全文获取类型
收费全文 | 14144篇 |
免费 | 1365篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 109篇 |
儿科学 | 370篇 |
妇产科学 | 282篇 |
基础医学 | 1727篇 |
口腔科学 | 310篇 |
临床医学 | 1740篇 |
内科学 | 2489篇 |
皮肤病学 | 135篇 |
神经病学 | 1201篇 |
特种医学 | 498篇 |
外科学 | 1935篇 |
综合类 | 271篇 |
一般理论 | 6篇 |
预防医学 | 1577篇 |
眼科学 | 957篇 |
药学 | 1117篇 |
中国医学 | 14篇 |
肿瘤学 | 783篇 |
出版年
2023年 | 97篇 |
2022年 | 142篇 |
2021年 | 328篇 |
2020年 | 179篇 |
2019年 | 301篇 |
2018年 | 321篇 |
2017年 | 234篇 |
2016年 | 256篇 |
2015年 | 298篇 |
2014年 | 386篇 |
2013年 | 573篇 |
2012年 | 724篇 |
2011年 | 700篇 |
2010年 | 377篇 |
2009年 | 347篇 |
2008年 | 701篇 |
2007年 | 679篇 |
2006年 | 604篇 |
2005年 | 629篇 |
2004年 | 596篇 |
2003年 | 511篇 |
2002年 | 462篇 |
2001年 | 415篇 |
2000年 | 476篇 |
1999年 | 363篇 |
1998年 | 138篇 |
1997年 | 115篇 |
1996年 | 124篇 |
1995年 | 120篇 |
1994年 | 127篇 |
1993年 | 101篇 |
1992年 | 307篇 |
1991年 | 282篇 |
1990年 | 266篇 |
1989年 | 240篇 |
1988年 | 235篇 |
1987年 | 228篇 |
1986年 | 205篇 |
1985年 | 211篇 |
1984年 | 173篇 |
1983年 | 145篇 |
1982年 | 111篇 |
1981年 | 84篇 |
1979年 | 142篇 |
1978年 | 130篇 |
1977年 | 95篇 |
1976年 | 82篇 |
1974年 | 97篇 |
1973年 | 95篇 |
1972年 | 85篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
James A. Akingbasote Alison J. Foster Ian Wilson Sunil Sarda Huw B. Jones J. Gerry Kenna 《Archives of toxicology》2016,90(4):853-862
Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN?) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [14C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [14C]-diclofenac was incubated with HRN? mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN? mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN? mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN? mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN? mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN? mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment. 相似文献
2.
Paul J. Devlin Brian W. McCrindle James K. Kirklin Eugene H. Blackstone William M. DeCampli Christopher A. Caldarone Ali Dodge-Khatami Pirooz Eghtesady James M. Meza Peter J. Gruber Kristine J. Guleserian Bahaaladin Alsoufi Linda M. Lambert James E. OBrien Erle H. Austin Jeffrey P. Jacobs Tara Karamlou 《The Journal of thoracic and cardiovascular surgery》2019,157(2):684-695.e8
Objective
Arch obstruction after the Norwood procedure is common and contributes to mortality. We determined the prevalence, associated factors, and practice variability of arch reintervention and assessed whether arch reintervention is associated with mortality.Methods
From 2005 to 2017, 593 neonates in the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort underwent a Norwood procedure. Median follow-up was 3.7 years. Multivariable parametric models, including a modulated renewal analysis, were performed.Results
Of the 593 neonates, 146 (25%) underwent 218 reinterventions for arch obstruction after the Norwood procedure: catheter-based (n = 168) or surgical (n = 50) at a median age of 4.3 months (quartile 1-quartile 3, 2.6-5.7). Interdigitation of the distal aortic anastomosis was protective against arch reintervention. Development of ≥ moderate tricuspid valve regurgitation and right ventricular dysfunction at any point was associated with arch reintervention. Nonsignificant variables for arch reintervention included shunt type and preoperative aortic measurements. Surgical arch reintervention was protective against arch reintervention, but transcatheter reintervention was associated with increased reintervention. Arch reintervention was not associated with increased mortality. There was wide institutional variation in incidence of arch reintervention (range, 0-40 reinterventions per 100 years patient follow-up) and in preintervention gradient (range, 0-64 mm Hg).Conclusions
Interdigitation of the distal aortic anastomosis during the Norwood procedure decreased the risk of arch reintervention. Surgical arch reintervention is more definitive than transcatheter. Arch reintervention after the Norwood procedure is not associated with increased mortality. Serial surveillance for arch obstruction, integrated with changes in right ventricular function and tricuspid valve regurgitation, is recommended after the Norwood procedure to improve outcomes. 相似文献3.
The term “oligometastatic prostate cancer” refers to a heterogeneous group of disease states currently defined solely on the basis of clinical features. Oligorecurrent disease, de novo oligometastases, and oligoprogressive disease likely have unique biologic underpinnings and natural histories. Evidence suggesting the existence of a subset of patients who harbor prostate cancer with limited metastatic potential currently includes disparate and overwhelmingly retrospective reports. Nevertheless, emerging prospective data have corroborated the “better-than-expected,” retrospectively observed outcomes, particularly in the setting of oligorecurrent prostate cancer. Improved functional imaging with prostate-specific membrane antigen-targeted strategies may enhance the identification of patients with oligometastatic prostate cancer in the short term. In the long term, refinement of the oligometastatic case definition likely will require biologic risk-stratification schemes. To determine optimal treatment strategies and identify patients most likely to benefit from metastasis-directed therapy, future efforts should focus on conducting high-quality, prospective trials with much-needed molecular correlative studies. 相似文献
4.
5.
6.
7.
Alpha-melanocyte-stimulating hormone reduces endotoxin-induced liver inflammation. 总被引:6,自引:1,他引:5 下载免费PDF全文
H Chiao S Foster R Thomas J Lipton R A Star 《The Journal of clinical investigation》1996,97(9):2038-2044
Alpha-Melanocyte-stimulating hormone (MSH) is a potent anti-inflammatory agent in many models of inflammation, suggesting that it inhibits a critical step common to different forms of inflammation. We showed previously that alpha-MSH inhibits nitric oxide (NO) production in cultured macro-phages. To determine how alpha-MSH acts in vivo, we induced acute hepatic inflammation by administering endotoxin (LPS) to mice pretreated with Corynebacterium parvum, alpha-MSH prevented liver inflammation even when given 30 min after LPS administration. To determine the mechanisms of action of alpha-MSH, we tested its influence on NO, infiltrating inflammatory cells, cytokines, and chemokines. Alpha-MSH inhibited systemic NO production, hepatic neutrophil infiltration, and increased hepatic mRNA abundance for TNF alpha, and the neutrophil and monocyte chemokines (KC/IL-8 and MCP-1). We conclude that alpha-MSH prevents LPS-induced hepatic inflammation by inhibiting production of chemoattractant chemokines which then modulate infiltration of inflammatory cells. Thus, alpha-MSH has an effect very early in the inflammatory cascade. 相似文献
8.
9.
10.
C L Grady A M Grimes N Patronas T Sunderland N L Foster S I Rapoport 《Archives of neurology》1989,46(3):317-320
To determine if impaired dichotic performance in patients with dementia of the Alzheimer type is due to the inability to divide attention or the inability to perceive degraded auditory stimuli, we measured performance on tasks of both dichotic and degraded monotic speech materials. We also examined whether perception of degraded speech stimuli presented monaurally is related to abnormalities of temporal lobe anatomy and physiology, as we have shown for dichotic performance. Although the patients were impaired on both dichotic and monotic tests, significantly greater impairment was seen on the dichotic test. Our earlier finding of a significant relation between dichotic performance and measures of anterior temporal lobe atrophy and reduced glucose metabolism was replicated, but no significant relation was found between monotic tests and measures to temporal lobe integrity. We conclude that the inability to divide attention, rather than abnormal processing of degraded stimuli per se, is reflected in poor dichotic performance in patients with dementia of the Alzheimer type, and that dichotic performance, unlike degraded monotic perception, depends directly on the integrity of temporal cortex in these patients. 相似文献