全文获取类型
收费全文 | 94919篇 |
免费 | 7608篇 |
国内免费 | 144篇 |
专业分类
耳鼻咽喉 | 910篇 |
儿科学 | 3167篇 |
妇产科学 | 2822篇 |
基础医学 | 11810篇 |
口腔科学 | 1628篇 |
临床医学 | 13945篇 |
内科学 | 17529篇 |
皮肤病学 | 1432篇 |
神经病学 | 9346篇 |
特种医学 | 2814篇 |
外国民族医学 | 37篇 |
外科学 | 10602篇 |
综合类 | 1356篇 |
一般理论 | 113篇 |
预防医学 | 11265篇 |
眼科学 | 1705篇 |
药学 | 5875篇 |
3篇 | |
中国医学 | 141篇 |
肿瘤学 | 6171篇 |
出版年
2022年 | 472篇 |
2021年 | 1542篇 |
2020年 | 959篇 |
2019年 | 1605篇 |
2018年 | 1843篇 |
2017年 | 1371篇 |
2016年 | 1502篇 |
2015年 | 1665篇 |
2014年 | 2271篇 |
2013年 | 3743篇 |
2012年 | 5303篇 |
2011年 | 5646篇 |
2010年 | 3065篇 |
2009年 | 2818篇 |
2008年 | 5012篇 |
2007年 | 5673篇 |
2006年 | 5429篇 |
2005年 | 5206篇 |
2004年 | 5070篇 |
2003年 | 4787篇 |
2002年 | 4648篇 |
2001年 | 1901篇 |
2000年 | 1817篇 |
1999年 | 1753篇 |
1998年 | 1158篇 |
1997年 | 1002篇 |
1996年 | 911篇 |
1995年 | 810篇 |
1994年 | 759篇 |
1993年 | 701篇 |
1992年 | 1407篇 |
1991年 | 1389篇 |
1990年 | 1309篇 |
1989年 | 1257篇 |
1988年 | 1077篇 |
1987年 | 1212篇 |
1986年 | 1106篇 |
1985年 | 1139篇 |
1984年 | 966篇 |
1983年 | 827篇 |
1982年 | 656篇 |
1981年 | 608篇 |
1980年 | 560篇 |
1979年 | 830篇 |
1978年 | 634篇 |
1977年 | 575篇 |
1976年 | 566篇 |
1975年 | 487篇 |
1974年 | 600篇 |
1973年 | 541篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Tinghu Kang Yang Li Jiandong Guo Xingwen Ma Fatema Akhter Hiramoni Md Zahir Ahmed Mary C. Jobe Oli Ahmed 《International Journal of Mental Health Promotion, The》2022,24(2):207-217
The aim of the study was to explore the relationship between college graduates’ dual self-consciousness, job search
clarity and perceived stress, and reveal the mediating role of perceived stress between dual self-consciousness and
job search clarity. In this study, 467 college graduates were investigated using the Dual Self-Consciousness Scale,
Job Search Clarity Scale, and Perceived Stress Scale. After controlling for gender, age, and region, the results
revealed that: (1) private self-consciousness has a significant positive predictive effect on job search clarity; (2)
perceived stress has a significant negative predictive effect on job search clarity; (3) perceived stress plays partial
mediation effects between private self-consciousness and job search clarity; (4) perceived stress plays complete
mediation effects between public self-consciousness and job search clarity; (5) perceived stress has suppressing
effects between public self-consciousness and job search clarity. 相似文献
33.
34.
Nishard Abdeen Albert Cross Gregory Cron Steven White Thomas Rand David Miller Giles Santyr 《Magnetic resonance in medicine》2006,56(2):255-264
We used the dual capability of hyperpolarized 129Xe for spectroscopy and imaging to develop new measures of xenon diffusing capacity in the rat lung that (analogously to the diffusing capacity of carbon monoxide or DLCO) are calculated as a product of total lung volume and gas transfer rate constants divided by the pressure gradient. Under conditions of known constant pressure breath-hold, the volume is measured by hyperpolarized 129Xe MRI, and the transfer rate is measured by dynamic spectroscopy. The new quantities (xenon diffusing capacity in lung parenchyma (DLXeLP)), xenon diffusing capacity in RBCs (DLXeRBC), and total lung xenon diffusing capacity (DLXe)) were measured in six normal rats and six rats with lung inflammation induced by instillation of fungal spores of Stachybotrys chartarum. DLXeLP, DLXeRBC, and DLXe were 56 +/- 10 ml/min/mmHg, 64 +/- 35 ml/min/mmHg, and 29 +/- 9 ml/min/mmHg, respectively, for normal rats, and 27 +/- 9 ml/min/mmHg, 42 +/- 27 ml/min/mmHg, and 16 +/- 7 ml/min/mmHg, respectively, for diseased rats. Lung volumes and gas transfer times for LP (TtrLP) were 16 +/- 2 ml and 22 +/- 3 ms, respectively, for normal rats and 12 +/- 2 ml and 35 +/- 8 ms, respectively, for diseased rats. Xenon diffusing capacities may be useful for measuring changes in gas exchange associated with inflammation and other lung diseases. 相似文献
35.
Reem Haj-Ali BDS DDS MS ; Mary Walker DDS PhD ; Karen Williams PhD ; Yong Wang PhD ; Paulette Spencer DDS PhD 《Journal of prosthodontics》2006,15(2):82-88
PURPOSE: The purpose of this study was to compare the dentin/adhesive interfacial characteristics when bonding to noncarious as well as caries-affected dentin. MATERIALS AND METHODS: Seven extracted, unerupted, third molars were sectioned into halves. Artificial caries was created on one-half of each tooth, leaving the other half as a control. Dentin surfaces were treated with UNO adhesive according to the manufacturer's instructions for the wet-bonding technique and under environmental conditions present in the oral cavity. Dentin/adhesive interface sections of each half-tooth were stained with Goldner's trichrome, a classic bone stain, and examined using light microscopy. The width of exposed collagen was measured directly from photomicrographs, and adhesive penetration was analyzed qualitatively. RESULTS: The degree and extent to which the adhesive encapsulated the demineralized dentin matrix were reflected in the color difference in the stained sections with the noncarious dentin sections showing a degree of collagen encapsulation superior to that of the caries-affected dentin sections. The overall mean widths of exposed collagen were significantly (p < or = .05) greater at the caries-affected dentin/adhesive interface, 8.6 (1.7) microm, as compared with those at the noncarious dentin/adhesive interface, 6.0 (1.5) microm. CONCLUSIONS: The morphologic characteristics of the caries-affected dentin/interface suggest an increase in the exposed collagen zone and a decrease in the quality of the adhesive infiltration when compared with noncarious dentin. The evidence suggests that dentin substrate characteristics have a significant effect on the dentin/adhesive interface structure. 相似文献
36.
Andrea DiMartini Nancy Day Mary Amanda Dew Lubna Javed Mary Grace Fitzgerald Ashok Jain John J Fung Paulo Fontes 《Liver transplantation》2006,12(5):813-820
For patients who receive a liver transplant (LTX) for alcoholic liver disease (ALD), investigators are focusing beyond survival to determine specific alcohol use outcomes. Studies suggest the use of alcohol ranges from 8 to 22% for the first post-transplant year with cumulative rates reaching 30 to 40% by 5 years following transplantation. Yet while investigators are interested in determining specific rates of alcohol use and predictors of use, only three studies since 1990 have been prospective. In 1998, we began a prospective study of post-LTX alcohol consumption in ALD recipients using multiple repeated measures of alcohol use. After 5 years of follow-up, we found that 22% had used any alcohol by the first year and 42% had a drink by 5 years. By 5 years, 26% drank at a heavier use (binge) pattern and 20% drank in a frequent pattern. In a univariate model, predictors of alcohol use included pre-transplant length of sobriety, a diagnosis of alcohol dependence, a history of other substance use, and prior alcohol rehabilitation. 相似文献
37.
Mary Ann Richardson Helen M Chao Laura L Read James D Clelland Raymond F Suckow 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2006,(2):195-197
Phenylketonuria (PKU), an inborn error of phenylalanine metabolism, has been shown to be a risk factor for tardive dyskinesia (TD). In male psychiatric patients there was a significant relationship between TD and measures of plasma phenylalanine following ingestion of a standardized phenylalanine dose that was indicative of higher brain availability of phenylalanine in patients with TD. In addition, a medical food formulation consisting of branched chain amino acids, which compete with phenylalanine for transport across the blood-brain barrier, has been demonstrated to be an efficacious treatment for TD. Cumulatively these findings suggested that TD was related to phenylalanine metabolism and thus that sequence variants in the gene for phenylalanine hydroxylase (PAH), the rate-limiting enzyme in the catabolism of phenylalanine, could be associated with TD susceptibility. Genetic screening of PAH in a group of 123 psychiatric patients revealed ten sequence polymorphisms and two mutations, but none appeared to be a significant risk factor for TD. 相似文献
38.
39.
贺晓新 《结核与肺部疾病杂志》2006,1(3):153-156
科学研究的目标是创造和传播知识。这得通过对系统收集以及报告信息的批判性分析来完成。批判性分析始于一个简单的步骤,即在运用复杂统计学分析方法进行比较之前对所收集的数据进行深入检查。根据所收集的数据类型按照标准化方式进行统计学分析。在为解决研究问题而需采用合理、标准化步骤进行比较时,新知识就产生了,同时要避免错误的结论。在对数据进行仔细检查和分析之后,为了保证结论的正确性,再对数据进行一次批判性评论是非常重要的补充步骤。在科学文献中发表研究成果过程中涉及的同行评价对于传播新知识并保证其质量方面是一个非常重要的步骤。如果没有将研究成果发表供同行参考,这项研究就不算完整。 相似文献
40.