全文获取类型
收费全文 | 140486篇 |
免费 | 14547篇 |
国内免费 | 9479篇 |
专业分类
耳鼻咽喉 | 1139篇 |
儿科学 | 2274篇 |
妇产科学 | 1573篇 |
基础医学 | 13761篇 |
口腔科学 | 2531篇 |
临床医学 | 19482篇 |
内科学 | 18074篇 |
皮肤病学 | 1431篇 |
神经病学 | 5903篇 |
特种医学 | 4783篇 |
外国民族医学 | 52篇 |
外科学 | 11188篇 |
综合类 | 29028篇 |
现状与发展 | 38篇 |
一般理论 | 8篇 |
预防医学 | 12569篇 |
眼科学 | 3854篇 |
药学 | 16326篇 |
213篇 | |
中国医学 | 10565篇 |
肿瘤学 | 9720篇 |
出版年
2024年 | 719篇 |
2023年 | 2362篇 |
2022年 | 5992篇 |
2021年 | 7469篇 |
2020年 | 6122篇 |
2019年 | 4694篇 |
2018年 | 4735篇 |
2017年 | 5059篇 |
2016年 | 4219篇 |
2015年 | 6773篇 |
2014年 | 8384篇 |
2013年 | 8649篇 |
2012年 | 12343篇 |
2011年 | 13132篇 |
2010年 | 9196篇 |
2009年 | 7544篇 |
2008年 | 8664篇 |
2007年 | 8232篇 |
2006年 | 7607篇 |
2005年 | 6406篇 |
2004年 | 4328篇 |
2003年 | 4062篇 |
2002年 | 3205篇 |
2001年 | 2653篇 |
2000年 | 2295篇 |
1999年 | 2043篇 |
1998年 | 1083篇 |
1997年 | 1123篇 |
1996年 | 819篇 |
1995年 | 767篇 |
1994年 | 621篇 |
1993年 | 394篇 |
1992年 | 451篇 |
1991年 | 392篇 |
1990年 | 345篇 |
1989年 | 284篇 |
1988年 | 275篇 |
1987年 | 224篇 |
1986年 | 188篇 |
1985年 | 136篇 |
1984年 | 77篇 |
1983年 | 80篇 |
1982年 | 52篇 |
1981年 | 61篇 |
1980年 | 34篇 |
1979年 | 54篇 |
1978年 | 23篇 |
1977年 | 22篇 |
1974年 | 21篇 |
1973年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 51 毫秒
41.
Twenty patients with major depressive disorder were studied with evoked potential (EP) topographic mapping after receiving placebo, imipramine, or amoxapine for 2 days in a random-assignment, double-blind design. Patients performed the Continuous Performance Test (CPT), a visual vigilance test. The stimuli were the digits 0-9, with 0 a target to be responded to with a button press. EPs were recorded from 32 channels and were averaged separately for detected and undetected targets and for false positives and correctly identified nontargets (no button press). Twenty-one normal controls were also tested. Amoxapine enhanced N120 amplitude in midline parietal and right parietal cortex where selective attention effects have been found to be greatest in studies of normal controls. Both amoxapine and imipramine enhanced differences in P200 between target and nontarget stimuli in comparison to placebo, with amoxapine differences again being greatest over midline parietal locations. CPT performance was significantly better on amoxapine than placebo. 相似文献
42.
From Jan. to Oct. 1989, we investigated the role of various life style and dietary factors in areas of high and low incidences of cervical carcinoma, as well as infection with types 16 and 33 of human papillomavirus (HPV) in populations. The polymerase chain reaction (PCR) technique was used to detect the infection with HPV 16/33. The result showed that the infection rate of HPV was about 17.9% (Guangyuan, area of high incidence of cervical cancer), and the infection rate about 3.4% (Mian Zhu, area of low incidence of cervical cancer). It was clear that Guangyuan was 5-fold as the infection rate of HPV 16/33 as Mian Zhu. Strong and statistically significant associations were found to between infection rate of Guangyuan and Mian Zhu (P < 0.001). Other risk factors of cervical carcinoma, such as cigarette smoker, Vegetable intake, genital hygiene, personal hygiene etc, were also discussed and analysed in the article. 相似文献
43.
小儿先心病术后左房夺和肺动脉压力的监测在ICU中十分重要。心电图是论断和评价心脏疾患的常用方法。本文分析了32例小儿先心病手术前后(伴肺动脉高压16例)6个肢体导联心电图中P波和QRS波时限总和及振幅总和与左房、肺动脉压力的关系。结果表明两者均有良好的相关性(r=0.85 ̄0.88,r=0m74 ̄0.80,P〈0.01),该法简单、方便,可广泛开展,尤其在术后未放置PA和LA管或在IOU中已拨除L 相似文献
44.
测定110例肝病的抗凝血酶Ⅲ(AT-Ⅲ)活性,62例低于正常(56.4%),均值为60.1±38.2%。50例正常对照为100.0±26.7%。重症肝炎、慢性活动性肝炎及失代偿期肝硬化活性显著下降,均值分别为12.9±13.0%、51.0±34.6%、43.3±29.6%.AT-Ⅲ活性在评价肝脏功能方面较凝血酶原时间敏感,具有一定的实用意义。 相似文献
45.
A general equation was derived, which directly describes the mathematical relationship between the allometrically predicted pharmacokinetic (PK) parameters in humans and the body weights of animal species (along with their corresponding measured PK parameters). It was shown, with use of the derived equation, that the predicted values in humans, based on combinations of animal species commonly used in allometry, are heavily dependent on certain species, for example, the dog. In contrast, parameter values from the rat made no contribution to the predicted human values, as long as the rat was not the smallest species used. Monte Carlo simulations were further performed to examine the species or weight dependence. The cost-effective combinations of animal species, in terms of number and species type, were theoretically examined through simulations. Finally, literature data demonstrated the species or weight dependence predicted from the equation and as illustrated through the Monte Carlo simulations. Appreciation of this species or weight dependence should guide researchers in selecting animal species and designing optimal experiments in the application of allometric scaling. 相似文献
46.
47.
48.
Rongnong Zhou Ligong Tang Kurt E. Geckeler Wolfgang Gpel 《Macromolecular chemistry and physics.》1994,195(7):2409-2421
Polystyrene-bound metal [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4-dicarboxybenzoyl)]phthalocyaninates were synthesized by Friedel-Crafts reaction of polystyrene with the corresponding metal phthalocyaninates. Co(II) and Cu(II) [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4-dicarboxybenzoyl)]-phthalocyaninate (PS-CodaPc and PS-CudaPc) contained 0,13 mmol · g?1 (12,4 wt.-%) and 0,13 mmol · g?1 (12,8 wt.-%) of CodaPc and CudaPc, respectively. They were soluble in N,N'-dimethylformamide, but only partially soluble in chloroform, tetrahydrofuran (THF), dimethyl sulfoxide, N-methyl-2-pyrrolidone, and pyridine. The THF extracts contained 0,12 mmol · g?1 (11,4 wt.-%) and 0,18 mmol ? g?1 (17,2 wt.-%) of PS-CodaPc and PS-CudaPc, respectively. The thermal stability of the polymers was studied using thermogravimetric and differential thermal analysis in nitrogen and synthetic air atmosphere. The contents of MdaPc(M: metal) in THF-extracted polymers calculated from the data of residue in thermogravimetric analysis are 0,12 mmol · g?1 for PS-CodaPc and 0,19 mmol · g?1 for PS-CudaPc. In addition, the sensitive properties of the polymers towards toxic gases were also investigated by quartz microbalance transducers. The results show that the quartz microbalance sensors coated with both polymers were sensitive to NO2 and chlorinated hydrocarbons, i.e. chloroform and perchloroethylene. The sensitivity to NO2 was 6,53 · 10?7 m3 · mL?1 · s?1 for PS-CodaPc and 1,90 · 10?6 m3 · mL?1 · s?1 for PS-CudaPc, and that to chloroform and perchloroethylene was 2,33 · 10?8 and 4,60 · 10?8 m3 · mL?1 · s?1, respectively, for PS-CodaPc and 4,79 · 10?8 and 9,51 · 10?7 m3 · mL?1 · s?1 for PS-CudaPc. 相似文献
49.
超声引导下肿瘤内注射^90钇玻璃微球的肝癌综合治疗 总被引:12,自引:0,他引:12
超声引导下对28例肝癌病人进行了肿瘤内注射^90钇玻璃微球(Y-90GT MS)为主的综合性治疗(部分病人配合肿块周边注射无水酒精及门静脉穿刺化疗)。随访2~16个月(平均7.9个月),病人全健在。肿瘤缩小率为91%,其中显著缩小达75%;肿块回声呈致密增强,少数呈混合型或等回声型;肿瘤内及周边血流信号显著减少;原甲胎蛋白升高者13例,11例显著下降,其中6例降至正常;病人症状减轻,全身情况改善。 相似文献
50.
本文采用1:3病例对照研究方法,对甾体避孕药的使用与血栓栓塞性疾病(急性心肌梗塞、脑栓塞、脑血栓形成和深静脉血栓形成)间的关联进行多因素分析。结果提示在我国广泛应用的甾体避孕药(主要为国产Ⅰ号避孕药)并不增加血栓栓塞性疾病的危险性。用药和停药时间的长短与血栓栓塞性疾病的发生无关,并与高血压病之间亦不存在协同作用。 相似文献