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   270279篇
  免费   26208篇
  国内免费   19033篇
耳鼻咽喉   2538篇
儿科学   2873篇
妇产科学   3543篇
基础医学   30998篇
口腔科学   4877篇
临床医学   37060篇
内科学   38882篇
皮肤病学   2681篇
神经病学   14174篇
特种医学   10182篇
外国民族医学   156篇
外科学   26544篇
综合类   47279篇
现状与发展   65篇
一般理论   21篇
预防医学   17797篇
眼科学   7726篇
药学   28928篇
  277篇
中国医学   16464篇
肿瘤学   22455篇
  2024年   970篇
  2023年   4467篇
  2022年   11420篇
  2021年   14209篇
  2020年   10778篇
  2019年   9035篇
  2018年   9622篇
  2017年   8733篇
  2016年   8118篇
  2015年   12683篇
  2014年   15521篇
  2013年   13848篇
  2012年   20390篇
  2011年   22527篇
  2010年   14201篇
  2009年   11373篇
  2008年   14413篇
  2007年   14376篇
  2006年   14149篇
  2005年   13705篇
  2004年   8917篇
  2003年   8355篇
  2002年   7038篇
  2001年   6079篇
  2000年   6168篇
  1999年   6189篇
  1998年   3797篇
  1997年   3775篇
  1996年   3005篇
  1995年   2765篇
  1994年   2288篇
  1993年   1458篇
  1992年   1974篇
  1991年   1658篇
  1990年   1365篇
  1989年   1137篇
  1988年   1046篇
  1987年   920篇
  1986年   750篇
  1985年   537篇
  1984年   348篇
  1983年   249篇
  1982年   149篇
  1981年   147篇
  1980年   113篇
  1979年   143篇
  1978年   49篇
  1977年   53篇
  1975年   57篇
  1974年   56篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Gastric cancer, one of the most common disease, has become a major public health problem worldwide. Cisplatin (DDP) has been a widely used drug for the treatment of cancer, also usually applied in gastric cancer in clinic. However, the side effects including toxicity and drug-resistance restricted the usage of DDP in clinic, so we prepared a DDP-complexed hydrogel (DDP-Gel) and investigated its efficacy in gastric cancer. For in vivo studies, MKN45-Luc cells were injected into BLAB/C node mice subcutaneously to establish gastric cancer with orthotopically grown tumors. Mice bearing tumors were treated with normal saline, DDP and DDP-Gel. Body weight and survival condition were observed and recorded. The treatment efficacy in vivo was detected by luciferase imaging and histological evaluation was performed by H&E staining of different organs. Additionally, normal ICR mice were treated with different doses of DDP/DDP-Gel to calculate their LD50 in vivo. The results showed that DDP-Gel prolonged survival time and ameliorated body weight changes of mice bearing tumors. DDP-Gel exhibited higher efficacy to inhibit tumor growth and metastasis, compared to DDP. Besides, LD50 of DDP-Gel was 166.0?mg/kg, 13.2 folds higher than DDP. As a conclusion, DDP-Gel showed a more effective and safer function than DDP in gastric cancer, which indicating that DDP-Gel might be a novel strategy for gastric cancer therapy.  相似文献   
52.
53.
心血管专科医师规范化培训目标要求高于住院医师培训,完成心血管专培的医生应能在医疗、教学、科研能力上明显提高,达到心血管专科主治医师水平。如何提高心血管专培学员教学能力是专培中的难点。将专培学员随机分为两组,分别采用案例教学法(case-based learning, CBL)和传统教学法进行带教,课程结束后通过测验和调查问卷两种方式对教学效果进行考察。旨在探讨由心血管专培学员主导CBL教学法在实施过程中是否对其自身综合能力有所提升。结果显示,CBL教学法组学生临床理论及病例分析考试分数均高于对照组;心血管专培学员通过主导CBL教学,在教学能力、组织能力和学科协调均有提升;相较传统教学法,CBL教学法的教学效果更佳,有利于心血管专培学员自身综合能力提升。  相似文献   
54.
55.
56.

Background

Patients undergoing cardiac surgery are at significant risk of developing postoperative acute kidney injury (AKI). Neutrophil–lymphocyte ratio (NLR) is a widely available inflammatory biomarker which may be of prognostic value in this setting.

Methods

We conducted a systematic review and meta-analysis of studies reporting associations between perioperative NLR with postoperative AKI. We searched Medline, Embase and the Cochrane Library, without language restriction, from inception to May 2022 for relevant studies. We meta-analysed the reported odds ratios (ORs) with 95% confidence intervals (CIs) for both elevated preoperative and postoperative NLR with risk of postoperative AKI and need for renal replacement therapy (RRT). We conducted a meta-regression to explore inter-study statistical heterogeneity.

Results

Twelve studies involving 10,724 participants undergoing cardiac surgery were included, with eight studies being deemed at high risk of bias using PROBAST modelling. We found statistically significant associations between elevated preoperative NLR and postoperative AKI (OR 1.45, 95% CI 1.18–1.77), as well as postoperative need for RRT (OR 2.37, 95% CI 1.50–3.72). Postoperative NLR measurements were not of prognostic significance.

Conclusions

Elevated preoperative NLR is a reliable inflammatory biomarker for predicting AKI following cardiac surgery.  相似文献   
57.
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   
58.
本研究拟探讨染料木黄酮对前列腺癌细胞LNCaP和CWR22RV1的增殖、迁移和侵袭能力的影响。一、材料与方法1.材料:前列腺癌细胞株LNCaP和CWR22RV1(中国科学院上海生命科学研究院);Genistein(天津科瑞泰科技有限公司);RPMI 1640、胎牛血清(FBS)、胰蛋白酶(美国Gibco公司);E-钙黏蛋白(E-cadherin)、N-钙黏蛋白(N-cadherin)、波形蛋白(Vimentin,Abcam公司);聚氰基丙烯酸正丁酯(BCA)试剂盒、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)上样缓冲液(×5)及蛋白质印迹法(Western blot)试剂盒(上海市碧云天生物公司);2.实验方法:采用噻唑蓝(MTT)实验、划痕实验和Transwell实验检测Genistein对细胞增殖、迁移及侵袭能力的影响。采用Western blot检测E-cadherin、N-cadherin、Vimentin、CD44和Oct-4的表达水平。  相似文献   
59.
Journal of Public Health - Sleep-disordered breathing (SDB) is common among adolescents and is associated with short- and long-term consequences. Data on the prevalence and epidemiologic...  相似文献   
60.
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