全文获取类型
收费全文 | 1786篇 |
免费 | 134篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 32篇 |
妇产科学 | 27篇 |
基础医学 | 200篇 |
口腔科学 | 37篇 |
临床医学 | 195篇 |
内科学 | 342篇 |
皮肤病学 | 20篇 |
神经病学 | 62篇 |
特种医学 | 63篇 |
外科学 | 213篇 |
综合类 | 244篇 |
现状与发展 | 1篇 |
一般理论 | 3篇 |
预防医学 | 173篇 |
眼科学 | 26篇 |
药学 | 131篇 |
中国医学 | 51篇 |
肿瘤学 | 155篇 |
出版年
2023年 | 17篇 |
2022年 | 34篇 |
2021年 | 62篇 |
2020年 | 40篇 |
2019年 | 49篇 |
2018年 | 40篇 |
2017年 | 34篇 |
2016年 | 32篇 |
2015年 | 36篇 |
2014年 | 51篇 |
2013年 | 63篇 |
2012年 | 95篇 |
2011年 | 101篇 |
2010年 | 62篇 |
2009年 | 47篇 |
2008年 | 69篇 |
2007年 | 78篇 |
2006年 | 109篇 |
2005年 | 83篇 |
2004年 | 124篇 |
2003年 | 162篇 |
2002年 | 135篇 |
2001年 | 105篇 |
2000年 | 65篇 |
1999年 | 37篇 |
1998年 | 23篇 |
1997年 | 27篇 |
1996年 | 15篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 13篇 |
1991年 | 15篇 |
1990年 | 12篇 |
1989年 | 17篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1973年 | 7篇 |
1969年 | 4篇 |
1968年 | 4篇 |
1967年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有1984条查询结果,搜索用时 31 毫秒
61.
62.
63.
Amir Azarpazhooh Thuan Dao Wendy J. Ungar Faiza Chaudry Rafael Figueiredo Murray Krahn Shimon Friedman 《Journal of endodontics》2014
Introduction
To effectively engage patients in clinical decisions regarding the management of teeth with apical periodontitis (AP), there is a need to explore patients' perspectives on the decision-making process. This study surveyed patients for their preferred level of participation in making treatment decisions for a tooth with AP.Methods
Data were collected through a mail-out survey of 800 University of Toronto Faculty of Dentistry patients, complemented by a convenience sample of 200 patients from 10 community practices. The Control Preferences Scale was used to evaluate the patients' preferences for active, collaborative, or passive participation in treatment decisions for a tooth with AP. Using bivariate and logistic regression analyses, the Gelberg-Andersen Behavioral Model for Vulnerable Populations was applied to the Control Preferences Scale questions to understand the influential factors (P ≤ .05).Results
Among 434 of 1,000 respondents, 44%, 40%, and 16% preferred an active, collaborative, and passive participation, respectively. Logistic regression showed a significant association (P ≤ .025) between participants' higher education and preference for active participation compared with a collaborative role. Also, immigrant status was significantly associated with preference for passive participation (P = .025).Conclusions
The majority of patients valued an active or collaborative participation in deciding treatment for a tooth with AP. This pattern implied a preference for a patient-centered practice mode that emphasizes patient autonomy in decision making. 相似文献64.
Spatiotemporal Trend Analysis of Precipitation Extremes in Ho Chi Minh City,Vietnam During 1980-2017
Nguyen Trong Quan Dao Nguyen Khoi Nguyen Xuan Hoan Nguyen Ky Phung Thanh Duc Dang 《国际灾害风险科学学报(英文版)》2021,12(1):131-146
In this study,the spatiotemporal variability of trends in extreme precipitation events in Ho Chi Minh City during the period 1980-2017 was analyzed based on sev... 相似文献
65.
Thi Le Anh Nguyen Thi Hoai Nam Doan Dinh Hieu Truong Nguyen Thi Ai Nhung Duong Tuan Quang Dorra Khiri Sonia Taamalli Florent Louis Abderrahman El Bakali Duy Quang Dao 《RSC advances》2021,11(35):21433
Antioxidant and UV absorption activities of three aaptamine derivatives including piperidine[3,2-b]demethyl(oxy)aaptamine (C1), 9-amino-2-ethoxy-8-methoxy-3H-benzo[de][1,6]naphthyridine-3-one (C2), and 2-(sec-butyl)-7,8-dimethoxybenzo[de]imidazo[4,5,1-ij][1,6]-naphthyridin-10(9H)-one (C3) were theoretically studied by density functional theory (DFT). Direct antioxidant activities of C1–C3 were firstly evaluated via their intrinsic thermochemical properties and the radical scavenging activity of the potential antioxidants with the HOO˙/HO˙ radicals via four mechanisms, including: hydrogen atom transfer (HAT), single electron transfer (SET), proton loss (PL) and radical adduct formation (RAF). Kinetic calculation reveals that HOO˙ scavenging in water occurs via HAT mechanism with C1 (kapp, 7.13 × 106 M−1 s−1) while RAF is more dominant with C2 (kapp, 1.40 × 105 M−1 s−1) and C3 (kapp, 2.90 × 105 M−1 s−1). Antioxidant activity of aaptamine derivatives can be classified as C1 > C3 > C2. Indirect antioxidant properties based on Cu(i) and Cu(ii) ions chelating activity were also investigated in aqueous phase. All three studied compounds show spontaneous and favorable Cu(i) ion chelating activity with ΔG0 being −15.4, −13.7, and −15.7 kcal mol−1, whereas ΔG0 for Cu(ii) chelation are −10.4, −10.8, and −2.2 kcal mol−1 for C1, C2 and C3, respectively. In addition, all compounds show UVA and UVB absorption; in which the excitations are determined mostly as π–π* transition. Overall, the results suggest the potential applications of the aaptamines in pharmaceutics and cosmetics, i.e. as a sunscreen and antioxidant ingredient.Antioxidant and UV absorption activities of three aaptamine derivatives were theoretically studied by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). 相似文献
66.
The floods in the Vietnamese Mekong Delta have long caused a shortage of clean water supply, which has a significant impact on the indigenous people in the region. We have conducted a preliminary survey of the water quality of the Hau Giang River (one of the two main branches of the Mekong River) before, during, and after the flood season. The obtained results demonstrated that the water in the Hau Giang River was highly turbid and contaminated with a large number of harmful microorganisms. Thus, in this study, a simple filter system based on silver nanoparticles coated onto activated carbon derived from rice husk (AgNPs@AC) has been proposed for treating floodwater from the Hau Giang River. The optimal conditions for AgNPs@AC preparation were established. The prepared AgNPs@AC was then characterized using various surface analyses such as SEM, TEM, XRD, BET, FTIR, and DLS. The initial floodwater source would be pre-treated with polyaluminum chloride using the coagulation–sedimentation method to remove the suspended solids before being discharged into the filtration column containing AgNPs@AC. The results showed that the filter system based on AgNPs@AC performed well in removing turbidity, dissolved solids, suspended solids, color, and bacteria from the floodwater. In addition, it was determined that the filter column with a 30 mm thick AgNPs@AC layer could continuously process 1300 m3 of the floodwater and had a service life of more than two months. The findings of this study not only added to our understanding of the floodwater treatment capacity of activated carbon coated nanoparticles, but they also provided valuable information for water treatment plants along the Hau Giang River, aquatic ecosystem researchers, and public health researchers.In this study, a simple filter system based on silver nanoparticles coated onto activated carbon derived from rice husk (AgNPs@AC) has been proposed for treating floodwater from the Hau Giang River. 相似文献
67.
Dao Viet Hang Dinh Thi MinhTran Hieu HocLe Hong PhuocTran Que SonNgoan Tran Le 《Asian Pacific journal of cancer prevention》2020,21(8):2431-2437
Background: H. pylori infection may play a role in the development of colorectal cancers (CRC). We aimed to examine the association between H. pylori infection and the risk of CRC by anatomical locations. Methods: We conducted a case-control study on 91 incidence cases of CRC and 224 hospital controls. CRC was determined by histopathological examinations. H. pylori IgG antibody in serum was tested. We collected data on the diet, nutrition, and lifestyle by the validated semi-quantitative food frequency and demographic lifestyle questionnaire. The odds ratio and 95% confidence interval (OR (95%CI) were estimated for CRC and its subgroups. Results: Overall 54.95% of CRC cases and 42.41% of the controls were H. pylori-seropositive, OR (95%CI): 1.56 (0.88, 2.74), p for trend=0.115. Positive dose-response association in quartiles, highest vs lowest, was observed for total CRC, OR (95%CI): 2.14 (1.00, 4.58), p for trend=0.049, for proximal colon, OR (95%CI): 1.52 (0.37, 6.25), p for trend=0.571), and for distal colon and rectum cancers combined, OR (95%CI): 2.38 (1.03, 5.50), p for trend=0.039. Conclusions: There is a positive association between H. pylori and colorectal cancers, especially distal colon and rectum cancers combined, but additional research is needed to determine the underlying mechanism of chronic H. pylori infection-induced CRC in humans. 相似文献
68.
69.
花生四烯酸细胞色素P450表氧化酶在自发性高血压大鼠血压的调节中的作用 总被引:3,自引:0,他引:3
背景与目的花生四烯酸细胞色素P450(CYP)表氧化酶代谢花生四烯酸产生表氧化廿烷酸(EETs),又称为内皮源性超极化因子(EDHFs),在局部微循环的调节中起着重要作用。然而EETs在血压的调节中是否起作用还不清楚。本研究通过对成年自发性高血压大鼠导入花生四烯酸细胞色素表氧化酶基因来观察其血压变化,从而进一步明确EETs在血压调节中的作用。方法:将含人类细胞色素P450表氧化酶CYP2J2 cDNA的真核细胞表达质粒pcDNA.2J2经静脉注射(3mg/kg)人雄性成年自发性高血压大鼠,并以pcDNA3.1对照。然后用尾部血压计测量血压。并在注射后3周和4周时处死动物,检测CYP2J2在不同组织中的表达情况。结果:注射质粒后对照组血压一直无显著性变化,而pcDNA.2J2治疗组大鼠血压显著降低(P〈0.05),这一降压效应持续两周以上。Western blotting显示在实验组动物肺、肝和肾的总蛋白中通过特异性抗-CYP2J2抗体可检测出显著量的人类CYP2J2蛋白的表达。结论:本实验显示对成年自发性高血压大鼠导人人类CYP2J2基因,使CYP2J2可以在动物组织中高表达,从而引起相对持久的降压作用,这些结果提示花生四烯酸细胞色素P450表氧化酶通过产生EDHFs参与了动物血压的调节作用。 相似文献
70.
纤溶酶-α2抗纤溶酶复合物检测方法的建立和初步临床应用 总被引:1,自引:0,他引:1
目的 建立纤溶酶 α2 抗纤溶酶复合物 (PAP)的检测方法。方法 从血浆中纯化PAP作为免疫原制备单克隆抗体 (单抗 ) ,建立双抗体夹心法酶联免疫吸附试验 (ELISA) ,并对该法进行评价。结果 获取了特异针对PAP新抗原的单抗LW 3C10 ,和针对PAP及纤溶酶原 (Plg)的单抗LW 2B9。对PAP的亲和常数分别为 4 6 9× 10 10 mol/L、5 6 2× 10 9mol/L。以它们建立的夹心ELISA检测PAP在 0~ 15 0 μg/L范围内线性良好 ,批内、批间CV分别为 4 0 %~ 5 2 %、11 2 %~ 13 6 % ,回收率为 85%~ 10 5 % ,加入α2 抗纤溶酶 (α2 AP)及纤溶酶 α2 巨球蛋白复合物 (P α2 M)不干扰测定 ,与美国ADI公司PAP试剂盒相关良好 (r=0 96 2 9)。急性髓细胞白血病组、急性心肌梗死组、肝病组、健康老年人组的血浆PAP水平显著高于正常对照组 (P <0 0 0 1)。结论 该法可用于评估纤溶系统激活。 相似文献