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   1836篇
  免费   156篇
  国内免费   42篇
耳鼻咽喉   7篇
儿科学   108篇
妇产科学   28篇
基础医学   202篇
口腔科学   102篇
临床医学   219篇
内科学   406篇
皮肤病学   9篇
神经病学   119篇
特种医学   186篇
外科学   186篇
综合类   45篇
一般理论   2篇
预防医学   213篇
眼科学   5篇
药学   107篇
肿瘤学   90篇
  2022年   10篇
  2021年   39篇
  2020年   10篇
  2019年   17篇
  2018年   47篇
  2017年   29篇
  2016年   20篇
  2015年   33篇
  2014年   45篇
  2013年   58篇
  2012年   75篇
  2011年   87篇
  2010年   48篇
  2009年   61篇
  2008年   76篇
  2007年   95篇
  2006年   88篇
  2005年   79篇
  2004年   78篇
  2003年   64篇
  2002年   61篇
  2001年   54篇
  2000年   52篇
  1999年   57篇
  1998年   82篇
  1997年   52篇
  1996年   51篇
  1995年   37篇
  1994年   26篇
  1993年   41篇
  1992年   32篇
  1991年   35篇
  1990年   25篇
  1989年   37篇
  1988年   41篇
  1987年   45篇
  1986年   28篇
  1985年   32篇
  1984年   23篇
  1983年   19篇
  1982年   18篇
  1981年   21篇
  1980年   21篇
  1979年   6篇
  1978年   10篇
  1977年   11篇
  1976年   8篇
  1975年   7篇
  1960年   3篇
  1946年   3篇
排序方式: 共有2034条查询结果,搜索用时 31 毫秒
1.
2.
Glucose metabolism in injured tissue: a longitudinal study   总被引:1,自引:0,他引:1  
Injured tissue is characterized by increased glucose uptake and increased lactate production as compared to normal tissue. These metabolic changes have been attributed to the presence of inflammatory cells in injured tissues. To correlate these metabolic changes with changes in the inflammatory cell population at various times after injury, we studied the lambda-carrageenan hindlimb wound model in anesthetized rats. Perfusion studies demonstrated that at 3 and 5 days after injury glucose uptake was increased in injured hindlimbs, compared with hindlimbs from pair-fed control animals. At 3, 5, and 10 days after injury, lactate production from glucose was increased in injured hindlimbs, compared with hindlimbs from pair-fed control animals. These metabolic changes were not related to differences in body weight or food intake. There was no difference in glucose oxidation or in oxygen consumption in injured hindlimbs, compared with hindlimbs from pair-fed control animals. The increased glucose uptake and increased lactate production from glucose was coincident with the presence of inflammatory cells--predominantly macrophages--at the site of injury. It is suggested that the glucose metabolism in injured tissue reflects the metabolism of the inflammatory cells at the site of injury.  相似文献   
3.
Objective   To investigate the reliability and validity of the expressed emotion (EE) measure, the Pre-school Five Minute Speech Sample (PFMSS), in child-to-child sibling relationships.
Method   A total of 106 boys aged 7–11 were recruited from 12 mainstream primary schools in North Wales. The children completed the PFMSS regarding their sibling and two self-report measures of sibling relationship: the Sibling Relationship Questionnaire (SRQ) and a Child Visual Analogue Scale (CVAS). The parents of 60 participants completed the Strengths and Difficulties Questionnaire regarding the behavioural problems of the participating child and his younger sibling.
Results   The PFMSS demonstrated good inter-rater and code–recode reliability. The significant associations between EE dimensions such as relationship, positive comments and critical comments with various components of the SRQ and CVAS provided support for the concurrent validity of the PFMSS. Significantly higher levels of Conflict and Rivalry and significantly lower levels of Warmth/Closeness on the SRQ were reported by children with high EE, demonstrating good discriminant validity for the PFMSS. There was no significant association between the child's EE profile and the behavioural difficulties of both siblings as reported by parents.
Conclusions   The study found that the PFMSS is a valid and reliable measure of child EE. Future research is needed to clarify the concurrent validity of the warmth and initial statement components of the measure as well as the association between EE dimensions and behaviour.  相似文献   
4.
Substance abuse and schizophrenia: impediments to optimal care   总被引:1,自引:0,他引:1  
With lifetime prevalence estimates of substance abuse among schizophrenics as high as 47.01%, there is an increasing awareness of the importance of this dual diagnosis and the global deficiencies in our knowledge about this comorbid condition. Patients with substance abuse disorders and schizophrenia are problematic from a clinical, economic, and health care systems perspective. The lack of systematic research into phenomenology, etiology, and treatment approaches (both psychotherapeutic and psychopharmacologic) has hindered the development of an adequate strategy to care for the needs of these patients. Thus, these patients place a significant burden on the mental health delivery system through chronic disability, social dysfunction, frequent rehospitalizations, and poor overall treatment compliance. The authors critically review the contemporary literature relevant to concurrent substance abuse and schizophrenia, highlight major deficiencies in our knowledge, and call for research to reduce the individual, economic, and social costs of this condition.  相似文献   
5.
6.
7.
Interpreting hospital mortality data. The role of clinical risk adjustment   总被引:9,自引:0,他引:9  
S F Jencks  J Daley  D Draper  N Thomas  G Lenhart  J Walker 《JAMA》1988,260(24):3611-3616
This study uses national Medicare data as well as data that were abstracted to calibrate the Medicare Mortality Predictor System to assess the usefulness of a risk adjustment system in interpreting hospital mortality rates. The majority of variation in annual hospital death rates for the four conditions studied (stroke, pneumonia, myocardial infarction, and congestive heart failure) is chance variability that results from the relatively small numbers of patients treated in most hospitals in a year. For hospitals in the highest and lowest quartiles of observed death rates, the difference between observed rates and those predicted by the Medicare Mortality Predictor System is not quite on third smaller than the difference between observed rates and unadjusted national rates. Risk adjustment methods do not show whether the unexplained difference in mortality rates results from differences in effectiveness of care or unmeasured differences in patient risk at the time of admission. Risk-adjusted mortality rates, therefore, should be supplemented by review of the actual care rendered before conclusions are drawn regarding effectiveness of care.  相似文献   
8.
9.
Normal and diseased isolated lungs: high-resolution CT   总被引:8,自引:0,他引:8  
  相似文献   
10.
BACKGROUND. Tuberculosis typically develops from a reactivation of latent infection. Clinical tuberculosis may also arise from a primary infection, and this is thought to be more likely in persons infected with the human immunodeficiency virus (HIV). However, the relative importance of these two pathogenetic mechanisms in this population is unclear. METHODS. Between December 1990 and April 1991, tuberculosis was diagnosed in 12 residents of a housing facility for HIV-infected persons. In the preceding six months, two patients being treated for tuberculosis had been admitted to the facility. We investigated this outbreak using standard procedures plus analysis of the cultured organisms with restriction-fragment-length polymorphisms (RFLPs). RESULTS. Organisms isolated from all 11 of the culture-positive residents had similar RFLP patterns, whereas the isolates from the 2 patients treated for tuberculosis in the previous six months were different strains. This implicated the first of the 12 patients with tuberculosis as the source of this outbreak. Among the 30 residents exposed to possible infection, active tuberculosis developed in 11 (37 percent), and 4 others (13 percent) had newly positive tuberculin skin tests. Of 28 staff members with possible exposure, at least 6 had positive tuberculin-test reactions, but none had tuberculosis. CONCLUSIONS. Newly acquired tuberculous infection in HIV-infected patients can spread readily and progress rapidly to active disease. There should be heightened surveillance for tuberculosis in facilities where HIV-infected persons live, and investigation of contacts must be undertaken promptly and be focused more broadly than is usual.  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