全文获取类型
收费全文 | 1375025篇 |
免费 | 118268篇 |
国内免费 | 9279篇 |
专业分类
耳鼻咽喉 | 17038篇 |
儿科学 | 43620篇 |
妇产科学 | 37143篇 |
基础医学 | 188428篇 |
口腔科学 | 36936篇 |
临床医学 | 125933篇 |
内科学 | 283941篇 |
皮肤病学 | 32286篇 |
神经病学 | 112919篇 |
特种医学 | 56833篇 |
外国民族医学 | 290篇 |
外科学 | 214598篇 |
综合类 | 38101篇 |
现状与发展 | 7篇 |
一般理论 | 421篇 |
预防医学 | 108785篇 |
眼科学 | 29202篇 |
药学 | 97860篇 |
36篇 | |
中国医学 | 4067篇 |
肿瘤学 | 74128篇 |
出版年
2018年 | 14896篇 |
2017年 | 11948篇 |
2016年 | 14023篇 |
2015年 | 16139篇 |
2014年 | 22251篇 |
2013年 | 31804篇 |
2012年 | 39322篇 |
2011年 | 42201篇 |
2010年 | 26362篇 |
2009年 | 25521篇 |
2008年 | 38594篇 |
2007年 | 41023篇 |
2006年 | 42021篇 |
2005年 | 40647篇 |
2004年 | 38167篇 |
2003年 | 37229篇 |
2002年 | 35014篇 |
2001年 | 67024篇 |
2000年 | 68905篇 |
1999年 | 57703篇 |
1998年 | 17330篇 |
1997年 | 15702篇 |
1996年 | 16517篇 |
1995年 | 16697篇 |
1994年 | 15494篇 |
1993年 | 14441篇 |
1992年 | 47417篇 |
1991年 | 46020篇 |
1990年 | 44218篇 |
1989年 | 41982篇 |
1988年 | 38909篇 |
1987年 | 38220篇 |
1986年 | 35966篇 |
1985年 | 34730篇 |
1984年 | 26390篇 |
1983年 | 22127篇 |
1982年 | 13849篇 |
1981年 | 12449篇 |
1980年 | 11690篇 |
1979年 | 23545篇 |
1978年 | 17038篇 |
1977年 | 14351篇 |
1976年 | 13146篇 |
1975年 | 13703篇 |
1974年 | 16083篇 |
1973年 | 15393篇 |
1972年 | 14172篇 |
1971年 | 13027篇 |
1970年 | 11865篇 |
1969年 | 11097篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
1.
2.
目的 了解我国老年人中医证候分布特征,为中医药辨治老年人提供参考依据。方法 系统检索中国知识基础设施(CNKI)、中文科技期刊数据库(CCD)、万方数据资源系统数据库(CSPD),纳入研究对象为老年人的临床流行病学调查研究文献,对其调查目的、调查疾病及调查结果等进行描述统计。结果 ①最终纳入168篇文献,其中2010至2020年之间发表138篇(82.14%);调查地区涵盖全国28个省市自治区,共纳入43948例老年人,累计覆盖340个研究中心;②主要研究结果显示,老年人中医证候阴虚阳亢证(10.05%)>血瘀证(9.5%)>痰浊(湿)证(8.91%)>阴阳两虚证(4.98%)>痰瘀互结证(4.96%);单元证分布阴虚证(14.70%)>痰证(11.22%)>气虚证(7.15%)>肾虚证(4.72%)>血瘀证(4.18%);涉及病变脏腑肾>肝>脾>肺>心。结论 根据统计结果,可以看出老年人证候分布虚证多于实证,虚证中又以阴虚证、气虚证最为多见,实证常见血瘀证、痰浊(湿)证等,且多见痰瘀互结证;老年人五脏皆损,其中又以肾、肝、脾功能失调最为突出。 相似文献
3.
目的 鉴定当地民间应用普遍的野生药用真菌,并探讨其治疗肿瘤的作用机制。方法 采用形态学和分子生物学方法对一株采自定陶仿山野生药用真菌进行鉴定,确定为硬皮马勃。通过文献检索收集硬皮马勃化学成分,利用PubChem软件和TCMSP、GCS数据库得到化学成分结构信息及其药用动力学参数和相关靶点分析,通过SysDT和WES系统鉴定潜在化学成分靶点,利用CTD数据库获得靶点功能,将潜在化合物和肿瘤相关靶点导入Cytoscape3.8.0软件构建分子-靶标网络。应用DAVID数据库对肿瘤相关靶点进行GO和KEGG富集分析,揭示有关活性成分靶点所涉及的生物学过程和通路,将肿瘤相关靶点和通路导入Cytoscape3.8.0软件构建靶点-通路网络。结果 从文献中获得硬皮马勃的化学成分59个,通过ADME计算系统筛选出5个潜在活性的化合物即活性成分,预测到38个靶点,其中与肿瘤相关靶点16个。这些活性成分主要通过Toll-like receptor、PI3K-AKT、MAPK和NF-kappa B等通路参与免疫应答,抑制肿瘤细胞生长、增殖,促进其凋亡。结论 表明硬皮马勃治疗肿瘤具有多靶点、多途径协同作用的特点,并通过多层次效应达到治疗肿瘤的效果。本研究为更好理解硬皮马勃作用肿瘤的机制和肿瘤药物开发提供理论依据。 相似文献
4.
Xiao-Long Tang Yan-Dong Miao Deng-Hai Mi 《World journal of gastrointestinal oncology》2022,14(1):366-368
The present letter to the editor is in response to the research “Outcomes of curative liver resection for hepatocellular carcinoma in patients with cirrhosis” by Elshaarawy et al in World J Gastroenterol 2021; 13(5): 424–439. The preoperative assessment of the liver reserve function in hepatocellular carcinoma (HCC) patients with cirrhosis is crucial, and there is no universal consensus on how to assess it. Based on a retrospective study, Elshaarawy et al investigated the impact of various classical clinical indicators on liver failure and the prognosis after hepatectomy in HCC patients with cirrhosis. We recommend that we should strive to explore new appraisal indicators, such as the indocyanine green retention rate at 15 min. 相似文献
5.
6.
7.
Journal of Behavioral Medicine - Evidence supports the use of graphic warnings to educate the public about the health harms of smoking and suggests warnings eliciting negative emotional responses... 相似文献
8.
Ludefu Su Yu Liu Yanhong Tang Mingmin Zhou Liang Xiong Congxin Huang 《International journal of clinical and experimental pathology》2021,14(4):408
Background and objective: Myocardial infarction (MI) is a common critical disease of the cardiovascular system. The process of MI is often accompanied by the excessive activation of cardiac sympathetic nerves, which leads to arrhythmia. Resiniferatoxin (RTX) is a transient receptor potential vanilloid 1 (TRPV1), involved in the cardiac sympathetic afferent reflex. However, whether RTX can reduce the occurrence of arrhythmia and exert a cardioprotective effect by inhibiting the sympathetic reflex during MI is still unknown. Methods: The left anterior descending artery of cardiac was clamped to construct a model of MI. RTX (50 μg/ml) was used by epicardial application in MI rats. Ventricular electrophysiologic properties were continuously monitored by a body surface ECG. Yrosine hydroxylase (TH) and growth associated protein 43 (GAP43) were detected by Immunofluorescence staining. Connexin43 and transforming growth factor beta receptor 1 (TGF-β1) were detected by western blot. Norepinephrine (NE) and BNP levels in blood and tissue were determined by ELISA. Cardiac function was assessed by echocardiography. Results: The ERP, APD90, QRS, QT and the Tend-Tpeak intervals in MI rats were all prolonged, but decreased after RTX treatment (n = 3, P<0.05). In contrast, the RR interval was shortened in the MI group, but prolonged in the MI+RTX group (n = 3, P<0.05). RTX treatment significantly reduced ventricular arrhythmias after MI. TH- and GAP43-positive nerve densities and TGF-β1, and cx-43 protein expression were up-regulated in the MI group compared to the sham group, and they were decreased in the MI+RTX group compared to the MI group (n = 3, P<0.05). RTX can decrease serum and tissue NE and BNP levels (n = 3, P<0.05). RTX pretreatment significantly decreased heart rate, HW/BW ratio and LVIDS, and increased LVEF andLVFS values (n = 3, P<0.05). Conclusion: RTX improved cardiac dysfunction, ventricular electrophysiologic properties, and sympathetic nerve remodeling in rats with MI by inhibiting the excessive cardiac sympathetic drive. 相似文献
9.
Qian Zhang Larry D. Mesner Gina M. Calabrese Naomi Dirckx Zhu Li Angela Verardo Qian Yang Robert J. Tower Marie-Claude Faugere Charles R. Farber Thomas L. Clemens 《The Journal of clinical investigation》2021,131(7)
Bone mineral density (BMD) is a highly heritable predictor of osteoporotic fracture. GWAS have identified hundreds of loci influencing BMD, but few have been functionally analyzed. In this study, we show that SNPs within a BMD locus on chromosome 14q32.32 alter splicing and expression of PAR-1a/microtubule affinity regulating kinase 3 (MARK3), a conserved serine/threonine kinase known to regulate bioenergetics, cell division, and polarity. Mice lacking Mark3 either globally or selectively in osteoblasts have increased bone mass at maturity. RNA profiling from Mark3-deficient osteoblasts suggested changes in the expression of components of the Notch signaling pathway. Mark3-deficient osteoblasts exhibited greater matrix mineralization compared with controls that was accompanied by reduced Jag1/Hes1 expression and diminished downstream JNK signaling. Overexpression of Jag1 in Mark3-deficient osteoblasts both in vitro and in vivo normalized mineralization capacity and bone mass, respectively. Together, these findings reveal a mechanism whereby genetically regulated alterations in Mark3 expression perturb cell signaling in osteoblasts to influence bone mass. 相似文献
10.