全文获取类型
收费全文 | 1670篇 |
免费 | 108篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 53篇 |
妇产科学 | 34篇 |
基础医学 | 157篇 |
口腔科学 | 84篇 |
临床医学 | 88篇 |
内科学 | 391篇 |
皮肤病学 | 65篇 |
神经病学 | 146篇 |
特种医学 | 56篇 |
外科学 | 411篇 |
综合类 | 5篇 |
一般理论 | 1篇 |
预防医学 | 61篇 |
眼科学 | 12篇 |
药学 | 80篇 |
中国医学 | 2篇 |
肿瘤学 | 141篇 |
出版年
2023年 | 18篇 |
2022年 | 30篇 |
2021年 | 48篇 |
2020年 | 21篇 |
2019年 | 43篇 |
2018年 | 57篇 |
2017年 | 54篇 |
2016年 | 42篇 |
2015年 | 54篇 |
2014年 | 67篇 |
2013年 | 87篇 |
2012年 | 114篇 |
2011年 | 96篇 |
2010年 | 42篇 |
2009年 | 51篇 |
2008年 | 103篇 |
2007年 | 101篇 |
2006年 | 99篇 |
2005年 | 96篇 |
2004年 | 88篇 |
2003年 | 91篇 |
2002年 | 66篇 |
2001年 | 49篇 |
2000年 | 43篇 |
1999年 | 36篇 |
1998年 | 15篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 18篇 |
1991年 | 16篇 |
1990年 | 19篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 9篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1790条查询结果,搜索用时 15 毫秒
1.
2.
Stefano Di Domenico Giulio Bovio Maximiliano Gelli Ferruccio Ravazzoni Enzo Andorno Damiano Cottalasso Umberto Valente 《BMC surgery》2007,7(1):18
Background
Liver transplantation in presence of diffuse portal vein thrombosis is possible by using caval blood as portal inflow, through cavo-portal transposition. However, clinical results are heterogeneous and experimental studies are needed, but similar hemodynamic conditions are difficult to obtain, especially in small animals. Herein we describe a new simple model of cavo-portal transposition in rat. 相似文献3.
4.
Hemodynamic consequences of right ventricular isolation: the contribution of the right ventricular free wall to cardiac performance 总被引:2,自引:0,他引:2
R J Damiano T Asano P K Smith T B Ferguson J L Cox 《The Annals of thoracic surgery》1988,46(3):324-330
Surgical isolation of the right ventricular free wall was performed in 10 dogs to evaluate both the hemodynamic effects of the procedure and the postoperative contribution of right ventricular free wall contraction to overall cardiac performance. Following the procedure, there was no significant differences in peak right ventricular systolic pressure, right atrial pressure, right ventricular stroke volume, or cardiac index. Cardiac index remained at preoperative levels over a wide range of filling pressures. However, there was a significant decrease in right ventricular stroke work (6.0 +/- 1.3 gm-m/m2 to 5.1 +/- 0.5 gm-m/m2; p less than 0.05). Pacing the isolated right ventricular free wall resulted in marked hemodynamic improvement compared with an electrically silent right ventricular free wall. Cardiac index increased from 1.7 +/- 0.2 L/min/m2 to 2.6 +/- 0.2 L/min/m2 (p less than 0.0005), and right ventricular stroke work went from 3.0 +/- 0.6 gm-m/m2 to 6.4 +/- 0.9 gm-m/m2 (p less than 0.0005). Right ventricular performance was also significantly related to the timing of right ventricular free wall contraction. Thus, the right ventricular free wall played an important role in the maintenance of normal cardiac hemodynamics. 相似文献
5.
6.
Adriano Antonucci Angela Di Baldassarre Franco Di Giacomo Liborio Stuppia Giandomenico Palka 《Ultrastructural pathology》1997,21(5):449-452
Thirty-one patients affected by Down syndrome (DS) were investigated to study the presence of apoptosis in peripheral blood cells in relation to the plasma levels of zinc. Twelve patients had undergone therapy with ZnSO4, while the remaining 19 were untreated. The presence of programmed cell death was evaluated by means of electron microscopy, in situ nick translation (NT), and agarose gel electrophoresis of DNA. These approaches evidenced the presence of apoptosis in peripheral blood cells of patients before therapy with ZnSO4, while after zinc supplementation there was a reduction in the number of apoptotic cells. These results suggest that the process of programmed cell death in peripheral blood cells of patients with Down syndrome is related to the plasma levels of zinc ion. 相似文献
7.
Carlo Alberto Maggi Riccardo Patacchini Paolo Santicioli Sandro Giuliani Damiano Turini Gabriele Barbanti Patrizia Beneforti Daniele Misuri Alberto Meli 《Naunyn-Schmiedeberg's archives of pharmacology》1989,339(4):415-423
Summary (1) Longitudinal muscle strips from the human small intestine (jejunum/ileum) responded to electrical field stimulation (1–50 Hz) with frequency-related primary contractions which were largely atropine- (3 M) sensitive. When the tone was raised by addition of galanin (0.3 – 1 M), prostaglandin (PG) E2 (1–10 M) or neurokinin A (NKA, 0.1 M), a frequency-related relaxation was evident which was potentiated by atropine. All the responses to field stimulation were abolished by tetrodotoxin (1 M), thus indicating their neural origin. (2) The atropine-sensitive primary contraction to field stimulation was virtually abolished by omega conotoxin fraction GVIA (CTX, 0.1–0.3 M) while the relaxations were CTX-resistant. The field stimulation-induced relaxations, which were observed in the presence of atropine and guanethidine (3 M), were also unaffected by apamin (0.1 M). (3) NKA and substance P (SP) produced a concentration- (1 nM–1 M for both peptides) related contraction, NKA being about 53 times more potent than SP. [Pro9]SP sulphone and [MePhe7]-NKB, selective agonists of the NK-1 and NK-3 receptor, respectively, were barely effective. On the other hand, [\Ala8]NKA(4–10), a selective NK-2 receptor agonist, had a potent contractile activity, similar to that of NKA. (4) Galanin (1 nM–1M) produced an atropine- and tetrodotoxin-resistant concentration-related contraction of longitudinal muscle of human isolated small intestine. The response to galanin did not show any sign of fading and was particularly suitable to study the evoked relaxations. (5) Calcitonin gene-related peptide (CGRP) (10–100 nM) consistently inhibited the nerve-mediated contractions of strips from the ileum while the effect on the jejunum was less pronounced. Vasoactive intestinal polypeptide (VIP, 0.1–1 M) inhibited nerve-mediated contractions both in the ileum and the jejunum. (6) These experiments indicate that both cholinergic excitatory and non-adrenergic non-cholinergic nerves affect motility of the longitudinal muscle of the human small intestine. Furthermore, several neuropeptides produce potent motor effects, the contractile response to tachykinins being apparently mediated by activation of NK-2 receptors. 相似文献
8.
Fiore L Plebani A Buttinelli G Fiore S Donati V Marturano J Soresina A Martire B Azzari C Nigro G Cardinale F Trizzino A Pignata C Alvisi P Anastasio E Bossi G Ugazio AG 《Clinical immunology (Orlando, Fla.)》2004,111(1):98-102
Patients with agammaglobulinemia may excrete enteroviruses, including vaccine-derived poliovirus, for prolonged periods of time. This poses a risk to the patients but it also may pose a risk to the population after eradication of poliovirus and the cessation of routine vaccination. To assess this risk, a pilot study was performed to identify potential poliovirus long-term excretors in a cohort of 38 patients with a definite/presumptive diagnosis of X-linked agammaglobulinemia (XLA). Stool samples were analyzed to detect any polio or other enteroviruses replicating in the gut and neutralizing antibodies against polioviruses were measured in the sera. No viruses were isolated from the stool samples and most sera had neutralizing antibody levels against all three poliovirus serotypes considered by the WHO to be protective in immunocompetent individuals. This suggests that long-term excretion of enteroviruses in patients with agammaglobulinemia is relatively uncommon. 相似文献
9.
Damiano Zaccheo Manuela de Michele Maurizio Mancini Francesco Amenta 《Mechanisms of ageing and development》1991,60(3):255-265
The pharmacological profile and the anatomical localization of beta-adrenergic and muscarinic cholinergic receptors of the vasa nervorum were studied in sections of sciatic nerve using radioreceptor binding and light microscope autoradiography techniques. Sprague—Dawley rats of 4 and 24 months of age were used. [3H]Dihydroalprenolol (DHA) and [3H]quinuclidinyl benzilate (QNB) were used to label beta-adrenergic and muscarinic cholinergic receptors, respectively. The ligands were bound to sections of rat sciatic nerve in a manner consistent with the labelling of beta-adrenergic or muscarinic cholinergic receptors in the 2 age groups investigated. The dissociation constant (Kd) values (about 1.37 nM for [3H]DHA and 0.75 nM for [3H]QNB) did not significantly change between 4- and 24-month-old rats. The maximum concentration of binding sites (Bmax) for [3H]DHA was decreased by about 35% in 24 in comparison with 4-month-old rats. The Bmax value autoradiogaphy revealed the development of specific silver grains in the medial layer of epineurial and perineurial arteries in sections of sciatic nerve exposed either to [3H]DHA or [3H]QNB. The number of silver grains developed in epineurial and perineurial arteries of rats of 24 months is significantly lower than in animals of 4 months. The above results suggest the occurrence of an age-dependent loss in the density of beta-adrenergic and muscarinic cholinergic receptors of vasa nervorum. 相似文献
10.
Ultrastructural quantitation of peroxidase- and elastase-containing granules in human neutrophils. 总被引:3,自引:3,他引:3
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
V. V. Damiano U. Kucich E. Murer N. Laudenslager G. Weinbaum 《The American journal of pathology》1988,131(2):235-245
Previous ultrastructural studies of human neutrophils showed two distinctive granule types, the azurophil (peroxidase-positive) and the specific (peroxidase-negative). By identification of granules with peroxidase activity and those immunopositive for elastase antigen, the authors defined two subpopulations of azurophil granules, one that contained peroxidase activity and no measurable elastase antigen and another that contained elastase antigen associated with a small amount of peroxidase activity. They quantitated the peroxidase-positive as well as the elastase-positive granules in human peripheral blood neutrophils and found an average of 1536 +/- 69 peroxidase-positive granules per neutrophil. Of these, 399 +/- 20 were also elastase-positive. The average elastase concentration per neutrophil was 1.59 pg, and the average concentration per granule was 4 X 10(-3) pg. It is concluded that in normal individuals approximately one-third of the azurophil granules contain elastase antigen. Because neutrophil elastase has been implicated in the pathogenesis of emphysema, quantitation of its distribution within the cell presents an approach that may help define selective azurophil granule release and its relationship to the development of emphysema. 相似文献