全文获取类型
收费全文 | 31155篇 |
免费 | 1829篇 |
国内免费 | 502篇 |
专业分类
耳鼻咽喉 | 139篇 |
儿科学 | 383篇 |
妇产科学 | 394篇 |
基础医学 | 1606篇 |
口腔科学 | 148篇 |
临床医学 | 2644篇 |
内科学 | 3337篇 |
皮肤病学 | 475篇 |
神经病学 | 1118篇 |
特种医学 | 441篇 |
外科学 | 1445篇 |
综合类 | 3657篇 |
一般理论 | 1篇 |
预防医学 | 3964篇 |
眼科学 | 185篇 |
药学 | 10754篇 |
12篇 | |
中国医学 | 599篇 |
肿瘤学 | 2184篇 |
出版年
2024年 | 57篇 |
2023年 | 345篇 |
2022年 | 881篇 |
2021年 | 1024篇 |
2020年 | 887篇 |
2019年 | 864篇 |
2018年 | 851篇 |
2017年 | 835篇 |
2016年 | 889篇 |
2015年 | 1033篇 |
2014年 | 2299篇 |
2013年 | 2887篇 |
2012年 | 2224篇 |
2011年 | 2531篇 |
2010年 | 1840篇 |
2009年 | 1736篇 |
2008年 | 1732篇 |
2007年 | 1609篇 |
2006年 | 1365篇 |
2005年 | 1101篇 |
2004年 | 875篇 |
2003年 | 721篇 |
2002年 | 543篇 |
2001年 | 491篇 |
2000年 | 441篇 |
1999年 | 444篇 |
1998年 | 284篇 |
1997年 | 270篇 |
1996年 | 209篇 |
1995年 | 210篇 |
1994年 | 212篇 |
1993年 | 156篇 |
1992年 | 150篇 |
1991年 | 101篇 |
1990年 | 101篇 |
1989年 | 84篇 |
1988年 | 101篇 |
1987年 | 95篇 |
1986年 | 97篇 |
1985年 | 111篇 |
1984年 | 123篇 |
1983年 | 66篇 |
1982年 | 71篇 |
1981年 | 52篇 |
1980年 | 63篇 |
1979年 | 49篇 |
1978年 | 56篇 |
1977年 | 52篇 |
1976年 | 59篇 |
1975年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Michael M. Vanyukov Howard B. Moss Anthony E. Gioio Hugh B. Hughes Barry B. Kaplan Ralph E. Tarter 《Behavior genetics》1998,28(2):75-82
We have conducted a population-based association study of substance abuse and a microsatellite at the dopamine D5 receptor locus (DRD5) in a sample of European–American males and females with substance dependence (SA) or without any psychiatric disorder. Overrepresentation of the most frequent allele (148 bp) was found in males in the SA group (OR = 2.2, P= .02); this finding was reproduced in females (OR = 5.4, p< .001). The difference in the frequencies of this allele between SA males and SA females was statistically significant. The genotype coded in accordance with the dose of this allele correlated with substance abuse liability in males and females (stronger in females) and with novelty seeking in females. There was no evidence of correlation between the genotypes of spouses that could be induced by assortative mating for the liability to substance abuse. The data suggest that the DRD5 locus is involved in the variation and sex dimorphism of substance abuse liability.CEDAR is a consortium between St. Francis Medical Center and the University of Pittsburgh. 相似文献
83.
84.
Summary The whole cell lipid and sterol content of the drug resistant strains cyh1, cyh3 and cyh4 was compared with that of wild type by thin layer and gas liquid chromatography and by UV spectrophotometric analysis. The cyh3 and cyh4 strains had a decreased content of the unsaturated 18:1 fatty acid oleic acid, a decreased content of ergosterol and an increased content of 24,28 dehydroergosterol with respect to wild type. The cyh1 strain, however, only showed a decreased content of ergosterol and an increased content of 24,28 dehydro-ergosterol when compared to wild type. 相似文献
85.
Chronic cocaine exposure during critical periods of development induces short- and long-term effects. During the pubertal period, the hypothalamic–pituitary–gonadal (HPG) axis undergoes many dynamic changes. The present study investigated whether chronic periadolescent cocaine alters reproductive maturity in the rat. Sixty female Long–Evans hooded rats were randomly assigned to one of three conditions (20 mg cocaine/kg/day, saline injected and uninjected), for dosing from postnatal day 21 (P21) through P60. Several indicators of reproductive maturation and functioning were assessed during and following treatment. Cocaine exposure had no effect on the onset of puberty or on the date of first ovulation. The number of proestrus–estrus transitions was significantly lower in cocaine-exposed females compared to uninjected females, but not compared to saline-injected controls. This reduction was observed during exposure to cocaine, as well as after the cessation of injections. During the dosing period, cocaine-exposed rats also exhibited a greater number of cycles that had no clear P–E transition than did UN subjects; this effect disappeared once injections stopped. These alterations suggest immediate, and possibly persisting, alterations in the control of ovulation after chronic cocaine exposure throughout adolescence. Interestingly, during the injection period, the saline-injected females had a significantly greater number of diestrus days compared to uninjected and cocaine-injected animals, as well as a lower proportion of regular 4- and 5-day cycles. These differences disappeared once injections stopped. These results suggest a stress-induced irregularity of the estrous cycle, possibly attenuated by cocaine and recoverable after exposure. The present findings indicate that the HPG axis is susceptible to short-term, and possibly to long-term, alterations induced by cocaine exposure throughout the adolescent period. 相似文献
86.
研究了膜孔内接枝聚异丙基丙烯酰胺 (PNIPAM)“开关”的温敏型智能膜的制备 ,并对其进行了温度感应开关性能实验。实验中采用等离子体接枝填孔聚合法将 PNIPAM接枝在多孔平板膜的膜孔中 ,结果表明 ,这种接枝了 PNIPAM“开关”的多孔膜具有温度感应特性 ,其利用膜孔内 PNIPAM接枝链的膨胀 -收缩特性实现了感温性开关性能。当环境温度低于 PNIPAM的低临界溶解温度 (L CST)时 ,膜孔内 PNIPAM分子链膨胀而使膜孔呈“关闭”状态 ;而当环境温度高于 L CST时 ,PNIPAM分子链变为收缩状态而使膜孔“开启”。温敏开关的 L CST可通过添加丙烯酰胺 (AAM)与异丙基丙烯酰胺 (NIPAM)共聚来调节 ,AAM与 NIPAM共聚开关的 L CST随 AAM添加量的增加而单调上升。 相似文献
87.
不同剂量病毒唑治疗肾综合征出血热306例疗效分析 总被引:3,自引:0,他引:3
应用不同剂量病毒唑对306例肾综合征同血热患者进行治疗对比观察,发现两治疗组疗效无显著性差异,但两治疗组怀对照组相比,越期率高,肾功能恢复快,血小板数恢复早,病程缩短,并发症减少,病死率也有所下降,但无显著性差异。 相似文献
88.
The structuring of an allergy index based on IgE-mediated skin sensitivity to common environmental allergens 总被引:1,自引:0,他引:1
L R Freidhoff D G Marsh D A Meyers R Hussain 《The Journal of allergy and clinical immunology》1983,72(3):274-287
We computed skin-test sensitivity levels in 485 adults puncture-tested with eight standardized, high-quality inhalant allergens tested at single concentrations. In order to quantitate the "average" IgE-mediated skin sensitivity of each subject, we used both nonparametric and parametric statistical methods to generate two "allergy indices" (Allergy Index I and Allergy Index II) based on sensitivity end-point data from the subpopulations of individuals positive to six of the eight allergens. For the 192 skin test-positive subjects, Allergy Index I and Allergy Index II were significantly correlated with each other (rs = 0.98, p less than 0.001) and with the number of positive skin-test reactions (rs congruent to 0.9, p less than 0.001) as well as with log[total serum IgE] (r congruent to 0.4, p less than 0.01). In 102 ragweed-positive subjects, log[specific IgE to ragweed] was significantly correlated with ragweed-specific "ragweed indices I and II" (r congruent to 0.6, p less than 0.01). Furthermore, the average daily symptom scores reported by 14 ragweed-positive subjects during the ragweed pollination season were significantly correlated with ragweed indices I and II (p less than 0.05). We propose the use of Allergy Index II in epidemiologic and genetic studies of allergic phenotypes as well as in clinical decisions for diagnosis and immunotherapeutic intervention. 相似文献
89.
采用多巴酚丁胺试验心肌断层显像的方法对14例可疑冠心病,8例心绞痛和3例心肌梗塞病人进行了检查。试验中发现,病人用药前后心率和血压的变化有显著性差异(P<0.01)。大部分受检者出现心悸、胸闷,少数病人有恶心、头痛,一般在停药后10分钟完全恢复正常,未发现严重副作用。结果表明,多巴酚丁胺试验效应近似运动生理变化,是一种安全有效的药物应激试验方法。结合心肌断层显像,对评价心肌缺血有较大临床意义。 相似文献
90.
血糖感应型胰岛素给药智能载体的研究进展 总被引:1,自引:0,他引:1
胰岛素控制释放高分子载体系统一直是国内外科技工作者的研究热点 ,迄今已经研究报道了多种具有不同工作原理的血糖感应型胰岛素给药智能载体。本文基于国内外大量研究文献 ,综述了血糖感应型胰岛素控制释放智能化高分子载体的研究进展。 相似文献