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   757篇
  免费   48篇
  国内免费   27篇
耳鼻咽喉   1篇
儿科学   42篇
妇产科学   9篇
基础医学   63篇
口腔科学   29篇
临床医学   71篇
内科学   167篇
皮肤病学   21篇
神经病学   23篇
特种医学   115篇
外科学   107篇
综合类   11篇
预防医学   44篇
眼科学   2篇
药学   44篇
中国医学   2篇
肿瘤学   81篇
  2023年   18篇
  2022年   7篇
  2021年   4篇
  2020年   7篇
  2019年   19篇
  2018年   17篇
  2017年   13篇
  2016年   13篇
  2015年   17篇
  2014年   12篇
  2013年   43篇
  2012年   13篇
  2011年   27篇
  2010年   29篇
  2009年   32篇
  2008年   24篇
  2007年   24篇
  2006年   17篇
  2005年   22篇
  2004年   26篇
  2003年   11篇
  2002年   13篇
  2001年   12篇
  2000年   11篇
  1999年   15篇
  1998年   30篇
  1997年   32篇
  1996年   29篇
  1995年   30篇
  1994年   28篇
  1993年   20篇
  1992年   14篇
  1991年   7篇
  1990年   14篇
  1989年   20篇
  1988年   20篇
  1987年   15篇
  1986年   21篇
  1985年   14篇
  1984年   6篇
  1983年   9篇
  1982年   17篇
  1981年   15篇
  1980年   8篇
  1979年   7篇
  1978年   5篇
  1977年   3篇
  1976年   4篇
  1975年   9篇
  1969年   2篇
排序方式: 共有832条查询结果,搜索用时 31 毫秒
21.
Changes in cell surface antigen expression during hemopoietic differentiation   总被引:20,自引:1,他引:20  
Sieff  C; Bicknell  D; Caine  G; Robinson  J; Lam  G; Greaves  MF 《Blood》1982,60(3):703-713
Human bone marrow cells were separated on a fluorescence activated cell sorter (FACS) according to their binding of a series of monoclonal antibodies; the positive and negative fractions were cloned for erythroid burst and colony-forming units (BFU-E and CFU-E) and myeloid colony-forming units (CFU-GM), and cytocentrifuge slides were prepared for microscopy of maturing precursors. The pattern of antigen expression on hemopoietic progenitor and precursor populations has been established using antibodies defining blood group (A, I/i), HLA- associated (*A, B, C, DR, DC1), lineage specific, and transferrin receptor antigens. Like monomorphic HLA-DR, the antigen defined by monoclonal antibody OKT10 is expressed on the earliest progenitors and lost during differentiation, suggesting a role in interactions regulating the differentiation of these cells. The HLA-linked DC1 determinant, in contrast to HLA-DR, is not expressed at a detectable level on progenitor cells. Although a lineage-specific early antigen has not been identified, the transferrin receptor is expressed on the majority of erythroid progenitors, but only weakly on myeloid progenitors, and may provide an approach to isolating erythroid progenitors. These and earlier studies with monoclonal antibodies against HLA-DR and glycophorin now provide a detailed "map" of antigen expression during hemopoietic differentiation.  相似文献   
22.
23.
24.

Back ground

Stroke produces a wide range of mental and emotional disorders. Neuropsychiatric complications associated with stroke may have negative effects on the social functioning, overall quality of life and the recovery of motor functioning of stroke survivors.

Objective

To determine the prevalence and nature of psychiatric morbidity among stroke patients attending neurology outpatient clinic of the University of Ilorin Teaching Hospital (UITH), Ilorin-Nigeria.

Methods

All patients with stroke aged 18 years and above at an outpatient neurology clinic in Ilorin, Nigeria were assessed for mental and emotional disorders using the Schedule for Clinical Assessment in Neuropsychiatry (SCAN) over one year (March 2009 to February 2010).

Results

Overall prevalence of psychiatric morbidity was 36.0% (30/83) among 83 patients who constituted the study population. Specific diagnoses recorded were depression (19.2%), generalised anxiety disorder (9.6%), harmful alcohol use (2.4%); dementia, somatoform disorder, phobia and delusional disorder each had a prevalence of 1.2%. Clinical and sociodemographic variables were not significantly associated with psychiatric morbidity.

Conclusion

Psychiatric disorders are often associated with stroke. Identifying and treating stroke patients with these psychiatric co-morbidities could thus help to improve the overall quality of life of these patients.  相似文献   
25.
26.
27.
Introduction and ObjectivesThe emergence of SARS-CoV-2, which causes the coronavirus disease (COVID-19) has caused a great impact on healthcare systems worldwide, including hepatitis B and C viruses screening and elimination programs. The high number of COVID-19 hospitalizations represent a great opportunity to screen patients for hepatitis B virus (HBV) and hepatitis C virus (HCV), which was the aim of this study.Material and MethodsCross-sectional, retrospective study performed between April 2020 and 20201 at a referral center in Mexico dedicated to the care of adults with severe/critical COVID-19. We retrieved clinical, demographic, and laboratory results from each patient´s medical records, including antibodies against HCV (anti-HCV), HBV surface antigen (HBsAg), antibodies against the HBV core antigen (anti-HBcAg), and antibodies against HBsAg (anti-HBsAg).ResultsOut of 3620 patients that were admitted to the hospital, 24 (0.66%), 4 (0.11%), and 72 (1.99%) tested positive for anti-HCV, HBsAg, and anti-HBcAg, respectively. Of all seronegative patients, 954 (27%) had undetectable anti-HBsAg and 401 (12%) had anti-HBsAg at protective levels. Blood transfusion was the most relevant risk factor. Only 9.7% of the anti-HBc positive, 25% of the HBsAg positive, and 52% of the anti-HCV positive were aware of their serological status.ConclusionsIn this study we found a prevalence of anti-HCV of 0.66%, HBsAg in 0.11%, and isolated anti-HBcAg in 1.99%. We also found that HBV vaccination coverage has been suboptimal and needs to be reinforced. This study gave us a trustworthy insight of the actual seroprevalence in Mexico, which can help provide feedback to the Hepatitis National Elimination Plan.  相似文献   
28.
29.
INTRODUCTION: Patients with constipation often report dyspeptic symptoms, but whether constipation is associated with specific dyspeptic symptoms and altered gastrointestinal (GI) motility, remains to be established. Our aim was to study symptoms association and GI motility parameters in patients with constipation and functional dyspepsia. PATIENTS AND METHOD: 42 patients with different symptoms and severity of constipation and dyspepsia were enrolled. Scintigraphic gastric emptying, colonic transit time and gallbladder contraction were studied in all subjects. RESULTS: No significant association was observed between individual symptoms of constipation and dyspepsia. Patients with more severe constipation did not have higher dyspepsia severity scores. Colonic transit time, gastric half emptying and gallbladder contraction were not significantly correlated. Although patients with severe nausea had faster colonic transit than those with absent/mild symptom (19 +/- 2 vs. 48 +/- 7 h; p < 0.05), the multivariate analysis only revealed a significant association between severe postprandial fullness, delayed t1/2 (OR 1.05, CI 1-1.1) and impaired gallbladder contraction (OR 0.94, CI 0.89-0.99). CONCLUSIONS: Constipation was not associated with severity, or any particular dyspeptic symptom. Although motor abnormalities of both colon and proximal GI tract regions existed in the subset of constipated dyspeptic patients, they did not seem associated with the genesis of different dyspeptic symptoms.  相似文献   
30.
In vivo observations on the kinetics of F cells and of fetal hemoglobin (HbF) synthesis and in vitro studies of erythroid progenitors, their number, and the gamma-gene expression in their progeny were carried out in baboons (Papio cynocephalus) treated with 5-azacytidine. Maximum effect on the increase of HbF production in vivo was observed only when an expanded erythroid marrow population was present. In these animals, as well as in normal animals, treatment resulted in a significant reduction of the late erythroid progenitor cell pools (erythroid clusters and erythroid colony-forming units, CFU-E) in the marrow. This reduction was more pronounced among those progenitors grown in the absence of added erythropoietin, and it was followed by a rebound a few days after treatment cessation, reflecting the accumulation of regenerating progenitors. An early increase in the in vitro synthesis of HbF in erythroid clusters and CFU-E colonies was observed. This increase was further documented at the cellular level, with immunofluorescent labeling of colonies with monoclonal anti-gamma- globin chain antibodies. In contrast to the findings in late progenitors, the number of erythroid burst-forming unit (BFU-E) colonies and the synthesis of HbF in these colonies was not influenced significantly by 5-azacytidine treatment. It is proposed that the toxic effects of 5-azacytidine on late progenitors, leading to faster mobilization of earlier progenitors to the next more mature compartment, play a role in the in vivo augmentation of HbF synthesis by this drug. This perturbation in the progenitor cell population kinetics and the presumed hypomethylation of the surviving differentiating cells may act synergistically to produce a maximum HbF response after 5-azacytidine treatment.  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