全文获取类型
收费全文 | 34116篇 |
免费 | 2984篇 |
国内免费 | 1286篇 |
专业分类
耳鼻咽喉 | 139篇 |
儿科学 | 208篇 |
妇产科学 | 201篇 |
基础医学 | 2805篇 |
口腔科学 | 801篇 |
临床医学 | 3736篇 |
内科学 | 2237篇 |
皮肤病学 | 253篇 |
神经病学 | 986篇 |
特种医学 | 927篇 |
外科学 | 1978篇 |
综合类 | 7484篇 |
现状与发展 | 3篇 |
预防医学 | 4012篇 |
眼科学 | 321篇 |
药学 | 6184篇 |
183篇 | |
中国医学 | 5251篇 |
肿瘤学 | 677篇 |
出版年
2024年 | 211篇 |
2023年 | 541篇 |
2022年 | 1499篇 |
2021年 | 1744篇 |
2020年 | 1416篇 |
2019年 | 884篇 |
2018年 | 793篇 |
2017年 | 1110篇 |
2016年 | 1219篇 |
2015年 | 1238篇 |
2014年 | 2415篇 |
2013年 | 2455篇 |
2012年 | 2440篇 |
2011年 | 2557篇 |
2010年 | 1933篇 |
2009年 | 1589篇 |
2008年 | 1619篇 |
2007年 | 1828篇 |
2006年 | 1397篇 |
2005年 | 1166篇 |
2004年 | 1021篇 |
2003年 | 813篇 |
2002年 | 695篇 |
2001年 | 635篇 |
2000年 | 530篇 |
1999年 | 513篇 |
1998年 | 425篇 |
1997年 | 359篇 |
1996年 | 360篇 |
1995年 | 333篇 |
1994年 | 312篇 |
1993年 | 301篇 |
1992年 | 259篇 |
1991年 | 232篇 |
1990年 | 201篇 |
1989年 | 191篇 |
1988年 | 185篇 |
1987年 | 160篇 |
1986年 | 150篇 |
1985年 | 159篇 |
1984年 | 93篇 |
1983年 | 60篇 |
1982年 | 94篇 |
1981年 | 47篇 |
1980年 | 38篇 |
1979年 | 30篇 |
1978年 | 33篇 |
1977年 | 22篇 |
1976年 | 25篇 |
1974年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Lars Bendtsen Rigmor Jensen Jannick Brennum Lars Arendt-Nielsen Jes Olesen 《Cephalalgia : an international journal of headache》1993,13(3):184-191
The duration of the late exteroceptive suppression period (ES2 ) of temporal muscle EMG activity has been reported to be reduced in patients suffering from chronic tension-type headache. Methods of recording and analysing ES2 have varied between centers and reproducibility of results within subjects , although insufficiently studied, has generally been poor. ES2 was investigated in 30 healthy subjects, using a computerized technique of recording, rectifying and averaging the EMG signals. Hour to hour and week to week variations of ES2 durations were calculated, and the influence of pain during a cold pressor test and of sustained muscle contraction on ES2 durations was investigated. The intra-individual variation of ES2 durations was 16.0% from hour to hour and 20.7% from week to week. The inter-individual variation was 36.7%. The present method for analysis of ES2 periods proved to be reliable, as the intra-observer variation was 4.2% and the inter-observer variation 4.6%. ES2 periods were significantly shorter on the first compared to the second day of examination ( p = 0.006) and during experimental pain ( p = 0.0005). We recommend the use of the computerized averaging technique in future studies and caution against the dependence of results upon factors such as conditioning and pain. 相似文献
12.
甲氟哌酸药代动力学研究 总被引:3,自引:0,他引:3
本文报道国产甲氟哌酸片剂的人体药代动力学研究结果。血、尿药物浓度用微生物打孔法测定。健康志愿者口服甲氟哌酸400mg片剂后,体内药物转运过程符合一室开放模型。甲氟哌酸的血药浓度达峰时间、峰浓度为1.27小时和4.76μg/ml。T_(1/2)Ka和T_(1/2)Ke分别为0.22和10.40小时。研究结果表明,甲氟哌酸吸收快,达峰迅速,血清峰浓度有所提高,消除半衰期长,体内分布广泛,值得在临床推广使用。 相似文献
13.
A. E. P. Villa E. M. Rouiller G. M. Simm P. Zurita Y. de Ribaupierre F. de Ribaupierre 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1991,86(3):506-517
Summary Single unit activity of 355 cells was recorded in the auditory thalamus of anesthetized cats before, during, and after the inactivation by cooling of the ipsilateral primary auditory cortex (AI). Most of the units (n = 288) showed similar functional characteristics of firing before and after the cryogenic blockade of AI. The spontaneous firing rate remained unchanged by cooling in 20% of the units and decreased in the majority of them (60%). In some regions, i.e. dorsal division of the medial geniculate body (MGB), lateral part of the posterior group of the thalamus, and auditory sector of the reticular nucleus of the thalamus, the maximum firing rate evoked by white noise bursts was generally affected by cooling in the same direction and to the same extent as the spontaneous activity. Units in the ventral division of MGB showed a characteristic increase of signal-to-noise ratio during cortical cooling. The corticofugal modulation led to the appearance or disappearance of the best frequency of tuning in 51 units and changed it by more than 0.5 octave in 34 units. The bandwidths of different response patterns to pure tones stimulation were used to define a set of functional properties. During cryogenic blockade of AI, two cortically modulated sub-populations of units were usually distinguished that exhibited changes for a given functional property. The complexity and diversity of the effects of cortical inactivation suggest that the corticothalamic projection may be the support for selective operations such as an adaptive filtering of the incoming acoustic signal at the thalamic level adjusted as a function of cortical activity. 相似文献
14.
15.
K Kamakura S Ishiura S Imajoh N Nagata H Sugita 《Journal of neuroscience research》1992,31(3):543-548
The ubiquitous existence of calcium-activated neutral protease (CANP, calpain), an enzyme whose activity is regulated by calcium ions and a specific endogenous CANP inhibitor (calpastatin), is well known. Although there has been much investigation concerning the distribution and role of CANP, investigations of the distribution of the CANP inhibitor using immunohistochemical techniques are rare. We made antiserum against a 40K fragment of cDNA corresponding to two C-terminal repeats of rat liver CANP inhibitor expressed in Escherichia coli. Using this antiserum, we examined the distribution of CANP inhibitor in the rat central nervous system by the ABC technique and compared it with the distribution of CANP. Neurons and glias were stained, with the cytosol stained diffusely and the cell membranes stained clearly and strongly. Axons and myelin were stained faintly, but nuclei and vessels were not stained. The distribution of CANP inhibitor was thus found to be similar to that of CANP. 相似文献
16.
17.
近年来由于训练强度不断增大,高水平运动员心律失常的发生率显著增加。本文研究资料表明,男心律失常组安静时心搏量明显大于正常组(P<0.05),而运动后心搏量降低(正常组心搏量增加),说明心律失常的运动员心脏储备能力差,心脏泵血功能降低,应予慎重对待。 相似文献
18.
采用连续延伸PCR方法克隆到粗糙脉孢菌(Neurospora crassa)漆酶基因,并将其克隆到表达载体pPIC9k,重组质粒经线性化、电激转化Pichia pastoris KM71,部分阳性克隆的PCR结果表明:漆酶基因已整合到巴斯德毕赤酵母染色体上,重组菌经甲醇诱导后3~5d产漆酶量最高,为2-3U/mL。 相似文献
19.
Evaluation of renal first pass blood flow with a functional image technique in hypertensive patients
Masatoshi Ishibashi Seiichiro Morita Noriyoshi Umezaki Hisashi Ohtake 《European journal of nuclear medicine and molecular imaging》1988,14(1):25-27
The renal circulation of patients with essential hypertension and renovascular hypertension was evaluated using 99mTc-DTPA. The first renal peak count (the first Cmax; FCmax), time phase distribution (the first Tmax; FTmax), and blood velocity (the FCmax/FTmax) were calculated by digital imaging. This yields a visual image of the renal circulation. We consider that the increase in the renal first pass blood flow in patients with essential hypertension is best observed pixel by pixel. The FCmax and FCmax/FTmax images before and after treatment by percutaneous transluminal renal angioplasty in patients with renovascular hypertension clearly show its therapeutic effect. The FI technique, therefore, has the advantage that it can be performed at the same time as the conventional routine examinations of renal function. This makes it very useful clinically. 相似文献
20.
本文对肺部三种疾病1536例患者的病历资料,按病种作了统计归类。运用模糊数学原理建立了征候一疾病间的模糊关系矩阵,用参量加权模糊综合评判模型,对肺部三种疾病鉴别诊断的符合率达82.91%以上,因此认为文中建立的模型,对肺部三种疾病鉴别诊断具有参考价值。 相似文献