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   412篇
  免费   23篇
  国内免费   10篇
耳鼻咽喉   2篇
儿科学   43篇
妇产科学   4篇
基础医学   46篇
口腔科学   4篇
临床医学   34篇
内科学   41篇
皮肤病学   2篇
神经病学   175篇
特种医学   34篇
外科学   5篇
综合类   6篇
预防医学   14篇
眼科学   3篇
药学   20篇
中国医学   1篇
肿瘤学   11篇
  2022年   4篇
  2021年   4篇
  2020年   6篇
  2018年   9篇
  2016年   10篇
  2015年   4篇
  2014年   12篇
  2013年   19篇
  2012年   12篇
  2011年   11篇
  2010年   9篇
  2009年   15篇
  2008年   12篇
  2007年   15篇
  2006年   12篇
  2005年   16篇
  2004年   12篇
  2002年   12篇
  2001年   16篇
  2000年   10篇
  1999年   9篇
  1998年   15篇
  1997年   8篇
  1996年   9篇
  1995年   9篇
  1994年   12篇
  1993年   11篇
  1992年   8篇
  1989年   9篇
  1988年   9篇
  1987年   4篇
  1986年   7篇
  1985年   5篇
  1984年   6篇
  1983年   5篇
  1982年   3篇
  1981年   4篇
  1980年   4篇
  1978年   5篇
  1977年   5篇
  1976年   8篇
  1975年   7篇
  1974年   6篇
  1973年   3篇
  1970年   6篇
  1969年   5篇
  1968年   5篇
  1967年   3篇
  1966年   5篇
  1965年   3篇
排序方式: 共有445条查询结果,搜索用时 23 毫秒
1.
Clinical characteristics of rapidly progressive leuko-araiosis   总被引:1,自引:0,他引:1  
Introduction – 38 patients found to have either pure leuko-araiosis (LA) or LA combined with infarction(s) on computer tomography (CT) in 1989 were re-examined in 1992 in order to evaluate the progression of LA. The follow-up period averaged 3.2 years. Material and methods - The clinical and radiological data on patients in 1989 were collected from hospital records and re-evaluated. The patients were re-examined clinically (including 24 hour ambulatory blood pressure measurement), and neuroradiologically (CT) in 1992 for this study. Results – 11 (29%) patients were found to have significant (rapid) progression of the extent of LA on CT during the follow-up. At baseline, there was no significant difference in the mean number of brain infarctions between the groups with progressing (prLA) and non-progressing LA (nprLA) or between the number of cortical and central infarctions within these groups. At follow-up, the total number of infarctions had increased significantly in both groups, but it was mostly because of the increase in cortical infarctions in the prLA group (p = 0.043) and, conversely, the central ones in the nprLA group (p = 0.011). prLA was found to be related to heart failure (82% vs 37%, p = 0.029) and atrial fibrillation (55% vs 19%, p = 0.047), whereas nprLA was strongly associated with a sudden onset of symptoms (78% vs prLA 18%, p = 0.001) like a-true brain infarction. Other clinical factors, including mean blood pressure and heart rate, did not clearly differentiate between the groups. Conclusion - The results suggest that there are different subgroups of patients with LA associated with various vascular factors. The occurrence of LA is not related to the distribution of infarctions. The progression of LA is not related to the number of brain infarctions or to the simultaneous increase of infarctions on CT.  相似文献   
2.
Helms  CA; Kaban  LB; McNeill  C; Dodson  T 《Radiology》1989,172(3):817-820
Magnetic resonance (MR) imaging has been used in the temporomandibular joint (TMJ) primarily to define the disk position. This report examines altered morphology and signal intensity characteristics of the TMJ disk as they relate to the severity of internal derangement. Two hundred sixteen joints in 133 patients with a history of such derangement. were imaged with MR. Disk position, signal intensity, morphology, and the presence of osteoarthritis were determined for each joint. The normal disk was not anteriorly displaced and had a normal "bow-tie" shape. A grade 1 disk was anteriorly displaced and had a normal shape; a grade 2 disk was anteriorly displaced and had an abnormal shape. Forty (19%) joints were considered normal; none of these exhibited osteoarthritis. One hundred thirty-nine (64%) joints were grade 1; osteoarthritis was found in 17%. Thirty-seven (17%) were grade 2; osteoarthritis was found in 95%. All forty normal joints had high or intermediate signal intensity in the disk. Osteoarthritic joints had a higher percentage of disks with diminished intensity (P less than .0001). Severe or untreated osteoarthritis is known to be a complication of TMJ internal derangements; hence this grading system seems to correlate with the severity of internal derangement.  相似文献   
3.
4.
5.
6.
Background: The aim of the study is to report parent/youth self-report agreement on emotional and behavioral symptoms among 15- to 16-year-old adolescents. Methods: A completed Child Behavior Checklist and Youth Self-Report were obtained from 580 subjects. Results: Adolescents reported significantly more problem behaviors than their parents. Adolescent girls reported a significantly higher level of distress than boys in most symptom domains. The discrepancies between parent reports and youth self-reports were greater, especially for internalizing symptoms, for girls than for boys. Conclusions: Many adolescents in need of psychiatric assessment do not receive appropriate help because their problems remain unnoticed by adults. Internalizing problems among girls seem especially likely to remain unrecognized by adults. Accepted: 21 October 1999  相似文献   
7.
This register study includes all patients under 18 years in Finland discharged from psychiatric inpatient treatment in 1990 (n = 818) and 1993 (n = 958). The prevalence of children and adolescents in the population who had previously been treated was about 7–8 per 10,000. The incidence of new cases of children and adolescents who had previously been inpatients within the last year was about 5–6 per 10,000 in this age group. The prevalence was lowest in the preschool group (about 1:10,000) and highest in the adolescent group (about 12–14:10,000). About two-thirds of inpatients were boys. Adjustment disorders (DSM-III-R) were the most common diagnosis both in 1990 and 1993 (about 30%). Mood and anxiety disorders were the second most frequent (19–23%) and disruptive behaviour disorders the third most frequent (13–15%) diagnostic category. The diagnostic profiles differed largely according to sex and age. Accepted: 18 May 1998  相似文献   
8.
Summary The internal vascularization of the brain was studied in foetuses of normal and protein-deprived rats from embryonic day (E) 12 to 15. The position of vascular branches showed distinct relations to the various zones of the neuroepithelium. The possibility that various parts of the vascular system may differ in function, maturation, and morphogenetic relations to the neuroepithelium must be considered. The distinct vascular layers were therefore given names relating them to the respective wall zone. The ingrowth of straight stem vessels from the epiparenchymal vascular plexus into the neuroepithelium and the formation of vascular branches close to the ventricular system were referred to as stage I of the internal vascularization. The resulting plexus was called the deep vascular plexus of the ventricular zone. Its formation followed the same temporospatial gradients as the formation of the marginal zone. Following the formation of the intermediate zone, more stem vessels entered the neuroepithelium and a superficial vascular plexus of the ventricular zone was formed (stage II). This plexus was positioned close to the border between the ventricular zone and the intermediate zone. Subsequently, vascular branches also formed plexuses of the intermediate and subventricular zones (stage III). No intraepithelial vessels were seen on E 12. The temporospatial gradients in the telencephalic vesicles were caudal to rostral and lateral to medial, starting in the parts corresponding to the ganglionic eminence in the floor of the lateral ventricle on E 13. Only the dorsomedial angles of the hemispheres showed no vessels on E 15.No obvious differences were seen between the normal and the protein-deprived foetuses regarding the timing and extent of vascularization or the size and appearance of wall zones in the immature central nervous (I-CNS).  相似文献   
9.
10.
The present population-based study examines associations between epilepsy and autism spectrum disorders (ASD). The cohort includes register data of 4,705 children born between 1987 and 2005 and diagnosed as cases of childhood autism, Asperger’s syndrome or pervasive developmental disorders—not otherwise specified. Each case was matched to four controls by gender, date of birth, place of birth, and residence in Finland. Epilepsy was associated with ASD regardless of the subgroup after adjusting for covariates. The associations were stronger among cases with intellectual disability, especially among females. Epilepsy’s age at onset was similar between the cases and controls regardless of the ASD subgroup. These findings emphasize the importance to examine the neurodevelopmental pathways in ASD, epilepsy and intellectual disability.  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