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   1702篇
  免费   82篇
  国内免费   11篇
耳鼻咽喉   14篇
儿科学   81篇
妇产科学   41篇
基础医学   234篇
口腔科学   23篇
临床医学   233篇
内科学   300篇
皮肤病学   15篇
神经病学   119篇
特种医学   57篇
外科学   142篇
综合类   24篇
预防医学   237篇
眼科学   40篇
药学   153篇
中国医学   7篇
肿瘤学   75篇
  2023年   5篇
  2022年   19篇
  2021年   39篇
  2020年   21篇
  2019年   22篇
  2018年   36篇
  2017年   25篇
  2016年   32篇
  2015年   47篇
  2014年   48篇
  2013年   80篇
  2012年   138篇
  2011年   138篇
  2010年   65篇
  2009年   48篇
  2008年   115篇
  2007年   118篇
  2006年   121篇
  2005年   123篇
  2004年   115篇
  2003年   92篇
  2002年   103篇
  2001年   16篇
  2000年   17篇
  1999年   13篇
  1998年   12篇
  1997年   16篇
  1996年   9篇
  1995年   9篇
  1994年   4篇
  1993年   8篇
  1992年   11篇
  1991年   3篇
  1990年   9篇
  1989年   9篇
  1988年   8篇
  1987年   4篇
  1986年   9篇
  1985年   4篇
  1984年   10篇
  1983年   12篇
  1982年   6篇
  1981年   14篇
  1980年   3篇
  1979年   3篇
  1978年   5篇
  1975年   6篇
  1974年   5篇
  1968年   3篇
  1966年   2篇
排序方式: 共有1795条查询结果,搜索用时 15 毫秒
1.
2.
OBJECTIVE: Restraint use is not monitored in the US, and only institutions that choose to do so collect statistics. In 1999, investigative journalists reported lethal consequences proximal to restraint use, making it a life-and-death matter that demands attention from professionals. This paper reviews the literature concerning actual and potential causes of deaths proximal to the use of physical restraint. METHOD: Searching the electronic databases Medline, Cinahl, and PsycINFO, we reviewed the areas of forensics and pathology, nursing, cardiology, immunology, psychology, neurosciences, psychiatry, emergency medicine, and sports medicine. CONCLUSIONS: Research is needed to provide clinicians with data on the risk factors and adverse effects associated with restraint use, as well as data on procedures that will lead to reduced use. Research is needed to determine what individual risk factors and combinations thereof contribute to injury and death.  相似文献   
3.
To conduct a formative and pilot impact evaluation of the State Technical Assessment Team (STAT) program, a visitation-based (visitatie) peer assessment program designed to enhance the organizational capacity of state health department injury prevention programs. The formative evaluation was based on observational, record review, and key informant interview data collected during the implementation of the first 7 STAT visits. Pilot impact data were derived from semi-structured interviews with state injury prevention personnel one year after the visit. Formative evaluation identified 6 significant implementation problems in the first visits that were addressed by the program planners, resulting in improvements to the STAT assessment protocol. Impact evaluation revealed that after one year, the 7 state injury prevention programs had acted on 81% of the recommendations received during their STAT visits. All programs reported gains in visibility and credibility within the state health department and increased collaboration and cooperation with other units and agencies. Other significant program advancements were also reported. Specific program standards and review procedures are important to the success of peer assessment programs such as STAT. Early impact evaluation suggests that peer assessment protocols using the visitatie model can lead to gains in organizational capacity.  相似文献   
4.
Alprazolam, a new benzodiazepine from triazolobenzodiazepine group, produced anxiolytic action in the conflict test with potency similar to that of diazepam. The myorelaxant activity of the drug was relatively weak. Unlike desipramine, alprazolam failed to reduce the immobility of rats in the forced swim test and was unable to prevent clonidine-induced hypothermia. Alprazolam, unlike desipramine, failed also to potentiate behavioral effect of noradrenaline injected into the hippocampus. Alprazolam after acute but not chronic administration antagonized the synchronizing effect of clonidine on EEG pattern. On the other hand, alprazolam similarly to tricyclic antidepressants, prevented the suppression of dominance behavior by clonidine in rats competing for food. The results indicate that alprazolam acts only weakly upon noradrenergic mechanisms related to depression and to antidepressant action of drugs.  相似文献   
5.
Superoxide dismutase (SOD) content estimated by rocket immunoelectrophoresis did not differ in various density (age) fractions of bovine erythrocytes though its specific activity decreased with increasing cell density. No changes were found, either, in the crossed immunoelectrophoretic pattern of SOD with increasing red cell age. Effects of different denaturing agents on the immunoelectrophoretic pattern and activity of the enzyme were compared, including H2O2 and free radicals generated by ionizing radiation. The yield for inactivation was higher than that for loss of antigenic properties in all cases studied which could correspond to the in vivo situation. However, changes in electro-phoretic mobility were revealed for all the denaturing agents, which is contrary to a main causative role of these agents in the in vivo inactivation of SOD. The results suggest spontaneous “subtle denaturation” as a chief cause for the SOD inactivation during erythrocyte aging.  相似文献   
6.
Many information systems have failed when deployed into complex health-care settings. We believe that one cause of these failures is the difficulty in systematically accounting for the collaborative and exception-filled nature of medical work. In this methodological review paper, we highlight research from the field of computer-supported cooperative work (CSCW) that could help biomedical informaticists recognize and design around the kinds of challenges that lead to unanticipated breakdowns and eventual abandonment of their systems. The field of CSCW studies how people collaborate with each other and the role that technology plays in this collaboration for a wide variety of organizational settings. Thus, biomedical informaticists could benefit from the lessons learned by CSCW researchers. In this paper, we provide a focused review of CSCW methods and ideas-we review aspects of the field that could be applied to improve the design and deployment of medical information systems. To make our discussion concrete, we use electronic medical record systems as an example medical information system, and present three specific principles from CSCW: accounting for incentive structures, understanding workflow, and incorporating awareness.  相似文献   
7.
Chondroconductive potential of tantalum trabecular metal   总被引:2,自引:0,他引:2  
Mesenchymal stem cells or chondrocytes have been implanted into joints in biodegradable matrices in order to improve the quality of healing cartilage defects; however, insufficient biomechanical strength of the construct at implantation is a limiting factor for clinical application. Logically, a construct with better biomechanical characteristics would provide better results. Tantalum trabecular metal (TTM) is osteoconductive and mechanically similar to subchondral bone. The objective of this pilot study was to determine if TTM is also chondroconductive. Small sections of TTM were cultured with emu and canine chondrocytes in static and dynamic culture environments. The sections cultured in dynamic bioreactors were diffusely covered with a cartilaginous matrix. Sections cultured in static conditions had no growth. Histologic evaluation from emu and canine dynamic cultures showed tissue that was heavily populated with mesenchymal cells that resembled chondrocytes, and glycosaminoglycan staining that was distributed throughout the matrix. Type II collagen content in the canine dynamic culture was 84% by SDS-PAGE. Tantalum trabecular metal is chondroconductive in vitro in a dynamic environment when cultured with adult canine or emu chondrocytes. This technology could be expanded to determine if cartilaginous-metallic constructs may be used for joint resurfacing of osteoarthritic joints.  相似文献   
8.
BACKGROUND: Montelukast is a leukotriene antagonist approved for the treatment of childhood asthma in children age 2 years and older. There are limited studies on its effects on allergic asthma in children. OBJECTIVE: We sought to evaluate montelukast's effects on upper and lower airway responses to intense cat allergen exposure. METHODS: In a double-blind, placebo-controlled, cross-over trial 18 subjects aged 6 to 14 years with cat-induced asthma were randomly assigned to receive 1 week each of either montelukast or placebo, followed by a 1-hour cat challenge in an environmental exposure unit. Upper and lower respiratory tract symptoms were rated, and spirometry and acoustic rhinometry were performed. Challenges were stopped early if the subject became too uncomfortable or had a greater than 50% decrease in FEV1. RESULTS: Overall changes in FEV1 were significantly different with montelukast treatment and remained significant after adjusting for allergen level (P =.02; adjusted P =.01). Lower respiratory tract symptom scores were significantly reduced with montelukast versus placebo (P =.007) but lost significance after adjusting for allergen level (P =.16). Challenge length was significantly longer with montelukast versus placebo (P <.001) and remained significant after adjusting for allergen level (P =.019). Montelukast did not significantly affect upper respiratory responses, as measured by means of symptom scores (P =.43) and changes in acoustic rhinometry (P =.078). CONCLUSIONS: Montelukast was significantly more effective than placebo in attenuating lower respiratory responses and extending challenge length when cat-sensitive children with mild persistent asthma were exposed to high levels of cat allergen.  相似文献   
9.
Genomic imprinting of rye origin rDNA sequences in triticale is modulated by DNA methylation responsible for ontogenic expression patterns of those sequences. Considering the dynamic nature of these phenomena, we evaluated the influence of plant development on the inheritance of modified rye rDNA expression patterns. DNA hypomethylation was induced in triticale by 5-azacytidine (5AC) treatments at distinct developmental stages of M1 plants, and expression patterns were analysed in M2. The activity of rye origin rRNA genes in progeny of untreated and 5AC-treated plants was evaluated by silver staining in meristematic root tip cells and in meiocytes at diplotene. In the progeny of 5AC-treated plants, a significant increase in rye rDNA expression was observed, contrasting with the residual activity in untreated plants. Significant differential effects of 5AC treatments were observed in M2 plants and correlated with the M1 plant developmental stage in which DNA hypomethylation was induced. Hypotheses to explain the origin of those differences are discussed here.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   
10.
ObjectivesThe objective of this study was to assess the performance of models of primary healthcare (PHC) delivered in First Nation and adjacent communities in Manitoba, using hospitalization rates for ambulatory care sensitive conditions (ACSC) as the primary outcome.MethodsWe used generalized estimating equation logistic regression on administrative claims data for 63 First Nations communities from Manitoba (1986–2016) comprising 140,111 people, housed at the Manitoba Centre for Health Policy. We controlled for age, sex, and socio-economic status to describe the relationship between hospitalization rates for ACSC and models of PHC in First Nation communities.ResultsHospitalization rates for acute, chronic, vaccine-preventable, and mental health-related ACSCs have decreased over time in First Nation communities, yet remain significantly higher in First Nations and remote non-First Nations communities as compared with other Manitobans. When comparing different models of care, hospitalization rates were historically higher in communities served by health centres/offices, whether or not supplemented by itinerant medical services. These rates have significantly declined over the past two decades.ConclusionLocal access to a broader complement of PHC services is associated with lower rates of avoidable hospitalization in First Nation communities. The lack of these services in many First Nation communities demonstrates the failure of the current Canadian healthcare system to meet the need of First Nation peoples. Improving access to PHC in all 63 First Nation communities can be expected to result in a reduction in ACSC hospitalization rates and reduce healthcare cost.  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