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   3208篇
  免费   208篇
  国内免费   11篇
耳鼻咽喉   34篇
儿科学   65篇
妇产科学   70篇
基础医学   798篇
口腔科学   39篇
临床医学   261篇
内科学   786篇
皮肤病学   77篇
神经病学   271篇
特种医学   109篇
外科学   299篇
综合类   36篇
一般理论   2篇
预防医学   206篇
眼科学   60篇
药学   215篇
中国医学   2篇
肿瘤学   97篇
  2023年   25篇
  2022年   33篇
  2021年   80篇
  2020年   28篇
  2019年   59篇
  2018年   66篇
  2017年   55篇
  2016年   36篇
  2015年   57篇
  2014年   67篇
  2013年   104篇
  2012年   136篇
  2011年   135篇
  2010年   88篇
  2009年   64篇
  2008年   115篇
  2007年   138篇
  2006年   137篇
  2005年   111篇
  2004年   107篇
  2003年   110篇
  2002年   97篇
  2001年   25篇
  2000年   39篇
  1999年   31篇
  1998年   28篇
  1997年   21篇
  1992年   21篇
  1989年   21篇
  1987年   22篇
  1984年   26篇
  1982年   28篇
  1978年   23篇
  1975年   18篇
  1974年   22篇
  1973年   19篇
  1972年   20篇
  1937年   16篇
  1934年   35篇
  1933年   40篇
  1932年   23篇
  1931年   44篇
  1930年   29篇
  1929年   19篇
  1928年   40篇
  1926年   22篇
  1925年   16篇
  1924年   20篇
  1923年   26篇
  1922年   21篇
排序方式: 共有3427条查询结果,搜索用时 15 毫秒
71.
"White coat" versus "sustained" borderline hypertension in Tecumseh, Michigan   总被引:10,自引:0,他引:10  
During a survey of young subjects not receiving treatment for hypertension in Tecumseh, Michigan, clinic and self-monitored blood pressures taken at home (14 readings in 7 days) were obtained in 737 subjects (387 men, 350 women, average age 31.5 years). Hypertension in the clinic was diagnosed if the clinic blood pressure exceeded 140 mm Hg systolic or 90 mm Hg diastolic. In the absence of firm criteria for what constitutes hypertension at home, subjects whose average home blood pressure was in the upper decile of the whole population were considered to have hypertension at home. By these criteria, 7.1% of the whole population had "white coat" hypertension (i.e., high clinic but not elevated home readings). The prevalence of "sustained" hypertension (i.e., high readings in the clinic and at home) was 5.1%. Subjects with white coat and sustained borderline hypertension in Tecumseh were very similar. Both groups showed, at previous examinations (at ages 5, 8, 21, and 23 years), significantly higher blood pressure readings than the normotensive subjects. As young adults (average age 33.3 years), the parents of both hypertensive groups had significantly higher blood pressure readings than the parents of normotensive subjects. Both hypertensive groups had faster heart rates, higher systemic vascular resistance, and higher minimal forearm vascular resistance. Both hypertensive groups were more overweight, had higher plasma triglycerides, insulin, and insulin/glucose ratios than normotensive subjects. The white coat hypertensive group also had lower values of high density lipoprotein than the normotensive group. White coat hypertension is a frequent condition.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
72.
Primary linitis plastica of the rectum   总被引:2,自引:0,他引:2  
Five cases of primary linitis plastica of the rectum are presented. The clinical, radiologic, and pathologic features of the disease are described with emphasis on the difficulty in establishing a correct preoperative diagnosis. Because the histologic features of primary and secondary linitis plastica are indistinguishable and because secondary involvement is twice as common as primary, it is mandatory that other sites of origin are excluded and that both the proximal and distal margins of the resected area be free of tumor. Read at the joint meeting of the American Society of Colon and Rectal Surgeons and the Royal Society of Medicine, London, England, June 18 to 20, 1979.  相似文献   
73.
The effect of elevating venous pressure (ΔPv) on the transcapillary escape of albumin (QT) in control and papverinized gracilis muscles perfused at constant flow was determined by means of direct monitoring of the rate of accumulation of tissue 125I-labeled albumin radioactivity. Simultaneously, transcapillary fluid movement (FM) was assessed volumetrically. Under control isovolumetric conditions, QT = 2.25 mg/min · 100 g. In addition to causing an FM of 0.03 ml/min · 100 g · mm Hg, increasing Pv enhanced QT by 0.06 mg/min · 100 g · mm Hg. Papverinization itself decreased QT to 2.0 mg/min · 100 g and affected FM only slightly. However, the superposition of Pv elevation caused a FM of 0.008 ml/min · 100 g · mm Hg and resulted in QT increasing by 0.29 mg/min · 100 g · mm Hg. The results of this study indicate that QT is sensitive to changes in microvascular hemodynamics, and thus changes in microvascular pressure may affect FM in two ways, first by increasing the transcapillary pressure gradient and second by augmenting QT which may superimpose an oncotic adjunct to FM.  相似文献   
74.
The medicinal plant, Syzygium leucoxylon or commonly known as Obah found in North Borneo was considered as traditional medicine by local committee. Two new phenolics, leucoxenols A (1) and B (2) were isolated and identified as major secondary metabolites from the leaves of S. leucoxylon. Their chemical structures were elucidated based on spectroscopic data such as NMR and HRESIMS. Furthermore, these compounds were active against selected strains of fungi.  相似文献   
75.
76.
77.
Recently, electrophysiological evidence was given for inhibitory postsynaptic responses at dopaminergic striatal synapses. These responses were independent of the vesicular GABA transporter, VGAT, but dependent on the vesicular dopamine transporter VMAT2. The identity and the exact source of the released molecule, as well as the presence of the putative inhibitory transmitter in VMAT2 containing synaptic vesicles remain to be shown. To clarify this, in particular to determine whether GABA is responsible for the inhibitory response at dopaminergic synapses, we used the electron microscopic immunogold method to label in vivo perfusion fixed striatal tissue with antibodies recognising GABA, VGAT, VMAT2 and tyrosine hydroxylase. We show that about 13 % of tyrosine hydroxylase positive and 11 % of VMAT2 axonal terminals in the caudo-putamen contain significant labelling for GABA. Immunogold signals for tyrosine hydroxylase and VGAT was totally segregated into different pools of nerve terminals. Quantitative analyses of the distance between gold particles signalling GABA and synaptic vesicles showed that GABA was as closely associated with synaptic vesicles in tyrosine hydroxylase positive as in tyrosine hydroxylase negative nerve terminals. Likewise, in dopaminergic terminals GABA and VMAT2 immunogold particles showed a close spatial localization, strongly suggesting the presence of GABA in VMAT2 positive synaptic vesicles. Our results suggest that GABA is exocytosed together with dopamine from dopaminergic nerve terminals in the caudo-putamen through VGAT negative and VMAT2 positive synaptic vesicles.  相似文献   
78.
79.
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