全文获取类型
收费全文 | 46052篇 |
免费 | 3663篇 |
国内免费 | 2343篇 |
专业分类
耳鼻咽喉 | 682篇 |
儿科学 | 528篇 |
妇产科学 | 486篇 |
基础医学 | 6114篇 |
口腔科学 | 863篇 |
临床医学 | 5466篇 |
内科学 | 7583篇 |
皮肤病学 | 660篇 |
神经病学 | 2733篇 |
特种医学 | 2190篇 |
外国民族医学 | 16篇 |
外科学 | 4952篇 |
综合类 | 5062篇 |
现状与发展 | 9篇 |
一般理论 | 3篇 |
预防医学 | 2613篇 |
眼科学 | 1076篇 |
药学 | 4579篇 |
46篇 | |
中国医学 | 2069篇 |
肿瘤学 | 4328篇 |
出版年
2024年 | 648篇 |
2023年 | 939篇 |
2022年 | 1793篇 |
2021年 | 2511篇 |
2020年 | 1871篇 |
2019年 | 1722篇 |
2018年 | 1642篇 |
2017年 | 1505篇 |
2016年 | 1497篇 |
2015年 | 2158篇 |
2014年 | 2488篇 |
2013年 | 2376篇 |
2012年 | 3402篇 |
2011年 | 3629篇 |
2010年 | 2272篇 |
2009年 | 1792篇 |
2008年 | 2394篇 |
2007年 | 2298篇 |
2006年 | 2164篇 |
2005年 | 2076篇 |
2004年 | 1493篇 |
2003年 | 1381篇 |
2002年 | 1175篇 |
2001年 | 922篇 |
2000年 | 864篇 |
1999年 | 932篇 |
1998年 | 500篇 |
1997年 | 489篇 |
1996年 | 378篇 |
1995年 | 341篇 |
1994年 | 309篇 |
1993年 | 176篇 |
1992年 | 303篇 |
1991年 | 222篇 |
1990年 | 226篇 |
1989年 | 193篇 |
1988年 | 181篇 |
1987年 | 155篇 |
1986年 | 128篇 |
1985年 | 99篇 |
1984年 | 68篇 |
1983年 | 50篇 |
1982年 | 20篇 |
1981年 | 31篇 |
1980年 | 19篇 |
1979年 | 30篇 |
1976年 | 25篇 |
1975年 | 17篇 |
1974年 | 20篇 |
1972年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
OBJECTIVE: The purpose of this research was to compare the Dr. SEDOC toothbrush, tufted with super-tapered bristles, to the ADA standard toothbrush in three laboratory procedures designed to evaluate 1) the cleaning ability of toothbrush bristles at the gingival margin (GMC), 2) interproximal access efficacy (IAE) and plaque removal efficacy, or 3) subgingival access (SA) into, and removal of artificial plaque deposits from under the gingival margin. METHODOLOGY: Efficacy was tested using three published laboratory methods, with pressure-sensitive paper placed around simulated teeth, at a brushing pressure of 250 or 500 g, with horizontal or vertical brushing motions. Twenty-four tests on each toothbrush design were conducted, and results were statistically analyzed using ANOVA. RESULTS: In all three assays, the Dr. SEDOC toothbrush had a significantly superior (p < 0.001) efficacy mean value compared to the ADA toothbrush. CONCLUSION: The Dr. SEDOC toothbrush, with super-tapered bristles, offers the potential for improved cleaning and plaque removal compared to the ADA standard control toothbrush. 相似文献
32.
GP-084泡沫硅橡胶和SY-1硅橡胶之间粘结性能的测定 总被引:1,自引:0,他引:1
目的:评价GP-084泡沫硅橡胶和SY-1硅橡胶之间的粘结性能。方法:分别测试有无Adhesive-AGP-084泡沫硅橡胶和SY-1硅橡胶之间的粘结强度;并采用电镜观察2种材料之间的粘结界面。结果:使用Adhesive-AGP-084泡沫硅橡胶和SY-1硅橡胶之间的粘结强度为(1.31±0.09)MPa,无Adhesive-AGP-084泡沫硅橡胶和SY-1硅橡胶之间的粘结强度为(1.29±0.11)MPa,2组测试结果的差异无统计学意义;电镜观察2种材料之间没有明显界面,完全融合在一起。结论:GP-084泡沫硅橡胶和SY-1硅橡胶2种材料之间具有良好的粘结效果,可以完全融合在一起,无明显界面形成。 相似文献
33.
目的 克隆表达牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg)牙龈素中黏附素区域的Hgp44基因,并纯化目的蛋白.方法 通过聚合酶链反应(PCR)和基因重组技术,克隆得到PgATCC33277的Hgp4基因,插入到克隆载体pMD18-T中并测序鉴定.经过酶切后将目的基因片段与表达载体pET22b相连,构建出表达质粒pET22b-Hgp44.将重组质粒转化到感受态细胞BL21(DE3)中,用异丙基-β-D-硫代半乳糖苷(isopropyl-β-D-thiogalactoside,IPTG)诱导表达融合蛋白,通过SDS聚丙烯酰胺凝胶电泳及蛋白质印迹法进行分析.用固定化金属亲和层析法对重组蛋白进行分离纯化.结果 目的基因片段约为1100 bp,与预期大小相符,测序结果与GenBank中ATCC33277国际标准菌株的RgpA的等位基因序列U15282一致.IPTG诱导后的菌体经SDS聚丙烯酰胺凝胶电泳后形成一个以包涵体形式存在的44 000的融合蛋白.蛋白质印迹法检测证实其具有免疫原性.用镍离子金属螯合层析柱纯化出了目的蛋白,最后得到约3.5 mg/L的目的蛋白.结论 成功克隆表达了PgHgp44基因,并纯化出了目的蛋白. 相似文献
34.
Zhang J Gao JM Li F Han J Chen L Zhang BY Wang XF Zhou W Liu Y Dong XP 《Biomedical and environmental sciences : BES》2006,19(3):214-218
Objective To report a protocol using biotin-labelled PrP protein in cell free conversion assay instead of isotope. Methods A hamster PrP protein (HaPrP) was expressed in E. coli and purified with HIS-tag affinity chromatograph. After being labelled with biotin, HaPrP was mixed with PrP^sen preparation from scrapie strain 263K. Results Protease-resistant bands were detected after four-day incubation. Conclusion The new conversion model provides a reliable, easily handling, and environment-friendly method for studies of prion and transmissible spongiform encephalopathies. 相似文献
35.
Hydrogen sulfide serves as a biomarker in the anterior segment of patients with diabetic retinopathy
Han Yuyi Zhang Xiaoqian Zhou Zhiyin Yu Mengxi Wang Qiuhong Yao Jin Han Yi 《International ophthalmology》2020,40(4):891-899
International Ophthalmology - The present study aims to determine hydrogen sulfide (H2S) concentrations of the aqueous humor from patients with diabetic retinopathy (DR) to compare its levels in... 相似文献
36.
37.
38.
Hui-Rong Chen Fu-Jun Zhao Xiao-Hai Wang Qi Jiang Qi Zhang Ban-Ming Han Jun Lu Shu-Jie Xia 《Asian journal of andrology》2014,16(5):792-793
Dear Editor,
I am Dr. Hui-Rong Chen, from the Department of Urology in Shanghai First People's Hospital at Shanghai Jiao Tong UnNersity, Shanghai, China. Premature ejaculation (PE) is a common sexual dysfunction, affecting approximately 20%-30% of sexually active men. According to intravaginal ejaculatory latency time (IELT) of l min, the incidence is approximately 1%-3%.1 PE is significantly associated with many personal and negative consequences, such as distress, frustration, and avoidance of sexual intimacy due to the inability of successful delayed ejaculation, α1-adrenergic blockers were effective in delaying ejaculation in approximately 50%-67% of the cases.2,3 Recently, abnormal ejaculation, an adverse infrequent side effect associated with the use of α1A-adrenergic blockers such as silodosin or tamsulosin, has drawn significant attention. Clinical studies suggested that this represents a relative anejaculation rather than a retrograde ejaculation. We present here the study to investigate the role of urethral pressure profile (UPP) on treating PE by tamsulosin. 相似文献
I am Dr. Hui-Rong Chen, from the Department of Urology in Shanghai First People's Hospital at Shanghai Jiao Tong UnNersity, Shanghai, China. Premature ejaculation (PE) is a common sexual dysfunction, affecting approximately 20%-30% of sexually active men. According to intravaginal ejaculatory latency time (IELT) of l min, the incidence is approximately 1%-3%.1 PE is significantly associated with many personal and negative consequences, such as distress, frustration, and avoidance of sexual intimacy due to the inability of successful delayed ejaculation, α1-adrenergic blockers were effective in delaying ejaculation in approximately 50%-67% of the cases.2,3 Recently, abnormal ejaculation, an adverse infrequent side effect associated with the use of α1A-adrenergic blockers such as silodosin or tamsulosin, has drawn significant attention. Clinical studies suggested that this represents a relative anejaculation rather than a retrograde ejaculation. We present here the study to investigate the role of urethral pressure profile (UPP) on treating PE by tamsulosin. 相似文献
39.
40.
ATP binding cassette G8 T400K polymorphism may affect the risk of gallstone disease among Chinese males 总被引:3,自引:0,他引:3
Wang Y Jiang ZY Fei J Xin L Cai Q Jiang ZH Zhu ZG Han TQ Zhang SD 《Clinica chimica acta; international journal of clinical chemistry》2007,384(1-2):80-85
BACKGROUND: Supersaturation of bile with cholesterol is a primary step in the formation of cholesterol gallstones. ATP binding cassette (ABC) G5 and G8 play an important role in regulating sterol absorption and secretion. To investigate a possible association between transporter gene polymorphism and gallstone formation, we examined five common polymorphisms in the ABCG5 (Q604E) and ABCG8 (D19H, Y54C, T400K, A632V) genes in patients with gallstone disease (GS). METHODS: Study subjects included 287 patients with GS and 219 gallstone free controls (GSF). Polymorphisms were determined using PCR-RFLP analysis or the Taqman MGB assay. Plasma and biliary lipid levels were measured. RESULTS: 2 SNPs of ABCG8 gene (Y54C and T400K) showed strong linkage disequilibrium (D'=0.824, r2=0.579). Male carriers of the less frequent K allele of ABCG8 T400K had a 2.31-fold elevated risk [95% confidence interval (CI) 1.12 approximately 4.76, P=0.023] for gallstone disease compared to male with the common genotype after the adjustment for age, body mass index. Males with the K allele had lower plasma triglyceride (P=0.044) and biliary phospholipid (P=0.035) levels than TT homozygotes. No such association was found in female or other 4 SNPs. CONCLUSIONS: These findings indicate that the T400K polymorphism in ABCG8 may be associated with the incidence of gallstone disease in males. 相似文献