全文获取类型
收费全文 | 400838篇 |
免费 | 37648篇 |
国内免费 | 23103篇 |
专业分类
耳鼻咽喉 | 4035篇 |
儿科学 | 6472篇 |
妇产科学 | 2653篇 |
基础医学 | 27738篇 |
口腔科学 | 7819篇 |
临床医学 | 47853篇 |
内科学 | 37859篇 |
皮肤病学 | 4825篇 |
神经病学 | 10845篇 |
特种医学 | 16273篇 |
外国民族医学 | 26篇 |
外科学 | 33936篇 |
综合类 | 104446篇 |
现状与发展 | 90篇 |
一般理论 | 7篇 |
预防医学 | 44994篇 |
眼科学 | 5606篇 |
药学 | 47988篇 |
588篇 | |
中国医学 | 37756篇 |
肿瘤学 | 19780篇 |
出版年
2024年 | 1821篇 |
2023年 | 4891篇 |
2022年 | 12308篇 |
2021年 | 15597篇 |
2020年 | 13251篇 |
2019年 | 8002篇 |
2018年 | 8575篇 |
2017年 | 11003篇 |
2016年 | 9119篇 |
2015年 | 15975篇 |
2014年 | 20377篇 |
2013年 | 25247篇 |
2012年 | 36198篇 |
2011年 | 38274篇 |
2010年 | 33453篇 |
2009年 | 29918篇 |
2008年 | 31411篇 |
2007年 | 30213篇 |
2006年 | 26905篇 |
2005年 | 21678篇 |
2004年 | 15680篇 |
2003年 | 13661篇 |
2002年 | 10483篇 |
2001年 | 9294篇 |
2000年 | 6899篇 |
1999年 | 3229篇 |
1998年 | 1198篇 |
1997年 | 1217篇 |
1996年 | 906篇 |
1995年 | 758篇 |
1994年 | 687篇 |
1993年 | 434篇 |
1992年 | 450篇 |
1991年 | 387篇 |
1990年 | 333篇 |
1989年 | 267篇 |
1988年 | 211篇 |
1987年 | 213篇 |
1986年 | 161篇 |
1985年 | 168篇 |
1984年 | 100篇 |
1983年 | 87篇 |
1982年 | 63篇 |
1981年 | 30篇 |
1979年 | 37篇 |
1978年 | 34篇 |
1973年 | 27篇 |
1959年 | 25篇 |
1958年 | 28篇 |
1957年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
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
992.
目的 探讨累积空腹血糖暴露(cumFBG)对心脑血管事件的影响。方法 采用前瞻性队列研究方法,以连续参加2006-2007、2008-2009、2010-2011年3次健康体检的开滦集团职工为观察对象,排除心肌梗死、脑卒中、心力衰竭患者,最终纳入统计分析52 980例。以观察对象完成第3次健康体检时间为随访起点,以发生心脑血管事件为终点事件,随访终止时间为发生心脑血管事件、全因死亡或末次随访时间(2017年12月31日)。按cumFBG四分位分组,用Kaplan-Meier法计算各组心脑血管事件累积发病率,并用Log-rank检验比较各组心脑血管事件累积发病率的差异;采用Cox比例风险模型分析cumFBG对心脑血管事件的影响。结果 随访(6.76±1.03)年,cumFBG第1至第4四分位组心脑血管事件发病密度分别为3.42/千人年、4.57/千人年、5.68/千人年和9.53/千人年,且随着cumFBG增加,心脑血管事件、脑卒中、缺血性脑卒中累积发病率均呈上升趋势,经Log-rank检验及组间两两比较,差异有统计学意义(均P<0.01)。Cox比例风险模型显示校正年龄、性别、体... 相似文献
993.
Su Young Kim Yeon Seo Cho Hyun-Soo Kim Jung Kuk Lee Hee Man Kim Hong Jun Park Hyunil Kim Jihoon Kim Dae Ryong Kang 《Gut and liver》2022,16(4):555
Background/AimsInflammatory bowel disease (IBD) is associated with the occurrence of venous thromboembolism (VTE). However, to date, there have been few studies on the risk of VTE in Asian IBD patients. We aimed to estimate the incidence of VTE in Asian IBD patients and to determine if IBD is related to increased VTE risk.MethodsWe performed a population-based cohort study between 2004 and 2015 using Korean National Health Insurance data. IBD and VTE were defined by ICD-10 codes. Incidence rates of VTE were calculated among patients with IBD and among age- and sex-matched controls. Hazard ratios were estimated using Cox regression with adjustment for multiple variables. We performed additional analyses stratifying by age, sex, Charlson comorbidity index (CCI) score, and disease type.ResultsAmong the 45,037 patients with IBD (IBD cohort) and 133,019 matched controls (non-IBD cohort) included in our analysis, 411 IBD patients and 641 controls developed VTE. The IBD cohort had a higher incidence rate ratio and risk of VTE than the non-IBD cohort (incidence rate ratio 1.92 and hazard ratio 1.93). Older age, female sex, higher CCI scores, cardiovascular disease, chronic kidney disease, use of steroids, and hospitalization were significant risk factors for VTE in patients with IBD.ConclusionsThe IBD patients in this study were approximately two times more likely to develop VTE than the non-IBD individuals. Our findings support the need for thromboprophylaxis in Asian IBD patients with various factors that further increase the risk of VTE. 相似文献
994.
995.
骨髓内皮祖细胞EPCs两种分离方法及其对比研究 总被引:1,自引:0,他引:1
目的:研究免疫磁珠法和贴壁换液法分离骨髓内皮祖细胞的可行性和条件,并比较两种方法优缺点.方法:利用免疫磁珠法和贴壁换液法从骨髓中分别提取内皮祖细胞,体外观察细胞生长及形态变化,通过检测细胞血管内皮生长因子受体-2(VEGFR-2)、Ⅷ因子相关抗原抗体表达、摄取乙酰化-低密度脂蛋白(Ac-LDL)情况和超微结构等进行鉴定.同时,流式细胞检测分离所得细胞的纯度、细胞计数测定分离所得细胞的数量及MTT法检测细胞生长增殖状况等,对两种分离方法进行对比研究.结果:用免疫磁珠法和贴壁换液法从骨髓中分别提取的细胞,体外培养后细胞呈铺路石形,透射电镜显示细胞内具有特征性的W-P小体,免疫荧光染色检测细胞相关抗原VEGFR-2, Ⅷ/vWF 呈阳性,同时细胞摄取Ac-LDL,证实为内皮祖细胞.免疫磁珠法与贴壁换液法相比,分离所得内皮祖细胞数量是后者2倍,纯度为76%,明显高于贴壁换液法的29%;同时,两者对细胞增殖生长无明显影响.结论:利用免疫磁珠法和贴壁换液法均可分离得到骨髓内皮祖细胞,它将成为新的组织工程种子细胞.免疫磁珠法分离得到细胞纯度更高、数量更大,但步骤复杂、价格昂贵;贴壁换液法得到细胞纯度和数量偏低,但方法简单、经济、实用性强. 相似文献
996.
目的: 应用重症肌无力(MG) 临床绝对和相对评分法以量化的形式对MG患者、非MG患者和健康人进行新斯的明试验评分,以确定该评分方法在临床上应用的意义.方法: 对38例反复出现症状的MG患者和13例非MG患者和健康人(非MG患者9例、健康人4例)作对照,肌注新斯的明注射液1.5 mg和阿托品1.0 mg,记录注射前及注射后1 h内每10 min 1次的临床绝对和相对评分,用配对t检验比较试验前与显效时绝对评分,并分析相对评分的阳性和阴性界定值的灵敏度,特异度,约登指数(Youdens index).结果: MG组试验前与显效时绝对评分有显著差异(α=0.05,P<0.05),对照组试验前绝对评分和症状改善时绝对评分无差异(α=0.05,P>0.05).以相对评分60%为新斯的明试验阳性界定值,25%为阴性界定值,其约登指数最高.结论: MG临床绝对评分法和相对评分法有助于对MG患者的临床诊断与鉴别诊断. 相似文献
997.
Based on lithium aluminosilicate glass, the composition of glass was optimized by replacing SiO2 with B2O3, and the influence of glass composition on structure and performance was studied. With the increase in B2O3 concentrations from 0 to 6.5 mol%, Al2O3 always existed in the form of four-coordinated [AlO4] in the network structure, and B2O3 mainly entered the network in the form of four-coordinated [BO4]. The content of Si-O-Si linkages (Q4(0Al)) was always dominant. The incorporation of boron oxide improved the overall degree of polymerization and connectivity of the lithium aluminosilicate glass network structure. An increase in the degree of network polymerization led to a decrease in the thermal expansion coefficient of the glass and an increase in Vickers hardness and density. The durability of the glass in hydrofluoric acid and NaOH and KOH solutions was enhanced overall. 相似文献
998.
Fatigue Cracking Evolution and Model of Cold Recycled Asphalt Mixtures during Different Curing Times
This paper aims to investigate the fatigue cracking evolution of cold recycled asphalt mixtures with asphalt emulsion (CRME) under different curing times. The fatigue cracking model of CRME based on damage mechanics and fracture mechanics was analyzed according to the fatigue loading curve. Firstly, the fatigue cracking evolution of CRME was studied through an SCB strength test and SCB fatigue test. Then, the fatigue damage mechanics were used to establish a nonlinear fatigue cracking model, and the damage degree of CRME at the initial cracking point was determined. The Paris formula was used to characterize the law of fatigue crack propagation. Finally, the microstructure of CRME was observed by scanning electron microscopy (SEM) with the backscattering method. The results indicate that the initial cracking point appears at around 60% of the fatigue life according to the SCB fatigue test by means of image analysis. The damage variable was obtained through the cracking model, and the value of the damage variable was determined as 0.06–0.17 at the initial cracking point. In addition, the Paris formula showed that the crack growth of CRME can be reflected by the stress intensity factor and correlative parameters. Moreover, cement hydration products were mixed with the asphalt membrane to form a denser spatial structure during the curing process, which may provide higher fatigue performance of CRME. This research may provide a theoretical reference for studying the fatigue cracking behavior of CRME. 相似文献
999.
新砭石疗法治疗肩关节周围炎的临床疗效研究与评价 总被引:4,自引:0,他引:4
目的研究新砭石疗法的临床疗效。方法根据随机分组、平行对照、单盲(研究者、操作者、统计者三分离)的临床试验原则,试验组40例,采用新砭石疗法;对照组40例,采用电针疗法,对比两组的临床疗效。结果镇痛疗效方面,试验组总有效率为85%,对照组总有效率为75%,两组总有效率比较差异无统计学意义(P>0.05);肩部功能活动改善方面,试验组总有效率为57.5%,对照组总有效率为42.5%,两组总有效率比较差异无统计学意义(P>0.05);两组治疗即刻镇痛效果均明显。结论新砭石疗法治疗肩关节周围炎疗效显著,镇痛效果迅速,其疗效与针灸疗法无显著差异。 相似文献
1000.
升阳益胃汤出自《脾胃论》,功能健脾益气、化湿升阳。李东垣设此方用于治疗“脾胃气虚,怠惰嗜卧,四肢不收……口苦舌干。食无味,大便不调,小便频数,不嗜食,食不消,兼见肺病”等肺之脾胃虚弱证。笔者运用此方治疗慢性病每获良效。现不揣陋见。介绍如下。 相似文献