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   6709篇
  免费   366篇
  国内免费   41篇
耳鼻咽喉   193篇
儿科学   435篇
妇产科学   70篇
基础医学   672篇
口腔科学   200篇
临床医学   563篇
内科学   1610篇
皮肤病学   65篇
神经病学   511篇
特种医学   191篇
外科学   1010篇
综合类   206篇
一般理论   1篇
预防医学   286篇
眼科学   291篇
药学   405篇
中国医学   25篇
肿瘤学   382篇
  2023年   45篇
  2022年   102篇
  2021年   251篇
  2020年   124篇
  2019年   150篇
  2018年   196篇
  2017年   137篇
  2016年   167篇
  2015年   200篇
  2014年   282篇
  2013年   320篇
  2012年   516篇
  2011年   512篇
  2010年   301篇
  2009年   234篇
  2008年   416篇
  2007年   457篇
  2006年   357篇
  2005年   311篇
  2004年   296篇
  2003年   265篇
  2002年   223篇
  2001年   115篇
  2000年   90篇
  1999年   87篇
  1998年   64篇
  1997年   45篇
  1996年   32篇
  1995年   25篇
  1994年   31篇
  1993年   29篇
  1992年   57篇
  1991年   68篇
  1990年   58篇
  1989年   56篇
  1988年   56篇
  1987年   47篇
  1986年   39篇
  1985年   43篇
  1984年   17篇
  1983年   28篇
  1982年   15篇
  1980年   14篇
  1979年   31篇
  1978年   19篇
  1975年   21篇
  1972年   21篇
  1970年   14篇
  1968年   13篇
  1965年   13篇
排序方式: 共有7116条查询结果,搜索用时 15 毫秒
71.
Cypermethrin, a class II pyrethroid pesticide, is used to control insects in the household and agricultural fields. Despite beneficial roles, its uncontrolled and repetitive applications lead to unintended effects in non-target organisms. Cypermethrin crosses the blood-brain barrier and induces neurotoxicity and motor deficits. Cypermethrin prolongs the opening of sodium channel, a major site of its action, leading to hyper-excitation of the central nervous system. In addition to sodium channel, cypermethrin modulates chloride, voltage-gated calcium and potassium channels, alters the activity of glutamate and acetylcholine receptors and adenosine triphosphatases and induces DNA damage and oxidative stress in the neuronal cells. Cypermethrin also modulates the level of neurotransmitters, including gamma-aminobutyric acid and dopamine. It is one of the most commonly used pesticides in neurotoxicology research not only because of its variable responses depending upon the doses, time and routes of exposure and strain, age, gender and species of animals used across multiple studies but also owing to its ability to induce the nigrostriatal dopaminergic neurodegeneration. This article describes the effect of acute, chronic, developmental and adulthood exposures to cypermethrin in experimental animals. The article sheds light on cypermethrin-induced changes in the central nervous system, including its contribution in the onset of specific features, which are associated with the nigrostriatal dopaminergic neurodegeneration. Resemblances and dissimilarities of cypermethrin-induced nigrostriatal dopaminergic neurodegeneration with sporadic and chemicals-induced disease models along with its advantages and pitfalls are also discussed.  相似文献   
72.
73.
74.
Human hydatid disease or cystic echinococcosis (CE), caused by the larval form of cestode Echinococcus granulosus still continues to a common problem in health care environments as different as Europe/North America and resource poor countries of the South America and the East. The Liver is the most frequently parasatized organ in humans. While ultrasonography remains the main diagnostic tool, computed tomography and serology improve the accuracy of diagnosis in Liver hydatid cysts (LHC). Although surgery is the only modality applicable over the entire spectrum of the disease, systemic chemotherapy and percutaneous drainage have evolved as alternative therapies in the last three decades. Various laparoscopic techniques have also been described for safe and optimal management of this entity. In this paper, we review the current management procedures of LHC with particular emphasis on the evidence base and setting specific problems.  相似文献   
75.
76.
77.
78.
79.
ObjectiveThe objective of the study is to evaluate cardiac risk factors and risk scores for prediction of coronary artery disease (CAD) and adverse outcomes in an emergency department (ED) population judged to be at low to intermediate risk for acute coronary syndrome.MethodsInformed consent was obtained from consecutive ED patients who presented with chest pain and were evaluated with coronary computed tomography angiography (cCTA). Cardiac risk factors, clinical presentation, electrocardiogram, and laboratory studies were recorded; the Thrombolysis in Myocardial Infarction (TIMI) and Global Registry of Acute Coronary Events (GRACE) scores were tabulated. Coronary computed tomography angiography findings were rated on a 6-level plaque burden scale and classified for significant CAD (stenosis ≥ 50%). Adverse cardiovascular outcomes were recorded at 30 days.ResultsAmong 250 patients evaluated by cCTA, 143 (57%) had no CAD, 64 (26%) demonstrated minimal plaque (< 30% stenosis), 26 (10%) demonstrated mild plaque (< 50% stenosis), 9 (4%) demonstrated moderate single vessel disease (50%-70% stenosis), 2 (1%) demonstrated moderate multivessel disease, and 6 (2%) demonstrated severe disease (> 70% stenosis). Six patients developed adverse cardiovascular outcomes. Among traditional cardiac risk factors, only age (older) and sex (male) were significant independent predictors of CAD. Correlation with CAD was poor for the TIMI (r = 0.12) and GRACE (r = 0.09-0.23) scores. The TIMI and GRACE scores were not useful to predict adverse outcomes. Coronary computed tomography angiography identified severe CAD in all subjects with adverse outcomes.ConclusionAmong ED patients who present with chest pain judged to be at low to intermediate risk for acute coronary syndrome, traditional risk factors are not useful to stratify risk for CAD and adverse outcomes. Coronary computed tomography angiography is an excellent predictor of CAD and outcome.  相似文献   
80.
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