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   878篇
  免费   47篇
  国内免费   1篇
  926篇
  2023年   4篇
  2022年   16篇
  2021年   22篇
  2020年   22篇
  2019年   17篇
  2018年   21篇
  2017年   32篇
  2016年   44篇
  2015年   55篇
  2014年   56篇
  2013年   63篇
  2012年   70篇
  2011年   83篇
  2010年   51篇
  2009年   39篇
  2008年   54篇
  2007年   60篇
  2006年   39篇
  2005年   44篇
  2004年   34篇
  2003年   21篇
  2002年   25篇
  2001年   5篇
  2000年   4篇
  1999年   1篇
  1998年   5篇
  1997年   1篇
  1996年   4篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1989年   5篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1978年   2篇
  1977年   1篇
  1975年   2篇
  1973年   2篇
  1972年   1篇
  1971年   3篇
  1970年   1篇
  1959年   1篇
排序方式: 共有926条查询结果,搜索用时 15 毫秒
921.
Obesity is a chronic disease characterized by excessive accumulation of body fat and the presence of metabolic disorders such as insulin resistance. In this sense, zinc is an important nutrient that stimulates insulin secretion and increases sensitivity to insulin. The aim of this study was to investigate the effect of zinc supplementation on insulin resistance in obese subjects through a systematic review of the available clinical trials. The search for articles was conducted using the PubMed, SciVerse Scopus, SciVerse ScienceDirect, and Cochrane databases, on May 25, 2016, by two authors independently. The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed in the conduct of this review. The Cochrane Collaboration tool was used to assess the risk of bias of the trials included in this review. After screening of the articles, six clinical trials were included in this systematic review. The scientific evidence presented in this systematic review shows that zinc supplementation improves insulin resistance in obese individuals of both sexes.  相似文献   
922.
923.
One way to monitor minimal residual disease (MRD) is to screen cells for multiple surface markers using flow cytometry. In order to develop an alternative microfluidic based method, isolation of B type acute lymphoblastic cells using two types of antibodies should be investigated. The immunomagnetic beads coated with various antibodies are used to capture the B type acute lymphoblastic cells. Single beads, two types of beads and surface immobilized antibody were used to measure the capture efficiency. Both micro and nanosize immunomagnetic beads can be used to capture B type acute lymphoblastic cells with a minimum efficiency of 94% and maximum efficiency of 98%. Development of a microfluidic based biochip incorporating immunomagnetic beads and surface immobilized antibodies for monitoring MRD can be an alternative to current cost and time inefficient laboratory methods. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2737, 2019  相似文献   
924.
Abstract

Purpose: To examine thiol-disulphide homeostasis auto painters.

Materials and methods: A total of 115 male workers, including 60 auto painters workers and 55 reference group, of the painting and assembly line units respectively, were included in the study. Thiol-disulphide parameters and ischaemia-modified albumin (IMA) of groups were determined. Urinary hippuric acid, (HA) phenol, hexanedione, trichloroacetic acid, arsenic and blood lead and manganese were analysed.

Results: The median urinary HA level was significantly higher in auto painters when compared to the reference group [(2461 (1212) vs. 520 (513) µgr/L), (p?<?0.001)] . The mean disulphide level [19.7 (4.3) vs 0.15.1(4.1) μmol/L, (p?<?0.001)], the disulphide/native thiol ratio [4.72 (1.47) vs. 3.13 (1.21, (p?<?0.001)] and the disulphide/total thiol ratio [4.31 (1.23) vs. 2.94 (1.06), (p?<?0.001)] were higher in auto painters when compared to the reference group. There was a statistically significant positive correlation between urinary HA and disulphide concentrations (r?=?0.536 and p?<?0.001), disulphide/native thiol ratio (r?=?0.564 and p?<?0.001) and the disulphide/total thiol ratio (r?=?0.564 and p?<?0.001) and IMA (r?=?0.396 and p?<?0.001).

Conclusion: The results presented in this study showed that oxidative stress can be associated with occupational exposure to toluene denoted by alteration of thiol disulphide homeostasis and ischaemia-modified albumin levels.  相似文献   
925.
Disordered regions of proteins are highly abundant in various biological processes, involving regulation and signaling and also in relation with cancer, cardiovascular, autoimmune diseases and neurodegenerative disorders. Hence, recognizing disordered regions in proteins is a critical task. In this paper, we presented a new feature encoding technique built from physicochemical properties of residues selected as per the chaotic structure of related protein sequence. Our feature vector has been tested with various classification algorithms on an up-to-date data set and also compared to other methods. The proposed method shows better classification performance than many methods in terms of accuracy, sensitivity and specificity. Our results suggest that the new method that links the residues and their physicochemical properties using Lyapunov exponents is highly effective in recognition of disordered regions.  相似文献   
926.
AimsConsidering the implications that arose from several recent experimental studies using recombinant human erythropoietin in rodents, erythropoietin has been regarded as a pharmacological preconditioning agent. The purpose of the present study was to evaluate whether erythropoietin has a preconditioning effect against ischemia and reperfusion injury in the small intestine of the rat.Main methodsIntestinal ischemia was induced in male Wistar rats by clamping the superior mesenteric artery for 30 min, followed by reperfusion for 180 min. Recombinant human erythropoietin (1000 or 3000 U/kg) or vehicle was administered intraperitoneally 24 h prior to ischemia. After collection of ileal tissue, evaluation of damage was based on measurements of the accumulation of polymorphonuclear neutrophils by technetium-99m-labeled leukocyte uptake, content of malondialdehyde, reduced glutathione, contractile responses to agonists, and an evaluation of histopathological features in intestinal tissue.Key findingsTreatment with erythropoietin 24 h before ischemia significantly reduced the tissue content of malondialdehyde and increased that of reduced glutathione. Pretreatment also significantly suppressed leukocyte infiltration into the postischemic tissue, as evidenced by the lower content of myeloperoxidase and technetium-99m-labeled leukocytes. Physiological and histopathological improvements were also significant with the rHuEpo treatment.SignificanceResults of the present study indicate that rHuEpo is an effective preconditioning agent in ischemic injury of the small intestine. Protection provided by recombinant human erythropoietin is closely related to the inhibition of oxidative stress and leukocyte infiltration, which might be among the possible protective mechanisms of erythropoietin in intestinal ischemia and reperfusion.  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