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   6744篇
  免费   469篇
  国内免费   13篇
耳鼻咽喉   30篇
儿科学   158篇
妇产科学   196篇
基础医学   1189篇
口腔科学   88篇
临床医学   771篇
内科学   1428篇
皮肤病学   156篇
神经病学   644篇
特种医学   145篇
外科学   734篇
综合类   17篇
一般理论   4篇
预防医学   483篇
眼科学   75篇
药学   410篇
中国医学   11篇
肿瘤学   687篇
  2023年   37篇
  2022年   59篇
  2021年   137篇
  2020年   100篇
  2019年   120篇
  2018年   155篇
  2017年   122篇
  2016年   147篇
  2015年   188篇
  2014年   236篇
  2013年   318篇
  2012年   541篇
  2011年   547篇
  2010年   299篇
  2009年   282篇
  2008年   469篇
  2007年   463篇
  2006年   484篇
  2005年   489篇
  2004年   437篇
  2003年   461篇
  2002年   433篇
  2001年   66篇
  2000年   42篇
  1999年   52篇
  1998年   86篇
  1997年   67篇
  1996年   40篇
  1995年   56篇
  1994年   42篇
  1993年   27篇
  1992年   30篇
  1991年   23篇
  1990年   21篇
  1989年   19篇
  1988年   10篇
  1987年   16篇
  1986年   17篇
  1985年   19篇
  1984年   10篇
  1983年   6篇
  1982年   12篇
  1981年   6篇
  1980年   6篇
  1979年   7篇
  1978年   2篇
  1977年   5篇
  1974年   5篇
  1970年   4篇
  1966年   1篇
排序方式: 共有7226条查询结果,搜索用时 234 毫秒
101.
Numerous extracellular proteins and glycosaminoglycans (GAGs) undergo limited enzymatic cleavage resulting in the release of fragments exerting biological activities, which are usually different from those of the full‐length molecules. In this review, we define matrikines and matricryptins, which are bioactive fragments released from the extracellular matrix proteins, proteoglycans and GAGs and report their major biological activities. These fragments regulate a number of physiopathological processes including angiogenesis, cancer, fibrosis, inflammation, neurodegenerative diseases and wound healing. The challenges to translate these fragments from molecules biologically active in vitro and in experimental models to potential drugs are discussed in the last part of the review.  相似文献   
102.
103.
IntroductionPremature ejaculation (PE) is quite common. Although effective treatments do exist, only a few affected people consult a practitioner in order to overcome their problem. At the same time, studies have shown that reading didactical documents about their PE problem (bibliotherapy) can be useful to men.AimThe aim of this study was to improve the bibliotherapy approach using up‐to‐date knowledge and techniques. The expected benefits were the following: (i) an effective manual shorter than previous ones; (ii) easier to assimilate therapeutic principles; and (iii) a method thereby made accessible to a broad population most of whom usually do not consult for this type of sexual problem.MethodA short bibliotherapy titled The Practical Guide of PE[in French] was tested among PE subjects who were diagnosed with PE according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision criteria. Assessments were made at baseline (N = 421), at 4–8 months (N = 120), and at 10–14 months (N = 79) after they read The Practical Guide. A control group of 66 subjects was left on a waiting list and was assessed 2 months after baseline.Main Outcome MeasuresThe main outcome measures are self‐reported ejaculatory latency time, feeling of control upon ejaculation, sexual satisfaction, distress related to PE, anxiety experienced during sexual intercourse, and sexual cognitions (Sexual Irrationality Questionnaire).ResultsSignificant improvements were found for all the self‐reported parameters, both at 4–8 and at 10–14 months after the bibliotherapy. The improvements were associated with an adjustment of sexual cognitions. The response to treatment seemed better for those subjects with moderate PE. Although the severity criteria used in this study did not precisely meet the International Society for Sexual Medicine criteria for lifelong PE, they were likely related. The response did not seem to be affected by variables such as age, education, or personality.ConclusionIts cost/benefit ratio makes The Practical Guide a valuable therapeutic tool. Kempeneers P, Andrianne R, Bauwens S, Georis I, Pairoux J‐F, and Blairy S. Clinical outcomes of a new self‐help booklet for premature ejaculation. J Sex Med 2012;9:2417–2428.  相似文献   
104.
105.
Maternal infection/inflammation represents one of the most important factors involved in the etiology of brain injury in newborns. We investigated the modulating effect of prenatal melatonin on the neonatal brain inflammation process resulting from maternal intraperitoneal (i.p.) lipopolysaccharide (LPS) injections. LPS (300 μg/kg) was administered to pregnant rats at gestational days 19 and 20. Melatonin (5 mg/kg) was administered i.p. at the same time as LPS. Melatonin counteracted the LPS sensitization to a second ibotenate‐induced excitotoxic insult performed on postnatal day (PND) 4. As melatonin succeeded in reducing microglial activation in neonatal brain at PND1, pathways previously implicated in brain inflammation regulation, such as endoplasmic reticulum (ER) stress, autophagy and silent information regulator 1 (SIRT1), a melatonin target, were assessed at the same time‐point in our experimental groups. Results showed that maternal LPS administrations resulted in an increase in CHOP and Hsp70 protein expression and eIF2α phosphorylation, indicative of activation of the unfolded protein response consequent to ER stress, and a slighter decrease in the autophagy process, determined by reduced lipidated LC3 and increased p62 expression. LPS‐induced inflammation also reduced brain SIRT1 expression and affected the expression of miR‐34a, miR146a, and miR‐126. All these effects were blocked by melatonin. Cleaved‐caspase‐3 apoptosis pathway did not seem to be implicated in the noxious effect of LPS on the PND1 brain. We conclude that melatonin is effective in reducing maternal LPS‐induced neonatal inflammation and related brain injury. Its role as a prophylactic/therapeutic drug deserves to be investigated by clinical studies.  相似文献   
106.
Structural alteration to the microanatomical organization of the glomerular filtration barrier results in proteinuria. Conventional transmission electron microscopy is an important diagnostic tool to assess the degree of ultrastructural damage of the corpusclar filtration unit. However, this approach lacks the ability to collect accurate stereological insights in a relative large tissue volume. Transmission electron tomography offers the ability to gather three-dimensional information with relative ease. Therefore, this contribution aims to highlight what electron tomography can bring to the pathologist in this challenging area of diagnostic practice.  相似文献   
107.
108.
109.
Waters receiving textile discharges can exhibit genotoxic and mutagenic activity, which has been related to the presence of dyes and aromatic amines as synthesis precursors or byproducts. The aim of this study was to identify dyes and aromatic amines in water samples impacted by textile discharges, and to evaluate the genotoxic responses of these samples using the Salmonella/microsome assay in strains TA98 and YG1041, and the Fpg‐modified comet assay in the RTL‐W1 fish cell line. The genotoxicity of river samples downstream of the discharge was greater than the upstream samples in both of the Ames tests. The Fpg‐modified comet assay detected similar levels of DNA damage in the upstream and downstream samples. Mutagenicity was not detected with TA98, except for the Quilombo River samples, but when YG1041 was used as the tester strain mutagenicity was detected for all sites with a very different profile in upstream sites relative to the other sites. The mutagenic response strongly indicated that aromatic amines or dyes were contributing to the mutagenic activity downstream. The impact of textile discharges was also confirmed by chemical analysis, because the highest concentrations of azo dyes and aromatic amines were detected in the river downstream. This study shows the value of combining assays measuring complementary endpoints to better characterize the mutagenicity of environmental samples, with the advantage that this approach provides an indication of what classes of compounds are responsible for the effect. Environ. Mol. Mutagen. 57:559–571, 2016. © 2016 Wiley Periodicals, Inc.  相似文献   
110.
Workplace design and upkeep, or human factors, are frequently advanced for explaining so-called Occupational Slip, Trip and Fall Accidents (OSTFAs). Despite scientific progress, these accidents, and more broadly Occupational Accidents with Movement Disturbance (OAMDs), are also commonly considered to be “simple”. This paper aims to stimulate changes in such perceptions by focusing on organisational factors that often combine with other accident factors to cause movement disturbance and injury in work situations. These factors frequently lead to arbitration between production and safety, which involves implementation of controls by workers. These controls can lead to greater worker exposure to OAMD risk. We propose a model that focuses on such controls to account specifically for the need to confront production and safety logics within a company and to enhance the potential for appropriate prevention action. These are then integrated into the set of controls highlighted by work organisation model developed by the NIOSH.  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