全文获取类型
收费全文 | 81697篇 |
免费 | 4965篇 |
国内免费 | 579篇 |
专业分类
耳鼻咽喉 | 967篇 |
儿科学 | 2837篇 |
妇产科学 | 1747篇 |
基础医学 | 10790篇 |
口腔科学 | 1641篇 |
临床医学 | 9231篇 |
内科学 | 17364篇 |
皮肤病学 | 2045篇 |
神经病学 | 7005篇 |
特种医学 | 1830篇 |
外国民族医学 | 2篇 |
外科学 | 9081篇 |
综合类 | 1665篇 |
一般理论 | 70篇 |
预防医学 | 8389篇 |
眼科学 | 1799篇 |
药学 | 5155篇 |
6篇 | |
中国医学 | 565篇 |
肿瘤学 | 5052篇 |
出版年
2023年 | 525篇 |
2022年 | 757篇 |
2021年 | 2099篇 |
2020年 | 1155篇 |
2019年 | 2127篇 |
2018年 | 2880篇 |
2017年 | 1827篇 |
2016年 | 1705篇 |
2015年 | 1881篇 |
2014年 | 2478篇 |
2013年 | 3775篇 |
2012年 | 5994篇 |
2011年 | 6534篇 |
2010年 | 3409篇 |
2009年 | 2488篇 |
2008年 | 5384篇 |
2007年 | 5449篇 |
2006年 | 5200篇 |
2005年 | 5123篇 |
2004年 | 4803篇 |
2003年 | 4594篇 |
2002年 | 4220篇 |
2001年 | 1831篇 |
2000年 | 2125篇 |
1999年 | 1460篇 |
1998年 | 742篇 |
1997年 | 591篇 |
1996年 | 548篇 |
1995年 | 486篇 |
1994年 | 403篇 |
1993年 | 395篇 |
1992年 | 371篇 |
1991年 | 304篇 |
1990年 | 279篇 |
1989年 | 277篇 |
1988年 | 240篇 |
1987年 | 223篇 |
1986年 | 185篇 |
1985年 | 200篇 |
1984年 | 237篇 |
1983年 | 215篇 |
1982年 | 238篇 |
1981年 | 200篇 |
1980年 | 197篇 |
1979年 | 118篇 |
1978年 | 102篇 |
1977年 | 108篇 |
1976年 | 82篇 |
1975年 | 75篇 |
1974年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
OBJECTIVE: To investigate the factors responsible for Pseudomonas aeruginosa nosocomial cross-infection in the intensive care unit (ICU) and provide effective measure for the prevention and management. METHODS: The homology of 7 Pseudomonas aeruginosa strains isolated from the patients in the ICU and the environment was examined by biological, serological, drug-resistance and plasmid analysis. RESULTS: The results of serological and plasmid analyses had good consistency, which demonstrated that the 7 Pseudomonas aeruginosa strains originated from solution in the oxygen humidifier, with uniform serological and plasmid type, and belonged to the same clone with cross-infection by contact between the patients or nursing staff and the objects in the ICU. CONCLUSION: Serological and plasmid analyses are more practical for identifying the sources of Pseudomonas aeruginosa cross-infection, which can be prevented by strict disinfection of the instrument and supervision of the nursing staff in the ICU. 相似文献
132.
José Ramón Cansino Alcaide Luis Martínez-Piñeiro 《Clinical & translational oncology》2006,8(3):148-152
Summary Genes involved in cancer generation are usually tumor suppressors and oncogenes. Progressive genetic alterations in these
genes are involved in the mechanisms of tumorigenesis. In prostate cancer, additionally several chromosomal loci that should
harbor mutated genes have been proposed. Some genes have been found altered in prostate cancer, such as PTEN, TP53, AR, RNASEL
(HPC1), ELAC2 (HPC2), CDKN2A and MSR1 and those can be natural targets for new strategies of treatment. Besides, gene therapy
has been suggested to be suitable for prostate cancer treatment. This approach includesex vivo corrective therapy, suicide, and antisense therapy. 相似文献
133.
Cesar G. Victora Nubia Muoz Nicholas E. Day Lucio B. Barcelos Debora A. Peccin Noris M. Braga 《International journal of cancer. Journal international du cancer》1987,39(6):710-716
There is a cluster of high-incidence areas of oesophageal cancer in south-eastern South America, including Southern Brazil, Uruguay and parts of Argentina. The present case-control study investigated the hypothesis that this may be due to the drinking of maté, a traditional beverage drunk at a very high temperature, and also studied the role of other known risk factors such as alcohol and tobacco. Cases (171) and age- and sex-matched controls (342) were recruited from hospitals in the State of Rio Grande do Sul in Southern Brazil. The crude odds ratio for daily maté drinkers was 1.92 relative to those drinking less frequently than daily (p = 0.006). Other risk factors included the drinking of cachaça (a sugar cane spirit), smoking, rural residence, low fruit consumption and high intake of meats. After adjustment for these variables through conditional logistic regression, the odds ratio associated with daily maté drinking was reduced to 1.47 (90% CI = 0.87 - 2.50). Although the study failed to provide evidence of a strong association between maté and oesophageal cancer, the cluster of high rates could be explained by relative risks of the magnitude observed. This is due to the fact that approximately 70% of adult males and 50% of females are daily drinkers. In addition, this study revealed that alcohol, tobacco smoking and rural residence are the main risk factors for oesophageal cancer in this population and the fruit consumption confers some degree of protection. 相似文献
134.
A firefly luciferase bioluminescent assay of bacterial adenosine triphosphate (ATP) was used to measure the toxic effects of metal ions on six bacterial genera isolated from two geographically different marsh treatment systems. The toxicity of eleven different metals, as well as metal mixtures, was monitored using the agar plate test and the resazurin reduction test in addition to measurement of intracellular ATP. All the organisms surveyed tended to be sensitive to much lower concentrations of metals when the metals were present in mixtures. Isolates from a marsh system constructed on normal soil exhibited lower metal resistance patterns than organisms isolated from a marsh built on mine tailings. The intracellular ATP assay appeared to be the most sensitive method of determining the viability of bacterial cells following metal treatment. 相似文献
135.
136.
耳源性脑疝25例,抢救成功者19例。采用单纯脑脓肿穿刺抽脓抢救脑疝6例,仅1例成功;开颅减压术抢救脑疝20例,18例抢救成功。本组临床实践和文献报道都说明耳源性脑疝一旦发生应即刻行开颅减压术,能卓有成效地抢救生命 相似文献
137.
吡酮酸类抗菌药物的研究Ⅷ.1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其类似物的合成和构效关系 总被引:1,自引:0,他引:1
为探讨构效关系,合成了1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其喹啉、萘啶、吡啶[2,3-C]哒嗪环系类似物16个。测定了对大肠杆菌的MIC。用Hückel分子轨道理论(HMO)方法计算了四个母体环上电子密度。结果表明:环中氮的位置对药效团——3位羧基和4位羰基氧原子上电子密度的影响较大而影响其抗菌活性。喹啉、萘啶两环系的3位羧基和4位羰基氧原子上的电子密度较高,其体外抗菌活性较高;而噌啉及吡啶[2,3-C]哒嗪两环系的电子密度较低,其体外抗菌活性较低甚至消失。 相似文献
138.
139.
Patricia H. Arford 《Journal of nursing scholarship》2004,36(3):265-271
PURPOSE: To provide a primer for novice nurse scientists about the increasingly regulated human research environment. ORGANIZING CONSTRUCTS: Federal regulations and international guidelines about protection of human research participants are discussed, with particular attention to institutional review boards for human research. CONCLUSION: Understanding the processes used by institutional review boards to foster ethical human research promotes collaborative interactions and supports compliant research work. 相似文献
140.