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   30968篇
  免费   1948篇
  国内免费   678篇
耳鼻咽喉   675篇
儿科学   177篇
妇产科学   291篇
基础医学   4858篇
口腔科学   2163篇
临床医学   1569篇
内科学   3004篇
皮肤病学   2154篇
神经病学   2609篇
特种医学   885篇
外国民族医学   1篇
外科学   4819篇
综合类   2897篇
现状与发展   1篇
预防医学   589篇
眼科学   4346篇
药学   1575篇
  8篇
中国医学   370篇
肿瘤学   603篇
  2024年   50篇
  2023年   372篇
  2022年   445篇
  2021年   1193篇
  2020年   885篇
  2019年   771篇
  2018年   810篇
  2017年   817篇
  2016年   939篇
  2015年   885篇
  2014年   1516篇
  2013年   2018篇
  2012年   1330篇
  2011年   1480篇
  2010年   1292篇
  2009年   1372篇
  2008年   1332篇
  2007年   1318篇
  2006年   1186篇
  2005年   1085篇
  2004年   1044篇
  2003年   937篇
  2002年   780篇
  2001年   731篇
  2000年   612篇
  1999年   563篇
  1998年   623篇
  1997年   576篇
  1996年   590篇
  1995年   488篇
  1994年   512篇
  1993年   436篇
  1992年   449篇
  1991年   427篇
  1990年   401篇
  1989年   349篇
  1988年   355篇
  1987年   317篇
  1986年   301篇
  1985年   352篇
  1984年   303篇
  1983年   224篇
  1982年   220篇
  1981年   193篇
  1980年   168篇
  1979年   123篇
  1978年   138篇
  1977年   97篇
  1976年   60篇
  1975年   37篇
排序方式: 共有10000条查询结果,搜索用时 47 毫秒
1.
2.
3.
目的 探讨577 nm激光光凝联合玻璃体内注射康柏西普治疗糖尿病性黄斑水肿的效果。方法 选取2016年1月至2017年3月在我院治疗的糖尿病性黄斑水肿患者81例81眼,根据患者最终选取的治疗方案分为观察组43例43眼和对照组38例38眼,观察组给予577 nm激光光凝联合玻璃体内注射康柏西普治疗,对照组仅给予577 nm激光光凝,观察两组治疗前后最佳矫正视力(best corrected visual acuity,BCVA)和黄斑中心凹厚度(central fovea of macula thickness,CMT),分析观察组BCVA和CMT变化值与初始因素的相关性。结果 随治疗时间延长,观察组和对照组BCVA、CMT相应改善(均为P<0.05);观察组治疗后1个月、3个月和6个月BCVA分别为0.37±0.09、0.44±0.10和0.52±0.13,均明显高于对照组(均为P<0.05);观察组治疗后1个月、3个月和6个月CMT分别为(351.03±41.43)μm、(270.32±40.03)μm和(220.01±32.91)μm,均明显低于对照组(均为P<0.05);BCVA变化值与糖尿病性黄斑水肿病程、治疗前BCVA呈负相关(r=-0.422、-0.410,均为P<0.05);CMT变化值与糖尿病性黄斑水肿病程、治疗前CMT呈负相关(r=-0.430、-0.415,均为P<0.05)。结论 577 nm激光光凝联合玻璃体内注射康柏西普治疗糖尿病性黄斑水肿效果较好,其效果与患者基线BCVA、糖尿病性黄斑水肿病程有一定相关性。  相似文献   
4.
Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.  相似文献   
5.
6.
Hailey–Hailey disease (HHD), also known as benign familial pemphigus, is an autosomal dominant skin condition that affects the adhesion of epidermal keratinocytes. Although the initial manifestation of flaccid vesicles on erythematous or normal skin in flexure sites frequently goes unnoticed, large, macerated, exudative plaques of superficial erosions with crusting are observed at the time of diagnosis. There is no specific treatment for HHD, and most cases are symptomatically supported. However, infrared laser ablation has been somewhat helpful. We present a case successfully treated with fractional CO2 laser showing a long-term favourable outcome and no adverse effects. Thus, this modality could be an alternative to full ablation for this condition.  相似文献   
7.
The cellular mechanisms underlying hereditary photoreceptor degeneration are still poorly understood, a problem that is exacerbated by the enormous genetic heterogeneity of this disease group. However, the last decade has yielded a wealth of new knowledge on degenerative pathways and their diversity. Notably, a central role of cGMP-signalling has surfaced for photoreceptor cell death triggered by a subset of disease-causing mutations.In this review, we examine key aspects relevant for photoreceptor degeneration of hereditary origin. The topics covered include energy metabolism, epigenetics, protein quality control, as well as cGMP- and Ca2+-signalling, and how the related molecular and metabolic processes may trigger photoreceptor demise. We compare and integrate evidence on different cell death mechanisms that have been associated with photoreceptor degeneration, including apoptosis, necrosis, necroptosis, and PARthanatos. A special focus is then put on the mechanisms of cGMP-dependent cell death and how exceedingly high photoreceptor cGMP levels may cause activation of Ca2+-dependent calpain-type proteases, histone deacetylases and poly-ADP-ribose polymerase. An evaluation of the available literature reveals that a large group of patients suffering from hereditary photoreceptor degeneration carry mutations that are likely to trigger cGMP-dependent cell death, making this pathway a prime target for future therapy development.Finally, an outlook is given into technological and methodological developments that will with time likely contribute to a comprehensive overview over the entire metabolic complexity of photoreceptor cell death. Building on such developments, new imaging technology and novel biomarkers may be used to develop clinical test strategies, that fully consider the genetic heterogeneity of hereditary retinal degenerations, in order to facilitate clinical testing of novel treatment approaches.  相似文献   
8.
9.
AIM: To compare and evaluate the clinical outcomes of deep anterior lamellar keratoplasty (DALK) and excimer laser assisted anterior lamellar keratoplasty (ELLK) in eyes with keratoconus. METHODS: In this study, 57 eyes of 56 patients operated between 2013 to 2017 were included. Thirty-one eyes underwent big-bubble DALK and twenty-six eyes underwent ELLK. Preoperative and at control visits complete ophthalmic examination was performed. RESULTS: The mean patient age at the time of DALK surgery was 27y and mean follow-up period was 21±5.4mo. The mean patient age at the time of ELLK surgery was 27y and mean follow-up period was 40±18mo. Mean best spectacle corrected visual acuity (BSCVA) at postoperative period was significantly higher for DALK group (0.66±0.11) versus ELLK group (0.4±0.2) (P<0.05). Descemet’s membrane microperforation was occurred in 7 patients in DALK group versus in 1 patient in ELLK group. In 4 eyes, interface irregularity was developed in ELLK group. None of the patients in follow-up had graft rejection in both groups. CONCLUSION: In ELLK group, complication rate is lower, the surgical technique is simpler, faster and safer and also ELLK requires less experience with respect to DALK. Further, DALK can be performed unless satisfactory visual acuity is achieved after ELLK.  相似文献   
10.
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