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   26526篇
  免费   2350篇
  国内免费   1316篇
  2024年   14篇
  2023年   210篇
  2022年   268篇
  2021年   821篇
  2020年   694篇
  2019年   858篇
  2018年   937篇
  2017年   732篇
  2016年   1078篇
  2015年   1645篇
  2014年   1925篇
  2013年   2053篇
  2012年   2498篇
  2011年   2340篇
  2010年   1393篇
  2009年   1325篇
  2008年   1605篇
  2007年   1432篇
  2006年   1313篇
  2005年   1144篇
  2004年   1080篇
  2003年   911篇
  2002年   723篇
  2001年   502篇
  2000年   416篇
  1999年   366篇
  1998年   222篇
  1997年   200篇
  1996年   169篇
  1995年   139篇
  1994年   140篇
  1993年   84篇
  1992年   134篇
  1991年   113篇
  1990年   115篇
  1989年   97篇
  1988年   81篇
  1987年   73篇
  1986年   53篇
  1985年   49篇
  1984年   46篇
  1983年   32篇
  1982年   21篇
  1981年   13篇
  1979年   13篇
  1978年   15篇
  1976年   13篇
  1975年   9篇
  1972年   8篇
  1971年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
We encountered a patient with heavy Hymenolepis nana infection. The patient was a 44-year-old Korean man who had suffered from chronic hepatitis (type B) for 15 years. A large number of H. nana adult worms were found during colonoscopy that was performed as a part of routine health screening. The parasites were scattered throughout the colon, as well as in the terminal ileum, although the patient was immunocompetent. Based on this study, colonoscopy may be helpful for diagnosis of asymptomatic H. nana infections.  相似文献   
2.
3.
4.
5.
6.
Abstract Two new species of water mites, Pionopsis (s.s.)longicosta sp. nov. and Pionopsis (s.s.) zhaoi sp. nov. are described in the present paper. This is the first record of the genus of the subfamily Tiphyinae in the family Pionidae from China.  相似文献   
7.
Alterations in immune function have been documented during or post-spaceflight and in ground based models of microgravity. Identification of immune parameters that are dysregulated during spaceflight is an important step in mitigating crew health risks during deep space missions. The in vitro analysis of leukocyte activity post-spaceflight in both human and animal species is primarily focused on lymphocytic function. This report completes a broader spectrum analysis of mouse lymphocyte and monocyte changes post 13 days orbital flight (mission STS-135). Analysis includes an examination in surface markers for cell activation, and antigen presentation and co-stimulatory molecules. Cytokine production was measured after stimulation with T-cell mitogen or TLR-2, TLR-4, or TLR-5 agonists. Splenocyte surface marker analysis immediate post-spaceflight and after in vitro culture demonstrated unique changes in phenotypic populations between the flight mice and matched treatment ground controls. Post-spaceflight splenocytes (flight splenocytes) had lower expression intensity of CD4+CD25+ and CD8+CD25+ cells, lower percentage of CD11c+MHC II+ cells, and higher percentage of CD11c+MHC I+ populations compared to ground controls. The flight splenocytes demonstrated an increase in phagocytic activity. Stimulation with ConA led to decrease in CD4+ population but increased CD4+CD25+ cells compared to ground controls. Culturing with TLR agonists led to a decrease in CD11c+ population in splenocytes isolated from flight mice compared to ground controls. Consequently, flight splenocytes with or without TLR-agonist stimulation showed a decrease in CD11c+MHC I+, CD11c+MHC II+, and CD11c+CD86+ cells compared to ground controls. Production of IFN-γ was decreased and IL-2 was increased from ConA stimulated flight splenocytes. This study demonstrated that expression of surface molecules can be affected by conditions of spaceflight and impaired responsiveness persists under culture conditions in vitro.  相似文献   
8.
9.
10.
A 45-year-old-male who had underlying ulcerative colitis and presented with fever and dry cough. Initially, the patient was considered to have invasive aspergillosis due to a positive galactomannan assay. He was treated with amphotericin B followed by voriconazole. Nevertheless, the patient deteriorated clinically and radiographically. The lung biopsy revealed eosinophilic pneumonia, and ELISA for Toxocara antigen was positive, leading to a diagnosis of pulmonary toxocariasis. After a 10-day treatment course with albendazole and adjunctive steroids, the patient recovered completely without any sequelae. Pulmonary toxocariasis may be considered in patients with subacute or chronic pneumonia unresponsive to antibiotic agents, particularly in cases with eosinophilia.  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