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   4349篇
  免费   391篇
  国内免费   13篇
耳鼻咽喉   21篇
儿科学   108篇
妇产科学   171篇
基础医学   633篇
口腔科学   119篇
临床医学   766篇
内科学   765篇
皮肤病学   53篇
神经病学   356篇
特种医学   133篇
外科学   394篇
综合类   66篇
一般理论   5篇
预防医学   430篇
眼科学   98篇
药学   299篇
中国医学   2篇
肿瘤学   334篇
  2021年   52篇
  2020年   25篇
  2019年   74篇
  2018年   81篇
  2017年   46篇
  2016年   54篇
  2015年   78篇
  2014年   110篇
  2013年   189篇
  2012年   235篇
  2011年   257篇
  2010年   146篇
  2009年   128篇
  2008年   238篇
  2007年   269篇
  2006年   254篇
  2005年   283篇
  2004年   234篇
  2003年   221篇
  2002年   206篇
  2001年   83篇
  2000年   99篇
  1999年   70篇
  1998年   58篇
  1997年   45篇
  1996年   54篇
  1995年   36篇
  1994年   33篇
  1993年   43篇
  1992年   77篇
  1991年   57篇
  1990年   69篇
  1989年   54篇
  1988年   47篇
  1987年   35篇
  1986年   41篇
  1985年   46篇
  1984年   38篇
  1983年   43篇
  1982年   44篇
  1981年   31篇
  1980年   31篇
  1979年   30篇
  1978年   27篇
  1977年   25篇
  1976年   23篇
  1975年   31篇
  1973年   24篇
  1972年   28篇
  1968年   23篇
排序方式: 共有4753条查询结果,搜索用时 0 毫秒
21.
Prednisone-Free Maintenance Immunosuppression—A 5-Year Experience   总被引:1,自引:0,他引:1  
Concern persists that prednisone-free maintenance immunosuppression in kidney transplant recipients will be associated with an increase in late allograft dysfunction and graft loss. We herein report 5-year follow-up of a trial of prednisone-free maintenance immunosuppression. From October 1, 1999, through January 31, 2005, at our center, 589 kidney transplant recipients were treated with a protocol incorporating discontinuation of their prednisone on postoperative day 6. At 5 years, actuarial patient survival was 91%; graft survival, 84%; death-censored graft survival, 92%; acute rejection-free graft survival, 84% and chronic rejection-free graft survival, 87%. The mean serum creatinine level (+/-SD) at 1 year was 1.6 +/- 0.6; at 5 years, 1.7 +/- 0.8. In all, 86% of kidney recipients with functioning grafts remain prednisone-free as of April 30, 2005. As compared with historical controls, recipients on prednisone-free maintenance immunosuppression had a significantly lower rate of a number of complications, including cataracts (p < 0.001), posttransplant diabetes mellitus (p < 0.001), avascular necrosis (p = 0.001), and fractures (p = 0.004). We conclude that prednisone-related side effects can be minimized in a protocol incorporating prednisone-free maintenance immunosuppression. Five-year graft outcome remains good.  相似文献   
22.
23.
Purpose: The purposes of this survey were to identify the current participation in Continuing Professional Development (CPD) of radiographers in the South and West Regional Health Authority (SWRHA), and to invite them to comment on issues related to CPD activities.Methods: A questionnaire was sent to 1686 diagnostic and therapy radiographers in the SWRHA. This was designed to gain a profile of those radiographers currently practising and their participation in, and comments on, CPD activities.Results: A response rate of 51% was achieved, although only 634 questionnaires were used for the final analysis. The population of radiographers who responded were predominantly diagnostic, in the age range 26–45 years, female and employed on a full-time basis. Most respondents did not hold any post-registration qualifications, and only 149 respondents were involved in formal studies. Most respondents were involved in statutory CPD activities such as resuscitation and manual lifting, and fewer, although a majority, were involved in activities associated with changing roles and developing new competencies. Other CPD activities which respondents considered as benefiting their professional role were wide ranging. Most of the issues raised concerning CPD related to provision, support and funding.Conclusions: The challenge for the future is to develop a coherent, progressive and affordable scheme of CPD to meet the needs of individual radiographers, the health services, the patient and the profession.  相似文献   
24.
BACKGROUND: Neuromuscular blocking agents used for therapeutic purposes, such as facilitating mechanical ventilation and relieving life-threatening agitation, paralyze patients but leave them fully conscious. Aggressive sedation or analgesia is necessary to reduce awareness, relieve fear, produce comfort, decrease anxiety, induce unconsciousness, and minimize possible complications such as posttraumatic stress syndrome. Little information is available on the extent to which patients experience awareness during therapeutic paralysis. OBJECTIVES: To determine and describe the remembered experiences of critical care patients who were given neuromuscular blocking agents and sedatives and/or analgesics to facilitate mechanical ventilation, improve hemodynamic stability, and improve oxygenation. METHODS: A phenomenological approach with in-depth interviews with 11 patients was used. Data were analyzed by using the constant comparative approach. RESULTS: A total of 4 themes and 3 subthemes were identified. The first theme was back and forth between reality and the unreal, between life and death; the subtheme was having weird dreams. The second theme was loss of control; the 2 subthemes were (1) fighting or being tied down and (2) being scared. The third theme was almost dying, and the fourth theme was feeling cared for. CONCLUSIONS: Patients can remember having both negative and positive experiences during neuromuscular blockade. Steps to improve the experiences of patients receiving neuromuscular blockers include improving assessment parameters, developing and using sedation/analgesia guidelines, and investing in quality improvement programs to provide assessment of awareness during therapeutic paralysis and follow-up and referral as necessary. Ways to decrease the use of neuromuscular blockers would also be useful.  相似文献   
25.
Cost-effectiveness analysis (CEX) refers to a set of research methods that consider the resources consumed by a medical technology in decisions about how best to use the technology. This analytic method is an evolving, controversial, and often misunderstood field in health services research. The basic set of principles underlying CEA is deceptively simple, but sufficient methodological challenges and controversies exist that have, thus far, limited its use in the development of health policy and in bedside decision making. Nonetheless, neurologists like other specialty groups may feel concerned that the results from such analyses may prove unfavorable to their specialty and the patients they serve. This article reviews the fundamental notions surrounding CEA, provides examples from the literature with particular relevance to the neurological community, and highlights critical issues for neurologists regarding the future of CEA.  相似文献   
26.
Twenty male Sprague-Dawley rats were trained to discriminate pentylenetetrazole (PTZ, 15 mg/kg, intraperitoneally) from saline (SAL) under a drug discrimination procedure. Test sessions were conducted with 10 randomly selected subjects. Tests with various doses of PTZ resulted in a dose-dependent increase in the percentage of total session responses emitted on the PTZ-appropriate lever without a significant change in response rates across a wide range of test PTZ doses. Rats did not generalize the PTZ stimulus to ethanol (ETOH) up to ETOH test doses that completely suppressed responding. High acute ETOH doses (2, 3, and 4 g/kg) administered at various time points prior to discrimination test sessions engendered responding on the PTZ-appropriate level in a quantitative fashion, that was dose- and time-dependent. This acute ETOH delayed effect from these high doses replicates our previously published study using a Drug 1-Drug 2 discrimination task with Chlordiazepoxide and PTZ. More importantly, we suggest that the present behavioral assay may be a sensitive animal analogue of human "hangover" phenomena.  相似文献   
27.
The dog and cat are useful experimental animals, and information regarding their cerebrovascular patterns and the source of blood supplying their brains is important. Blood vessels to brains and heads of cats and dogs were injected with various contrast media. Extracranial and intracranial arteries were studied grossly and in cleared sections. The proximal part of the internal carotid artery is small in the dog and nonfunctional in the cat. The largest single source of arterial blood supplying the brains of these species comes from the maxillary artery over an anastomotic ramus leading to an internal rete mirabile enmeshed in the cavernous sinus. The distal segment of the internal carotid arises from this anastomosis. The brainstem of both animals is supplied by C1 branches of the vertebral arteries, and in the dog an occipital ramus makes a large contribution to it. In addition to an internal rete mirabile, the cat possesses a large external rete mirabile surrounding the maxillary artery and giving rise to all branches in the area. It is functionally equivalent to the ramus anastomoticus in the dog. Arterial patterns over brains of Carnivora are similar. They resemble those of lower mammals more than those of primates. Extensive extracranial arterial anastomoses located in the orbit, retia mirabilia and neck musculature are significant and make it difficult to render the brains ischemic.  相似文献   
28.
PIGQ (OMIM *605754) encodes phosphatidylinositol glycan biosynthesis class Q (PIGQ) and is required for proper functioning of an N‐acetylglucosamine transferase complex in a similar manner to the more established PIGA, PIGC, and PIGH. There are two previous patients reported with homozygous and apparently deleterious PIGQ mutations. Here, we provide the first detailed clinical report of a patient with heterozygous deleterious mutations associated with glycosylphosphatidylinositol‐anchored protein (GPI‐AP) biosynthesis deficiency. Our patient died at 10 months of age. The rare skeletal findings in this disorder expand the differential diagnosis of long bone radiolucent lesions and sphenoid wing dysplasia. This clinical report describes a new and rare disorder—PIGQ GPI‐AP biosynthesis deficiency syndrome.  相似文献   
29.
A newly developed rapid coagglutination test for identifying Haemophilus influenzae type b organisms isolated from clinical specimens correlated 100% with the slide agglutination test but was 100- to 200-fold more sensitive.  相似文献   
30.
UNILATERAL BRAIN DAMAGE AND BILATERAL SKIN CONDUCTANCE LEVELS IN HUMANS   总被引:1,自引:0,他引:1  
Left and right, palmar and dorsal skin conductance levels (SCLs) were obtained from hospital controls, left hemisphere lesion Ss, right hemisphere lesion Ss, and diffuse or bilateral lesion Ss during several experimental conditions involving rest, passive auditory stimulation, motor reactions, and simple “perception”. The unilateral lesion groups generally displayed significantly higher palmar SCLs on the side contralateral to their lesion. Such “laterality” was not demonstrated in dorsal recordings or in the hospital controls or diffuse lesion group. These unilateral lesion groups had higher palmar SCLs during passive stimulation than during rest, motor, or perception phases. Results were discussed in terms of possible neural mechanisms underlying the phenomena.  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