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   7831篇
  免费   421篇
  国内免费   36篇
耳鼻咽喉   145篇
儿科学   170篇
妇产科学   187篇
基础医学   1195篇
口腔科学   120篇
临床医学   554篇
内科学   2184篇
皮肤病学   272篇
神经病学   428篇
特种医学   159篇
外科学   1182篇
综合类   19篇
一般理论   1篇
预防医学   249篇
眼科学   88篇
药学   506篇
中国医学   12篇
肿瘤学   817篇
  2023年   55篇
  2022年   80篇
  2021年   161篇
  2020年   87篇
  2019年   135篇
  2018年   132篇
  2017年   119篇
  2016年   156篇
  2015年   152篇
  2014年   184篇
  2013年   243篇
  2012年   461篇
  2011年   486篇
  2010年   271篇
  2009年   267篇
  2008年   426篇
  2007年   471篇
  2006年   483篇
  2005年   514篇
  2004年   491篇
  2003年   447篇
  2002年   458篇
  2001年   173篇
  2000年   172篇
  1999年   174篇
  1998年   85篇
  1997年   88篇
  1996年   93篇
  1995年   68篇
  1994年   55篇
  1993年   55篇
  1992年   102篇
  1991年   108篇
  1990年   95篇
  1989年   96篇
  1988年   80篇
  1987年   62篇
  1986年   68篇
  1985年   58篇
  1984年   35篇
  1983年   50篇
  1982年   24篇
  1981年   24篇
  1980年   20篇
  1979年   19篇
  1978年   21篇
  1976年   19篇
  1975年   22篇
  1970年   17篇
  1969年   22篇
排序方式: 共有8288条查询结果,搜索用时 17 毫秒
131.
BACKGROUND: Heart failure consists of two phenotypes: systolic heart failure and diastolic heart failure (DHF). A growing body of evidence demonstrated benefits of beta-blocker, angiotensin-converting enzyme inhibitor, and angiotensin II receptor blocker in systolic heart failure; however, evidence leading to therapeutic strategy of DHF is lacking. METHODS AND RESULTS: The Japanese Diastolic Heart Failure Study (J-DHF) is a multicenter, prospective, randomized trial designed to assess effects of beta-blocker in patients with DHF. A total of 800 patients (400 patients in each group) will be enrolled. The primary outcome is a composite of cardiovascular death and unplanned admission to hospital for congestive heart failure. Other outcomes include all-cause mortality, worsening of the symptoms of heart failure, or a need for modification of the treatment for heart failure. Serial assessment of echocardiographic and neurohumoral parameters and cost analysis of the treatment regimen will be conducted. The follow-up period is a minimum of 2 years. CONCLUSION: This study will provide important evidences for the treatment of DHF.  相似文献   
132.
Behavioral and psychological problems are often observed in patients with dementia such as that associated with Alzheimer disease, and these noncognitive symptoms place an extremely heavy burden on the family and caregivers. Although it is well know that these symptoms often are triggered by infection of peripheral organs, the underlying mechanisms for these pathological conditions are still unclear. In this study, using an Alzheimer amyloid precursor protein (APP)-transgenic mouse, we analyzed behavioral changes and brain inflammatory response induced by peripheral administration of lipopolysaccharide. Application of a unique in vivo microdialysis system revealed that the increase in brain inflammatory cytokine (interleukin-6) level was significantly higher in APP-Tg than in wild-type mice after peripheral lipopolysaccharide injection, which was associated with more severe sickness behaviors. The blood–brain barrier became more permeable in APP-Tg mice during peripherally evoked inflammation, suggesting the increased vulnerability of the blood–brain barrier to inflammation in this animal model of Alzheimer's disease. These findings might provide insight into the pathogenesis of noncognitive symptoms in dementia and a basis to develop new therapeutic treatments for them.  相似文献   
133.
We previously found that cancer metastasis is accelerated by immunosuppression during Snail-induced epithelial-to-mesenchymal transition (EMT). However, the molecular mechanism still remained unclear. Here, we demonstrate that CCL2 is a critical determinant for both tumor metastasis and immunosuppression induced by Snail+ tumor cells. CCL2 is significantly upregulated in various human tumor cells accompanied by Snail expression induced by snail transduction or TGFβ treatment. The Snail+ tumor-derived CCL2 amplifies EMT events in other cells including Snail? tumor cells and epithelial cells within tumor microenvironment. CCL2 secondarily induces Lipocalin 2 (LCN2) in the Snail+ tumor cells in an autocrine manner. CCL2 and LCN2 cooperatively generate immunoregulatory dendritic cells (DCreg) having suppressive activity accompanied by lowered expression of costimulatory molecules such as HLA-DR but increased expression of immunosuppressive molecules such as PD-L1 in human PBMCs. The CCL2/LCN2-induced DCreg cells subsequently induce immunosuppressive CD4+FOXP3+ Treg cells, and finally impair tumor-specific CTL induction. In murine established tumor model, however, CCL2 blockade utilizing the specific siRNA or neutralizing mAb significantly inhibits Snail+ tumor growth and metastasis following systemic induction of anti-tumor immune responses in host. These results suggest that CCL2 is more than a chemoattractant factor that is the significant effector molecule responsible for immune evasion of Snail+ tumor cells. CCL2 would be an attractive target for treatment to eliminate cancer cells via amelioration of tumor metastasis and immunosuppression.  相似文献   
134.
Muta  Hiromi  Podack  Eckhard R. 《Immunologic research》2013,57(1-3):151-158
Immunologic Research - The FDA recently approved an agonistic anti-CD30 drug conjugate, Brentuximab vedotin, for the treatment for CD30-positive lymphomas. The potent clinical activity of...  相似文献   
135.
136.
137.
Numerous studies have been carried out to investigate the solute removal efficiency of hemodiafiltration (HDF). However, the effect of the dilution mode on blood cell damage during HDF has not yet been examined in detail. Here, we compared predilution and postdilution HDF with respect to their effects on blood cells. Five patients were allocated to one session each of predilution HDF and postdilution HDF. Concentrations of interleukin (IL)-6, intercellular adhesion molecule (ICAM)-1, and platelet-derived microparticles (PDMP), and the phagocytotic and sterilizing functions of neutrophils before and after the HDF sessions were evaluated. Lymphocyte blastoid transformation induced by mitogens was also evaluated by measurement of the [3H]-thymidine uptake. The IL-6 and ICAM-1 concentrations decreased after predilution HDF, and increased after postdilution HDF. Lymphocyte blastoid transformation was more pronounced after predilution HDF than after postdilution HDF. There was no significant difference in PDMP between the dilution modes. We conclude that predilution HDF could be more favorable for dialysis patients than postdilution HDF from the point of view of the effects on the blood cells, especially neutrophils and lymphocytes.  相似文献   
138.
139.
The approach using pyrrolidine enamine as substrate has been studied for this synthesis, and an important catalyst structural feature has been developed. After survey of pyrrolidine-based Br?nsted acid catalyst, tetrazole catalyst (3f) was found to be optimal in synthesis of aminooxy carbonyl compounds in high yields, with complete enantioselectivity not only for aldehydes but also for ketones.  相似文献   
140.
We report a case of a 50-year-old male with ulcerative colitis who developed well-differentiated adenocarcinoma in the ileal J-pouch, which had been defunctioning for 18 years. The extension of the carcinoma in the pouch suggested that it had recently appeared in the pouch. Monitoring by endoscopic examination and biopsy or pouch excision seems to be an appropriate action if a pouch is out of the fecal stream.  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