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   4693篇
  免费   319篇
  国内免费   26篇
耳鼻咽喉   77篇
儿科学   150篇
妇产科学   102篇
基础医学   841篇
口腔科学   146篇
临床医学   454篇
内科学   828篇
皮肤病学   93篇
神经病学   656篇
特种医学   124篇
外科学   395篇
综合类   29篇
一般理论   2篇
预防医学   314篇
眼科学   180篇
药学   284篇
中国医学   23篇
肿瘤学   340篇
  2024年   4篇
  2023年   41篇
  2022年   53篇
  2021年   80篇
  2020年   76篇
  2019年   104篇
  2018年   95篇
  2017年   121篇
  2016年   118篇
  2015年   135篇
  2014年   140篇
  2013年   229篇
  2012年   387篇
  2011年   354篇
  2010年   213篇
  2009年   208篇
  2008年   323篇
  2007年   360篇
  2006年   324篇
  2005年   296篇
  2004年   313篇
  2003年   273篇
  2002年   259篇
  2001年   44篇
  2000年   28篇
  1999年   60篇
  1998年   64篇
  1997年   61篇
  1996年   43篇
  1995年   24篇
  1994年   21篇
  1993年   18篇
  1992年   14篇
  1991年   19篇
  1990年   11篇
  1989年   14篇
  1988年   8篇
  1987年   10篇
  1986年   6篇
  1985年   8篇
  1984年   7篇
  1983年   7篇
  1982年   6篇
  1981年   9篇
  1980年   6篇
  1978年   10篇
  1977年   4篇
  1974年   3篇
  1973年   5篇
  1966年   3篇
排序方式: 共有5038条查询结果,搜索用时 15 毫秒
71.
72.
73.
Mycobacteria, the etiological agents of tuberculosis and leprosy, have coevolved with mammals for millions of years and have numerous ways of suppressing their host''s immune response. It has been suggested that mycobacteria may contain genes that reduce the host''s ability to elicit CD8+ T cell responses. We screened 3,290 mutant Mycobacterium bovis bacillus Calmette Guerin (BCG) strains to identify genes that decrease major histocompatibility complex (MHC) class I presentation of mycobacterium-encoded epitope peptides. Through our analysis, we identified 16 mutant BCG strains that generated increased transgene product-specific CD8+ T cell responses. The genes disrupted in these mutant strains had disparate predicted functions. Reconstruction of strains via targeted deletion of genes identified in the screen recapitulated the enhanced immunogenicity phenotype of the original mutant strains. When we introduced the simian immunodeficiency virus (SIV) gag gene into several of these novel BCG strains, we observed enhanced SIV Gag-specific CD8+ T cell responses in vivo. This study demonstrates that mycobacteria carry numerous genes that act to dampen CD8+ T cell responses and suggests that genetic modification of these genes may generate a novel group of recombinant BCG strains capable of serving as more effective and immunogenic vaccine vectors.  相似文献   
74.
Parasitology Research - In Europe, up to 90% of isolated Trichomonas vaginalis strains are naturally infected with Mycoplasma hominis, a facultative pathogen of the human genital tract. The...  相似文献   
75.
A group from Germany, Canada, and the United Kingdom undertook country-specific scoping reviews and stakeholder consultations before joining to holistically compare migration and maternity in all three countries. We examined four interlinking dimensions to understand how international migrant/minority maternal health might be improved upon using transnational research: (a) wider sociopolitical context, (b) health policy arena, (c) constellation, outcomes, and experiences of maternity services, and (d) existing research contexts. There was clear evidence that the constellation and delivery of services may undermine good experiences and outcomes. Interventions to improve access and quality of care remain small scale, short term, and lacking in rigorous evaluation.  相似文献   
76.
77.
The aim of this article is to introduce a systematic, structured conceptual framework for the comparative analysis of welfare-state reform policies towards long-term senior care and the care structures in a cross-European perspective. A welfare state’s policies on the long-term care of senior citizens frame the different aspects of their care: the care options of the older people, the employment situation of the different types of caregivers and the care quality. The actual structure of senior care is mainly based on the specific care-provision mix in a welfare state and on the main types of care employment. It is should not, however, be treated as a direct outcome of care policies in analyses of welfare-state policies, since the care recipients and care givers all act within the broader framework of the complex and often contradictory cultural, institutional, social and economic context—the specific ‘care arrangement’ of a country.  相似文献   
78.
Acquired immunoglobulin G (IgG)‐mediated thrombotic thrombocytopenic purpura (TTP) has not yet been described in non‐twin siblings. We report two cases of acquired TTP in Caucasian sisters with inactive ADAMTS13 metalloprotease due to ADAMTS13 autoantibodies suggesting a role of genetic determinants in this life‐threatening disease. However, human leucocyte antigen (HLA) class II types presumably associated with acquired TTP were not identified in the patients, indicating that HLA class II typing may not be useful in acquired TTP risk assessment of family members.  相似文献   
79.
80.
Background: Hepatitis C virus (HCV) infection is associated with multiple extrahepatic manifestations. It is unclear to what extent extrahepatic manifestations occur in HIV/HCV coinfection. Methods: We prospectively assessed cross-sectional frequencies of autoimmune manifestations in HIV/HCV-coinfected patients (n=98), HIV-mono-infected (n=45) and HCV-mono-infected patients (n=78). Diagnostic vasculitis scores, HCV and HIV loads, CD4 cell counts, thyroid-, cardiolipin-, non-organ-specific tissue antibodies (nuclear, smooth muscle, anti-liver-kidney-microsome, neutrophil-cytoplasmic) and cryoglobulins were determined. Results: Synergistic effects of HCV and HIV infection were observed with respect to the prevalence of antibodies against thyroglobulin (HCV infection 15.4%, HIV infection 8.8%, HIV/HCV coinfection 30.6%; P<0.001) and cardiolipin antibodies (HCV infection 9.0%, HIV infection 31%, HIV/HCV coinfection 46%; P<0.001). Cryoglobulinemia type III, was significantly associated with HCV infection (HCV, 25.6%; HIV/HCV, 20.4%) but not with HIV infection (4.4%, P<0.05). Rheumatoid factor was commonly detected in patients with HCV infection (48%), but occurred considerably less frequently in patients with HIV infection (4.4%) or HIV/HCV coinfection (9.5%, P<0.01). Conclusion: HIV coinfection appears to differentially modulate the frequency of HCV-related autoimmunity. However, autoimmunity is rarely accompanied by clinical manifestations.  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