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   58142篇
  免费   5581篇
  国内免费   4096篇
耳鼻咽喉   648篇
儿科学   599篇
妇产科学   563篇
基础医学   6003篇
口腔科学   874篇
临床医学   7442篇
内科学   7785篇
皮肤病学   570篇
神经病学   2763篇
特种医学   2276篇
外国民族医学   36篇
外科学   6313篇
综合类   10852篇
现状与发展   13篇
一般理论   3篇
预防医学   4058篇
眼科学   1621篇
药学   6349篇
  54篇
中国医学   4143篇
肿瘤学   4854篇
  2024年   212篇
  2023年   779篇
  2022年   2053篇
  2021年   2921篇
  2020年   2383篇
  2019年   1859篇
  2018年   2006篇
  2017年   1995篇
  2016年   1792篇
  2015年   2887篇
  2014年   3623篇
  2013年   3336篇
  2012年   4848篇
  2011年   5194篇
  2010年   3605篇
  2009年   2913篇
  2008年   3382篇
  2007年   3152篇
  2006年   3052篇
  2005年   2819篇
  2004年   1841篇
  2003年   1741篇
  2002年   1447篇
  2001年   1190篇
  2000年   1112篇
  1999年   1055篇
  1998年   659篇
  1997年   584篇
  1996年   490篇
  1995年   458篇
  1994年   350篇
  1993年   260篇
  1992年   316篇
  1991年   309篇
  1990年   211篇
  1989年   165篇
  1988年   187篇
  1987年   152篇
  1986年   101篇
  1985年   80篇
  1984年   60篇
  1983年   32篇
  1982年   29篇
  1981年   31篇
  1980年   23篇
  1979年   38篇
  1978年   13篇
  1977年   11篇
  1975年   11篇
  1973年   12篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
991.
992.
Retinopathy of prematurity (ROP) is a retinopathy characterized by retinal neovascularization (RNV) occurring in preterm infants treated with high concentrations of oxygen and may lead to blindness in severe cases. Currently, anti‐VEGF therapy is a major treatment for ROP, but it is costly and may cause serious complications. The previous study has demonstrated that melatonin exerted neuroprotective effect against retinal ganglion cell death induced by hypoxia in neonatal rats. However, whether melatonin is anti‐angiogenic and neuroglial protective in the progression of ROP remains unknown. Thus, this study was to investigate the effect of melatonin on RNV and neuroglia in the retina of oxygen‐induced retinopathy (OIR) mice. The results showed a reduction in retinal vascular leakage in OIR mice after melatonin treatment. Besides, the size of retinal neovascular and avascular areas, the number of preretinal neovascular cell nuclei, and the number of proliferative vascular endothelial cells within the neovascular area were significantly decreased in mice treated with melatonin. After oxygen‐induced injury, the density of astrocytes was decreased, accompanied by morphologic and functional changes of astrocytes. Besides, retinal microglia were also activated. Meanwhile, the levels of inflammatory factors were elevated. However, these pathologic processes were all hindered by melatonin treatment. Furthermore, HIF‐1α‐VEGF pathway was activated in the retina of OIR mice, yet was suppressed in melatonin‐treated OIR mice retinas. In conclusion, melatonin prevented pathologic neovascularization, protected neuroglial cells, and exerts anti‐inflammation effect via inhibition of HIF‐1α‐VEGF pathway in OIR retinas, suggesting that melatonin could be a promising therapeutic agent for ROP.  相似文献   
993.
994.
背景与目的:乳腺癌手术方式的选择受到诸多因素影响,本研究旨在分析乳腺癌患者选择乳房重建手术的影响因素,重点探讨居住地距离与乳房重建的关系。方法:回顾性分析了1999年1月—2015年12月复旦大学附属肿瘤医院收治的因单侧或双侧0~Ⅱ期乳腺癌行全乳切除术的女性患者临床资料,分析居住地距离与乳房重建比例的关系。结果:非上海患者选择全乳切除术后乳房重建比例高于上海患者(6.1% vs 4.5%,P<0.001)。居住地距离影响乳房重建比例(P=0.035)。单因素分析显示,居住地距离越远,选择乳房重建手术比例越高,而年龄、体质量指数(body mass index,BMI)、TNM分期与乳房重建的选择呈负相关(P均<0.001)。多因素分析显示,年龄增长、BMI增加、TNM分期较晚是拒绝行乳房重建的独立影响因素(P均<0.001),而居住地距离不是乳房重建的独立影响因素(P>0.05),且与具体乳房重建方式无交互作用。年龄与居住地距离呈负相关(P<0.001)。结论:乳腺癌患者的居住地距离与乳房重建比例呈线性相关;年龄、BMI和疾病分期是影响乳房重建的主要因素。  相似文献   
995.
996.
997.
998.
We conducted a retrospective study of 135 patients of stage IE/IIE extranodal natural killer/T cell lymphoma, nasal type (ENKTL) treated with CHOP as induction chemotherapy to find some valuable prognostic factors and analyze the usefulness of International Prognostic Index (IPI) and Korean Prognostic Index (KPI) in predicting prognosis. Most of the patients were in the low-risk group (IPI score 0?C1). Complete remission (CR) after induction chemotherapy was achieved in 31.8?% of the patients, which increased to 69.6?% after radiotherapy. The 2-, 5-, and 10-year overall survival (OS) rates were 60, 48, and 43?%, respectively. Patients with better performance status (ECOG 0-1), normal serum LDH level, without local invasiveness, low KPI scores, and IPI score of 0 had significantly better overall survival (P?<?0.05) in univariate analysis. Using multivariate analysis, we identified serum LDH level, ECOG PS score and local invasiveness to be independent prognostic factors. In conclusion, ENKTL is an aggressive lymphoma that shows heterogeneity. The IPI and KPI score systems should be improved further to classify patients into different groups, and should be validated in larger prospective trials. Due to the multi-drug resistance mechanism of ENKTL, CHOP is no longer the state of art and novel drugs should be incorporated into future treatments.  相似文献   
999.
The mechanism of phosgene-induced acute lung injury (ALI) remains unclear and it is still lack of effective treatments. Previous study indicated that oxidative stress was involved in phosgene-induced ALI. Caffeic acid phenethyl ester (CAPE) has been proved to be an anti-inflammatory agent and a potent free radical scavenger. The purpose of this study was to investigate the protective effects of CAPE on phosgene-induced ALI and identify the mechanism, in which oxidative stress and inflammation were involved. The phosgene was used to induce ALI in rats. The results showed that after phosgene exposure, total protein content in BALF was not significantly changed. The increase of MDA level and SOD activity induced by phosgene was significantly reduced by CAPE administration, and the decrease of GSH level in BALF and lung were significantly reversed by CAPE. CAPE also partially blocked the translocation of NF-κB p65 to the nucleus, but it had little effect on the phosphorylation of p38 MAPK. In conclusion, CAPE showed protective effects on lung against phosgene-induced ALI, which may be related with a combination of the antioxidant and anti-inflammatory functions of CAPE.  相似文献   
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