全文获取类型
收费全文 | 164341篇 |
免费 | 13698篇 |
国内免费 | 5556篇 |
专业分类
耳鼻咽喉 | 1127篇 |
儿科学 | 2966篇 |
妇产科学 | 1908篇 |
基础医学 | 25584篇 |
口腔科学 | 3187篇 |
临床医学 | 16032篇 |
内科学 | 21718篇 |
皮肤病学 | 1666篇 |
神经病学 | 8087篇 |
特种医学 | 3516篇 |
外国民族医学 | 34篇 |
外科学 | 13264篇 |
综合类 | 25956篇 |
现状与发展 | 14篇 |
一般理论 | 25篇 |
预防医学 | 11545篇 |
眼科学 | 4324篇 |
药学 | 17847篇 |
24篇 | |
中国医学 | 8475篇 |
肿瘤学 | 16296篇 |
出版年
2024年 | 352篇 |
2023年 | 1939篇 |
2022年 | 4166篇 |
2021年 | 5793篇 |
2020年 | 5084篇 |
2019年 | 5149篇 |
2018年 | 5081篇 |
2017年 | 5116篇 |
2016年 | 5285篇 |
2015年 | 5446篇 |
2014年 | 8402篇 |
2013年 | 9467篇 |
2012年 | 7974篇 |
2011年 | 9206篇 |
2010年 | 7991篇 |
2009年 | 7859篇 |
2008年 | 7941篇 |
2007年 | 9053篇 |
2006年 | 8254篇 |
2005年 | 8227篇 |
2004年 | 7234篇 |
2003年 | 6426篇 |
2002年 | 4780篇 |
2001年 | 4709篇 |
2000年 | 3839篇 |
1999年 | 3554篇 |
1998年 | 2532篇 |
1997年 | 2232篇 |
1996年 | 2329篇 |
1995年 | 2225篇 |
1994年 | 1953篇 |
1993年 | 1746篇 |
1992年 | 1497篇 |
1991年 | 1319篇 |
1990年 | 1123篇 |
1989年 | 1044篇 |
1988年 | 972篇 |
1987年 | 754篇 |
1986年 | 574篇 |
1985年 | 658篇 |
1984年 | 703篇 |
1983年 | 430篇 |
1982年 | 544篇 |
1981年 | 458篇 |
1980年 | 410篇 |
1979年 | 327篇 |
1978年 | 274篇 |
1977年 | 222篇 |
1976年 | 259篇 |
1975年 | 162篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
[目的]探讨产前分娩预演对初产妇自然分娩成功率和产后并发症的影响.[方法]收集2016年9月至2018年10月在本院妇产科分娩的初产妇86例,按产前分娩教育方式分为观察组(n=42)和对照组(n=44).对照组孕妇产前接受常规产前健康教育课程培训,观察组在对照组的基础上进行分娩预演实践.比较两组自我效能感量表(GSES)、抑郁自评量表(SDS)和焦虑自评量表(SAS)评分及自然分娩成功率和产后并发症发生率等.[结果]与对照组相比,观察组分娩总产程和第一、二、三明显缩短;新生儿窒息率和产后SDS、SAS评分均明显降低;自然分娩成功率、GSES评分均明显提高,其差异均有统计学意义(P<0.05).观察组产后出血、感染、尿潴留、乳汁淤积发生率及总并发症发生率均低于对照组(P<0.05).[结论]采用常规产前健康教育培训结合产前分娩预演实践的产前管理方式,可有效提高初产妇自然分娩成功率,缩短产程,减少产后并发症的发生,值得临床推广应用. 相似文献
72.
目的探讨依维莫司联合全反式维甲酸(简称维甲酸)逆转急性早幼粒细胞白血病(APL)细胞株NB4-R1耐药的作用。方法应用CD11b染色流式细胞术及硝基四唑氮蓝(NBT)还原实验检测两药联合应用对细胞分化的影响, 流式细胞术检测细胞周期情况, Annexin V/PI双染色检测细胞凋亡情况, 蛋白质印迹法检测自噬相关蛋白微管结合蛋白轻链3(LC3)、Beclin 1及早幼粒白血病-维甲酸受体融合蛋白(PML-RARα)、磷酸化核糖体S6激酶(P-P70S6K)、磷酸化4E结合蛋白1(P-4E-BP1) 等表达水平。结果与维甲酸组比较, 联用组能诱导耐药细胞株NB4-R1细胞的分化, 并将细胞增殖阻止在G 1期而对细胞凋亡无明显影响。100 nmol/L依维莫司组、1μmol/L维甲酸组、联用组、对照组NB4-R1细胞培养48 h后分化百分率分别为(2.29±0.57)%、(17.06±2.65)%、(54.47±4.91)%、(2.54±0.53)%; 处于G 1期的细胞百分率分别为(35.20±11.97)%、(33.54±6.25)%、(53.70±8.73)%、(27.40±6.01)%; 四组细胞凋亡细胞百分率分别为(2.30±0.14)%、(2.25±0.21)%、(2.40±0.28)%、(1.95±0.07)%。与维甲酸组比较, 联用组mTOR信号通路下游的P70S6K、4E-BP1分子磷酸化水平下降, LC3-II和Beclin 1的表达上调, 且能部分降解融合蛋白PML-RARα。 结论依维莫司联合维甲酸能诱导NB4-R1细胞分化, 且能阻滞细胞周期而不致细胞凋亡, 其机制可能与依维莫司联合维甲酸抑制mTOR信号通路激活自噬作用从而降解PML-RARα蛋白有关。 相似文献
73.
74.
Yaobin Ouyang Gongmeizi Liu Wenting Xu Zhen Yang Nianshuang Li Chuan Xie Chun Zhou Jiang Chen Yin Zhu Junbo Hong Nonghua Lu 《Oncology Letters》2021,21(2)
Helicobacter pylori (H. pylori) is a main risk factor for gastric cancer (GC). Epithelial-mesenchymal transition (EMT) is involved in the development and progression of H. pylori-associated GC. However, the exact molecular mechanism of this process remains unclear. The AKT/GSK3β signaling pathway has been demonstrated to promote EMT in several types of cancer. The present study investigated whether H. pylori infection induced EMT, and promoted the development and metastasis of cancer in the normal gastric mucosa, and whether this process was dependent on AKT activation. The expression levels of the EMT-associated proteins, including E-cadherin and N-cadherin, were determined in 165 gastric mucosal samples of different disease stages by immunohistochemical analysis. The expression levels of E-cadherin, N-cadherin, AKT, phosphorylated (p-)AKT (Ser473), GSK3β and p-GSK3β (Ser9) were further determined in H. pylori-infected Mongolian gerbil gastric tissues and cells co-cultured with H. pylori by immunohistochemical analysis and western blotting. The results indicated that the expression levels of the epithelial marker E-cadherin were decreased, whereas the expression levels of the mesenchymal marker N-cadherin were increased during gastric carcinogenesis. Their expression levels were associated with H. pylori infection. Furthermore, H. pylori infection resulted in downregulation of E-cadherin expression and upregulation of N-cadherin expression in Mongolian gerbils and GES-1 cells. In addition, an investigation of the associated mechanism of action revealed that p-AKT (Ser473) and p-GSK3β (Ser9) were activated in GES-1 cells following co-culture with H. pylori. Furthermore, following pretreatment of the cells with the AKT inhibitor VIII, the expression levels of E-cadherin, N-cadherin, p-AKT and p-GSK3β did not show significant differences between GES-1 cells that were co-cultured with or without H. pylori. The levels of p-AKT and p-GSK3β were increased in H. pylori-infected Mongolian gerbils. In conclusion, the present study demonstrated that H. pylori infection activated AKT and resulted in the phosphorylation and inactivation of GSK3β, which in turn promoted early stage EMT. These effects were AKT-dependent. This mechanism may serve as a prerequisite for GC development. 相似文献
75.
76.
随着对肿瘤热疗和肿瘤免疫微环境(TIME)的深入研究,近年来热疗对TIME的作用越来越受到学者们的重视。本文就目前国内外研究进展,对热疗与TIME中几类主要免疫细胞和免疫相关细胞因子的影响及作用机制作一综述。全面而透彻的了解热疗对TIME的调控作用,有助于为肿瘤治疗提供新的思路和方法。 相似文献
77.
78.
79.
Roberto V.P. Ribeiro Mitesh V. Badiwala Danny Ramzy Laura C. Tumiati Vivek Rao 《The Journal of thoracic and cardiovascular surgery》2019,157(2):615-625.e1
Objective
Hypertonic saline (HTS) has potent immune and vascular effects. We assessed recipient pretreatment with HTS on allograft function in a porcine model of heart transplantation and hypothesized that HTS infusion would limit endothelial and left ventricular (LV) dysfunction following transplantation.Methods
Heart transplants were performed after 6 hours of cold ischemic storage. Recipient pigs were randomized to treatment with or without HTS (7.5% NaCl) before cardiopulmonary bypass (CPB). Using a myograft apparatus, coronary artery endothelial-dependent (Edep) and -independent (Eind) relaxation was assessed. LV performance was determined using pressure-volume loop analysis. Pulmonary interleukin (IL)-2, IL-6, and tumor necrosis factor (TNF)-α expression was measured.Results
Weaning from CPB and LV performance after transplantation were improved in HTS-treated animals. Successful weaning from CPB was greater in the HTS-treated hearts (8 of 8 vs 2 of 8; P < .05). Mean LV functional recovery was improved in the HTS-treated animals, as assessed by preload recruitable stroke work (65 ± 10% vs 27 ± 10%; P < .001) and end-systolic elastance (55 ± 7% vs 37 ± 4%; P < .001). Treatment with HTS resulted in improved Edep (mean maximum elastance [Emax], 56 ± 5% vs 37 ± 7%; P < .001) and Eind (mean Emax%, 77 ± 6% vs 52 ± 4%; P < .001) vasorelaxation compared with control. Pulmonary expression of IL-2, IL-6, and TNF-α increased following transplantation, whereas HTS therapy attenuated IL production (P < .001). Transplantation increased plasma TNF-α levels and LV TNF-α expression, whereas HTS prevented this up-regulation (P < .001).Conclusions
Recipient HTS pretreatment preserves allograft vasomotor and LV function, and HTS therapy limits CPB-induced injury. HTS may be a novel recipient intervention to prevent graft dysfunction. 相似文献80.
目的:建立液相色谱-串联质谱法(UPLC-MS/MS)同时测定人血浆中头孢哌酮与舒巴坦的浓度,分析头孢哌酮/舒巴坦血药浓度监测结果,为临床合理用药提供参考。方法:以氯唑沙宗为内标,采用Waters BEHC18柱(2.1 mm×100 mm,1.7 μm)进行分离,通过串联质谱仪,负离子检测模式下,以多反应监测(MRM)方式进行定量测定。对某院2018年以不同给药方案进行治疗的73例住院患者测定的头孢哌酮/舒巴坦血药浓度结果进行分析。结果:头孢哌酮与舒巴坦在测定条件下1~200 mg·L-1范围内线性关系良好,两者日内精密度RSD均<10%,基质效应分别为(72.77±0.99)%与(75.72±0.11)%,提取回收率均>90%。73例患者共监测血药浓度96次,其中不同给药方案2 g,q8 h(43例次);2 g,q12 h(26例次);2 g,q6 h(27例次),各组头孢哌酮血药浓度的中位数分别为34.12 mg·L-1(4.12~177.79 mg·L-1)、31.23 mg·L-1(1.89~251.8 mg·L-1)、59.96 mg·L-1(1.77~140.58 mg·L-1),舒巴坦血药浓度的中位数分别为6.3 mg·L-1(0.61~136.01 mg·L-1)、28.83 mg·L-1(0.5~133.69 mg·L-1)、11.17 mg·L-1(0.73~143.53 mg·L-1)。Mann-Whitney U检验显示,头孢哌酮血药浓度结果无统计学差异(P>0.05),舒巴坦有统计学差异(P<0.05)。结论:本检测方法操作简便、快速、重复性好,可满足临床头孢哌酮与舒巴坦浓度的检测;头孢哌酮/舒巴坦在不同给药方案下血药浓度结果与个体差异相关,有必要开展血药浓度监测并依据结果适时调整用药方案,提高治疗效果减少耐药率的发生。 相似文献