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   350篇
  免费   9篇
  国内免费   1篇
耳鼻咽喉   18篇
儿科学   40篇
妇产科学   4篇
基础医学   36篇
口腔科学   10篇
临床医学   64篇
内科学   38篇
皮肤病学   4篇
神经病学   7篇
特种医学   28篇
外科学   32篇
综合类   23篇
预防医学   15篇
眼科学   5篇
药学   27篇
中国医学   4篇
肿瘤学   5篇
  2022年   3篇
  2021年   6篇
  2020年   3篇
  2019年   8篇
  2018年   3篇
  2017年   4篇
  2016年   2篇
  2015年   8篇
  2014年   24篇
  2013年   23篇
  2012年   19篇
  2011年   14篇
  2010年   13篇
  2009年   20篇
  2008年   5篇
  2007年   10篇
  2006年   8篇
  2005年   6篇
  2004年   2篇
  2003年   8篇
  2002年   4篇
  2001年   2篇
  2000年   8篇
  1999年   2篇
  1998年   14篇
  1997年   19篇
  1996年   11篇
  1995年   9篇
  1994年   10篇
  1993年   12篇
  1991年   4篇
  1990年   5篇
  1989年   3篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   2篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1978年   3篇
  1977年   1篇
  1976年   1篇
  1958年   1篇
  1957年   2篇
  1956年   2篇
  1954年   2篇
  1952年   16篇
  1951年   23篇
  1950年   2篇
排序方式: 共有360条查询结果,搜索用时 15 毫秒
91.
BACKGROUND: One of the most recognizable features of psychopathy is the reduced ability to successfully learn and adapt overt behavior. This might be due to deficient processing of error information indicating the need to adapt controlled behavior. METHODS: Event-related potentials (ERPs) and behavioral components of error-monitoring processes were investigated in 16 individuals with psychopathy and in 18 healthy subjects. A letter version of the Eriksen flanker task was used in two conditions. The first condition (normal condition) required participants to press one of two buttons depending on the identity of the target stimulus. The second condition (signaling condition) required them to signal each time they had committed an error by making a second press on a signaling button. Early stages of error monitoring were investigated by using the error-related negativity (ERN/Ne) and post-error slowing as indexes. Later stages were explored by examining the error positivity (Pe) and signaling rates. RESULTS: Both groups showed similar ERN amplitudes and amounts of post-error slowing. The psychopathic group exhibited both reduced Pe amplitudes and diminished error-signaling rates compared with the control group. CONCLUSIONS: Individuals with psychopathy show intact early error processing and automatic behavioral adaptation but have deficits in later stages of error processing and controlled behavioral adaptation. This is an indication that individuals with psychopathy are unable to effectively use error information to change their behavior adequately.  相似文献   
92.
In one neonatal intensive care unit during a 15 month period 6 infants developed septicaemia which was resistant to antibiotic treatment. The infants' mean gestational age and birthweight were 32.7 weeks and 1519 g respectively. Intravenous infusions of polymorphonuclear leucocytes were given. Three infants died and the remainder survived without complications. No side effects of the treatment were identified.  相似文献   
93.
94.
目的:探讨能谱CT虚拟平扫(VNC)替代常规平扫在肾癌中的临床应用价值。方法回顾分析32例经病理证实为肾癌的患者影像资料,均行能谱CT常规平扫及动脉期、静脉期能谱成像(GSI),采用MSI软件生成动脉期VNC和静脉期VNC图像。分别测量3组图像(常规平扫、动脉期VNC、静脉期VNC)肾脏病灶的CT值、病灶-正常肾脏的对比噪声比(CNR),同层面病灶的长径、橫径,采用单因素方差分析;由2位放射科医师对3组图像分别行5分制图像质量主观评分,3分制影像学征象主观评分,对2位医师评价结果的一致性行Kappa 检验,对3组图像的图像质量主观评分行单因素方差分析。结果2位医师对3组图像评价结果的一致性较好(Kappa 值均>0.700);3组图像间图像质量主观评分无统计学差异(P>0.05);影像学征象主观评分动脉期 VNC为2.88±0.34,静脉期VNC为2.84±0.37,均可接受。3组图像的CNR分别为0.52±0.11、0.72±0.16、0.69±0.12,动脉期VNC、静脉期 VNC的对比噪声比(CNR)均高于常规平扫,有统计学差异(P<0.05)。3组图像同层面病灶的长径和横径无统计学差异(P>0.05)。3组图像肾脏病灶的CT值分别为(30.04±4.09)HU、(32.69±4.07)HU、(32.56±3.52)HU,有统计学差异(P<0.05),常规平扫病灶的CT值低于动脉期 VNC和静脉期 VNC,但差值均在5 HU内。结论在肾癌检查中 VNC能替代常规平扫,可减少患者的扫描次数,降低辐射剂量。  相似文献   
95.
96.
2±7.2)天,住院时间(13.2±6.4)天vs(23.6±4.8)天(P<0.05,<0.01).结论 与常规胸穿术比较,C型套管针辅助胸腔内置入细胃管治疗结核性胸腔积液方法更加简单、安全、有效.  相似文献   
97.
98.
PURPOSE: To evaluate the long-term outcome of involutional entropion repair by means of a combined procedure of lateral tarsal strip and Quickert everting sutures. METHODS: Noncomparative interventional case series of patients who underwent a combined procedure of lateral tarsal strip and Quickert sutures for treatment of involutional entropion between September 1999 and September 2002. Of 75 patients who underwent surgery, 36 were followed for at least 2 years. At the 2-year clinical examination, patient comfort, complications, recurrence rates, overcorrection, and cosmetic appearance were assessed. RESULTS: The average age of the 36 patients was 76.67 years. There were 5 bilateral cases, for a total of 41 eyelids. Nine eyelids underwent the procedure to correct recurrent entropion. The recurrence rate was 0% at 1 month after surgery, 2 of 41(4.9%) at 6 months, and 5 of 41 (12.2%) at 2 years. The recurrence rate after a primary procedure was 3 of 32 (9.4%), and, after a failed previous procedure, 2 of 9 (22.2%). There were no cases of secondary ectropion, and all patients were happy with their cosmetic appearance. CONCLUSIONS: A combined lateral tarsal strip and Quickert sutures procedure is effective, simple, and addresses all of the factors that contribute to involutional entropion formation, with a good long-term success rate and cosmetic outcome.  相似文献   
99.
The changes in the male voice in relation to the biological characteristics of puberty were assessed longitudinally in 26 boys. Speaking and singing fundamental frequencies were analysed in relation to the Tanner staging of puberty, saliva testosterone levels, and the Cooksey classification of voice analysis. There were abrupt changes in voice characteristics between Tanner stages G3 and G4 and more gradually from stages C3 to C5 of Cooksey. Although testosterone concentrations were not predictive of the changes, there was a correlation with testis volume. Voice fundamental frequencies were seen to change abruptly in late puberty, in contrast with previous studies. There is a good correlation between the Tanner and Cooksey methods of classification during male puberty.  相似文献   
100.
Nitric oxide (NO) regulates blood flow in the human placenta. As increased resistance to blood flow is seen in the fetal-placental vasculature in pregnancies complicated by pre-eclampsia and/or intrauterine growth restriction (IUGR), we examined expression of endothelial nitric oxide synthase (eNOS) in these placentas. Placental villous tissue sections were obtained from normotensive control (n = 5), IUGR alone (n = 5) or pre-eclamptic (with or without IUGR (n = 9) patients, immunostained for eNOS and scored for localization, type (punctate or diffuse) and intensity of eNOS staining in syncytiotrophoblast and placental vessels. The significance of differences was calculated using the Mann-Whitney U-test. No differences in intensity or type of immunostaining in syncytiotrophoblast were seen. Placentas from patients with pre- eclampsia with or without IUGR had a significantly more basal distribution of eNOS in syncytiotrophoblast. eNOS immunostaining was absent in terminal villous capillary and faint in stem villous vessel endothelium of normal placentas, but was intense in the endothelium of both of these types of vessels in the IUGR and pre-eclampsia groups, with significantly greater staining seen in stem vessels of patients with IUGR alone. This increased eNOS expression and hence increased NO production in the fetal-placental vasculature may be an adaptive response to the increased resistance and poor perfusion in these pathological pregnancies.   相似文献   
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