence of effectiveness and develop methods of evaluation.  相似文献   
110.
The community-based course presented is a longitudinal course running through four semesters in the Faculty of Medicine, University of Gezira, Sudan. Students combine their regular work in primary health care centres with attachments to a number of families in Wad Medani town. They continue to visit these families regularly throughout their entire medical course with the aim of studying them and helping them with some of their medical and psychosocial problems.  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