全文获取类型
收费全文 | 25690篇 |
免费 | 2406篇 |
国内免费 | 2105篇 |
专业分类
耳鼻咽喉 | 210篇 |
儿科学 | 265篇 |
妇产科学 | 365篇 |
基础医学 | 3224篇 |
口腔科学 | 506篇 |
临床医学 | 3492篇 |
内科学 | 3958篇 |
皮肤病学 | 195篇 |
神经病学 | 1504篇 |
特种医学 | 973篇 |
外国民族医学 | 14篇 |
外科学 | 2695篇 |
综合类 | 4058篇 |
现状与发展 | 8篇 |
一般理论 | 4篇 |
预防医学 | 1610篇 |
眼科学 | 604篇 |
药学 | 2804篇 |
15篇 | |
中国医学 | 1496篇 |
肿瘤学 | 2201篇 |
出版年
2024年 | 94篇 |
2023年 | 412篇 |
2022年 | 1074篇 |
2021年 | 1359篇 |
2020年 | 1004篇 |
2019年 | 913篇 |
2018年 | 873篇 |
2017年 | 870篇 |
2016年 | 759篇 |
2015年 | 1163篇 |
2014年 | 1537篇 |
2013年 | 1266篇 |
2012年 | 1875篇 |
2011年 | 1946篇 |
2010年 | 1276篇 |
2009年 | 983篇 |
2008年 | 1398篇 |
2007年 | 1339篇 |
2006年 | 1270篇 |
2005年 | 1388篇 |
2004年 | 929篇 |
2003年 | 913篇 |
2002年 | 729篇 |
2001年 | 589篇 |
2000年 | 642篇 |
1999年 | 657篇 |
1998年 | 429篇 |
1997年 | 383篇 |
1996年 | 324篇 |
1995年 | 313篇 |
1994年 | 276篇 |
1993年 | 181篇 |
1992年 | 204篇 |
1991年 | 171篇 |
1990年 | 138篇 |
1989年 | 99篇 |
1988年 | 103篇 |
1987年 | 76篇 |
1986年 | 77篇 |
1985年 | 52篇 |
1984年 | 34篇 |
1983年 | 27篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1975年 | 2篇 |
1929年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Jing Zhao Kaixin Ding Manting Hou Yuanhua Li Xiaorong Hou Wenzhang Dai Zhiyong Li Jun Zhao Wenlong Liu Zhaofang Bai 《Pharmaceutical biology》2022,60(1):958
ContextSchisandra chinensis (Turcz.) Baill. (Magnoliaceae) essential oil (SCEO) composition is rich in lignans that are believed to perform protective effects in the liver.ObjectiveThis study investigates the effects of SCEO in the treatment of acetaminophen (APAP)-induced liver injury in mice.Materials and methodsC57BL/6 mice (n = 56) were randomly divided into seven groups: normal; APAP (300 mg/kg); APAP plus bicyclol (200 mg/kg); APAP plus SCEO (0.25, 0.5, 1, 2 g/kg). Serum biochemical parameters for liver function, inflammatory factors, and antioxidant activities were determined. The protein expression levels of Nrf2, GCLC, GCLM, HO-1, p62, and LC3 were assessed by western blotting. Nrf2, GCLC, HO-1, p62, and LC3 mRNA were detected by real-time PCR.ResultsCompared to APAP overdose, SCEO (2 g/kg) pre-treatment reduced the serum levels of AST (79.4%), ALT (84.6%), TNF-α (57.3%), and IL-6 (53.0%). In addition, SCEO (2 g/kg) markedly suppressed cytochrome P450 2E1 (CYP2E1) (15.4%) and attenuated the exhaustion of GSH (43.6%) and SOD (16.8%), and the accumulation of MDA (22.6%) in the liver, to inhibit the occurrence of oxidative stress. Moreover, hepatic tissues from our experiment revealed that SCEO pre-treatment mitigated liver injury caused by oxidative stress by increasing Nrf2, HO-1, and GCL. Additionally, SCEO activated autophagy, which upregulated hepatic LC3-II and decreased p62 in APAP overdose mice (p < 0.05).Discussion and conclusionsOur evidence demonstrated that SCEO protects hepatocytes from APAP-induced liver injury in vivo and the findings will provide a reliable theoretical basis for developing novel therapeutics. 相似文献
72.
大鼠静注常咯啉再注射乌头硷,或同时用常咯啉和乌头硷,明显推迟乌头硷引起的心律紊乱。先静注乌头硷出现心律失常后,再注射常咯啉,抗心律失常作用较弱。剪断二侧迷走神经,或静注六烃季铵,都不影响常咯啉抗静注乌头硷所致心律失常的疗效。从静脉恒速注射乌头硷,记录室性早搏、室性心动过速和心室颤动阈值。预先静脉注射常咯啉明显提高这三种阈值。利血平化加常咯啉组,这些阀值也比对照组明显提高,与常咯啉组相比,仅显著提高心室颤动阈值。脑室内注射常咯啉后,再脑室内注射乌头硷,明显推迟心律失常出现时间。常咯啉对大鼠坐骨神经的局麻作用甚微,这与利多卡因有明显不同。 相似文献
73.
皱纹盘鲍中几种营养成分的测定 总被引:11,自引:0,他引:11
本文报道了皱纹盘鲍体内所含有的蛋白质(50.81%),粗脂肪(6.24%)氨基酸和矿物质元素的含量,为鲍的药用提供理论依据。 相似文献
74.
黄芪、丹参、山药及其复方对高糖所致雪旺细胞凋亡的保护作用 总被引:1,自引:0,他引:1
目的:观察中药对高葡萄糖条件下与内皮细胞(以下简称EC)共培养的雪旺细胞(以下简称SC)凋亡的干预作用。方法:建立大鼠SC与EC的共培养模型,根据存活率(形态学和MTT)筛选药物最有效作用浓度。将细胞分为正常共培养SC组、高糖共培养SC组、高糖黄芪组、高糖丹参组、高糖山药组、高糖复方组,通过凋亡率(流式细胞仪)和凋亡相关基因Bcl-2和Casepase-3的mRNA(Realtime PCR)和蛋白(Western Blot)的表达观察细胞凋亡。结果:与正常共培养组相比高糖共培养组SC凋亡率明显增高、Bcl-2mRNA和蛋白表达量明显减少,Casepase-3mRNA和蛋白表达量显著增加。加中药干预后SC凋亡率都明显降低,Bcl-2mRNA和蛋白表达量都明显增加,除高糖山药组Casepase-3mRNA减少和高糖丹参组Casepase-3蛋白减少无明显统计学意义,其余各组Casepase-3mRNA和蛋白表达量均显著减少。中药干预组之间比较,高糖复方组作用最显著。中药干预组与正常组相比,SC凋亡率无明显增高,Bcl-2mRNA和蛋白表达量明显减少,Casepase-3mRNA和蛋白表达量显著增加。结论:中药对高糖环境下与内皮细胞共培养的雪旺细胞的凋亡有保护作用,不同中药作用效果不同,复方效果最佳。 相似文献
75.
消瘀接骨散对骨折肢体血液循环的影响及其与骨折愈合的关系 总被引:8,自引:4,他引:8
为探讨消瘀接骨散治疗骨折的作用机理,采用健康雄性家兔10只,用直接撞击法造成家兔左胫骨中段闭合性骨折模型,并随机分为2组。实验组外敷消瘀接骨散,空白对照组不用任何药物。以血液粘度和骨折肢体血流量为指标,观察消瘀接骨散对骨折肢体的血液循环的影响。结果显示骨折后14天实验组血液粘度明显低于空白组(P<0.05),肢体血流量明显高于空白组(P<0.05)。说明消瘀接骨散能够改善骨折肢体的血液循环,从而为骨折愈合创造良好的环境。 相似文献
76.
77.
78.
牙周炎是一种以牙周袋形成和牙槽骨吸收为特征的炎症性疾病,是40岁以上成人牙齿脱落的主要原因之一。牙周组织产生的龈沟液可以一定程度的揭示牙周的状态,其中的微小RNA (miRNA)的表达水平会根据牙周炎症的发展发生改变,可以作为牙周诊断的指标之一。miR-146a及miR-223是牙周炎进展中表达水平显著变化的miRNA,它们是目前利用龈沟液miRNA对牙周炎诊断最有潜力的生物标志物。不同miRNA可以通过调控牙周炎信号通路的不同阶段发挥作用,如通过细菌脂多糖与Toll样受体的结合、核因子κB配体信号通路及炎症因子的释放等过程调控牙周炎症进程。本文就牙周炎龈沟液中miRNA的表达差异及调控机制作一综述,以期为龈沟液miRNA准确诊断牙周炎提供新思路和新进展。 相似文献
79.
Tao Wang FuChao Yu Qin Wei Xuan Xu Liang Xie Ning Ding JiaYi Tong 《Clinical cardiology》2022,45(7):778
BackgroundThe prevalence of sleep‐disordered breathing (SDB) is closely related to the severity of heart failure (HF), and the severity of HF is different in patients with HF of different etiologies. Hypothesis: This study aimed to explore the prevalence of SDB in patients with HFof different etiologies.MethodsHospitalized HF patients were consecutively enrolled. All patients underwent portable overnight cardiorespiratory polygraphy. Patients were divided into five groups according to the etiology of HF: ischemic, hypertensive, myocardial, valvular, and arrhythmic. The prevalence of SDB and clinical data was compared among the five groups.ResultsIn total, 248 patients were enrolled in this study. The prevalence of SDB in HF was 70.6%, with the prevalence of obstructive sleep apnea (OSA) at 47.6% and central sleep apnea (CSA) at 23.0%. Patients were divided into five groups: ischemic, hypertensive, myocardial, valvular, and arrhythmic. The prevalence of SDB among the five groups was 75.3%, 81.4%, 77.8%, 51.9%, and 58.5% (p = .014), respectively. The prevalence of OSA among the five groups was 42.7%, 72.1%, 36.1%, 37.0%, and 49.1% (p = .009), whereas the CSA was 32.6%, 9.3%, 41.7%, 14.8%, and 9.4% (p < .001), respectively.ConclusionsSDB is common in HF patients. The prevalence and types of SDB varied in HF with different etiologies, which may be related to the different severities of HF. SDB was highly prevalent in patients with ischemic, hypertensive, and myocardial HF. Hypertensive HF patients were mainly complicated with OSA, while myocardial HF patients were mainly complicated with CSA. Both conditions were highly prevalent in ischemic HF patients. The prevalence of SDB was relatively low in valvular and arrhythmic HF patients, and OSA was the main type. 相似文献
80.
In order to study the influence of brace failure on the seismic response of concentrically braced frames and the improvement of the residual structure’s resistance to collapse due to reserve capacity, a series of concentrically braced frame prototypes with different story numbers is designed. A matrix of six finite-element concentrically braced-frame (CBF) models is established, which is varied by the number of stories and the level of reserve capacities. Accuracy of the numerical model is verified by comparing the responses of the shaking-table test of the concentrically braced frames, under 10 different working conditions. Then, a nonlinear time-history analysis, considering brace failure in one specified story, is carried out. The results show that the story-drift angle of the failure story as well as its adjacent stories increases greatly in the ideal pinned model. The above phenomenon is particularly serious, when the failure occurs at the top or bottom of the structure. With the reserve capacity brought by column continuity, and the semi-rigid rotation capacity of the beam-to-column and column-to-base connections are taken into consideration, the increase in story-drift angle caused by the brace failure is effectively reduced. However, the inherent reserve capacity has little influence on the dynamic characteristics of concentrically braced frames in the elastic stage. 相似文献