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   107403篇
  免费   10870篇
  国内免费   3338篇
耳鼻咽喉   749篇
儿科学   1697篇
妇产科学   1212篇
基础医学   20043篇
口腔科学   2855篇
临床医学   6716篇
内科学   16236篇
皮肤病学   1910篇
神经病学   11453篇
特种医学   2864篇
外国民族医学   27篇
外科学   8571篇
综合类   10604篇
现状与发展   14篇
预防医学   4371篇
眼科学   1092篇
药学   17102篇
  34篇
中国医学   4045篇
肿瘤学   10016篇
  2024年   310篇
  2023年   1951篇
  2022年   4385篇
  2021年   4949篇
  2020年   4189篇
  2019年   4439篇
  2018年   4243篇
  2017年   4205篇
  2016年   3935篇
  2015年   4454篇
  2014年   6452篇
  2013年   6687篇
  2012年   5918篇
  2011年   7054篇
  2010年   5658篇
  2009年   5681篇
  2008年   5603篇
  2007年   4767篇
  2006年   4092篇
  2005年   3772篇
  2004年   3186篇
  2003年   2831篇
  2002年   2123篇
  2001年   1795篇
  2000年   1493篇
  1999年   1408篇
  1998年   1355篇
  1997年   1317篇
  1996年   1211篇
  1995年   1107篇
  1994年   1019篇
  1993年   968篇
  1992年   761篇
  1991年   682篇
  1990年   586篇
  1989年   497篇
  1988年   474篇
  1987年   473篇
  1986年   572篇
  1985年   779篇
  1984年   741篇
  1983年   581篇
  1982年   579篇
  1981年   488篇
  1980年   449篇
  1979年   374篇
  1978年   229篇
  1977年   190篇
  1976年   197篇
  1975年   121篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.

Background

Since recent reports have shown that (-)-Epigallocatechin-3-gallate (EGCG) could be used for treating proliferative and inflammatory disorders, we explored its use for the management of corneal chemical burns.

Materials and methods

Initially, EGCG was assayed on the rabbit corneal epithelial cell line RCE1(5T5) to establish the best testing conditions, and to avoid unwanted outcomes in the experimental animals. Then, we studied its effects on cell proliferation, cell cycle progression and cell differentiation. Afterwards, we instilled EGCG in experimental grade II corneal alkali burns in mice, three times a day up to 21 days, and evaluated by slit lamp examination and histological sections of corneal epithelial, corneal endothelial and stromal edema, as well as the presence of inflammatory cells and neovascularization.

Results

EGCG reduced cell growth and led to a decline in the proportion of proliferative cells in a concentration dependent manner. At 10 μM, EGCG promoted cell differentiation, an effect not related with apoptosis or cytotoxicity. When 10 μM EGCG was instilled in corneal alkali burns in mice three times a day up to 21 days, EGCG significantly reduced corneal opacity and neovascularization. The improved clinical appearance of the cornea was associated to a controlled epithelial growth; epithelial morphology was similar to that observed in normal epithelium and contrasted with the hyperproliferative, desquamating epithelium observed in control burn wounds. EGCG reduced corneal, stromal and endothelial edema, and wound inflammation.

Conclusion

This work constitutes the first evidence for the use of EGCG in the acute phase of a corneal alkali burn, representing a possible novel alternative to improve patient outcomes as an add-on therapy.  相似文献   
12.
丝氨酸生物合成途径活性的上调是许多癌症明显的共同特征。该途径的第一种限速酶3-磷酸甘油酸脱氢酶(PHGDH)在黑色素瘤、乳腺癌和肾癌等癌组织中高表达,对肿瘤细胞增殖、转移、侵袭有着重要作用。糖酵解中间产物3-磷酸甘油酸在PHGDH作用下,氧化为磷酸羟基丙酮酸并最终合成丝氨酸。丝氨酸转化为甘氨酸,然后在核苷酸、s-腺苷甲硫氨酸(SAM)和还原型谷胱甘肽(GSH)的合成中起着重要的作用。PHGDH 有望成为肿瘤治疗的新靶点。  相似文献   
13.
目的探讨对先天性耳甲腔型小耳畸形患者行全扩张法全耳再造术后,利用残耳皮瓣改善再造耳颅耳沟的效果。方法回顾分析 2012 年 1 月—2017 年 1 月收治的 150 例先天性耳甲腔型小耳畸形患者。其中男 92 例,女 58 例;年龄 6.5~35.0 岁,平均 11.1 岁。采用一期扩张器埋置、二期全扩张法全耳再造术后发现上部颅耳沟浅显;于 6~12 个月后行三期再造耳修整。将残耳垂通过“Z”字改型转移以再造耳垂。在残耳上部作蒂在轮屏切迹的残耳上部皮瓣,弧形切开松解并加深上部颅耳沟,将上部残耳皮瓣向颅耳沟创面旋转推进缝合以覆盖创面;将带皮下组织蒂的残耳软骨组织瓣插入支架底部形成的腔隙内,并缝合固定,以增加支架的高度;耳甲腔区其余残耳皮瓣用以覆盖耳甲腔创面。结果术后拆线时 1 例患儿皮瓣远端出现直径约 0.5 cm 的表皮水疱,经换药 2 周后愈合;其余患者皮瓣成活良好。患者均获随访,随访时间 6~12 个月,平均 9.6 个月。再造耳上部颅耳沟均明显加深,再造耳支架高度不同程度增加,双耳对称性佳,耳甲腔无明显挛缩变小,再造耳外观满意。再造耳上部表面毛发明显减少,耳周发际线上移。结论采用耳甲腔型小耳畸形的残耳皮瓣及残耳软骨瓣转移,不仅可加深颅耳沟,而且可增加上部支架的高度,术后颅耳沟变形较轻,再造耳与正常耳廓的对称性更佳。  相似文献   
14.
15.
16.
17.
18.
A pulmonary artery (PA) sling is a very rare congenital cardiovascular anomaly, and only a few studies have reported PA slings in fetuses. The relationship of the PA, aorta, ductus arteriosus, and trachea can be evaluated in the 3‐vessel and 3‐vessel and trachea views during fetal echocardiography. A PA sling can be detected by abnormal positioning of the left PA in relation to the trachea when sweeping from the 3‐vessel view cranially to the 3‐vessel and trachea view. Here we report 3 cases of fetal PA slings and their follow‐ups. Two cases were confirmed by postnatal echocardiography, and the other case was confirmed by a cardiovascular cast after pregnancy termination. We emphasize that the 3‐vessel and 3‐vessel and trachea views are of crucial importance in the prenatal diagnosis of a PA sling.  相似文献   
19.
BackgroundConsiderable progress has been made in therapeutic options for multiple myeloma (MM). Understanding the current landscape of MM treatment options and associated outcomes in the real world is important in providing key insights into clinical and knowledge gaps which could be targeted for further optimization.MethodsThe Canadian Myeloma Research Group Database (CMRG-DB) is a prospectively maintained disease-specific database with >7000 patients. The objective of this study was to describe the trends in the treatment landscape and outcomes including early mortality, time to next treatment, and overall survival (OS) in each line of treatment stratified by autologous stem cell transplant (ASCT) receipt among newly-diagnosed MM patients in Canada between 2007 and 2018.ResultsA total of 5154 patients were identified among which 3030 patients (58.8%) received an upfront ASCT and 2124 (41.2%) did not. At diagnosis, the median age was 64 years and 58.6% were males. Bortezomib and lenalidomide were most frequently used (>50%) in first and second-line treatment respectively among both the ASCT and non-ASCT cohort. The median OS was 122.0 months (95% Cl 115.0-135.0 months) and 54.3 months (95% CI 50.8-58.8 months) for the ASCT and non-ASCT cohort respectively with an incremental decrease in OS in each subsequent line of treatment.ConclusionWe present the largest study to date in the Canadian landscape showing the characteristics, therapy usage, and outcomes among MM patients. This information will be critical in benchmarking current outcomes and provide key insight into areas of unmet needs and gaps for improvement of MM patients nationally.  相似文献   
20.
目的:通过3D打印的方法制备的不同重量比例的纳米羟基磷灰石/聚乳酸/聚乙烯醇(n-HA/PLA/PVA)复合膜,并对其相关性能检测。方法:采用3D打印技术制备不同重量比例的n-HA/PLA/PVA复合膜,分别为PLA/PVA复合膜、15%n-HA/PLA/PVA复合膜、50%n-HA/PLA/PVA复合膜、75%n-HA/PLA/PVA复合膜。扫描电镜下观察各组膜形态,对其力学性能、细胞毒性及动物实验相应指标进行检测。结果:扫描电镜下观察,n-HA/PLA/PVA复合膜呈现三维网状结构,各材料间相互结合,孔隙分布不均,大小不一。随着n-HA质量浓度的提高,电镜下见各材料间孔隙逐渐减小,形成结构均匀的复合膜。力学性能及吸水率检测中,随着nHA含量的增加,n-HA/PLA/PVA复合膜的拉伸强度及吸水率呈下降趋势;细胞毒性检测,不同比例复合膜的细胞增殖率无明显差别,无细胞毒性。动物实验测量牙周菌斑指数及龈沟出血指数未发现不同比例n-HA/PLA/PVA复合膜有统计学差异。结论:3D打印不同比例的n-HA/PLA/PVA复合膜具有良好的物理性能和细胞生物相容性,n-HA比例更高的复合膜可能具有更好的物理性能及良好的生物相容性。  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