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   1040篇
  免费   91篇
  国内免费   21篇
耳鼻咽喉   4篇
儿科学   11篇
妇产科学   2篇
基础医学   181篇
临床医学   30篇
内科学   34篇
皮肤病学   50篇
神经病学   46篇
特种医学   3篇
外科学   10篇
综合类   71篇
预防医学   9篇
眼科学   639篇
药学   21篇
中国医学   41篇
  2024年   6篇
  2023年   21篇
  2022年   30篇
  2021年   42篇
  2020年   40篇
  2019年   31篇
  2018年   57篇
  2017年   35篇
  2016年   33篇
  2015年   31篇
  2014年   43篇
  2013年   72篇
  2012年   39篇
  2011年   54篇
  2010年   31篇
  2009年   48篇
  2008年   44篇
  2007年   52篇
  2006年   50篇
  2005年   40篇
  2004年   30篇
  2003年   33篇
  2002年   33篇
  2001年   34篇
  2000年   15篇
  1999年   16篇
  1998年   21篇
  1997年   17篇
  1996年   12篇
  1995年   26篇
  1994年   6篇
  1993年   7篇
  1992年   10篇
  1991年   5篇
  1990年   9篇
  1989年   9篇
  1988年   7篇
  1987年   3篇
  1986年   3篇
  1985年   12篇
  1984年   7篇
  1983年   6篇
  1982年   10篇
  1981年   5篇
  1980年   5篇
  1979年   4篇
  1978年   5篇
  1977年   1篇
  1975年   1篇
  1970年   1篇
排序方式: 共有1152条查询结果,搜索用时 0 毫秒
11.
目的 分析原发性闭角型青光眼合并视网膜色素变性患者的临床特征。 方法 本研究纳入2013年4月至2017年4月于首都医科大学附属北京同仁医院眼科中心住院治疗的原发性闭角型青光眼(primary angle closure glaucoma ,PACG)合并视网膜色素变性(retinitis pigmentosa,RP)患者32例,和同期入院的不合并RP的PACG患者229例。根据青光眼类型将其分为4组,急性闭角型青光眼合并RP组(acute angle closure glaucoma with retinitis pigmentosa, AACG-RP)12例、慢性闭角型青光眼合并RP组(chronic angle closure glaucoma with retinitis pigmentosa, CACG-RP)20例、急性闭角型青光眼不合并RP组(AACG-non RP)94例、慢性闭角型青光眼不合并RP组(CACG-non RP)135例,比较4组患者的发病年龄和眼轴长度等参数。 结果 患者平均发病年龄AACG-RP组(39.00±12.07)岁、CACG-RP组(43.85±12.79)岁、AACG-non RP组(66.44±9.40)岁、CACG-non RP组(63.95±10.42)岁,4组之间差异有统计学意义(F=47.70,P<0.05)。患者平均眼轴长度AACG-RP组(21.31±1.37)mm、CACG-RP组(22.33±1.09)mm、AACG-non RP组(22.31±1.03)mm、CACG-non RP组(22.47±1.01)mm,4组之间差异有统计学意义(F=19.09,P<0.05)。 结论 原发性闭角型青光眼患者合并视网膜色素变性患者中,急性闭角型青光眼患者较慢性闭角型青光眼患者发病更早,眼轴更短。原发性闭角型青光眼合并视网膜色素变性患者,尤其是急性闭角型青光眼合并视网膜色素变性患者较无视网膜色素变性者发病年龄更早,且眼轴更短。  相似文献   
12.
张清炯  张丰生 《眼科学报》1999,15(4):204-206
目的:对国人视网膜色素变性(retinitis pigmentosa RP)患者中视紫红质基因不同突变与临床表型相关性进行初步研究。方法:对经异源双链-SSCP和序列分析确定为视紫红质基因不同位点突变的3例RP患者,收集其详细临床资料,比较其异同。结果:详细描述了3例已知突变患者的临床表现。视紫红质基因不同位点突变,临床表现不尽相同,发生在杆细胞外节胞液侧的突变,常导致严重类型的Ⅰ型视网膜色素变性;而发生在杆细胞外节盘膜内的突变,常引起相对较轻的Ⅱ型视网膜色素变性。结论:本文3例视紫红质基因不同位点突变与临床表型有一定关系,但要建立基因突变与表型间确切的对应关系和规律,尚需积累更多病例资料进一步分析研究。眼科学报1999;15:204-206。  相似文献   
13.
Background Retinitis pigmentosa belongs to a large group of degenerative diseases of the retina with a hereditary background. It involves loss of retinal photoreceptor cells and consequently peripheral vision. At present there are no satisfactory therapeutic options for this disease. Just recently the use of mesenchymal stem cells has been discussed as one therapeutical option for retinal degeneration, as they have been shown to differentiate into various cell types, including photoreceptor cells. In this article we wanted to investigate the potency of mesenchymal stem cells to induce rescue effects in an animal model for retinitis pigmentosa, the rhodopsin knockout mouse. Methods For the experiments, three experimental groups of 10 animals each were formed. The first group consisted of untreated rhodopsin knockout (rho-/-) animals used as controls. The second group consisted of rho-/- mice that had received an injection of mouse mesenchymal stem cells, which were transduced using an adenoviral vector containing the sequence for the green fluorescent protein (GFP) prior to transplantation. In the third sham group, animals received an injection of medium only. Thirty-five days after transplantation, GFP-expressing cells were detected in whole-mount preparations of the retinas as well as in cryostat sections. For the detection of rescue effects, semi-thin sections of eyes derived from all experimental groups were produced. Furthermore, rescue effects were also analysed ultrastructurally in ultrathin sections. Results Histological analysis revealed that after transplantation, cells morphologically integrated not only into the retinal pigment epithelium but also into layers of the neuroretina displaying neuronal and glial morphologies. Furthermore, significant rescue effects, as demonstrated by the occurrence of preserved photoreceptor cells, were detected. Conclusions Our data indicate that mesenchymal stem cells can prolong photoreceptor survival in the rhodopsin knockout mouse, also providing evidence of a therapeutical benefit in retinitis pigmentosa. This work was funded by “Pro Retina”.  相似文献   
14.
15.

Purpose

To identify a mutation in the PRPF31 gene in a family (Family K) with autosomal dominant retinitis pigmentosa (adRP) linked to 19q13.4 (RP11) and to find the frequency of mutations in the PRPF31 gene among Japanese families with adRP.

Methods

Genomic DNA specimens were prepared from five symptomatic and two asymptomatic members of Family K and an additional 39 patients of 39 unrelated families with adRP. Coding regions of the PRPF31 gene were amplified by polymerase chain reaction. The amplicons were analyzed by a direct sequencing method.

Results

All seven family members had a heterozygous c.1142delG mutation in the PRPF31 gene, which was identical to the mutation previously reported in a different Japanese family. No other mutation was found in the PRPF31 gene among the 39 additional patients with adRP.

Conclusion

Although the frequency of mutations in the PRPF31 gene is about 2.5% in Japanese families with adRP, it is possible that c.1142delG is a common mutation among Japanese patients with adRP associated with mutations in the PRPF31 gene.?Jpn J Ophthalmol 2007;51:45–48 © Japanese Ophthalmological Society 2007
  相似文献   
16.
目的分析结晶样视网膜色素变性的荧光素眼底血管造影(FFA)特点,进一步探索其发病机制。设计回顾性病例系列。研究对象结晶样视网膜色素变性患者。方法北京同仁医院眼科中心2004~2006年门诊诊断的结晶样视网膜色素变性患者32例。所有患者均行FFA检查。主要指标FFA表现。结果全部患者FFA显示后极部斑驳状、点状透见荧光。背景荧光部分增高,部分减弱。视盘高荧光或部分高荧光8例。2例环以低荧光。动脉血管变细18例,但其中仅3例出现血管充盈迟缓。4例视网膜血管闭塞,且全部位于周边部。3例视网膜后极部血管渗漏。仅1例出现无灌注区。6例黄斑拱环结构破坏或结构不清。结论结晶样视网膜色素变性的FFA特点显示:其病变主要是视网膜色素上皮细胞改变和脉络膜毛细血管的萎缩,同时累及神经视网膜及其视网膜血管组织。  相似文献   
17.
Lack of c-kit mutation in familial urticaria pigmentosa   总被引:1,自引:0,他引:1  
Somatic mutations within c-kit have been reported in individuals with mastocytoses, including urticaria pigmentosa (UP). We have identified three siblings with UP. We aimed to determine whether the c-kit proto-oncogene was playing a part in the aetiology of UP in these three siblings. Using seven microsatellite repeat markers spanning an 8-cM interval encompassing the c-kit gene we followed the transmission of the c-kit gene in this family. Furthermore, single-strand conformation polymorphism analysis was used to scan exon 17 of the c-kit gene for mutations in genomic DNA of all family members and somatic DNA extracted from skin of the eldest affected sibling, the proband. No mutations were found in exon 17 in either genomic DNA of all family members or somatic DNA of the proband. Patients with UP have been shown to possess somatic mutations of the c-kit gene. However, this locus has been excluded as playing a part in the three siblings examined here in whom a second gene locus must be determining their UP. Therefore, this study emphasizes genetic heterogeneity in UP. Future study to identify primary molecular determinants of UP should include affected sib-pair studies.  相似文献   
18.
Retinitis pigmentosa refers to a family of inherited photoreceptor degenerations resulting in blindness. During and after photoreceptor loss, neurons of the inner retina are known to undergo plastic changes. Here, we have investigated in detail whether ganglion cells are altered at late stages of degeneration, well after the total loss of photoreceptors. We used mice, rd1‐Thy1, that carry a mutation in the β‐subunit of phosphodiesterase 6 and a fluorescent protein that labels a subset of ganglion cells and B6‐Thy1 control mice. Retinal wholemounts from mice aged 3–11 months were processed for immunohistochemistry and analyzed. Ganglion cells were classified based on soma area, dendritic field size, and branching of dendrites. The dendritic fields of some ganglion cells were further analyzed for their length, area and quantity of branching points. There was a decrease in size and level of branching of A2, B1, and D type ganglion cells in the degenerated retina at 11 months of age. In contrast, C1 ganglion cells remained unchanged. In addition, there was a shift in the proportion of ganglion cells ramifying in the different layers of the inner plexiform layer. Careful analysis of the dendrites of ganglion cells revealed some projecting to new, more distal regions of the inner plexiform layer. We propose that these changes in ganglion cell morphology could impact the function of individual cells as well as the retinal circuitry in the degenerated retina. J. Comp. Neurol. 522:1155–1170, 2014. © 2013 Wiley Periodicals, Inc.  相似文献   
19.
目的观察温肾活血方对RCS大鼠视网膜感光细胞凋亡的影响。方法纯合子RCS大鼠16只在出生后14 d随机分为2组,即模型组、治疗组,每组8只,另8只SD大鼠作为正常对照组。治疗组予温肾活血方灌胃治疗,而模型组及对照组予蒸馏水灌胃治疗,连续治疗28 d。HE染色观察视网膜各层细胞形态和结构的变化,TUNEL荧光染色观察视网膜外核层细胞凋亡情况。免疫组化荧光染色测定视网膜Caspase-3,Bax,Bcl-2的表达。结果(1)HE染色:治疗后28 d,RCS大鼠各组视网膜外核层较对照组明显变薄,感光细胞数量明显减少,但治疗组较模型组视网膜更厚,感光细胞数更多。(2)TUNEL检测:治疗后28 d,RCS大鼠各组视网膜外核层凋亡细胞计数较对照组明显增多,3组间比较差异有显著统计学意义(F=71.58,P=0.000);与模型组比较,治疗组凋亡细胞计数显著减少(t=4.74,P=0.001)。(3)免疫组化:治疗后28 d,3组间比较,视网膜Caspase-3(F=59.37,P=0.000)、Bcl-2(F=31.35,P=0.000)表达水平差异有统计学意义;与模型组比较,治疗组Caspase-3表达显著减少(t=2.36,P=0.040),Bcl-2表达显著增多(t=3.15,P=0.010),均有统计学意义。结论温肾活血方可以抑制RCS大鼠视网膜感光细胞凋亡,其作用可能与抑制Caspase-3的表达并促进Bcl-2的表达有关。  相似文献   
20.
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