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   299277篇
  免费   8740篇
  国内免费   1129篇
耳鼻咽喉   3079篇
儿科学   8454篇
妇产科学   4878篇
基础医学   36603篇
口腔科学   4662篇
临床医学   24050篇
内科学   53037篇
皮肤病学   4705篇
神经病学   26566篇
特种医学   16055篇
外科学   44987篇
综合类   2830篇
现状与发展   3篇
一般理论   27篇
预防医学   24573篇
眼科学   5952篇
药学   20264篇
中国医学   2122篇
肿瘤学   26299篇
  2023年   677篇
  2022年   2697篇
  2021年   4506篇
  2020年   2159篇
  2019年   3038篇
  2018年   25150篇
  2017年   19963篇
  2016年   22945篇
  2015年   6440篇
  2014年   7382篇
  2013年   8462篇
  2012年   18225篇
  2011年   31450篇
  2010年   24636篇
  2009年   16558篇
  2008年   26682篇
  2007年   28472篇
  2006年   7058篇
  2005年   8207篇
  2004年   8595篇
  2003年   8866篇
  2002年   6403篇
  2001年   3302篇
  2000年   3209篇
  1999年   2294篇
  1998年   1114篇
  1997年   877篇
  1996年   599篇
  1995年   558篇
  1994年   487篇
  1993年   392篇
  1992年   789篇
  1991年   782篇
  1990年   761篇
  1989年   632篇
  1988年   517篇
  1987年   505篇
  1986年   359篇
  1985年   398篇
  1984年   283篇
  1983年   212篇
  1982年   161篇
  1981年   168篇
  1980年   168篇
  1979年   224篇
  1978年   170篇
  1976年   144篇
  1975年   125篇
  1974年   159篇
  1973年   122篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
991.
Background The purpose of this study was to explore neuroretinal transplantation in a large animal model of severe retinitis pigmentosa and to establish graft development, long-term survival, graft-host integration, and effects on the host retina. Methods Rhodopsin transgenic pigs, aged 6 months, received in one eye a fetal full-thickness neuroretinal sheet in the subretinal space by means of vitrectomy and retinotomy. Six months postoperatively, eyes were studied in the light microscope and with immunohistochemical markers. Full-field electroretinography (ERG) was performed at 4 and 6 months. Results Laminated grafts with well-organized photoreceptors, rod bipolar cells, and Müller cells were found in five of six eyes. Neuronal connections between graft and host retina were not seen. In the five eyes containing a graft, the number of surviving rods in the host retina was significantly higher compared with unoperated eyes. The ERG did not reveal any significant difference in b-wave amplitude between operated and control eyes, but the cone-derived response in operated eyes increased significantly from 4 to 6 months while the rod response in control eyes decreased significantly. Conclusions Fetal full-thickness neuroretina can be transplanted safely to an eye with severe retinal degeneration. In their major part, the transplants develop a normal laminated morphology and survive for at least 6 months. Graft and host retinal neurons do not form connections. Retinal function in the host is reduced initially by the surgical trauma, but the presence of a well-laminated graft counteracts this effect and rescues rods from degeneration. Supported by The Foundation Fighting Blindness (grant# C-NC02-798-0078), The Faculty of Medicine, University of Lund, The Swedish Research Council, The Princess Margaretas Foundation for Blind Children, The 2nd ONCE International Award for New Technologies for the Blind.  相似文献   
992.
993.
Background Optic disc anomalies are frequently associated with Alagille syndrome. We report here the first case of a patient with Alagille syndrome combined with optic pit and serous macular detachment. Methods A male patient with Alagille syndrome was referred from the pediatric hepatology department for investigation of visual loss in the right eye. Anterior segment examination showed evidence of posterior embryotoxon, confirmed by gonioscopic evaluation. Dilated fundus examination revealed serous macular detachment and optic pit. Results OCT 3 scans confirmed the clinical findings. Conclusions Optic pit is uncommon and should prompt a search for genetic disorders or development abnormalities. The association between the two syndromes in this patient might be due to failure of correct neuroectodermal development, for which a common genetic pathway is likely.  相似文献   
994.

Background  

January 1, 2002, copayment for outpatient female sterilization in Norwegian public hospitals increased from 33 euros to 750 euros after a revision of the health care system. The aim of the present study was to investigate the effect of the new copayment system on female sterilization epidemiology.  相似文献   
995.
BACKGROUND: Two new tonometers have been introduced that are based on the impedance principle. Both the TGDc-01 (transpalpebral measurement) and the iCare (corneal measurement) do not require corneal anaesthesia. The present work presents an evaluation of both devices. METHODS: Comparative measurements using one of the new tonometers and applanation tonometry were performed by one investigator according to the international standard for ocular tonometer (ISO 8612). Measurements were performed on 445 eyes without corneal pathology from 243 patients. Six measurements were performed for iCare and 3 for TGDc, immediately followed by 3 applanation tonometry measurements. RESULTS: The correlation coefficient with respect to applanation tonometry was 0.81 for TGDc and 0.95 for iCare. TGDc-01 measurements showed an average deviation of 3.1 +/- 2.6 mmHg to those of Perkins applanation tonometry. The maximum difference was 28.7 mmHg below and 9.8 mmHg above the results of applanation tonometry. iCare showed an average deviation of 2.5 +/- 1.1 mmHg to Goldmann tonometry. The maximum difference was 14.5 mmHg below and 9.8 mmHg above. CONCLUSIONS: The results of both new tonometers showed a good correlation with the reference applanation tonometric methods, but the strict requirements of ISO 8612 are not fulfilled by either tonometer at present. Additionally, transpalpebral measurements with the TGDc-01 showed unacceptably high variability.  相似文献   
996.
997.

Background  

To date, the literature has provided an abundance of evidence on the adverse outcomes of restraint use on patients. Reportedly, nurses are often the personnel who initiate restraint use and attribute its use to ensuring the safety of the restrained and the others. A clinical trial using staff education and administrative input as the key components of a restraint reduction program was conducted in a rehabilitation setting to examine whether there were any significant differences in the prevalence of restraint use pre- and post-intervention. Subsequent to the implementation of the intervention program, focus group interviews were conducted to determine the perspective of the nursing staff on the use of restraints and their opinions of appropriate means to reduce their use.  相似文献   
998.
999.
1000.
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