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   3018篇
  免费   157篇
  国内免费   11篇
耳鼻咽喉   22篇
儿科学   129篇
妇产科学   78篇
基础医学   346篇
口腔科学   60篇
临床医学   253篇
内科学   631篇
皮肤病学   54篇
神经病学   171篇
特种医学   108篇
外科学   504篇
综合类   47篇
一般理论   4篇
预防医学   129篇
眼科学   78篇
药学   287篇
中国医学   9篇
肿瘤学   276篇
  2023年   29篇
  2022年   72篇
  2021年   157篇
  2020年   51篇
  2019年   86篇
  2018年   122篇
  2017年   72篇
  2016年   76篇
  2015年   73篇
  2014年   123篇
  2013年   150篇
  2012年   261篇
  2011年   267篇
  2010年   127篇
  2009年   125篇
  2008年   166篇
  2007年   164篇
  2006年   125篇
  2005年   113篇
  2004年   106篇
  2003年   111篇
  2002年   61篇
  2001年   51篇
  2000年   58篇
  1999年   51篇
  1998年   24篇
  1997年   13篇
  1996年   13篇
  1995年   12篇
  1992年   19篇
  1991年   23篇
  1990年   23篇
  1989年   20篇
  1988年   21篇
  1987年   28篇
  1986年   20篇
  1985年   18篇
  1984年   13篇
  1983年   18篇
  1979年   15篇
  1978年   5篇
  1977年   7篇
  1976年   6篇
  1975年   7篇
  1974年   11篇
  1973年   11篇
  1972年   6篇
  1971年   11篇
  1970年   5篇
  1969年   5篇
排序方式: 共有3186条查询结果,搜索用时 15 毫秒
31.
32.
33.
Objective  Cushing syndrome (CS) in children is associated with symptoms that may impair health related quality of life (HRQL). There are no prospective reports of HRQL in children with CS.
Methods  Prospective study of 40 children (mean age 13 ± 3·2 years) with CS evaluated prior to and 1-year post-treatment. The Child Health Questionnaire (CHQ) was used to assess HRQL; Wechsler Intelligence Scale for Children (WASI) was used to assess cognitive function, and patient-reported symptoms were assessed with a CS symptom checklist.
Results  Active CS was associated with low physical and psychosocial summary scores compared to US population data ( P <  0·001). Despite improvement from pre- to 1-year postcure, residual impairment remained in physical summary and function, and role-physical, global health and emotional impact (parent) scores. Incomplete recovery of adrenal function at 1-year post-treatment was associated with impaired scores. WASI IQ scores declined and a correlation was noted between age at first evaluation and IQ score changes. Most self-reported CS symptoms showed improvement, but forgetfulness, unclear thinking and decreased attention span did not improve after cure of CS.
Conclusion  CS in children and adolescents is associated with impaired HRQL, with residual impairment 1 year after cure. Our results also suggest that younger children are more likely to experience negative changes in cognitive function. HRQL is an important outcome measure in children and adolescents with CS and identification of factors that contribute to HRQL may help to diminish the physical and psychological burden of disease in this population of patients.  相似文献   
34.
35.
Atrial reentrant tachycardias are a common source of morbidity in children with significant structural heart disease, especially following cardiac surgery. Preexisting atrial geometry combined with the hemodynamic effect of a congenital cardiac defect and electrophysiological alterations caused by surgical lesions can create large anatomic-functional barriers to conduction, allowing reentrant wavefronts to flourish. Elucidation of the genesis of reentrant arrhythmias in children has led to catheterization and surgical therapies. The primary goals of these procedures are to restore synchronous atrioventricular conduction and eliminate hemodynamically significant residual physiologic lesions. Debilitating arrhythmias may be cured, and patients have an improvement in functional class.  相似文献   
36.
37.
Clinical Rheumatology - To address the diagnostic delay in axial spondyloarthritis (axSpA), we have cross-culturally adapted the Hamilton axSpA questionnaire, a self-administered screening...  相似文献   
38.
The usefulness of fluorescence in studying protein motions derives from its sensitivity, kinetic resolution, and compatibility with both live cells and physiological assays. Recent advances in microscopy and membrane protein purification have permitted the observation of fluorescence changes that accompany the functional transitions of complex eukaryotic membrane proteins. These techniques rely on probes that can clearly report the environmental changes of specific residues, but most commonly available side-chain-reactive probes are not well suited for this purpose. Here, we introduce a red Cys-reactive probe, aminophenoxazone maleimide (APM), designed with improved chemical and spectral properties for reporting protein conformational change. APM is compact, uncharged, and has a short linker between probe and protein, all of which ensure that it can closely track the motions of the side chain to which it is attached. It undergoes large polarity-dependent changes in Stokes shift, as well as large bathochromic shifts in both excitation maximum (from 521 nm in toluene to 598 nm in water) and emission maximum (580 nm to 633 nm). These polarity-dependent spectral changes offer a potentially simple means of relating fluorescence to local structure and motion, although they are partially offset by some complicating factors in APM fluorescence. We find that, like a rhodamine maleimide, APM senses the conformational changes underlying voltage sensing in the Shaker potassium channel, and it is superior at a site that shows limited reactivity to the rhodamine. The spectral characteristics of APM can also report subtle differences between aqueous positions in purified preparations of the beta2 adrenergic receptor.  相似文献   
39.
40.

Objectives

To evaluate the ovicidal and oviposition deterrent activities of five medicinal plant extracts namely Aegle marmelos (Linn.), Limonia acidissima (Linn.), Sphaeranthus indicus (Linn.), Sphaeranthus amaranthoides (burm.f), and Chromolaena odorata (Linn.) against Culex quinquefasciatus and Aedes aegypti mosquitoes. Three solvents, namely hexane, ethyl acetate, and methanol, were used for the preparation of extracts from each plant.

Methods

Four different concentrations—62.5 parts per million (ppm), 125 ppm, 250 ppm, and 500 ppm—were prepared using acetone and tested for ovicidal and oviposition deterrent activities. One-way analysis of variance (ANOVA) was used to determine the significance of the treatments and means were separated by Tukey''s test of comparison.

Results

Among the different extracts of the five plants screened, the hexane extract of L. acidissima recorded the highest ovicidal activity of 79.2% and 60% at 500 ppm concentration against the eggs of Cx. quinquefasciatus and Ae. aegypti, respectively. Similarly, the same hexane extract of L. acidissima showed 100% oviposition deterrent activity at all the tested concentrations against Cx. quinquefasciatus and Ae. aegypti adult females.

Conclusion

It is concluded that the hexane extract of L. acidissima could be used in an integrated mosquito management program.  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