全文获取类型
收费全文 | 57097篇 |
免费 | 5386篇 |
国内免费 | 4143篇 |
专业分类
耳鼻咽喉 | 353篇 |
儿科学 | 490篇 |
妇产科学 | 571篇 |
基础医学 | 6620篇 |
口腔科学 | 1036篇 |
临床医学 | 7898篇 |
内科学 | 8101篇 |
皮肤病学 | 493篇 |
神经病学 | 2920篇 |
特种医学 | 2078篇 |
外国民族医学 | 42篇 |
外科学 | 5395篇 |
综合类 | 10483篇 |
现状与发展 | 19篇 |
一般理论 | 1篇 |
预防医学 | 3815篇 |
眼科学 | 1786篇 |
药学 | 6202篇 |
43篇 | |
中国医学 | 3566篇 |
肿瘤学 | 4714篇 |
出版年
2024年 | 234篇 |
2023年 | 1061篇 |
2022年 | 2591篇 |
2021年 | 3337篇 |
2020年 | 2416篇 |
2019年 | 1921篇 |
2018年 | 2146篇 |
2017年 | 1829篇 |
2016年 | 1769篇 |
2015年 | 2762篇 |
2014年 | 3412篇 |
2013年 | 2807篇 |
2012年 | 4200篇 |
2011年 | 4701篇 |
2010年 | 2724篇 |
2009年 | 2260篇 |
2008年 | 2879篇 |
2007年 | 2879篇 |
2006年 | 2885篇 |
2005年 | 2867篇 |
2004年 | 1894篇 |
2003年 | 1761篇 |
2002年 | 1515篇 |
2001年 | 1212篇 |
2000年 | 1281篇 |
1999年 | 1344篇 |
1998年 | 902篇 |
1997年 | 842篇 |
1996年 | 657篇 |
1995年 | 626篇 |
1994年 | 520篇 |
1993年 | 316篇 |
1992年 | 398篇 |
1991年 | 315篇 |
1990年 | 289篇 |
1989年 | 245篇 |
1988年 | 227篇 |
1987年 | 172篇 |
1986年 | 145篇 |
1985年 | 105篇 |
1984年 | 46篇 |
1983年 | 42篇 |
1982年 | 18篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1935年 | 4篇 |
1910年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
211.
采用双波长薄层色谱扫描法同时测定复方苯甲酸苄酯洗剂中苯甲酸苄酯与邻苯二甲酸二丁酯的含量,点样后能将本品中两个有效成分很好地分离,在GF254板上,经甲苯∶二氯甲烷(2∶1)混合溶剂展开,反射锯齿扫描测定,λs235nm,λR260nm,以外标两点法定量。苯甲酸苄酯与苯二甲酸二丁酯测定的线性范围分别为6.0~30.0μg和10.0~50.0μg。方法可行,结果满意。 相似文献
212.
213.
目的探讨平调饮对原发性肝癌患者AFP mRNA、GPC-3 mRNA表达的影响。方法抽取60例肝癌患者的抗凝血液,配对法随机分为试验组和对照组各30例。采用Tr-Izol一步法提取总RNA,用逆转录巢式聚合酶链反应(RT-nested PCR)技术检测治疗前后试验组及对照组患者AFP mRNA、GPC-3 mRNA的表达情况。结果治疗后试验组及对照组AFP mRNA、GPC-3 mRNA表达均显著下降,在降低AFP mRNA表达方面试验组与对照组无显著性差异,降低GPC-3 mRNA表达方面试验组明显优于对照组(P0.05)。结论平调饮能有效抑制人血液中AFP mRNA、GPC-3 mRNA的高表达,在降低GPC-3 mRNA表达方面效果优于华蟾素。其治疗原发性肝癌机制与临床应用价值值得进一步研究。 相似文献
214.
215.
Yang Liu Hongyan Wang Sen Yang Yuanyuan Yang Yufeng Wu Zhen He Shuxiang Ma Yuqing Mo Haiyang Chen Qiming Wang Hong Ge 《Journal of thoracic disease》2022,14(6):2254
BackgroundEpidermal growth factor receptor tyrosine kinases inhibitors (EGFR-TKIs) are currently recognized as the standard treatment for advanced non-small cell lung cancer (NSCLC) patients with EGFR mutations. Clinically found patients with different EGFR mutational status have different prognosis.MethodsA retrospective cohort study was performed to explore the relationship between EGFR mutations and abundance with patient survival by using patient data from the Affiliated Cancer Hospital of Zhengzhou University between January 2013 and November 2016. All patients involved in the present study had sensitive EGFR mutations [either exon 19 deletion (DEL) or exon 21 L858R] and treated by EGFR-TKIs. They were followed up every three months until lost or dead. Mutation abundance was calculated as the copies of EGFR mutation divided by copies of EGFR locus, and the cut-off values for 19DEL and L858R were 4.9% and 9.5%, respectively.ResultsTotal of 236 patients were included, comprising 116 (49.2%) patients with 19DEL mutation and 120 (50.8%) patients with L858R mutation. The median follow-up duration was 23.2 months (95% CI: 14.9–26.7 months). Overall survival (OS) was significantly longer in patients with 19DEL mutation (20.9 months, 95% CI: 17.7–24.1 months versus 17.0 months, 95% CI: 14.4–19.6 months in patients with L858R; P=0.008) and in patients with high mutation abundance (20.9 months, 95% CI: 18.3–23.5 months versus 13.0 months, 95% CI: 10.3–15.7 months in patients with low mutation abundance; P<0.001). Multivariate Cox regression including age, performance status and tumor stage revealed that longer OS was independently associated with 19DEL mutation (HR: 0.48, 95% CI: 0.39–0.67, P=0.033) and high mutation abundance (HR: 0.62, 95% CI: 0.50–0.79, P=0.027).ConclusionsEGFR mutation types and abundance was associated with the patients’ survival which might be used to predict the efficacy of targeted therapy by EGFR-TKIs. 相似文献
216.
Shuting Qiu Jiajia Chen Yan Bai Jincan He Hua Cao Qishi Che Jiao Guo Zhengquan Su 《Nutrients》2022,14(13)
The treatment of nonalcoholic fatty liver disease (NAFLD) remains very challenging. This study investigated the therapeutic effect of galactose oligosaccharide (GOS), an important prebiotic, on NAFLD through in vivo and in vitro experiments and preliminarily explored the mechanism by which GOS improves liver lipid metabolism and inflammation through liver and intestinal microbiological analysis. The results of mouse liver lipidomics showed that GOS could promote body thermogenesis in mice with high-fat and high-sugar diet (HFHSD)-induced NAFLD, regulate lipolysis in liver fat cells, and accelerate glycine and cholesterol metabolism. GOS dose-dependently reduced the contents of total cholesterol (TC) and triglyceride (TG) in cells and reduced the accumulation of lipid droplets in cells. GOS also reduced the Firmicutes/Bacteroidetes ratio and altered the composition of the intestinal microbiota in mice fed a HFHSD. GOS can improve liver lipid metabolism and intestinal structure of NAFLD. These results provide a theoretical and experimental basis supporting the use of GOS as a health food with anti-NAFLD functions. 相似文献
217.
218.
Energy harvesting devices made of piezoelectric material are highly anticipated energy sources for power wireless sensors. Tremendous efforts have been made to improve the performance of piezoelectric energy harvesters (PEHs). Noticeably, topology optimization has shown an attractive potential to design PEHs with enhanced energy conversion efficiency. In this work, an alternative yet more practical design objective was considered, where the open-circuit voltage of PEHs is enhanced by topologically optimizing the through-thickness piezoelectric material distribution of plate-type PEHs subjected to harmonic excitations. Compared to the conventional efficiency-enhanced designs, the open-circuit voltage of PEHs can be evidently enhanced by the proposed method while with negligible sacrifice on the energy conversion efficiency. Numerical investigations show that the voltage cancellation effect due to inconsistent voltage phases can be effectively ameliorated by optimally distributed piezoelectric materials. 相似文献
219.
Background:Chronic kidney disease (CKD) can lead to systemic inflammatory responses and other cardiovascular disease. Diffusion tensor imaging findings generated by gadolinium-based MRI (DTI-GBMRI) is regarded as a standard method for assessing the pathology of CKD. To evaluate the diagnostic value of DTI-GBMRI for renal histopathology and renal efficiency, renal fibrosis and damage, noninvasive quantification of renal blood flow (RBF) were investigated in patients with CKD.Methods:CKD patients (n = 186) were recruited and underwent diagnosis of renal diffusion tensor imaging findings generated by MRI (DTI-MRI) or DTI-GBMRI to identify the pathological characteristics and depict renal efficiency. The cortical RBFs and estimated glomerular filtration rate were compared in CKD patients undergone DTI-GBMRI (n = 92) or DTI-MRI (n = 94).Results:Gadolinium enhanced the diagnosis generated by DTI-MRI in renal fibrosis, renal damage, and estimated glomerular filtration rate. The superiority in sensitivity and accuracy of the DTI-GBMRI method in assessing renal function and evaluating renal impairment was observed in CKD patients compared with DTI-MRI. Outcomes demonstrated that DTI-GBMRI had higher accuracy, sensitivity, and specificity than DTI-MRI in diagnosing patients with CKD.Conclusion:In conclusion, DTI-GBMRI is a potential noninvasive method for measuring renal function, which can provide valuable information for clinical CKD diagnosis. 相似文献
220.
背景 抑郁障碍患者的主观认知功能与客观认知功能存在差异。目前,关于主客观认知功能差异影响因素的研究有限。目的 探索抑郁障碍患者主观和客观认知功能的差异及其影响因素,为进一步理解抑郁障碍患者认知功能受损情况提供参考。方法 纳入2022年1月13日—2023年12月11日在成都市第四人民医院门诊就诊或住院治疗的、符合《精神障碍诊断与统计手册(第5版)》(DSM-5)抑郁障碍诊断标准的77例患者为研究对象。采用蒙哥马利-艾森贝格抑郁量表(MADRS)评定患者抑郁症状严重程度,采用抑郁感知缺陷问卷(PDQ-D)和中国简版神经认知成套测验(C-BCT)分别评定患者的主观认知功能和客观认知功能,采用席汉残疾量表(SDS)评定患者的社会功能,以临床总体印象量表-疾病严重程度量表(CGI-SI)评定患者病情严重程度。采用Pearson相关分析考查年龄、受教育年限、MADRS总评分、SDS总评分、CGI-SI评分与主客观认知功能及其差异的相关性。采用多元线性回归探索主客观认知功能差异的影响因素。结果 是否用药的抑郁障碍患者PDQ-D总评分和主客观认知功能差异(D值)比较差异均有统计学意义(t=-4.2... 相似文献