全文获取类型
收费全文 | 34221篇 |
免费 | 2502篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 374篇 |
儿科学 | 1219篇 |
妇产科学 | 707篇 |
基础医学 | 4364篇 |
口腔科学 | 642篇 |
临床医学 | 4321篇 |
内科学 | 6375篇 |
皮肤病学 | 425篇 |
神经病学 | 3136篇 |
特种医学 | 971篇 |
外国民族医学 | 1篇 |
外科学 | 4674篇 |
综合类 | 480篇 |
一般理论 | 32篇 |
预防医学 | 3583篇 |
眼科学 | 613篇 |
药学 | 2345篇 |
中国医学 | 31篇 |
肿瘤学 | 2509篇 |
出版年
2023年 | 192篇 |
2022年 | 274篇 |
2021年 | 761篇 |
2020年 | 491篇 |
2019年 | 845篇 |
2018年 | 907篇 |
2017年 | 675篇 |
2016年 | 704篇 |
2015年 | 789篇 |
2014年 | 1153篇 |
2013年 | 1679篇 |
2012年 | 2568篇 |
2011年 | 2605篇 |
2010年 | 1449篇 |
2009年 | 1336篇 |
2008年 | 2340篇 |
2007年 | 2383篇 |
2006年 | 2347篇 |
2005年 | 2312篇 |
2004年 | 2118篇 |
2003年 | 1825篇 |
2002年 | 1757篇 |
2001年 | 347篇 |
2000年 | 313篇 |
1999年 | 348篇 |
1998年 | 361篇 |
1997年 | 282篇 |
1996年 | 233篇 |
1995年 | 234篇 |
1994年 | 203篇 |
1993年 | 182篇 |
1992年 | 179篇 |
1991年 | 183篇 |
1990年 | 166篇 |
1989年 | 170篇 |
1988年 | 163篇 |
1987年 | 151篇 |
1986年 | 125篇 |
1985年 | 120篇 |
1984年 | 136篇 |
1983年 | 127篇 |
1982年 | 122篇 |
1981年 | 124篇 |
1980年 | 89篇 |
1979年 | 87篇 |
1978年 | 87篇 |
1977年 | 65篇 |
1975年 | 62篇 |
1973年 | 66篇 |
1972年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Phase I study of high-dose cytosine arabinoside and etoposide in patients with advanced malignancies
Bayard L. Powell Hyman B. Muss Robert L. Capizzi Mary E. Caponera Douglas R. White Patricia J. Zekan James N. Atkins Don V. Jackson Jr. Frederick Richards II John B. Craig Julia M. Cruz Charles L. Spurr 《Cancer chemotherapy and pharmacology》1987,19(3):250-252
Summary Cytosine arabinsodie (ara-C) and etoposide (VP-16) display synergy in the laboratory. Twenty-six patients participated in a phase I study of high-dose ara-C in combination with VP-16. The dose of VP-16 was held constant at 50 mg/m2 as an intermittent infusion over 33 h; escalating doses of ara-C were given as infusions during hours 9–12 and 21–24. Myelosuppression was the dose-limiting toxicity and occurred with doses considerably less than those expected from studies of the two drugs as single agents. The suggested initial doses for phase II trials with this schedule are 750 mg/m2×2 doses of ara-C and 50 mg/m2 of VP-16. Nonhematologic toxicity was minimal; therefore, further dose escalation is feasible in patients in whom myelosuppression is acceptable.Supported in part by grants from the National Cancer Institute (CA-12197 and CA-09422) and the American Cancer Society CF-85-182 相似文献
22.
Elevated levels of the NR2C subunit of the NMDA receptor in the locus coeruleus in depression. 总被引:2,自引:0,他引:2
Low levels of the intracellular mediator of glutamate receptor activation, neuronal nitric oxide synthase (nNOS) were previously observed in locus coeruleus (LC) from subjects diagnosed with major depression. This finding implicates abnormalities in glutamate signaling in depression. Receptors responding to glutamate in the LC include ionotropic N-methyl-D-aspartate receptors (NMDARs). The functional NMDAR is a hetero-oligomeric structure composed of NR1 and NR2 (A-D) subunits. Tissue containing the LC and a nonlimbic LC projection area (cerebellum) was obtained from 13 and 9 matched pairs, respectively, of depressed subjects and control subjects lacking major psychiatric diagnoses. NMDAR subunit composition in the LC was evaluated in a psychiatrically normal subject. NR1 and NR2C subunit immunoreactivities in LC homogenates showed prominent bands at 120 and 135 kDa, respectively. In contrast to NRI and NR2C, very weak immunoreactivity of NR2A and NR2B subunits was observed in the LC. Possible changes in concentrations of NR1 and NR2C that might occur in depression were assessed in the LC and cerebellum. The overall amount of NR1 immunoreactivity was normal in the LC and cerebellum in depressed subjects. Amounts of NR2C protein were significantly higher (+ 61%, p = 0.003) in the LC and modestly, but not significantly, elevated in the cerebellum (+ 35%) of depressives as compared to matched controls. Higher levels of NR2C subunit implicate altered glutamatergic input to the LC in depressive disorders. 相似文献
23.
Michael C. Dalsing MD Melissa Kevorkian BS Beth Raper BA Craig Nixon MS Stephen G. Lalka MD Dolores F. Cikrit MD Joseph L. Unthank PhD Malcolm B. Herring MD 《Annals of vascular surgery》1989,3(2):127-133
This study evaluates the potential for endothelial seeding of a collagen-impregnated Dacron graft with or without surface modifiers (fibronectin, heparin) to attach and retain these cells during flow. Human umbilical endothelial cells were harvested, cultured, labeled with Indium111-oxine and seeded onto 30 mm X 4 mm diameter grafts. Six graft surfaces were studied: 1) a collagen-impregnated Dacron graft, HemashieldR (C); 2) C + fibronectin (C + F); 3) C + heparin (C + H); 4) C + F + H; 5) HytrelR + F (Hyt + F); and 6) Hyt + F + H. Radioactive loss determined the percentage attachment and then percentage retention of labeled inoculum after a one-hour in vitro perfusion. Scanning electron and light microscopy demonstrated the endothelium on the graft surface following perfusion. Fibronectin-coated grafts had a significantly higher percentage attachment than those without fibronectin (ANOVA, P less than 0.05). However, the percentage retention following perfusion was similar for all Dacron grafts and statistically inferior to the HytrelR grafts studied (ANOVA, P less than 0.05). SEM evaluation of the C + F + H graft surface was qualitatively the most impressive Dacron surface for seeding, yet was inferior to the HytrelR graft. We conclude that fibronectin benefits the initial attachment of endothelium to collagen-coated Dacron rivaling the HytrelR surface. Fibronectin does not improve percentage retention of the HemashieldR surface during perfusion, therefore, some of its initial benefit is lost. 相似文献
24.
Heung Bae Kim James J Pomposelli Craig W Lillehei Roger L Jenkins Maureen M Jonas Laura E Krawczuk Steven J Fishman 《Liver transplantation》2005,11(11):1389-1394
Extrahepatic portal vein thrombosis (EHPVT) may occur in children or adults and usually comes to clinical attention due to complications of portal hypertension such as variceal hemorrhage. A variety of standard surgical techniques exist to manage these patients, but when these fail surgical options are limited. We describe two novel portosystemic shunts that utilize the gonadal vein as an autologous conduit. Four patients were evaluated for EHPVT with variceal bleeding. None of the patients were candidates for a standard splenorenal shunt due to prior surgical procedures. The first patient underwent a left mesogonadal shunt and the remaining 3 patients underwent a right mesogonadal shunt. Postoperative ultrasound or computed tomography (CT) scan confirmed early patency of the shunt in each patient. There have been no further episodes of variceal hemorrhage with follow-up of 3.5 years in the child who underwent the left mesogonadal shunt, and 17, 19, and 20 months in the patients who underwent the right mesogonadal shunt. Three of the 4 shunts remain patent. One shunt thrombosis occurred in a patient homozygous for the Factor V Leiden mutation despite anticoagulation with coumadin. This is the first report of the successful use of the gonadal vein as an in situ conduit for constructing a portosystemic shunt. In conclusion, the right and left mesogonadal shunts may be useful as salvage operations for patients with EHPVT who have failed standard surgical shunt procedures. 相似文献
25.
26.
27.
Alan Willmore Tim Sladden Lucy Bates Craig B Dalton 《International journal of health geographics》2006,5(1):30-14
Background
To determine patterns of childhood lead exposure in a community living near a lead and zinc smelter in North Lake Macquarie, Australia between 1991 and 2002. 相似文献28.
29.
30.
Sanjay Sisodiya J Helen Cross Ingmar Blümcke David Chadwick John Craig Peter B Crino Paul Debenham Norman Delanty Frances Elmslie Mark Gardiner Jeffrey Golden David Goldstein David A Greenberg Renzo Guerrini Michael Hanna John Harris Paul Harrison Michael R Johnson George Kirov Dimitri M Kullman Andrew Makoff Carla Marini Rima Nabbout Lina Nashef Jeffrey L Noebels Ruth Ottman Munir Pirmohamed Asla Pitk?nen Ingrid Scheffer Simon Shorvon Graeme Sills Nicholas Wood Sameer Zuberi 《Epileptic Disord》2007,9(2):194-236
The Sixth Epilepsy Research Foundation workshop, held in Oxford in March 2006, brought together basic scientists, geneticists, epidemiologists, statisticians, pharmacologists and clinicians to consider progress, issues and strategies for harnessing genetics to improve the understanding and treatment of the epilepsies. General principles were considered, including the fundamental importance of clear study design, adequate patient numbers, defi ned phenotypes, robust statistical data handling, and follow-up of genetic discoveries. Topics where some progress had been made were considered including chromosomal abnormalities, neurodevelopment, hippocampal sclerosis, juvenile myoclonic epilepsy, focal cortical dysplasia and pharmacogenetics. The ethical aspects of epilepsy genetics were reviewed. Principles and limitations of collaboration were discussed. Presentations and their matched discussions are produced here. There was optimism that further genetic research in epilepsy was not only feasible, but might lead to improvements in the lives of people with epilepsy. 相似文献