全文获取类型
收费全文 | 1257篇 |
免费 | 76篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 90篇 |
妇产科学 | 10篇 |
基础医学 | 109篇 |
口腔科学 | 26篇 |
临床医学 | 141篇 |
内科学 | 281篇 |
皮肤病学 | 20篇 |
神经病学 | 41篇 |
特种医学 | 318篇 |
外科学 | 133篇 |
综合类 | 14篇 |
一般理论 | 1篇 |
预防医学 | 39篇 |
眼科学 | 6篇 |
药学 | 41篇 |
肿瘤学 | 68篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 13篇 |
2018年 | 17篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 21篇 |
2014年 | 19篇 |
2013年 | 34篇 |
2012年 | 23篇 |
2011年 | 34篇 |
2010年 | 35篇 |
2009年 | 28篇 |
2008年 | 31篇 |
2007年 | 57篇 |
2006年 | 38篇 |
2005年 | 35篇 |
2004年 | 31篇 |
2003年 | 16篇 |
2002年 | 17篇 |
2001年 | 18篇 |
2000年 | 12篇 |
1999年 | 24篇 |
1998年 | 96篇 |
1997年 | 70篇 |
1996年 | 76篇 |
1995年 | 52篇 |
1994年 | 54篇 |
1993年 | 61篇 |
1992年 | 12篇 |
1991年 | 12篇 |
1990年 | 13篇 |
1989年 | 40篇 |
1988年 | 25篇 |
1987年 | 40篇 |
1986年 | 24篇 |
1985年 | 29篇 |
1984年 | 24篇 |
1983年 | 17篇 |
1982年 | 22篇 |
1981年 | 23篇 |
1980年 | 28篇 |
1979年 | 6篇 |
1978年 | 16篇 |
1977年 | 18篇 |
1976年 | 20篇 |
1975年 | 13篇 |
1970年 | 2篇 |
排序方式: 共有1344条查询结果,搜索用时 15 毫秒
231.
232.
RAJ Windhaber AG Holbrook RJ Krysztopik 《Annals of the Royal College of Surgeons of England》2010,92(4):e10-e11
Chylothorax is a well-recognised complication of oesophagectomy, occurring in around 3% of cases. If managed conservatively, the mortality rate can be over 50%. We describe our experience of managing a patient with a chylothorax following oesophagectomy, and the use of a blood patch (a novel technique) to overcome persistent leakage following re-operation. The authors feel that this technique has the potential for a wider application in the treatment of chyle leak, especially if combined with minimally invasive or radiological techniques. 相似文献
233.
234.
Michael JJ Chu Rakesh Premkumar Anthony JR Hickey Yannan Jiang Brett Delahunt Anthony RJ Phillips Adam SJR Bartlett 《World journal of gastroenterology : WJG》2016,22(19):4673-4684
AIM: To assess the effects of ischemic preconditioning (IPC, 10-min ischemia/10-min reperfusion) on steatotic liver mitochondrial function after normothermic ischemia-reperfusion injury (IRI).
METHODS: Sixty male Sprague-Dawley rats were fed 8-wk with either control chow or high-fat/high-sucrose diet inducing > 60% mixed steatosis. Three groups (n = 10/group) for each dietary state were tested: (1) the IRI group underwent 60 min partial hepatic ischemia and 4 h reperfusion; (2) the IPC group underwent IPC prior to same standard IRI; and (3) sham underwent the same surgery without IRI or IPC. Hepatic mitochondrial function was analyzed by oxygraphs. Mitochondrial Complex-I, Complex-II enzyme activity, serum alanine aminotransferase (ALT), and histological injury were measured.
RESULTS: Steatotic-IRI livers had a greater increase in ALT (2476 ± 166 vs 1457 ± 103 IU/L, P < 0.01) and histological injury following IRI compared to the lean liver group. Steatotic-IRI demonstrated lower Complex-I activity at baseline [78.4 ± 2.5 vs 116.4 ± 6.0 nmol/(min.mg protein), P < 0.001] and following IRI [28.0 ± 6.2 vs 104.3 ± 12.6 nmol/(min.mg protein), P < 0.001]. Steatotic-IRI also demonstrated impaired Complex-I function post-IRI compared to the lean liver IRI group. Complex-II activity was unaffected by hepatic steatosis or IRI. Lean liver mitochondrial function was unchanged following IRI. IPC normalized ALT and histological injury in steatotic livers but had no effect on overall steatotic liver mitochondrial function or individual mitochondrial complex enzyme activities.
CONCLUSION: Warm IRI impairs steatotic liver Complex-I activity and function. The protective effects of IPC in steatotic livers may not be mediated through mitochondria. 相似文献
235.
236.
237.
OBJECTIVE: Prevotella intermedia has been reported to be associated with periodontal disease whilst P. nigrescens has predominantly been isolated from more specific conditions and healthy sites. The aim of the present study was to compare the enzyme activity of these species.
MATERIALS AND METHODS Nine strains of P. intermedio and 12 strains of P. nigrescens were studied. Lipolytic. saccharolytic, nucleolytic and proteolytic activity was determined by traditional microbiological and chromo-genic substrate methods.
RESULTS: All strains hydrolysed gelatine, casein. DNA and RNA. Lipase activity was produced by all strains except P. nigrescens ATCC 33563T . Lipolytic activity of P. nigrescens strains decreased as the environmental glucose concentration was increased. Only two strains, both P. intermedia , hydrolysed benzyl-arg-p-nitroanilide. All strains hydrolysed alkaline pnitrophenolphosphate (except P. intermedia DAL 100). produced glycylprolyl dipeptidase activity and demonstrated elastase-like activity. All but three strains (2 P. intermedia and I P. nigrescens) hydrolysed suc-ala-ala-pro-phe-p-nitroanilide. Overall, no qualitatively analysed enzyme activity was exclusive to all strains of either species. Quantitatively analysed activity exhibited a high degree of variability both within and between species.
CONCLUSIONS: P. intermedia and P. nigrescens degrade natural and synthetic substrates, but intra- and interspec-ies activity is variable. 相似文献
MATERIALS AND METHODS Nine strains of P. intermedio and 12 strains of P. nigrescens were studied. Lipolytic. saccharolytic, nucleolytic and proteolytic activity was determined by traditional microbiological and chromo-genic substrate methods.
RESULTS: All strains hydrolysed gelatine, casein. DNA and RNA. Lipase activity was produced by all strains except P. nigrescens ATCC 33563
CONCLUSIONS: P. intermedia and P. nigrescens degrade natural and synthetic substrates, but intra- and interspec-ies activity is variable. 相似文献
238.
N Molenaar RM Bijkerk A Beishuizen CM Hempen MF de Jong I Vermes G van der Sluijs Veer AR Girbes AJ Groeneveld 《Critical care (London, England)》2012,16(4):R121-9
ABSTRACT: INTRODUCTION: This study was aimed at characterizing basal and adrenocorticotropic hormone (ACTH)-induced steroidogenesis in sepsis and nonsepsis patients with a suspicion of critical illness-related corticosteroid insufficiency (CIRCI), taking the use of etomidate-inhibiting 11β-hydroxylase into account. METHOD: This was a prospective study in a mixed surgical/medical intensive care unit (ICU) of a university hospital. The patients were 62 critically ill patients with a clinical suspicion of CIRCI. The patients underwent a 250-μg ACTH test (n = 67). ACTH, adrenal steroids, substrates, and precursors (modified tandem mass spectrometry) also were measured. Clinical characteristics including use of etomidate to facilitate intubation (n = 14 within 72 hours of ACTH testing) were recorded. RESULTS: At the time of ACTH testing, patients had septic (n = 43) or nonseptic critical illness (n = 24). Baseline cortisol directly related to sepsis and endogenous ACTH, independent of etomidate use. Etomidate was associated with a lower baseline cortisol and cortisol/11β-deoxycortisol ratio as well as higher 11β-deoxycortisol, reflecting greater 11β-hydroxylase inhibition in nonsepsis than in sepsis. Cortisol increases < 250 mM in exogenous ACTH were associated with relatively low baseline (HDL-) cholesterol, and high endogenous ACTH with low cortisol/ACTH ratio, independent of etomidate. Although cortisol increases with exogenous ACTH, levels were lower in sepsis than in nonsepsis patients, and etomidate was associated with diminished increases in cortisol with exogenous ACTH, so that its use increased, albeit nonsignificantly, low cortisol increases to exogenous ACTH from 38% to 57%, in both conditions. CONCLUSIONS: A single dose of etomidate may attenuate stimulated more than basal cortisol synthesis. However, it may only partly contribute, particularly in the stressed sepsis patient, to the adrenal dysfunction of CIRCI, in addition to substrate deficiency. 相似文献
239.
自美国国家骨髓库(NMDP)开展第一例无关供者移植以来,至今已有20年.NMDP目前的库容量已逾700万,已为6大洲提供了30 000多份无关供者造血干细胞.这一辉煌成就是美国国家骨髓库600多名工作人员共同努力的结果,同时也得益于广泛的国际合作,包括171个移植中心,73个供者中心,24个脐血库,97个骨髓采集中心,91个血液净化中心,26个HLA分型实验室和26个合作供者登记处.本文回顾了美国国家骨髓库的历史,阐述了20年来移植病人、移植物来源和预处理方案几方面的主要变化趋势. 相似文献
240.