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   1485篇
  免费   136篇
  国内免费   3篇
耳鼻咽喉   12篇
儿科学   66篇
妇产科学   22篇
基础医学   251篇
口腔科学   29篇
临床医学   160篇
内科学   282篇
皮肤病学   46篇
神经病学   196篇
特种医学   38篇
外科学   155篇
综合类   2篇
现状与发展   1篇
一般理论   1篇
预防医学   171篇
眼科学   19篇
药学   65篇
中国医学   2篇
肿瘤学   106篇
  2023年   18篇
  2022年   27篇
  2021年   46篇
  2020年   44篇
  2019年   30篇
  2018年   45篇
  2017年   40篇
  2016年   50篇
  2015年   52篇
  2014年   74篇
  2013年   65篇
  2012年   119篇
  2011年   129篇
  2010年   70篇
  2009年   79篇
  2008年   132篇
  2007年   110篇
  2006年   113篇
  2005年   90篇
  2004年   96篇
  2003年   78篇
  2002年   57篇
  2001年   4篇
  2000年   6篇
  1999年   13篇
  1998年   5篇
  1997年   2篇
  1996年   5篇
  1995年   5篇
  1994年   2篇
  1993年   7篇
  1992年   5篇
  1991年   2篇
  1990年   3篇
  1987年   1篇
排序方式: 共有1624条查询结果,搜索用时 15 毫秒
71.
72.
General anesthesia as used for rodent research can have adverse effects on physiologic mechanisms. Thermoregulation is often greatly inhibited, with resultant deleterious effects on cardiac and respiratory function. These potential effects can be mitigated by providing external heat support. The circulating warm water blanket and associated heat pump are often used in rodent procedures. The current study demonstrated that the heating pump and water blanket require quality control assessment to ensure adequate function. Our data showed that of the 6 pumps tested, 5 were able to achieve a temperature that met or exceeded the documented thermoneutral zone for mice. Pumps required 20 min of warming to reach their maximal attainable temperatures for the designated user setting. Although the pumps reached a temperature that was sufficient to provide external thermal support, only 1 of the 6 pumps reached the temperature that was set by the user during the trial. Surface temperatures across the water blanket were recorded to analyze whether a difference in heat support was influenced by animal placement along the water blanket; however, the location points did not yield statistically different results. Two pumps were eliminated from the study due to failure to pass the preparation phase of the trial. The results of this study support the need for facilities to establish quality control measures to ensure that heat support systems are functioning at a level required to maintain normothermia during anesthetic procedures.  相似文献   
73.
BackgroundAntimicrobial resistance poses a risk for healthcare, both in the community and hospitals. The spread of multidrug-resistant organisms (MDROs) occurs mostly on a local and regional level, following movement of patients, but also occurs across national borders.AimThe aim of this observational study was to determine the prevalence of MDROs in a European cross-border region to understand differences and improve infection prevention based on real-time routine data and workflows.MethodsBetween September 2017 and June 2018, 23 hospitals in the Dutch (NL)–German (DE) cross-border region (BR) participated in the study. During 8 consecutive weeks, patients were screened upon admission to intensive care units (ICUs) for nasal carriage of meticillin-resistant Staphylococcus aureus (MRSA) and rectal carriage of vancomycin-resistant Enterococcus faecium/E. faecalis (VRE), third-generation cephalosporin-resistant Enterobacteriaceae (3GCRE) and carbapenem-resistant Enterobacteriaceae (CRE). All samples were processed in the associated laboratories.ResultsA total of 3,365 patients were screened (median age: 68 years (IQR: 57–77); male/female ratio: 59.7/40.3; NL-BR: n = 1,202; DE-BR: n = 2,163). Median screening compliance was 60.4% (NL-BR: 56.9%; DE-BR: 62.9%). MDRO prevalence was higher in DE-BR than in NL-BR, namely 1.7% vs 0.6% for MRSA (p = 0.006), 2.7% vs 0.1% for VRE (p < 0.001) and 6.6% vs 3.6% for 3GCRE (p < 0.001), whereas CRE prevalence was comparable (0.2% in DE-BR vs 0.0% in NL-BR ICUs).ConclusionsThis first prospective multicentre screening study in a European cross-border region shows high heterogenicity in MDRO carriage prevalence in NL-BR and DE-BR ICUs. This indicates that the prevalence is probably influenced by the different healthcare structures.  相似文献   
74.
75.
Six hundred ninety-five mice received adeno-associated virus (AAV) vectors, mostly via portal vein injection. At necropsy, the livers were inspected for tumors, and tissue sections were prepared for histology. We observed only one tumor, a lipoma, resulting in a tumor frequency of 0.14%. This tumor contained fewer vector genomes per total DNA than the surrounding liver tissue, as shown by quantitative PCR. In another mouse we found a macroscopically visible nodule containing lymphocytes. Immunohistochemistry revealed cells not of monoclonal origin, and they contained fewer AAV genomes than the surrounding hepatocytes. There were no macroscopic tumors in 226 control mice. Upon microscopic examination, lymphocytic infiltrates were found in 5% of livers of both control and vector-treated mice; no transgene expression was seen in those infiltrates in AAV-injected animals. Compared to an average frequency of spontaneous liver tumors in C57BL/6 mice (0-10%), and given the absence of high levels of vector DNA in the observed tumor, we conclude that AAV vectors do not predispose these target animals to the formation of liver tumors.  相似文献   
76.
77.
78.
79.
Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease affecting multiple organs and tissues. Although there is a wide range of therapeutic applications, the coexistence of severe side effects and contraindications outlines the necessity of new therapeutic options in the treatment of severe RA. We report on the case of a 71‐year‐old patient with successful treatment of a complicated RA with tryptophan immunoadsorption combined with low‐dose steroids. Bacterial spondylitis developed in this patient during long‐term treatment with infliximab and methotrexate. Weekly immunoadsorption sessions with tryptophan columns resulted in continuous suppression of RA activity over a period of more than 5 months, as indicated by laboratory findings, the disease activity score, and the visual analog scale. This is the first report of successful treatment of a refractory and complicated RA using tryptophan immunoadsorption columns. In conclusion, immunoadsorption is a safe and effective therapeutic alternative, which should be considered to bridge infectious complications in patients with severe RA. J. Clin. Apheresis, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   
80.
PURPOSE: The balance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) is crucial for homeostasis of ocular extracellular matrices. To assess altered MMP activity as a determinant in the migration of human retinal pigment epithelial (RPE) cells, expression characteristics of several MMPs and TIMP-1 in RPE cell cultures were investigated. METHODS: Expression studies were performed with RT-PCR, ELISA, and immunofluorescence analysis. Secretion of MMP-2 was demonstrated by zymography. Migration of cytokine-stimulated RPE cells was evaluated with microporous membranes of permeable chambers. RESULTS: MMP-1, -2, -3, and -9; MT2-MMP; and TIMP-1 were expressed in cultured RPE cells. MMP-2 was detected on the cell surface and in secreted inactive and active forms. TGF-beta(2), IL-1beta, and TNF-alpha enhanced secretion of MMP-1, -2, and -3. TGF-beta(2) also stimulated MT2-MMP cell surface expression and release of TIMP-1. The mRNA levels of MMP-1, -2, and -3 and TIMP-1 were markedly increased by TNF-alpha and TGF-beta(2). MMP-2 mRNA levels were also upregulated by PDGF-BB. Migration of RPE cells stimulated by TGF-beta(2) or PDGF-BB was inhibited in presence of a synthetic MMP inhibitor. CONCLUSIONS: Proinflammatory cytokines and TGF-beta(2) play an important role in the upregulation of expression of MMP-1, -2, and -3 in RPE cells and account for a directional shift in the balance between MMPs and TIMPs. Facilitation of RPE cell migration stimulated by cytokines (i.e., TGF-beta(2) or PDGF-BB) in ocular diseases may be due to increased release of MMPs, in the presence of comparatively lower levels of their inhibitors.  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