全文获取类型
收费全文 | 10580篇 |
免费 | 625篇 |
国内免费 | 300篇 |
专业分类
耳鼻咽喉 | 148篇 |
儿科学 | 186篇 |
妇产科学 | 111篇 |
基础医学 | 889篇 |
口腔科学 | 80篇 |
临床医学 | 1645篇 |
内科学 | 1981篇 |
皮肤病学 | 13篇 |
神经病学 | 1193篇 |
特种医学 | 1239篇 |
外科学 | 1156篇 |
综合类 | 1552篇 |
预防医学 | 182篇 |
眼科学 | 147篇 |
药学 | 650篇 |
2篇 | |
中国医学 | 237篇 |
肿瘤学 | 94篇 |
出版年
2024年 | 19篇 |
2023年 | 112篇 |
2022年 | 222篇 |
2021年 | 321篇 |
2020年 | 311篇 |
2019年 | 288篇 |
2018年 | 314篇 |
2017年 | 253篇 |
2016年 | 281篇 |
2015年 | 347篇 |
2014年 | 637篇 |
2013年 | 664篇 |
2012年 | 521篇 |
2011年 | 611篇 |
2010年 | 521篇 |
2009年 | 551篇 |
2008年 | 557篇 |
2007年 | 565篇 |
2006年 | 520篇 |
2005年 | 468篇 |
2004年 | 371篇 |
2003年 | 327篇 |
2002年 | 278篇 |
2001年 | 218篇 |
2000年 | 211篇 |
1999年 | 183篇 |
1998年 | 196篇 |
1997年 | 149篇 |
1996年 | 130篇 |
1995年 | 141篇 |
1994年 | 108篇 |
1993年 | 99篇 |
1992年 | 111篇 |
1991年 | 85篇 |
1990年 | 76篇 |
1989年 | 64篇 |
1988年 | 64篇 |
1987年 | 51篇 |
1986年 | 64篇 |
1985年 | 90篇 |
1984年 | 78篇 |
1983年 | 49篇 |
1982年 | 62篇 |
1981年 | 56篇 |
1980年 | 48篇 |
1979年 | 26篇 |
1978年 | 26篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1975年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
目的:报道1例偶然发现的右侧永久性三叉动脉形态、特点,并进行文献复习。方法:利用显微解剖对此例永久性三叉动脉的起源、走行、分支、分布、与后循环连接关系、以及相关动脉解剖特点等进行了研究。结果:此例永久性三叉动脉与脑膜垂体干共干起源于颈内动脉海绵窦段,于展神经外侧进入后颅窝,分支与基底动脉和小脑上动脉吻合,其终末支之一延续为同侧的小脑下后动脉,此动脉与三叉神经关系密切,分支分布于脑干和小脑。结论:永久性三叉动脉与后循环关系复杂,广泛参与正常脑组织供血。 相似文献
82.
Kapilevich LV Nosarev AV Kovalev IV D'yakova EY Baskakov MB 《Bulletin of experimental biology and medicine》2003,135(6):610-612
The involvement of cAMP- and cGMP-dependent signal systems into the regulation of the contractile reaction of smooth muscles of the rabbit pulmonary arteries was studied using a mechanographic method. For modulation of intracellular level of cyclic nucleotides we used adenylate cyclase activators -adrenoceptor agonist isadrin, guanylate cyclase inhibitor methylene blue, penetrating analog dibutyryl-cAMP, and phosphodiesterase inhibitors. The mechanisms of cAMP- and cGMP-dependent regulation of smooth muscle contractile activity were realized in close interrelationship, and the key component of this was cyclic nucleotide phosphodiesterases. The ratio of activities of phosphodiesterase subtypes in smooth-muscle cells can essentially modulate the adrenergic effects in the pulmonary artery wall and even invert them. 相似文献
83.
Cassio V. Penteado 《Surgical and radiologic anatomy : SRA》1983,5(2):125-127
Summary An anatomical study of the superficial and deep circumflex iliac arteries in 43 formalin-fixed cadavers is presented. The origin, calibre, course, branches, symmetry and variations of the vessels are pointed out as well as their special features related to surgical applications.
Etude anatomochirurgicale des artères circonflexes iliaques superficielle et profonde: bases anatomiques de la confection du lambeau libre iliaque composé cutanéo-osseux
Résumé Une étude anatomique des artères circonflexes iliaque superficielle et profonde est effectuée sur 43 cadavres formulés. L'origine, le calibre, le trajet, les branches, la symétrie et les variations des vaisseaux sont mis en évidence ainsi que leurs caractères particuliers en vue d'une application chirurgicale.相似文献
84.
N. N. Lobanova N. I. Medvedev V. I. Popov A. N. Murashev 《Bulletin of experimental biology and medicine》2008,146(6):691-694
Bilateral occlusion of carotid arteries in awake hypertensive rats (SHR-SP) was used as a model of global brain ischemia (duration
of occlusion — until appearance of seizures). In normotensive rats (WKY), no seizures developed over 60 min. We revealed swelling
of mitochondria in dendrites of hippocampal CA1 pyramidal cells, which was more pronounced in SHP-SP than in WKY rats. Blood
pressure and heart rate in SHR-SP rats increased starting from the first minutes of occlusion, while in WKY rats these parameters
remained unchanged. We proved that bilateral occlusion of the carotid arteries in awake SHR-SP rats can be used as an adequate
model of global cerebral ischemia.
Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 146, No. 12, pp. 627–630, December, 2008 相似文献
85.
The aim of the study was to test the hypothesis that baroreceptor unloading increases jejunal fluid absorption rate via an α2-adrenergic effect on electrogenic active transport. In 13 chloralose-anaesthetized cats, the carotid sinus baroreceptors were isolated and perfused with arterial blood, and we studied the effects of a graded decrease in carotid sinus pressure on intestinal vascular resistance, net fluid absorption rate and the potential difference between the intestinal lumen and the peritoneal cavity (PD). Experiments were performed in seven control animals and in six animals pretreated with yohimbine, an α2-adrenergic antagonist, at a dose of 0.1 mg kg-I i.v. Yohimbine per se had no significant effects on systemic arterial pressure, intestinal vascular resistance, net fluid absorption rate or PD. In the control animals, baroreceptor unloading induced an increase in systemic arterial pressure, intestinal vascular resistance and net fluid absorption rate, and a decrease in the PD. Yohimbine pretreatment did not significantly affect the systemic blood pressure response to baroreceptor unloading, but abolished the effect on intestinal vascular resistance and PD. After yohimbine treatment, decreases in carotid sinus pressure still enhanced net fluid absorption rate, but this response was observed in a higher range of carotid sinus pressures than in control animals. We conclude that (1) a major component of the increase in jejunal absorption rate during baroreceptor unloading is due to a non-electrogenic mechanism, which may be either active or passive; (2) this component of the response is not blocked by yohimbine at a dose sufficient for an effect on presynaptic α2-receptors; (3) the absorptive response to baroreceptor unloading is not a phenomenon secondary to the concomitant jejunal vasoconstriction. 相似文献
86.
S. Juskiewenski Ph. Vaysse J. Moscovici S. Hammoudi E. Bouissou 《Surgical and radiologic anatomy : SRA》1982,4(2):101-107
Summary Two arterial systems contribute to the blood supply of the penis. The deeper system, responsible for supplying the erectile tissues, arises from the internal pudendal arteries (a. pudendae internae), or sometimes from an accessory internal artery. Four branches, either collateral or terminal, should be considered: the artery to the bulb of the penis, the urethral artery, the deep artery of the penis and the dorsal artery of the penis. Variations are frequently present in the origin, distribution and symmetry of these arteries, but on the whole the blood supply is organised into three planes, inferior or ventral, middle and deep, superior or dorsal. These three planes are complementary: when the blood supply to any one of them is occluded, at whatever level this may be, the blood supply is supplemented by the plane immediately above it. Arteriograms should be interpreted with caution because anatomical variations may at first sight be taken for pathological change.The superficial system, supplying the tissues around the erectile organs, arises from the lateral inferior pudendal arteries. Three types of supply have been described, according to whether the right and left arteries have a symmetrical distribution or whether the arterial network arises in large part or totally from one side.
Contribution à l'étude de la vascularisation artérielle du pénis
Résumé Deux systèmes artériels participent à la vascularisation du pénis. Le système profond, tenant sous sa dépendance les organes érectiles, a pour origine les artères honteuses internes (a. pudendae internae), parfois une artère interne accessoire. Quatre branches, collatérales ou terminales sont à considérer: l'artère du bulbe du pénis, l'artère urètrale, l'artère profonde du pénis, l'artère dorsale. Il existe de fréquentes variations dans l'origine, la distribution et la symétrie de ces artères mais, dans son ensemble, la vascularisation est organisée selon trois plans, inférieur ou ventral, moyen ou profond, supérieur ou dorsal. Ces trois plans sont complémentaires: lorsque l'un d'eux s'épuise, à quelque niveau que ce soit, le relais est pris par le plan immédiatement supérieur.Le système superficiel, vascularisant les enveloppes provient des artères honteuses externes inférieures. Trois types de vascularisation sont décrits, selon que les deux artères droite et gauche ont une distribution symétrique ou que le réseau artériel provient en majeure partie ou totalement d'un seul côté.相似文献
87.
Rutger L. van Bezooijen Marco C. DeRuiter Nathalie Vilain Rui M. Monteiro Annemieke Visser Lianne van der Wee‐Pals Conny J. van Munsteren Pancras C.W. Hogendoorn Michel Aguet Christine L. Mummery Socrates E. Papapoulos Peter Ten Dijke Clemens W.G.M. Löwik 《Developmental dynamics》2007,236(2):606-612
Spatial-temporal regulation of bone morphogenetic protein (BMP) and Wnt activity is essential for normal cardiovascular development, and altered activity of these growth factors causes maldevelopment of the cardiac outflow tract and great arteries. In the present study, we show that SOST, a Dan family member reported to antagonize BMP and Wnt activity, is expressed within the medial vessel wall of the great arteries containing smooth muscle cells. The ascending aorta, aortic arch, brachiocephalic artery, common carotids, and pulmonary trunk were all associated with SOST expressing smooth muscle cells, while the heart itself, including the valves, and more distal arteries, that is, pulmonary arteries, subclavian arteries, and descending aorta, were negative. SOST was expressed from embryonic day 15.5 up to the neonatal period. SOST expression, however, did not correspond with inhibition of Smad-dependent BMP activity or beta-catenin-dependent Wnt activity in the great arteries. Activity of both signaling pathways was already down-regulated before induction of SOST expression. 相似文献
88.
Daudu PA Roy A Rozanov C Mokashi A Lahiri S 《Respiratory physiology & neurobiology》2002,130(1):21-31
The hypothesis that chelation of free iron, by decreasing reactive oxygen species (ROS), might mimic hypoxia and stimulate the carotid body was tested. We used the iron chelators, desferrioxamine (DFO, 200-400 microM) initially, and later ciclopirox olamine (CPX, 2.5-5.0 microM), on rat carotid body in vitro and measured chemosensory activity and [Ca2+]i in isolated cultured glomus cell clusters during normoxia and hypoxia. Although acute treatment of DFO might not penetrate the cell, and extracellular DFO would not influence these activities whereas CPX significantly increased chemosensory activities as well as increased [Ca2+]i in normoxia. We concluded that chelation of extracellular free iron did not alter ROS formation and oxygen sensing. Chelation of intracellular free iron and, therefore, a decrease in intracellular ROS appears to influence oxygen sensing in the carotid body. 相似文献
89.
Matturri L Ottaviani G Lavezzi AM 《Virchows Archiv : an international journal of pathology》2005,447(1):74-80
Cigarette smoking is associated with an increased incidence of atherosclerotic diseases. The aim of this study was to examine the progression of the preatherosclerotic lesions previously observed by us in coronary arteries of fetuses of smoker mothers and in infants with smoker parents. We examined the coronary arteries of 34 infants, aged 1–36 months, and the histological and biological [c-fos, proliferating cell nuclear antigen (PCNA), and apoptosis] features of the early atherosclerotic lesions. In 17 infants (50%), at least one parent smoked, generally more than five cigarettes a day. In 18 cases (53%), we observed variable thickening of the coronary walls from preatherosclerotic lesions to juvenile atherosclerotic plaques, related to parental smoking habit. This morphological progression of the lesions was accompanied by a sequence of biological changes in the smooth muscle cells of the tunica media. We suggest that the oxidants present in the gas phase of the parental cigarette smoke pass through the endothelium and induce at first the c-fos gene activation and subsequently the PCNA positivity, that is, a proliferative process. 相似文献
90.
Björn Jonson Rolf Nilsén Hans-Göran Karlsson 《Medical & biological engineering & computing》1975,13(2):209-213
The relationship between the arterial blood pressure and the volume of the arteries within a segment of an extremity is nonlinear. The present paper shows how the flow and volume pulsations of the arteries within a limb segment can be simulated taking this property into account. An electrical model was constructed comprising one resistor and two voltage dependent ‘capacitors’, the latter corresponding to the pressure dependent elasticity, or compliance, of the arteries. Adequate simulations were obtained over a wide pressure range, which is impossible with linear models. The nonlinear, i.e. pressure dependent, relationship between the volume and pressure of arteries, observed under static conditions, must also be taken into consideration when studying pulsatile events with models whether mathematical or physical. 相似文献