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   114019篇
  免费   30848篇
  国内免费   1176篇
耳鼻咽喉   2722篇
儿科学   3004篇
妇产科学   2727篇
基础医学   4298篇
口腔科学   5425篇
临床医学   28328篇
内科学   27768篇
皮肤病学   3697篇
神经病学   13592篇
特种医学   4309篇
外科学   20166篇
综合类   764篇
现状与发展   40篇
一般理论   12篇
预防医学   14694篇
眼科学   2460篇
药学   2052篇
  1篇
中国医学   119篇
肿瘤学   9865篇
  2024年   771篇
  2023年   5157篇
  2022年   1236篇
  2021年   3002篇
  2020年   5610篇
  2019年   2195篇
  2018年   7266篇
  2017年   7585篇
  2016年   8218篇
  2015年   8379篇
  2014年   10915篇
  2013年   13109篇
  2012年   4637篇
  2011年   4498篇
  2010年   7419篇
  2009年   9702篇
  2008年   4366篇
  2007年   3333篇
  2006年   4519篇
  2005年   3027篇
  2004年   2291篇
  2003年   1932篇
  2002年   1837篇
  2001年   2032篇
  2000年   1324篇
  1999年   1897篇
  1998年   2372篇
  1997年   2184篇
  1996年   2220篇
  1995年   1952篇
  1994年   1286篇
  1993年   1094篇
  1992年   915篇
  1991年   792篇
  1990年   629篇
  1989年   679篇
  1988年   656篇
  1987年   501篇
  1986年   490篇
  1985年   459篇
  1984年   432篇
  1983年   453篇
  1982年   372篇
  1981年   338篇
  1980年   261篇
  1979年   137篇
  1978年   195篇
  1977年   196篇
  1976年   171篇
  1974年   142篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
141.
Purpose: It was investigated whether alterations in neuronal structure and function occasioned by strabismic amblyopia also may be reflected in alterations in the expression on Y type neurons of a Cat-301 antibody sensitive antigen in the lateral geniculate nucleus (LGN) and cortex of our cat model of strabismic amblyopia. Methods/Results: The percentage of positively labelled cells was reduced in LGN laminae that received input from the deviated eye in strabismic amblyopic cats compared with normal cats. In the strabismic cortex, the density of immunopositive neurons was significantly reduced compared with normal, the effect being most pronounced in layer IV Conclusions: Despite previous physiological recordings indicating a decrease in X-cell associated acuity in strabismic amblyopia, the present findings imply that the changes in the early visual experience occasioned by strabismus also produce specific molecular changes in theY neuronal class.  相似文献   
142.
143.
144.
The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma.  相似文献   
145.
This paper describes a complex set of patient and nursing data from 83 psychiatric wards. It explains how the data were collected and organized into a meaningful format using a quality league-table. The patient and nursing characteristics of high quality psychiatric wards ranking above the 74th percentile and the characteristics of low quality wards falling below the 26th percentile are compared and examined in detail. Startling similarities and differences in patient activity, nursing activity, and nursing quality in high and low quality wards are highlighted. Finally, some implications of the findings for nursing practice, management, and education are considered.  相似文献   
146.
Pyomyositis: characteristics at CT and MR imaging   总被引:9,自引:0,他引:9  
Gordon  BA; Martinez  S; Collins  AJ 《Radiology》1995,197(1):279
  相似文献   
147.
Epidermal growth factor receptors (EGFR) andras mutations are known to play a significant role in controlling cell growth and tumor promotion. Both of them transmit mitogenic signals to the nucleus by activation of Raf-1 kinase. In this study, the expression of EGFR and mutant Ras proteins, and, for the first time, the expression, phosphorylation and kinase activity of Raf-1 kinase have been determined in paired samples of colorectal cancer and mucosa. The tumor and mucosa samples did not differ significantly with regard to Raf-1 kinase content and activity. A major difference between tumors and mucosa was found, however, in the phosphorylation of Raf-1. Most of the mucosa samples (13/20), but only 1/20 of the cancer samples, contained hyperphosphorylated Raf-1. EGFR were significantly (p=0.0025) decreased in the tumors. The decreased phosphorylation of Raf-1 in colonic carcinomas could be the result of activation of Raf-1 phosphatases or inactivation of kinases phosphorylating Raf-1. New forms of treatment based on EGFR overexpression do not seem to be suitable for the majority of colonic cancers.This work was supported by the state of Baden-Württemberg (Verbundforschungsprojekt: Aufklärung von Mechanismen der Tumorentstehung und Tumorabwehr).  相似文献   
148.
Clusterlike Headache as a First Sign of Brain Metastases of Lung Cancer   总被引:1,自引:0,他引:1  
Dr.  J. Tajti  MD  PhD ; Dr.  K. Sas  MD ; Dr.  D. Szok  MD ; Dr.  E. Vörös  MD ; Dr.  L. Vécsei  MD  DSc 《Headache》1996,36(4):259-260
We report on a patient with clusterlike headache and multiple brain metastases of lung cancer. Initially, cluster headache was suggested clinically by characteristic symptoms without any focal central nervous system signs. However, magnetic resonance imaging demonstrated multiple brain metastases. It is possible that tumor necrosis factor may have played a role in initiating the clusterlike headache.  相似文献   
149.
The clinical records of five men who had sexually assaulted women aged 60 or over were compared to the records of seven men who had sexually assaulted younger victims. Details of childhood adjustment, psychiatric and criminal histories, psychiatric diagnosis, psychological assessment findings, and offence characteristics were examined to determine psychological and social factors specifically associated with the sexual assault of older women. The findings suggest that when victims are older women, the sexual assault is likely to be particularly brutal and largely motivated by anger, a need for power, or sadistic intent. Further, the gratuitous violence involved in the offences and clinical evidence of psychotic features, suggest more severe psychopathological processes in men who sexually assault older women than in those who assault younger victims. Implications for theory and clinical practice are discussed.  相似文献   
150.
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