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   1431篇
  免费   68篇
耳鼻咽喉   15篇
儿科学   42篇
妇产科学   34篇
基础医学   190篇
口腔科学   9篇
临床医学   87篇
内科学   242篇
皮肤病学   33篇
神经病学   211篇
特种医学   57篇
外科学   224篇
综合类   2篇
预防医学   96篇
眼科学   22篇
药学   160篇
中国医学   2篇
肿瘤学   73篇
  2023年   8篇
  2022年   19篇
  2021年   34篇
  2020年   20篇
  2019年   40篇
  2018年   29篇
  2017年   22篇
  2016年   19篇
  2015年   23篇
  2014年   41篇
  2013年   43篇
  2012年   99篇
  2011年   71篇
  2010年   53篇
  2009年   50篇
  2008年   71篇
  2007年   73篇
  2006年   75篇
  2005年   66篇
  2004年   64篇
  2003年   66篇
  2002年   55篇
  2001年   44篇
  2000年   61篇
  1999年   40篇
  1998年   7篇
  1996年   9篇
  1995年   15篇
  1994年   7篇
  1993年   8篇
  1992年   29篇
  1991年   19篇
  1990年   27篇
  1989年   13篇
  1988年   16篇
  1987年   7篇
  1986年   7篇
  1985年   12篇
  1984年   10篇
  1983年   8篇
  1980年   6篇
  1979年   10篇
  1978年   7篇
  1973年   11篇
  1972年   8篇
  1971年   5篇
  1970年   10篇
  1969年   6篇
  1967年   9篇
  1966年   5篇
排序方式: 共有1499条查询结果,搜索用时 31 毫秒
1.
2.

Objective  

The aim of the project was to assess the effectiveness and safety of weekly epoetin-beta (EB) in patients with gastrointestinal cancer (GIC) subjected to concomitant chemoradiotherapy (CCTRT).  相似文献   
3.
An ECG and respiration-gated spin-labeling gradient-echo imaging technique is proposed for the quantitative and completely noninvasive measurement and mapping of myocardial perfusion in small animals in vivo. In contrast to snapshot FLASH imaging, the spatial resolution of the perfusion maps is not limited by the heart rate. A significant improvement in image quality is achieved by synchronizing the inversion pulse to the respiration movements of the animals, thereby allowing for spontaneous respiration. High-resolution myocardial perfusion maps (in-plane resolution=234 x 468 microm2) demonstrating the quality of the perfusion measurement were obtained at 4.7 T in a group of seven freely breathing Wistar-Kyoto rats under isoflurane anesthesia. The mean perfusion value (group average +/- SD) was 5.5 +/- 0.7 ml g(-1)min(-1). In four animals, myocardial perfusion was mapped and measured under cardiac dobutamine stress. Perfusion increased to 11.1 +/- 1.9 ml g(-1)min(-1). The proposed method is particularly useful for the study of small rodents at high fields.  相似文献   
4.
5.
Between 1985-1990 we studied by means of two-dimensional echocardiography 286 patients with isolated ventricular septal defect (VSD). A hundred and sixty three being male and 123 female, as a mean age of 5 +/- 3 months. Sixty two cases (22.3%) reveales associated anomalies and in other 63 (22.4%) there was in the evolution an aneurysm of the septum membranous. The projections used were apical 4-chamber, with or without aortic root; parasternal long-short axis of great arterias or at ventricular level; subcostal 4-chamber; right oblique outlet right outflow tract and left oblique outlet left and right outflow tracts. Patients with VSD smaller than 3 mm were excluded. Perimembranous defects, 189 cases (66%), were more frequent than muscular, 91 31.8%), and subarterial defects, 6 (2.1%). Only 19 (9 apical muscular, 6 perimembranous outlet and 4 perimembranous trabecular) were initially misclassified. The diameter of the VSD was large in subarterial (0.85 +/- 0.1 cm) and perimembranous outlet VSD (0.75 +/- 0.5 cm) compared with the rest. Each group of defects was more easily shown by one particular projection except trabecular muscular defect. In conclusion, we are able to state that two-dimensional echocardiography enables us to discover the size and situation of isolated ventricular defects.  相似文献   
6.
STUDY OBJECTIVE--This study examined the incidence of cervical cancer and survival rates according to migrant experience of women from different regions of Spain to Girona, Catalonia (Spain). DESIGN--Using data from the population based cancer registry of Girona for the period 1980-89, crude and age adjusted incidence rates were calculated for local-born and first generation migrants from other Spanish regions. The age standardised rate ratio (SRR) was calculated and Cox's regression model was used to adjust survival according to migrant status for age and stage at diagnosis. MAIN RESULTS--The incidence of cervical cancer was significantly higher in first generation Spanish migrants compared with locally born women (SRR: 2.02; 95% CI 1.40:2.92). The stage at diagnosis was more advanced among migrants. Survival probability was significantly associated with stage at diagnosis, but age and region of birth were not. CONCLUSIONS--Migrants from the southern Spanish regions show a twofold excess in the incidence of cervical cancer compared with the Girona-born female population. Cases of cervical cancer in migrants are diagnosed at a more advanced stage and as a consequence have a poorer prognosis.  相似文献   
7.
An infant was born to a woman who received intravenous esmolol for intrapartum supraventricular tachyarrhythmia. Despite the very short acting and cardio-selective beta-1 adrenergic blockade induced by that agent, neonatal effects can occur up to 48 hours after delivery.  相似文献   
8.
9.
10.
The hippocampus and amygdala, the entorhinal cortex and the parietal cortex participate, in that sequence, both in the formation and in the expression of memory for a step-down inhibitory avoidance task in rats. Bilateral infusion of AP5 or muscimol caused retrograde amnesia when given O min after training into both hippocampus and amygdala, when given or 180 min after training into the entorhinal cortex, or when given 180 min after training into the parietal cortex. Therefore, memory formation requires the sequential and integrated activity of all these areas mediated by glutamate NMDA receptors in each case. Pre-test administration of CNQX 1 day after training into hippocampus and amygdala, 1 or 31 days after training in entorhinal cortex, or 1, 31 or 60 days after training in the parietal cortex temporarily blocked retention test performance. Therefore, 1 day after training, all these brain structures are necessary for retrieval; 1 month later, the hippocampus and amygdala are no longer necessary for retrieval but the entorhinal and parietal cortex still are; and 60 days after training only the parietal cortex is needed. In all cases the mechanisms of retrieval require intact glutamate AMPA receptors.  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