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   410篇
  免费   24篇
耳鼻咽喉   28篇
儿科学   11篇
妇产科学   8篇
基础医学   43篇
口腔科学   25篇
临床医学   23篇
内科学   49篇
皮肤病学   2篇
神经病学   47篇
特种医学   62篇
外科学   55篇
综合类   2篇
预防医学   21篇
药学   31篇
肿瘤学   27篇
  2021年   3篇
  2020年   6篇
  2019年   5篇
  2018年   6篇
  2017年   9篇
  2016年   4篇
  2015年   10篇
  2014年   7篇
  2013年   19篇
  2012年   23篇
  2011年   15篇
  2010年   9篇
  2009年   11篇
  2008年   16篇
  2007年   15篇
  2006年   18篇
  2005年   13篇
  2004年   12篇
  2003年   11篇
  2002年   16篇
  2001年   14篇
  2000年   10篇
  1999年   19篇
  1998年   7篇
  1997年   5篇
  1995年   5篇
  1994年   2篇
  1993年   2篇
  1992年   6篇
  1991年   7篇
  1990年   5篇
  1989年   17篇
  1988年   10篇
  1987年   8篇
  1986年   5篇
  1985年   11篇
  1984年   2篇
  1982年   4篇
  1980年   4篇
  1979年   12篇
  1978年   3篇
  1977年   3篇
  1976年   4篇
  1975年   11篇
  1974年   6篇
  1973年   4篇
  1972年   3篇
  1970年   4篇
  1968年   2篇
  1966年   3篇
排序方式: 共有434条查询结果,搜索用时 15 毫秒
1.
In a prospective multicenter study of 1,052 patients with clinical signs of a scaphoid fracture, mammo-graphic films and fine intensifying screens were used at the radiographic examination. 5 standardized projections including 3 special projections focused on the scaphoid were taken. 150 fractures were diagnosed at the first examination but in 10 cases the fracture was first diagnosed at a second radiographic examination after 10-14 days.

The second examination still seems mandatory despite the use of high quality radiographs with optimal spatial resolution and contrast, and the value of supplementary special projections.  相似文献   
2.
Low brain uptake is a generally accepted problem in developing technetium-99m brain receptor imaging agents. For a class of potential 5-HT2A receptorbinding agents we tried to improve the original low brain uptake of 0.4% injected dose (ID) in rats 5 min p.i. by modifying the lipophilic properties of the molecules. Because of the presence of a protonable nitrogen, which according to the pK a value leads to ionization of the molecule at blood pH, the pK a value was considered to be the parameter most suitable for adjustment of lipophilicity. Insertion of ether-oxygen in the molecule of five candidates lowers the apparent pK a value from 10.0 to 8.3 and dramatically increases the brain uptake to 1.3% ID at 5 min. The direct relationship between brain uptake and apparent pK a cannot be simply explained by the increase in the pK a-governed proportion of the neutral species.  相似文献   
3.
Leg thickness in piglets was found to be an autosomal recessive defect resulting in a primary developmental disturbance of the periosteal and connective components of the soft tissues of the fore- and, less frequently, hindlegs. Histologically there is periosteal thickening with periosteal proliferation of woven bone spiculae and also of myxoid elements of the soft tissue between bone and skin. Similar entities are not known in the human literature. Analogies with human hereditary congenital elephantiasis and pes equinovarus are incorrect.  相似文献   
4.
Cholecystokinin (CCK) reduces food intake and promotes non-rapid-eye-movement sleep (NREMS) in rats. The purpose of present experiments was to determine if CCK is somnogenic in rabbits; another species in which CCK suppresses feeding. White New Zealand rabbits were treated intracerebroventricularly (ICV; 0.05, 0.5 and 2 μg) or intraperitoneally (IP; 2.5, 10 and 40 μg/kg) with CCK or saline, and sleep-wake activity and brain temperature (Tbr) were recorded for 6 h. Injections of 10 and 40 μg/kg CCK IP elicited a decrease in wakefulness and an increase in NREMS during the first hour postinjection. The hypnogenic effects were accompanied by a decrease in Tbr. After the IP injection of a lower dose (2.5 μg/kg) a slight, nonsignificant increase in NREMS during the first hour postinjection was followed by a decrease in NREMS. ICV injections of CCK had relatively small inhibitory effects on sleep. We conclude that circulating, hormone CCK might be a hypnogenic signal with a peripheral site of action.  相似文献   
5.
6.
Clinical spirometry in normal Bantu   总被引:7,自引:0,他引:7  
  相似文献   
7.
Since detailed knowledge about velocity fields downstream of heart valve prostheses obtained from in vitro studies has not been followed up by similar detailed studies in vivo a pig model for acute velocity field studies downstream of aortic valve prostheses was established. Two mechanical and two bioprosthetic valves were studied and a dynamic three dimensional visualisation of velocity fields one diameter downstream performed under different haemodynamic conditions in a total of 22 pigs. The Ionescu-Shiley pericardial valve had velocity fields very similar to the normal native porcine aortic valve. The Edwards-Carpentier porcine valve caused a jet type flow, and the valve design of the St Jude Medical and Bj?rk-Shiley Monostrut valves was reflected in the velocity profile. Normalised (mean(SEM] systolic Reynolds normal stresses in the total cross sectional area were: native porcine 15(1.5) Nm-2; St Jude Medical 24(3.4) Nm-2; Bj?rk-Shiley Monostrut 25(1.6) Nm-2; Edwards-Carpentier Supra-annular 51(6.6) Nm-2; Ionescu-Shiley Pericardial 19(2.0) Nm-2. Reynolds normal stresses were higher in areas of rapidly changing or constantly high velocity gradients.  相似文献   
8.
Recently, a hexanucleotide (GGGGCC) repeat expansion in the first intron of C9ORF72 was reported as the cause of chromosome 9p21‐linked frontotemporal dementia‐amyotrophic lateral sclerosis (FTD‐ALS). We here report the prevalence of the expansion in a hospital‐based cohort and associated clinical features indicating a wider clinical spectrum of C9ORF72 disease than previously described. We studied 280 patients previously screened for mutations in genes involved in early onset autosomal dominant inherited dementia disorders. A repeat‐primed polymerase chain reaction amplification assay was used to identify pathogenic GGGGCC expansions. As a potential modifier, confirmed cases were further investigated for abnormal CAG expansions in ATXN2. A pathogenic GGGGCC expansion was identified in a total of 14 probands. Three of these presented with atypical clinical features and were previously diagnosed with clinical olivopontocerebellar degeneration (OPCD), atypical Parkinsonian syndrome (APS) and a corticobasal syndrome (CBS). Further, the pathogenic expansion was identified in six FTD patients, four patients with FTD‐ALS and one ALS patient. All confirmed cases had normal ATXN2 repeat sizes. Our study widens the clinical spectrum of C9ORF72related disease and confirms the hexanucleotide expansion as a prevalent cause of FTD‐ALS disorders. There was no indication of a modifying effect of the ATXN2 gene.  相似文献   
9.
10.
Sudden cardiac arrest is a devastating manifestation of coronary artery disease and a leading cause of death in the western world. Early and effective cardiopulmonary resuscitation is essential for return of spontaneous circulation. If manual compression is ongoing and return of spontaneous circulation has not been achieved, the prognosis is poor, and the logistics of performing cardiac catheterization are forbidding. With the advent of mechanical chest compression, however, this clinical scenario has become much more complex. Coronary angiography and percutaneous coronary intervention, although still cumbersome, has been established as feasible with ongoing mechanical chest compression. This article discusses the strengths and pitfalls of mechanical cardiopulmonary resuscitation, our experience, and current evidence behind activation of the catheterization laboratory with ongoing mechanical chest compression. © 2013 Wiley Periodicals, Inc.  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