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   2425篇
  免费   226篇
  国内免费   6篇
耳鼻咽喉   16篇
儿科学   74篇
妇产科学   66篇
基础医学   324篇
口腔科学   12篇
临床医学   438篇
内科学   432篇
皮肤病学   33篇
神经病学   305篇
特种医学   52篇
外科学   217篇
综合类   20篇
预防医学   309篇
眼科学   35篇
药学   169篇
中国医学   1篇
肿瘤学   154篇
  2023年   16篇
  2022年   13篇
  2021年   56篇
  2020年   37篇
  2019年   74篇
  2018年   62篇
  2017年   44篇
  2016年   59篇
  2015年   73篇
  2014年   88篇
  2013年   132篇
  2012年   167篇
  2011年   166篇
  2010年   95篇
  2009年   109篇
  2008年   162篇
  2007年   193篇
  2006年   171篇
  2005年   154篇
  2004年   131篇
  2003年   126篇
  2002年   120篇
  2001年   21篇
  2000年   21篇
  1999年   23篇
  1998年   29篇
  1997年   25篇
  1996年   18篇
  1995年   13篇
  1994年   19篇
  1993年   13篇
  1992年   13篇
  1991年   7篇
  1990年   12篇
  1989年   13篇
  1988年   11篇
  1987年   8篇
  1986年   15篇
  1985年   12篇
  1983年   10篇
  1982年   11篇
  1981年   7篇
  1980年   12篇
  1979年   8篇
  1978年   9篇
  1977年   9篇
  1976年   7篇
  1975年   6篇
  1973年   6篇
  1971年   4篇
排序方式: 共有2657条查询结果,搜索用时 15 毫秒
11.
The greater trochanter pain syndrome refers to pain on the lateral aspect of the hip joint. This is frequently attributed to trochanteric bursitis and distension of the subgluteal bursae. Associated tears of the tendons of gluteus medius and minimus have been described and may result from repetitive frictional trauma to these tendons and their associated bursae secondary to impingement beneath the tensor fascia lata. Occasionally tendinous damage may result from acute local direct trauma or a hyperadductive strain injury. We describe MRI in two patients with chronic lateral hip pain.  相似文献   
12.
Although Acinetobacter is usually a species of low virulence, it is becoming increasingly more important as a cause of hospital outbreaks, particularly on intensive care units. Antibiotic resistance can develop rapidly. This organism has not been reported to cause skin abscesses previously. We describe a case of a neonate who developed an Acinetobacter abscess on our neonatal intensive care unit.  相似文献   
13.
1. The effects of calcitonin gene-related peptide (CGRP) and other vasoactive mediators of inflammation on blood flow in the synovial vessels and plasma protein extravasation into the knee (femoro-tibial) joint of the pentobarbitone-anaesthetized rat were measured. 2. Changes in synovial blood flow were estimated by 133xenon clearance from the synovial cavity. CGRP (0.1 pmol and 10 pmol) and prostaglandin E1 (PGE1; 3 pmol and 300 pmol) significantly increased clearance from the knee joint measured 5 min after intra-articular injection. Substance P (10 pmol) had no effect on synovial blood flow. 3. Intra-articular perfusion of the rat knee with CGRP at concentrations up to 0.1 mM, or PGE1 at concentrations up to 10 microM, did not increase plasma extravasation into the synovial cavity measured by accumulation of intravenously injected 125I-albumin in the perfusate. 4. Plasma extravasation into the knee was significantly increased by infusion of bradykinin (0.1 microM), 5-hydroxytryptamine (1 microM) and histamine (0.1 mM), compared with the contralateral joints in the same animals which were perfused with Tyrode solution. 5. Perfusion of the knee joint with substance P did not specifically induce 125I-labelled albumin accumulation in the synovial cavity even at doses that had systemic effects as observed by marked plasma extravasation into other tissues. 6. The increase in plasma extravasation induced by histamine (0.1 mM) was potentiated by co-infusion with CGRP (0.1 microM) and PGE1 (3 microM). However the response to a submaximal dose (0.1 microM) of bradykinin, which induced similar plasma extravasation to histamine (0.1 mM), was not increased by co-infusion with CGRP or PGE1.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
14.
OBJECTIVE: Throughout health care literature, vulnerability is widely accepted as a potential issue for all patients yet the consensus on the meaning of and practical strategies to reduce or manage these 'harmful agents' in the clinical context are rarely offered. Three main themes emerge from the related literature which can be further refined into general terms of; social vulnerability--a person's basic statistical data in relation to their potential for illness; psychological vulnerability--the actual or potential harm to the identity of self and/or other emotional effects such as anxiety or stress caused by the ailment or treatment; and physical vulnerability--which refers to the actual physiological state where an individual is susceptible to further morbidity or mortality. SETTING: Acute care facilities. PRIMARY ARGUMENT: Although there is acknowledgment within the literature that individuals will experience some form of vulnerability when hospitalised, the complexity of what defines vulnerability for individuals causes further problems for patients and health professionals alike. CONCLUSIONS: This paper attempts to define vulnerability within the context of Western health care systems and raises the following issues: all states of vulnerability are accurate and appropriate in the context of the study or incidence alluded to, but further discussion and research is required to achieve a consensus to when, how, why and who is vulnerable. It is this recognition of the potentially differing classifications of vulnerability and the particular contexts that can be used that may assist nurses and other health care professionals with, not only problems associated with a patient's hospitalisation, but in the implementation of appropriate strategies to individual patient's cases.  相似文献   
15.
This survey investigated the prevalence of men with learning disabilities who have sex with men in public places in three south east London boroughs. The work was administered through contact with providers of services for people with leaming disabilities and was commissioned by the local health authority. It represents the first example of needs assessment work on this theme. Service responses to risk assessment and risk management in relation to HIV and the sexual behaviour of male service users were explored. The survey identified 13 services where this was a management or practice issue, and 16 and 18 men for whom this behaviour definitely or possibly applied. This paper reports the findings of the survey and identifies issues relevant to commissioning and providing services for people with learning disabilities.  相似文献   
16.
The primary lesion in rheumatoid arthritis (RA) is a destructive synovitis characterized by proliferation of endothelial cells, fibroblasts, and vascular smooth muscle cells, and with perivascular lymphocyte aggregates. A nonhematopoietic growth factor, acidic fibroblast growth factor (aFGF), may induce many of the biological features found in rheumatoid synovium, including T cell activation. To determine if aFGF-responsive T cells are increased in RA, we developed an assay to measure the frequency of peripheral blood T cells that are costimulated by aFGF. The data indicate that the frequency of aFGF-responsive T cells is increased in RA and may change with disease activity and treatment.  相似文献   
17.
18.
Antibody-antigen cross-reactions were examined with sera from patients with Escherichia coli O157 infection and lipopolysaccharide (LPS) purified from a range of enterohaemorrhagic E. coli (EHEC) including those belonging to serogroups O26, O103, O111, O145 and O157. Six of 10 patients infected with an O157 EHEC produced serum antibodies that cross-reacted with common LPS-core epitopes, which were expressed by 23 of 33 strains of EHEC examined. These common LPS-core epitopes were also present on strains of E. coli O26 which did not produce verocytotoxin. These cross-reacting antibodies did not influence the basic immunoblotting procedures used for the routine serodiagnosis of infections with E. coli O157.  相似文献   
19.
This is the first report of a naturally occurring Salmonella that is urea positive. The strain was identified as Salmonella cubana and it was typical in all biochemical, serological, and bacteriophage reactions, except that is produced urease strongly.  相似文献   
20.
The structural changes of the Z-line between small square net (ss) and basket weave (bw) cross-sectional patterns were examined using intact single fibers and mechanically skinned fibers in the passive state to determine if the pattern is related to the sarcomere length (SL) and if the pattern undergoes a reversible transition in low- and high-osmotic medium.Frog single fibers were isolated from the anterior tibial muscle in Ringer's solution. Entirely or partially skinned single fibers were prepared in relaxing solution (also called low-osmotic medium).The high osmotic medium contained 10% polyvinylpyrrolidone (PVP) in relaxing solution.The sarcomere length (SL) of each fiber was measured directly by use of a laser beam or indirectly from electron micrographs with use of a correction factor. The ss and bw forms in cross sections were quantified by analysis of electron micrographs. The results show that the structural change of Z-line occurs around bw 2.3–2.4m ss (n = 25) and bw 3.1–3.2m ss (n = 13) in intact single fibers and skinned fibers, respectively. With the quick freeze-freeze substitution method, an intact single fiber with a SL of 2.35m showed almost 100% of ss form. The structural transition in cross section was also confirmed in four partially skinned fibers, where patterns went from mostly ss form (intact portion) to mostly bw form (skinned portion) at the SL between 2.40 to 3.20m.The reversibility of the change between ss and bw was proved by using low- and high-osmotic medium. The transition and reversion of cross-sectional patterns both occur in the passive state.  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