首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7526篇
  免费   590篇
  国内免费   84篇
耳鼻咽喉   72篇
儿科学   350篇
妇产科学   160篇
基础医学   825篇
口腔科学   189篇
临床医学   901篇
内科学   1482篇
皮肤病学   132篇
神经病学   613篇
特种医学   553篇
外科学   956篇
综合类   159篇
一般理论   2篇
预防医学   804篇
眼科学   164篇
药学   401篇
  2篇
中国医学   6篇
肿瘤学   429篇
  2023年   66篇
  2022年   104篇
  2021年   233篇
  2020年   107篇
  2019年   172篇
  2018年   216篇
  2017年   150篇
  2016年   143篇
  2015年   194篇
  2014年   229篇
  2013年   300篇
  2012年   350篇
  2011年   356篇
  2010年   232篇
  2009年   237篇
  2008年   314篇
  2007年   337篇
  2006年   255篇
  2005年   274篇
  2004年   235篇
  2003年   202篇
  2002年   177篇
  2001年   167篇
  2000年   185篇
  1999年   143篇
  1998年   178篇
  1997年   185篇
  1996年   175篇
  1995年   140篇
  1994年   162篇
  1993年   132篇
  1992年   109篇
  1991年   124篇
  1990年   115篇
  1989年   128篇
  1988年   122篇
  1987年   101篇
  1986年   115篇
  1985年   96篇
  1984年   78篇
  1983年   70篇
  1982年   67篇
  1981年   63篇
  1980年   59篇
  1979年   61篇
  1978年   61篇
  1977年   44篇
  1976年   50篇
  1973年   32篇
  1970年   30篇
排序方式: 共有8200条查询结果,搜索用时 31 毫秒
1.

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   
2.
3.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
4.
5.
6.
7.
Microinjection of the indirect GABAA antagonist, picrotoxin, or the mu opioid agonist, Tyr-D-Ala-Gly-NMe-Phe-Gly-ol (DAGO), into the ventral pallidum and substantia innominata (VP/SI) increases locomotor activity in rats. The VP/SI has direct and indirect projections to the region of the ventral mesencephalon containing dopamine perikarya, and to certain dopamine terminal fields, including the nucleus accumbens. Thus, it is possible that modulation of the mesocorticolimbic dopamine system by pharmacological stimulation in the VP/SI may play a role in the locomotor stimulant response. It was shown that pretreatment with dopamine receptor antagonists, either peripherally or microinjected into the nucleus accumbens significantly attenuated the motor stimulant effect of DAGO or picrotoxin injection into the VP/SI. Injection of either picrotoxin or DAGO into the VP/SI increased the levels of dopamine metabolites in the nucleus accumbens and prefrontal cortex. Thus, the motor stimulant response following pharmacological stimulation of the VP/SI appears to be mediated by increased dopamine neurotransmission via feedback mechanisms to the mesocorticolimbic dopamine system.  相似文献   
8.
The aim of this study was to evaluate the cerebral synthesis of eicosanoids in the asphyctic newborn and to investigate the relation between the prostanoid profiles in cerebrospinal fluid (CSF) and the appearance and severity of hypoxic-ischaemic encephalopathy (HIE). Levels of 6-keto-PGF 1-α, TXB2, PGE2 and PGF2-α in CSF were measured in 40 full term newborns during the first day of life. Thirty of these newborns had birth asphyxia and were divided into three groups: 10 without HIE, 12 with mild HIE and 8 with moderate-severe HIE. They were compared to a control group of 10 non-hypoxic newborns. Determinations of the metabolites in CSF were performed by RIA and expressed as pg/ml (mean ± SD). The CSF TXB2 (thromboxane A2 metabolite) in asphyxiated newborns was always higher than in the control group (28.12 ± 10.6), and related to the severity of HIE ( p = 0:005): without HIE (50.84 ± 16.4; p = 0:02), mild HIE (80.65 ± 12.64; p ± 0:01) and moderate-severe HIE (178.14 ± 20.5; p < 0:01). The CSF 6-keto-PGF 1-α (prostacyclin metabolite) in asphyxiated newborns was always higher than in the control group (80.55 ± 12.56), but indirectly related to the severity of HIE: without HIE (240.95 ± 28.12; p < 0:01), mild HIE (183.65 ± 30.1; p < 0:01) and moderate-severe HIE (140.55 ± 25.12; p < 0:01). In the moderate-severe HIE group, the increase in TXB2 was higher than the rise in 6-keto-PGF 1-α.  相似文献   
9.
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号