全文获取类型
收费全文 | 64525篇 |
免费 | 5696篇 |
国内免费 | 4399篇 |
专业分类
耳鼻咽喉 | 678篇 |
儿科学 | 1056篇 |
妇产科学 | 708篇 |
基础医学 | 6700篇 |
口腔科学 | 1058篇 |
临床医学 | 8190篇 |
内科学 | 8973篇 |
皮肤病学 | 682篇 |
神经病学 | 3255篇 |
特种医学 | 2270篇 |
外国民族医学 | 17篇 |
外科学 | 6540篇 |
综合类 | 12545篇 |
现状与发展 | 13篇 |
一般理论 | 7篇 |
预防医学 | 5037篇 |
眼科学 | 1431篇 |
药学 | 6927篇 |
66篇 | |
中国医学 | 3854篇 |
肿瘤学 | 4613篇 |
出版年
2024年 | 272篇 |
2023年 | 949篇 |
2022年 | 2385篇 |
2021年 | 3028篇 |
2020年 | 2325篇 |
2019年 | 1928篇 |
2018年 | 1983篇 |
2017年 | 1868篇 |
2016年 | 1715篇 |
2015年 | 2628篇 |
2014年 | 3278篇 |
2013年 | 3408篇 |
2012年 | 5136篇 |
2011年 | 5399篇 |
2010年 | 3925篇 |
2009年 | 3263篇 |
2008年 | 3976篇 |
2007年 | 3929篇 |
2006年 | 3664篇 |
2005年 | 3310篇 |
2004年 | 2282篇 |
2003年 | 2123篇 |
2002年 | 1688篇 |
2001年 | 1587篇 |
2000年 | 1499篇 |
1999年 | 1349篇 |
1998年 | 701篇 |
1997年 | 755篇 |
1996年 | 556篇 |
1995年 | 498篇 |
1994年 | 431篇 |
1993年 | 314篇 |
1992年 | 375篇 |
1991年 | 336篇 |
1990年 | 274篇 |
1989年 | 251篇 |
1988年 | 227篇 |
1987年 | 198篇 |
1986年 | 176篇 |
1985年 | 140篇 |
1984年 | 77篇 |
1983年 | 87篇 |
1982年 | 51篇 |
1981年 | 54篇 |
1980年 | 33篇 |
1979年 | 45篇 |
1978年 | 22篇 |
1977年 | 20篇 |
1974年 | 18篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
31.
OBJECTIVE: To study the expression of S100 in oral submucose fibrosis(OSF). METHODS: Immunohistochemistry assay was performed on 10 cases of OSF, 10 cases of oral epithelial dysplasia (OED) and 8 cases of normal oral epithelium using monoclonal antibody against S100 protein. RESULTS: S100 did not express in the normal oral muscosal epithelium. The S100 positive nuclear staining was found in 50% of the OSF and OED cases, which was significantly higher than that in the normal oral epithelium (P < 0.05). But the positive staining in the OSF and OED cases had no difference (P > 0.05). CONCLUSION: S100 expression is closely related to the development of OSF and OED. The positive staining expression in the OSF and OED cases is the same. 相似文献
32.
33.
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
34.
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
35.
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
36.
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
37.
侧脑室注射东莨菪碱和酚妥拉明对幼兔分辨学习的影响 总被引:3,自引:1,他引:2
目的 探讨东莨菪碱和酚妥拉明对幼兔分辨学习的影响。方法 将30只比利时纯种幼兔从生后13日龄随机分为三组:东莨菪碱组、酚妥拉明组和生理盐水对照组,观察不同日龄各组幼兔的分辨学习能力。结果 幼兔分辨学习的正确反应一般始于生后15日龄。侧脑室注射东莨菪碱对16日龄以前幼兔分辨学习无明显影响,对17日龄以后幼兔分辨学习产生明显抑制作用。侧脑室注射酚妥拉明对13—23日龄幼兔分辨学习均有明显抑制作用。结论 幼兔生后发育过程中学习能力的发展具明显的阶段性,其原因可能与神经递质系统的发育成熟有关。 相似文献
38.
前列腺素E1对大鼠肝脏缺血再灌注损伤的保护作用 总被引:2,自引:0,他引:2
目的 探讨前列腺素E1(PGE1)对肝脏 因再灌注损伤的保护作用。方法 制作常温下大鼠部分肝叶缺血再灌注模型,于缺血前经门静脉给予PGE1,45min后恢复血流灌注,并于1h后取门静脉血测定血清谷草转氨酶(GOT)、谷丙转氨酶(GPT)、乳酸脱氢酶(LDH)、肿瘤坏死因子-α(TNF-α)及内皮素1(ET-1),同时取缺血肝叶行病理组织学检查。结果 缺血再灌注组GOT、GPT、LDH及TNF-α和ET-1均明显高于正常对照组,PGE1组则明显低于缺血再灌注组。PGE1组的肝脏病理组织学改变明显轻于缺血再灌注组,并接近正常对照组。结论 PGE1对肝缺血再灌注具有保护作用。 相似文献
39.
40.