全文获取类型
收费全文 | 5291篇 |
免费 | 630篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 162篇 |
妇产科学 | 77篇 |
基础医学 | 617篇 |
口腔科学 | 136篇 |
临床医学 | 658篇 |
内科学 | 1215篇 |
皮肤病学 | 114篇 |
神经病学 | 594篇 |
特种医学 | 430篇 |
外科学 | 768篇 |
综合类 | 157篇 |
一般理论 | 1篇 |
预防医学 | 439篇 |
眼科学 | 88篇 |
药学 | 221篇 |
中国医学 | 2篇 |
肿瘤学 | 218篇 |
出版年
2023年 | 65篇 |
2022年 | 39篇 |
2021年 | 106篇 |
2020年 | 124篇 |
2019年 | 78篇 |
2018年 | 151篇 |
2017年 | 131篇 |
2016年 | 130篇 |
2015年 | 123篇 |
2014年 | 183篇 |
2013年 | 246篇 |
2012年 | 232篇 |
2011年 | 218篇 |
2010年 | 167篇 |
2009年 | 202篇 |
2008年 | 183篇 |
2007年 | 214篇 |
2006年 | 221篇 |
2005年 | 189篇 |
2004年 | 164篇 |
2003年 | 143篇 |
2002年 | 138篇 |
2001年 | 140篇 |
2000年 | 141篇 |
1999年 | 145篇 |
1998年 | 127篇 |
1997年 | 137篇 |
1996年 | 110篇 |
1995年 | 104篇 |
1994年 | 75篇 |
1993年 | 79篇 |
1992年 | 94篇 |
1991年 | 87篇 |
1990年 | 96篇 |
1989年 | 127篇 |
1988年 | 119篇 |
1987年 | 90篇 |
1986年 | 83篇 |
1985年 | 70篇 |
1984年 | 53篇 |
1983年 | 39篇 |
1982年 | 41篇 |
1981年 | 31篇 |
1980年 | 35篇 |
1979年 | 36篇 |
1978年 | 41篇 |
1977年 | 32篇 |
1976年 | 30篇 |
1974年 | 30篇 |
1971年 | 26篇 |
排序方式: 共有5963条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
筛检对肝癌死亡率影响的研究 总被引:5,自引:0,他引:5
5581名HBsAg阳性的男性随机分入周期性筛检组(A组,3712人)及对照组(B组,1869人)。A组(19155.4人年)共发生肝癌257例,B组(9785.5人年)为117例,两组的肝癌发生率分别为1342/10万与1196/10万;两组肝癌死亡分别为218与109例,肝癌死亡率分别为1138/10万与1114/10万。两组中Ⅰ期肝癌病例分别为29.6%与6.0%,差异有非常显著性意义。1、3、5年相对生存率A组为23.7%、7.0%、4.0%,B组为9.7%、4.0%、4.1%。用Poisson回归模型拟合显示,在调正年龄、初筛AFP及入列年份后,筛检对于肝癌的相对危险度为0.83,95%CI为0.68~1.03,有较弱的“保护”作用,Cox回归模型拟合结果显示当临床分期未引入模型时,筛检对于肝癌有显著的“保护”作用:危险率为0.6617,95%CI为0.5234~0.8365;而模型经调整后,危险率即接近“1”,95%CI为0.74~1.26。 相似文献
15.
16.
Ralls PW; Johnson MB; Kanel G; Dobalian DM; Colletti PM; Boswell WD Jr; Radin DR; Halls JM 《Radiology》1986,161(2):451-454
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease. 相似文献
17.
18.
Hepatic processing of transforming growth factor beta in the rat. Uptake, metabolism, and biliary excretion. 总被引:21,自引:7,他引:14
下载免费PDF全文
![点击此处可从《The Journal of clinical investigation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
R J Coffey Jr L J Kost R M Lyons H L Moses N F LaRusso 《The Journal of clinical investigation》1987,80(3):750-757
Transforming growth factor beta (TGF beta), a recently discovered polypeptide, modulates growth of normal and neoplastic cells. Since little is known concerning in vivo disposition of TGF beta, we performed studies to examine the hepatic processing of biologically active 125I-TGF beta in the rat. After intravenous injection, 125I-TGF beta disappeared from the plasma with an initial t1/2 of 2.2 min; partial hepatectomy delayed the plasma disappearance of 125I-TGF beta by 80%. 60 min after intrafemoral injection, 63% of the recovered label was present in liver and/or bile; by 90 min, most of the label removed by the liver (83%) had been slowly excreted into bile. Nearly all the label in bile (96%) was soluble in trichloracetic acid and not immunoprecipitable by specific antiserum. Colchicine and vinblastine inhibited cumulative biliary excretion of label by 28 and 37%, respectively; chloroquine and leupeptin each increased the amount of label in bile that was precipitable by trichloracetic acid and that coeluted with authentic 125I-TGF beta on molecular sieve chromatography. There was efficient first-pass hepatic extraction of 125I-TGF beta (36%) in the isolated perfused rat liver, which was inhibited by unlabeled TGF beta (but not by epidermal growth factor, EGF) and by lectins in a dose-dependent manner; prolonged fasting also decreased clearance (26%). After fractionation of liver by differential or isopycnic centrifugation, radiolabel codistributed with marker enzymes for lysosomes. The results indicate rapid, extensive, inhibitable, and organ-selective extraction of TGF beta by the liver. After extraction, TGF beta undergoes efficient transhepatic transport, extensive intracellular metabolism, and slow but complete biliary excretion of its metabolites. Liver fractionation studies and pharmacologic manipulations suggest that these processes are associated with organelles that include microtubules and lysosomes. The data suggest that the liver is a major target tissue or site of metabolism for biologically active TGF beta. 相似文献
19.
G. P. Sadler S. McGee N. S. Dallimore I. J. Monypenny A. G. Douglas-Jones Mr K. Lyons K. Horgan 《The British journal of surgery》1994,81(9):1315-1317
Fine-needle aspiration cytology (FNAC) plays a key role in the preoperative diagnosis of carcinoma of the breast but is less reliable in the diagnosis of infiltrating lobular carcinoma. The method of diagnosis was reviewed in 56 patients with lobular carcinoma who had attended screening and symptomatic clinics. In 29 patients FNAC results demonstrated malignant cells; 15 of these had palpable disease and the mean tumour size was 21 mm. In 27 patients FNAC failed to demonstrate malignant cells; 13 lesions were palpable and the mean tumour size was 23 mm. Ten patients were diagnosed by needle-core biopsy when FNAC was not diagnostic. FNAC may fail to diagnose even large lobular carcinoma and needle-core biopsy is strongly recommended in this situation. 相似文献
20.