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   239917篇
  免费   23444篇
  国内免费   15797篇
耳鼻咽喉   2174篇
儿科学   2688篇
妇产科学   3449篇
基础医学   30395篇
口腔科学   4522篇
临床医学   31675篇
内科学   35674篇
皮肤病学   2712篇
神经病学   14558篇
特种医学   9203篇
外国民族医学   140篇
外科学   24852篇
综合类   37091篇
现状与发展   55篇
一般理论   27篇
预防医学   14255篇
眼科学   7230篇
药学   24867篇
  188篇
中国医学   12650篇
肿瘤学   20753篇
  2024年   210篇
  2023年   3224篇
  2022年   4968篇
  2021年   10159篇
  2020年   8721篇
  2019年   7851篇
  2018年   8579篇
  2017年   7512篇
  2016年   7088篇
  2015年   10747篇
  2014年   13188篇
  2013年   11574篇
  2012年   17198篇
  2011年   19136篇
  2010年   11266篇
  2009年   8831篇
  2008年   12215篇
  2007年   12267篇
  2006年   12315篇
  2005年   12242篇
  2004年   7841篇
  2003年   7384篇
  2002年   6138篇
  2001年   6986篇
  2000年   7292篇
  1999年   7299篇
  1998年   4010篇
  1997年   3799篇
  1996年   3027篇
  1995年   2865篇
  1994年   2376篇
  1993年   1587篇
  1992年   2797篇
  1991年   2425篇
  1990年   2020篇
  1989年   1892篇
  1988年   1754篇
  1987年   1518篇
  1986年   1328篇
  1985年   1085篇
  1984年   687篇
  1983年   533篇
  1982年   312篇
  1981年   270篇
  1980年   219篇
  1979年   329篇
  1977年   134篇
  1974年   138篇
  1973年   136篇
  1972年   135篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
目的:观察理肺消积丸对Lewis肺癌小鼠肿瘤生长的影响作用。方法:将50只小鼠随机分为空白对照组、模型对照组、理肺消积丸组[240μg/(g·d)]、顺铂组[0.5μg/(g·d)]、联合组[理肺消积丸240μg/(g·d)+顺铂0.5μg/(g·d)]。采用皮下接种法建立Lewis肺癌小鼠模型,制备模型次日进行药物干预。2周后分别采用活体成像技术检测小鼠体内肿瘤生长情况,HE染色评价肿瘤组织病理学形态,免疫组化技术观察肿瘤细胞增殖细胞核抗原(Proliferating cell nuclear antigen,PCNA)及人第10号染色体缺失的磷酸酶及张力蛋白同源物(gene of phosphate and tension homology deleted on chromosome ten,PTEN)的表达情况,TUNEL技术评价肿瘤细胞凋亡情况。结果:模型对照组小鼠体内肿瘤增殖明显,肿瘤细胞异型性明显、核分裂象多见,PCNA蛋白表达程度极高,而细胞凋亡率及PTEN蛋白表达量极低。与模型对照组对比,理肺消积丸组的肿瘤生长受到抵制,肿瘤细胞异型性及核分裂象减少,PCNA蛋白表达下降,肿瘤细胞凋亡率升高,PTEN蛋白表达升高,差异均有统计学意义(P<0.05)。而顺铂组和联合组除PTEN蛋白表达较模型对照组差异无统计学意义外,其余指标均有统计学意义。结论:理肺消积丸可显著抑制Lewis肺癌小鼠肿瘤生长,其机制可能与其抑制肺癌细胞增殖、上调细胞凋亡和PTEN蛋白表达有关。  相似文献   
52.
53.
54.
Background:Gastrointestinal complications and malnutrition are common problems that affect postoperative rehabilitation and survival of patients with esophageal cancer. Evidence has shown that probiotics have a positive effect on improving gastrointestinal complications and nutritional status of patients with esophageal cancer after surgery, but there is a lack of prospective studies on this topic. We designed this prospective randomized controlled trial to evaluate the effects of probiotics on gastrointestinal complications and nutritional status in patients with postoperative esophageal cancer.Methods:This is a prospective, randomized, double-blind, placebo-controlled trial. It was approved by the Clinical Research Ethics Committee of our hospital. 192 patients will be randomly divided into probiotics group and the placebo group in a 1:1 ratio. After operation, probiotics and placebo will be given orally for 8 weeks. The indexes of nutritional status and incidence of digestive tract complications will be recorded and the data will be analyzed by SPSS 18.0 software.Discussion:This study will evaluate the effect of probiotics on gastrointestinal complications and nutritional status of postoperative patients with esophageal cancer. The results of this study will provide clinical basis for the use of probiotics in postoperative treatment of esophageal cancer.Trial registration:OSF Registration number: D DOI 10.17605/OSF.IO/QHW86  相似文献   
55.
56.
57.
BackgroundCongenital ventricular diverticulum is a rare abnormality that may occur as an isolated malformation. Most cases are accompanied by pericardial effusion. Prenatal counseling can be difficult because the prognosis is uncertain and there is no consensus approach to prenatal management.Case presentation: We describe a case of congenital cardiac diverticulum complicated by large pericardial effusion in one of monochorionic diamniotic twins. The case was diagnosed by ultrasonography at 21 weeks of gestation. Therapeutic pericardiocentesis at 22 weeks resulted in complete resolution of the effusion and led to a favorable fetal outcome. We summarize the interventions and pregnancy outcomes in cases of cardiac diverticula reported in the literature.ConclusionsBetter awareness of clinical features, in utero therapies, and pregnancy outcomes could help define and improve prenatal management of congenital ventricular diverticula.  相似文献   
58.
Skin cancer is the deadliest type of malignant disease and causes primary mortality worldwide. Dioscin, which exists in medicinal plants, has potent anticancer effects. However, its effects on skin cancer remain unknown. In the present study, the activity and mechanism of dioscin on the human skin cancer A431 cell line were investigated, MTT, colony formation, Transwell, wound-healing, TUNEL, Comet, immunofluorescence and western blot assays were used to assess the effects of dioscin on A431 cells. The results of MTT, colony formation, Transwell and wound-healing assays revealed that dioscin suppressed proliferation, colony formation and invasion of the cancer cells. TUNEL and comet assays demonstrated that dioscin exhibited significant effects on cell apoptosis and DNA damage. Investigations into the mechanism revealed that the expression levels of phosphorylated Ataxia telangiectasia-mutated (ATM) were considerably activated by dioscin, which significantly upregulated the expression levels of p53 to activate mitochondrial apoptosis signaling. Furthermore, the expression levels of BAX, cleaved caspase-3/9 and cleaved poly (ADP-ribose) polymerase were upregulated, and the expression levels of BCL-2 were downregulated by dioscin. Additionally, dioscin markedly downregulated the expression levels of matrix metalloproteinase 2 (MMP2), MMP9, RHO and cdc42, which are all associated with tumor invasion. In addition, p53-small interfering RNA transfection experiments indicated that dioscin exhibited excellent activity against skin cancer in vitro by decreasing p53 expression. Overall, the present results suggested that dioscin inhibited skin cancer cell proliferation via adjusting ATM/p53-mediated cell apoptosis, migration and DNA damage, which should be considered as a potential option for future treatments of skin cancer.  相似文献   
59.
目的分析并探究双侧延髓内侧梗死(BMMI)的血管病因、临床表现、MRI特征和预后,以期提高BMMI的早期诊断率.方法对青岛大学附属烟台毓璜顶医院诊治的14例BMMI患者临床资料进行分析.结果BMMI血管病因以动脉粥样硬化为主;临床症状表现为四肢瘫痪、舌瘫、感觉异常、头晕、构音障碍、饮水呛咳等,危重时出现呼吸衰竭.头颅DWI示双侧延髓内侧可呈特征性"心型"、"Y"字型、"V"字型或倒"八"字型高信号影.出院NIHSS评分、卒中进展(尤其呼吸衰竭)为BMMI的预后不良因素.结论BMMI临床少见,临床表现多样,预后较差;头颅MRI为其主要的影像学检查,有助于早期诊断.  相似文献   
60.
Huang  Kangmo  Zha  Mingming  Gao  Jie  Du  Juan  Liu  Rui  Liu  Xinfeng 《Journal of thrombosis and thrombolysis》2021,51(2):536-544
Journal of Thrombosis and Thrombolysis - The impact of atrial fibrillation (AF) on outcomes of mechanical thrombectomy (MT) for acute ischemic stroke (AIS) is controversial, and with a paucity of...  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