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   3574篇
  免费   273篇
  国内免费   32篇
耳鼻咽喉   10篇
儿科学   110篇
妇产科学   30篇
基础医学   731篇
口腔科学   119篇
临床医学   482篇
内科学   682篇
皮肤病学   145篇
神经病学   173篇
特种医学   340篇
外科学   391篇
综合类   57篇
一般理论   1篇
预防医学   223篇
眼科学   40篇
药学   242篇
中国医学   3篇
肿瘤学   100篇
  2018年   45篇
  2016年   40篇
  2015年   47篇
  2014年   67篇
  2013年   133篇
  2012年   85篇
  2011年   95篇
  2010年   85篇
  2009年   73篇
  2008年   110篇
  2007年   121篇
  2006年   113篇
  2005年   86篇
  2004年   72篇
  2003年   60篇
  2002年   61篇
  2001年   60篇
  2000年   64篇
  1999年   71篇
  1998年   94篇
  1997年   109篇
  1996年   114篇
  1995年   87篇
  1994年   88篇
  1993年   92篇
  1992年   65篇
  1991年   72篇
  1990年   73篇
  1989年   102篇
  1988年   83篇
  1987年   75篇
  1986年   72篇
  1985年   55篇
  1984年   73篇
  1983年   46篇
  1982年   39篇
  1981年   44篇
  1980年   53篇
  1979年   40篇
  1978年   41篇
  1977年   52篇
  1976年   50篇
  1975年   49篇
  1972年   37篇
  1965年   57篇
  1964年   54篇
  1963年   51篇
  1962年   43篇
  1961年   43篇
  1960年   67篇
排序方式: 共有3879条查询结果,搜索用时 15 毫秒
101.
Nodding Syndrome is a poorly understood neurologic disorder of unknown aetiology that affects children and adolescents in Africa. Recent studies have suggested that the head nods are due to atonic seizures and Nodding Syndrome may be classified as probably symptomatic generalised epilepsy. As part of the Ugandan Ministry of Health clinical management response, a multidisciplinary team developed a manual to guide the training of health workers with knowledge and skills to manage the patients. In the absence of a known cause, it was decided to offer symptomatic care. The objective is to relieve symptoms, offer primary and secondary prevention for disability and rehabilitation to improve function. Initial management focuses on the most urgent needs of the patient and the immediate family until ‘stability’ is achieved. The most important needs were considered as seizure control, management of behavioural and psychiatric difficulties, nursing care, nutritional and subsequently, physical and cognitive rehabilitation. This paper summarises the processes by which the proposed guidelines were developed and provides an outline of the specific treatments currently being provided for the patients.  相似文献   
102.
Filaggrin gene (FLG) null mutations are considered associated with atopic dermatitis. This study was conducted to determine the prevalence of FLG null mutations R501X, 2282del4, R2447X and S3247X in the Croatian population and their role in the occurrence of allergic diseases including atopic dermatitis, allergic rhinitis, asthma and allergic contact dermatitis (ACD). Study enrolled 440 freshmen with defined allergic diseases by means of both present symptoms in International Study of Asthma and Allergies in Childhood questionnaire (relevant respiratory and/or skin symptoms) and markers of allergic sensitization (positive skin prick and/or patch test). FLG null mutations were successfully genotyped in 423 students of which 11 (2.6%) were carriers of FLG null mutation: 1/423 (0.2%) was heterozygous for R501X and 10/423 (2.4%) were heterozygous for 2282del4. No carriers of R2447X and S3247X mutations were identified. In wild‐type FLG carriers (412 subjects), atopic dermatitis was present in 45 (11%), allergic rhinitis in 70 (17%) and allergic asthma in 29 (7%) students. Twenty‐five of 393 (7%) patch‐tested wild‐type FLG carriers had ACD. Among 11 FLG null mutation carriers, four had one or more allergic diseases, and five had reported skin symptoms without defined allergic sensitization (positive skin prick test and/or patch test). FLG null mutations were not confirmed as a predictor of analysed allergic diseases, but were confirmed as an independent predictor of skin symptoms (OR 17.19, 95% CI 3.41–86.6, P < 0.001). Our results in general indicate a low frequency of FLG null mutations in the studied Croatian population supporting a theory of a latitude‐dependent distribution of FGL null mutations in Europe, with a decreasing north–south gradient of R501X and 2282del4 mutation frequency. The relation between FLG null mutations and skin disorders was confirmed.  相似文献   
103.
104.
Astrocytes, the star-shaped glial cells, are the most abundant non-neuronal cell population in the central nervous system. They play a key role in modulating activities of neural networks, including those involved in complex motor behaviors. Common marmosets (Callithrix jacchus), the most vocal non-human primate (NHP), have been used to study the physiology of vocalization and social vocal production. However, the neural circuitry involved in vocal production is not fully understood. In addition, even less is known about the involvement of astrocytes in this circuit. To understand the role, that astrocytes may play in the complex behavior of vocalization, the initial step may be to study their structural properties in the cortical and subcortical regions that are known to be involved in vocalization. Here, in the common marmoset, we identify all astrocytic subtypes seen in other primate's brains, including intralaminar astrocytes. In addition, we reveal detailed structural characteristics of astrocytes and perform morphometric analysis of astrocytes residing in the cortex and midbrain regions that are associated with vocal production. We found that cortical astrocytes in these regions illustrate a higher level of complexity when compared to those in the midbrain. We hypothesize that this complexity that is expressed in cortical astrocytes may reflect their functions to meet the metabolic/structural needs of these regions.  相似文献   
105.

INTRODUCTION

No national recording systems for knife injuries exist in the UK. Understanding the true size and nature of the problem of knife injuries is the first stage in reducing the burden of this injury. The aim of this study was to survey every knife injury seen in a single inner city emergency department (ED) over a one-year period.

METHODS

A cross-sectional observational study was performed of all patients attending with a knife injury to the ED of a London major trauma centre in 2011. Demographic characteristics, patterns of injury, morbidity and mortality data were collected.

RESULTS

A total of 938 knife injuries were identified from 127,191 attendances (0.77% of all visits) with a case fatality rate of 0.53%. A quarter (24%) of the major trauma team’s caseload was for knife injuries. Overall, 44% of injuries were selfreported as assaults, 49% as accidents and 8% as deliberate self-harm. The highest age specific incident rate occurred in the 16–24 year age category (263/100,000). Multiple injuries were seen in 19% of cases, of which only 81% were recorded as assaults. The mean length of stay for those admitted to hospital was 3.04 days. Intrathoracic injury was seen in 26% of cases of chest trauma and 24% of abdominal injuries had a second additional chest injury.

CONCLUSIONS

Violent intentional injuries are a significant contributory factor to the workload of the major trauma team at this centre. This paper contributes to a more comprehensive understanding of the nature of these injuries seen in the ED.  相似文献   
106.
The Gay Bowel Syndrome   总被引:4,自引:0,他引:4  
Our experience in the management of 260 male homosexuals with coloreetal problems is described. The increased incidence of amebiasis, shigellosis and hepatitis, specific and nonspecific protocolitides, venereal disease and anal warts, is emphasized. It is important to recognize homosexual patients and the conditions to which they are predisposed.  相似文献   
107.
In addition to its well known sedative and teratogenic effects, thalidomide also possesses potent immunomodulatory and antiinflammatory activities, being most effective against leprosy and chronic graft-versus-host disease. The immunomodulatory activity of thalidomide has been ascribed to the selective inhibition of tumor necrosis factor alpha from monocytes. The molecular mechanism for the immunomodulatory effect of thalidomide remains unknown. To elucidate this mechanism, we synthesized an active photoaffinity label of thalidomide as a probe to identify the molecular target of the drug. Using the probe, we specifically labeled a pair of proteins of 43-45 kDa with high acidity from bovine thymus extract. Purification of these proteins and partial peptide sequence determination revealed them to be alpha1-acid glycoprotein (AGP). We show that the binding of thalidomide photoaffinity label to authentic human AGP is competed with both thalidomide and the nonradioactive photoaffinity label at concentrations comparable to those required for inhibition of production of tumor necrosis factor alpha from human monocytes, suggesting that AGP may be involved in the immunomodulatory activity of thalidomide.  相似文献   
108.
The cytoskeleton in Chediak-Higashi syndrome fibroblasts   总被引:2,自引:0,他引:2  
The Chediak-Higashi syndrome (CHS) trait is expressed in cultured human skin fibroblasts as an abnormal perinuclear concentration of moderately enlarged lysosomes. The cytoskeleton of CHS fibroblasts appears intact. Microtubules are normal in number and morphology, as assessed by colchicine binding studies, antitubulin immunofluorescence, and electron microscopy. Deformability by shear force is unaltered and microfilaments are abundant. However, CHS lysosomes appear to interact abnormally with the cytoskeleton, since the perinculear aggregation partially disperses after depolymerization of cell microtubules with colchicine. These results suggest that CHS is associated with a defect of either the lysosomal membrane itself or of lysosomal membrane- microtubule interaction.  相似文献   
109.
We sought to investigate whether application of topical tetracycline has a limiting effect on seroma formation in patients undergoing hernia repair using a polypropylene mesh. This study was conducted in 96 patients undergoing an elective groin hernia repair. Patients were randomized and divided into 2 groups. After the graft was placed, and before external oblique muscle aponeurosis was closed, 5 mL tetracycline was administered on the graft in the tetracycline group (tetra group, n = 50), and 5 mL isotonic saline was administered in the control group (n = 46) without putting in a drain. Seroma checks via surface ultrasonography were done. Seroma amounts measured on the first day were significantly higher in the tetra group (P = 0.04). There were no significant differences regarding seroma measurements on the seventh day or in the first and second months. Topical tetracycline application has no limiting effect on seroma formation after a groin hernia operation.Key words: Lichtenstein technique, Polypropylene mesh, Topical tetracycline, Seroma, UltrasonographyHernia operations are among the most frequently performed surgical operations. Graft use to repair the defect is commonplace because graft use decreases recurrence rate, and defect closure in large abdominal hernias is easier with a mesh.1 The most commonly used and least expensive mesh is the polypropylene mesh. This mesh causes a foreign-body reaction where it is placed, which leads to seroma formation.2 Repeat aspirations of seromas cause infection, and recurrence is seen on follow-up, especially in large hernias.2 While drain use is not recommended in groin hernias, drain use in other abdominal-wall hernias is left to the physician''s discretion. The biggest problem with drain use is transport of the infection by an ascending route.3Tetracycline is an antibiotic, the solution form of which is topically used for pleurodesis in chest surgery.4 Some researchers also report successful topical use of its solution in seroma treatment, taking advantage of its sclerosing effect in cases with breast carcinoma.5,6 Tetracycline has demonstrated increased growth factor–like activity in mesothelial cells exposed to tetracycline leading to fibroblast proliferation.7 This study sought to investigate whether tetracycline has a reducing effect on seroma development in cases undergoing elective groin hernia repair using a polypropylene mesh.  相似文献   
110.
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