全文获取类型
收费全文 | 67690篇 |
免费 | 4526篇 |
国内免费 | 276篇 |
专业分类
耳鼻咽喉 | 939篇 |
儿科学 | 1675篇 |
妇产科学 | 1349篇 |
基础医学 | 8398篇 |
口腔科学 | 1428篇 |
临床医学 | 7202篇 |
内科学 | 13825篇 |
皮肤病学 | 1158篇 |
神经病学 | 6764篇 |
特种医学 | 2175篇 |
外科学 | 10880篇 |
综合类 | 865篇 |
一般理论 | 81篇 |
预防医学 | 5179篇 |
眼科学 | 1419篇 |
药学 | 4092篇 |
2篇 | |
中国医学 | 63篇 |
肿瘤学 | 4998篇 |
出版年
2023年 | 270篇 |
2022年 | 446篇 |
2021年 | 1252篇 |
2020年 | 754篇 |
2019年 | 1264篇 |
2018年 | 1530篇 |
2017年 | 1151篇 |
2016年 | 1334篇 |
2015年 | 1462篇 |
2014年 | 2109篇 |
2013年 | 2968篇 |
2012年 | 4667篇 |
2011年 | 5149篇 |
2010年 | 2756篇 |
2009年 | 2573篇 |
2008年 | 4513篇 |
2007年 | 4648篇 |
2006年 | 4597篇 |
2005年 | 4625篇 |
2004年 | 4384篇 |
2003年 | 4139篇 |
2002年 | 3866篇 |
2001年 | 697篇 |
2000年 | 652篇 |
1999年 | 759篇 |
1998年 | 815篇 |
1997年 | 665篇 |
1996年 | 609篇 |
1995年 | 614篇 |
1994年 | 519篇 |
1993年 | 438篇 |
1992年 | 481篇 |
1991年 | 391篇 |
1990年 | 404篇 |
1989年 | 345篇 |
1988年 | 380篇 |
1987年 | 319篇 |
1986年 | 304篇 |
1985年 | 299篇 |
1984年 | 332篇 |
1983年 | 316篇 |
1982年 | 383篇 |
1981年 | 345篇 |
1980年 | 289篇 |
1979年 | 213篇 |
1978年 | 217篇 |
1977年 | 176篇 |
1976年 | 136篇 |
1974年 | 135篇 |
1973年 | 111篇 |
排序方式: 共有10000条查询结果,搜索用时 734 毫秒
21.
22.
Jennifer Wang Jonathan G. Stine Scott L. Cornella Curtis K. Argo Steven M. Cohn 《临床与转化肝病杂志(英文版)》2015,3(4):254-259
Background and Aims: Gastric antral vascular ectasia (GAVE) is commonly found in patients with cirrhosis, but it is also associated with other diseases in the absence of cirrhosis. Whether GAVE confers a different severity of gastrointestinal (GI) bleeding between patients with and without cirrhosis remains unknown. We aim to examine whether there is a difference in clinically significant GI bleeding due to GAVE in patients with or without cirrhosis. Methods: This is a retrospective case-control study of patients who were diagnosed with GAVE between January 2000 and June 2014. Patients were categorized into cirrhosis and noncirrhosis groups, and those with an additional GI bleeding source were excluded. Univariate comparisons and multivariable models were constructed using logistic regression. Results: In total, 110 patients diagnosed with GAVE on esophagogastroduodenoscopy (EGD) were included in our analysis; 84 patients had cirrhosis (76.4%) and 26 (23.6%) did not. Active GI bleeding was more prevalent in patients without cirrhosis (63.4% vs. 32.1%, p=0.003) despite similar indications for EGD, and endoscopic treatment with argon plasma coagulation (APC) was required more often in this group, approaching statistical significance (27% vs. 10.7%, p=0.056). There was no difference in bleeding severity, as evidenced by similar re-bleeding rates, surgery, or death attributed to uncontrolled bleeding. The strongest independent risk factor for GI bleeding was the absence of cirrhosis (odds ratio (OR): 5.151 (95% confidence interval (CI): 1.08-24.48, p=0.039). Conclusions: Patients with GAVE in the absence of cirrhosis are at higher risk for active GI bleeding and require more frequent endoscopic treatment than similar patients with cirrhosis. It may be worthwhile to treat GAVE in this population even in the absence of active bleeding. 相似文献
23.
24.
25.
26.
Annals of Surgical Oncology - 相似文献
27.
Andriy
Derkach Steven C. Moore Simina M. Boca Joshua N. Sampson 《Statistics in medicine》2020,39(18):2423-2436
We consider the scenario where there is an exposure, multiple biologically defined sets of biomarkers, and an outcome. We propose a new two-step procedure that tests if any of the sets of biomarkers mediate the exposure/outcome relationship, while maintaining a prespecified familywise error rate. The first step of the proposed procedure is a screening step that removes all groups that are unlikely to be strongly associated with both the exposure and the outcome. The second step adapts recent advances in postselection inference to test if there are true mediators in each of the remaining candidate sets. We use simulation to show that this simple two-step procedure has higher statistical power to detect true mediating sets when compared with existing procedures. We then use our two-step procedure to identify a set of Lysine-related metabolites that potentially mediate the known relationship between increased body mass index and the increased risk of estrogen-receptor positive breast cancer in postmenopausal women. 相似文献
28.
Greaney Mary L. Cohen Steven A. Blissmer Bryan J. Earp Jacob E. Xu Furong 《Quality of life research》2019,28(12):3249-3257
Quality of Life Research - Health-related quality of life (HRQoL) is an important indicator of population health, yet no age-specific trend analyses in HRQoL have been conducted with a nationally... 相似文献
29.
30.
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