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   734篇
  免费   101篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   16篇
妇产科学   15篇
基础医学   98篇
口腔科学   32篇
临床医学   119篇
内科学   118篇
皮肤病学   5篇
神经病学   54篇
特种医学   19篇
外科学   83篇
综合类   30篇
一般理论   2篇
预防医学   157篇
眼科学   19篇
药学   25篇
肿瘤学   44篇
  2021年   12篇
  2020年   7篇
  2019年   5篇
  2018年   9篇
  2017年   5篇
  2016年   16篇
  2015年   14篇
  2014年   16篇
  2013年   33篇
  2012年   34篇
  2011年   36篇
  2010年   21篇
  2009年   18篇
  2008年   33篇
  2007年   34篇
  2006年   34篇
  2005年   36篇
  2004年   32篇
  2003年   38篇
  2002年   20篇
  2001年   23篇
  2000年   28篇
  1999年   28篇
  1998年   10篇
  1997年   9篇
  1996年   12篇
  1995年   12篇
  1994年   8篇
  1993年   10篇
  1992年   20篇
  1991年   20篇
  1990年   13篇
  1989年   12篇
  1988年   17篇
  1987年   13篇
  1986年   9篇
  1985年   10篇
  1984年   7篇
  1982年   6篇
  1981年   7篇
  1979年   13篇
  1978年   4篇
  1976年   5篇
  1971年   5篇
  1970年   6篇
  1969年   9篇
  1967年   6篇
  1966年   5篇
  1954年   4篇
  1949年   4篇
排序方式: 共有837条查询结果,搜索用时 9 毫秒
1.
2.
3.
We have previously defined viability limits in a rat transplantation model. All liver allografts stored in a simple preservation solution (NaCl 0.9%, CaCl2 2 mM) at 4 degrees C for 4 hr or at 37 degrees C for 1 hr were viable upon transplantation, but all those stored at 4 degrees C for 8 hr or at 37 degrees C for 2 hr were nonviable. Only cold-preserved, nonviable livers showed increased vascular resistance, platelet trapping and an initially low, but then high, rise in aspartate transaminase (AST) upon reperfusion, all suggesting injury to the microcirculation, with secondary injury to the hepatocyte. In the present study, we investigated the morphological changes that occur in livers stored for the defined critical times, using light and electron microscopy after perfusion-fixation. Accurate and reproducible identification of specimens as belonging to viable or nonviable and warm- or cold-preserved could be made in this way. Preservation in the cold first resulted in reversible changes consisting of cellular swelling, alterations of intracellular organelles, and partial denudation of the sinusoidal lining (cold-preserved viable group). Later, under conditions of nonviable cold preservation, detachment of cell bodies of sinusoidal lining cells with nuclear changes and almost complete denudation of the sinusoidal lining was observed. Endothelial cells of larger vessels were only injured mildly. In contrast, under conditions of warm preservation, changes involving mitochondria and later nuclei were found in hepatocytes, and blebbing was more extensive. Endothelial cells were spared relatively. We also examined livers stored in isotonic citrate solution at 4 degrees C for 8 hr and 16 hr, the critical times determined for this solution in another model of rat liver transplantation. The findings were very similar to storage in saline with respect to the changes in the sinusoidal lining cells after cold preservation for the two critical times. The results provide convincing evidence of a qualitative difference between warm and cold preservation injury, with relatively selective damage to hepatocytes or sinusoidal lining cells, respectively. Endothelial damage represents the primary event, resulting in the loss of organ viability following hypothermic storage. Thus morphology may serve as a useful viability marker after preservation.  相似文献   
4.
The formulae for immunoglobulin G (IgG) synthesis rate, IgG(loc), IgG index, and IgG extended index in determining increased autochthonous production (intra-blood-brain barrier synthesis) of IgG was assessed in 50 chronic progressive multiple sclerosis patients. The results of all four formulae clearly show elevated intra-blood-brain barrier IgG synthesis in 35 patients, 94% of whom had oligoclonal immunoglobulins detected by the method of isoelectric focusing with immunofixation and silver staining (IEF-IS). The results from the four formulae are all normal in seven patients (none have oligoclonal immunoglobulins by IEF-IS) and are discordant in eight patients (five have oligoclonal immunoglobulins by IEF-IS). Whenever intra-blood-brain barrier synthesis of IgG is suspected, IEF-IS should be used to assay for oligoclonal immunoglobulins because this method is more sensitive than agarose electrophoresis with either Coomassie blue dye or silver stain (94% vs. 74% vs. 54%).  相似文献   
5.
6.
Anthracycline cardiotoxicity.   总被引:3,自引:0,他引:3  
Anthracycline drugs have been widely used as chemotherapeuticagents against a range of cancers, including sarcomas, carcinomas,leukaemias, and lymphomas. However, cardiotoxic effects, inparticular the development of cardiomyopathy, have limited theirclinical use. The observation of dose-dependent cardiotoxicityhas resulted in a recommended empirical dose limit of 450 mg/m2of body surface area. Age, gender, pre-existing heart disease,hypertension, and mediastinal irradiation have also been implicatedas factors contributing to the development of doxorubicin-associatedcardiomyopathy. However, cardiotoxicity may still occur at relativelylow levels of drug administration, even in individuals withno additional risk factors, and the onset may be delayed bymany years.1 More recently, the use of trastuzumab, a monoclonalantibody directed against the HER2 receptor, has been  相似文献   
7.
8.
Partial trisomy of the long arm of chromosome 10 is a well-defined but rare syndrome. Clinical features of this chromosomopathy are a distinctive dysmorphic appearance, developmental delay, growth retardation, and in some cases, abnormalities of the extremities and renal, cardiac and ocular anomalies. This report describes a neonate with symmetric growth retardation and multiple dysmorphic features, in whom chromosomal analysis revealed a partial trisomy of chromosome 10q with a monosomy of the 13q34 region. The phenotype shares many common features with previously published cases. In addition to the typical features, our case also shows renal hypoplasia with early renal insufficiency and some genital anomalies.  相似文献   
9.
Matrix metalloproteinase-3 (MMP-3) has been proposed as an important mediator of the atherosclerotic process. The possible role of the functional -1612 5A/6A polymorphism of the MMP-3 gene in the susceptibility to ischaemic heart disease (IHD) was investigated in a well-defined Irish population using two recently described family based tests of association. One thousand and twelve individuals from 386 families with at least one member prematurely affected with IHD were genotyped. Using the combined transmission disequilibrium test (TDT)/sib-TDT and the pedigree disequilibrium test (PDT), no association between the MMP-3 -1612 5A/6A polymorphism and IHD was found. Our data demonstrate that, in an Irish population, the MMP-3 -1612 5A/6A polymorphism is not associated with IHD.  相似文献   
10.
'Race' as identified by skin colour has been traditionally associated with the notion of the Other. In western culture the black man as Other has acted as a type of repository into which white men have projected anxieties about, for example, their sexuality. In psychologized, post-colonial culture such projections have taken on a different form and in this study we utilize Q-analysis to explore how this manifests itself into a representation of the white man as a type of ideal, contained, thinking subject set in opposition to a representation of the black man as someone who is constituted from without, by his relationship to the external world. We conclude by considering the evaluative and practical implications of this duality for our understanding of the mental health of black and white men.  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