全文获取类型
| 收费全文 | 173187篇 |
| 免费 | 14101篇 |
| 国内免费 | 866篇 |
专业分类
| 耳鼻咽喉 | 1769篇 |
| 儿科学 | 4401篇 |
| 妇产科学 | 3171篇 |
| 基础医学 | 22584篇 |
| 口腔科学 | 3700篇 |
| 临床医学 | 17371篇 |
| 内科学 | 37778篇 |
| 皮肤病学 | 3643篇 |
| 神经病学 | 16235篇 |
| 特种医学 | 6929篇 |
| 外国民族医学 | 6篇 |
| 外科学 | 27478篇 |
| 综合类 | 2018篇 |
| 现状与发展 | 3篇 |
| 一般理论 | 142篇 |
| 预防医学 | 12796篇 |
| 眼科学 | 4139篇 |
| 药学 | 11622篇 |
| 2篇 | |
| 中国医学 | 328篇 |
| 肿瘤学 | 12039篇 |
出版年
| 2023年 | 1604篇 |
| 2022年 | 1730篇 |
| 2021年 | 3878篇 |
| 2020年 | 2745篇 |
| 2019年 | 3484篇 |
| 2018年 | 4648篇 |
| 2017年 | 3727篇 |
| 2016年 | 4090篇 |
| 2015年 | 4538篇 |
| 2014年 | 6349篇 |
| 2013年 | 8074篇 |
| 2012年 | 11824篇 |
| 2011年 | 12411篇 |
| 2010年 | 7388篇 |
| 2009年 | 7118篇 |
| 2008年 | 11256篇 |
| 2007年 | 11804篇 |
| 2006年 | 11187篇 |
| 2005年 | 11330篇 |
| 2004年 | 10634篇 |
| 2003年 | 10021篇 |
| 2002年 | 9401篇 |
| 2001年 | 2060篇 |
| 2000年 | 1602篇 |
| 1999年 | 2019篇 |
| 1998年 | 2298篇 |
| 1997年 | 1824篇 |
| 1996年 | 1560篇 |
| 1995年 | 1416篇 |
| 1994年 | 1243篇 |
| 1993年 | 1203篇 |
| 1992年 | 958篇 |
| 1991年 | 915篇 |
| 1990年 | 743篇 |
| 1989年 | 719篇 |
| 1988年 | 667篇 |
| 1987年 | 657篇 |
| 1986年 | 580篇 |
| 1985年 | 592篇 |
| 1984年 | 687篇 |
| 1983年 | 603篇 |
| 1982年 | 790篇 |
| 1981年 | 721篇 |
| 1980年 | 623篇 |
| 1979年 | 382篇 |
| 1978年 | 383篇 |
| 1977年 | 415篇 |
| 1976年 | 350篇 |
| 1975年 | 302篇 |
| 1974年 | 255篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
41.
Accuracy and Precision of Acetabular Component Placement With Imageless Navigation in Obese Patients
Leonard T. Buller Alexander S. McLawhorn Jose A. Romero Peter K. Sculco David J. Mayman 《The Journal of arthroplasty》2019,34(4):693-699
Background
Obesity is a risk factor for acetabular component malposition when total hip arthroplasty is performed with manual techniques. The utility of imageless navigation in obese patients remains unknown. This study compared the accuracy and precision of imageless navigation for component orientation between obese and nonobese patients.Methods
A total of 459 total hip arthroplasties performed for osteoarthritis using imageless navigation were reviewed from a single surgeon’s institutional review board–approved database. Einzel-Bild-Roentgen Analyse determined component orientation on 6-week postoperative anteroposterior radiographs. Mean orientation error (accuracy) and precision were compared between obese (body mass index ≥ 30 kg/m2) and nonobese patients. Regression analysis evaluated the influence of obesity on component position.Results
The difference in mean inclination and anteversion between obese and nonobese groups was 1.1° (43.0° ± 3.5°; range, 35.8°-57.8° vs 41.9° ± 4.4°; range, 33.0°-57.1° and 24.9° ± 6.3°; range, 14.2°-44.3° vs 23.8° ± 6.6°; range, 7.0°-38.6°, respectively). Inclination precision was better for nonobese patients. No difference in inclination accuracy or anteversion accuracy or precision was detected between groups. And 83% of components were placed within the target range. There was no relationship between obesity (dichotomized) and component placement outside the target ranges for inclination, anteversion, or both. As a continuous variable, increased body mass index correlated with higher odds of inclination outside the target zone (odds ratio, 1.06; P = .001).Conclusion
Using imageless navigation, inclination orientation was less precise for obese patients, but the observed difference is likely not clinically relevant. Accurate superficial registration of landmarks in obese patients is achievable, and the use of imageless navigation similarly improves acetabular component positioning in obese and nonobese patients.Level of Evidence
Therapeutic Level IV. 相似文献42.
43.
Bielik Peter Bonczek Ondřej Krejčí Přemysl Zeman Tomáš Izakovičová-Hollá Lydie Šoukalová Jana Vaněk Jiří Vojtěšek Bořivoj Lochman Jan Balcar Vladimir J. Šerý Omar 《Clinical oral investigations》2022,26(12):7045-7055
Clinical Oral Investigations - The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of... 相似文献
44.
45.
Julia Thornton Snider Jesse Sussell Mahlet Gizaw Tebeka Alicia Gonzalez Joshua T. Cohen Peter Neumann 《Value in health》2019,22(3):332-339
Background
Payers frequently rely on budget impact model (BIM) results to help determine drug coverage policy and its effect on their bottom line. It is unclear whether BIMs typically overestimate or underestimate real-world budget impact.Objective
We examined how different modeling assumptions influenced the results of 6 BIMs from the Institute for Clinical and Economic Review (ICER).Study Design
Retrospective analysis of pharmaceutical sales data.Methods
From ICER reports issued before 2016, we collected estimates of 3 BIM outputs: aggregate therapy cost (ie, cost to treat the patient population with a particular therapy), therapy uptake, and price. We compared these against real-world estimates that we generated using drug sales data. We considered 2 classes of BIM estimates: those forecasting future uptake of new agents, which assumed “unmanaged uptake,” and those describing the contemporaneous market state (ie, estimates of current, managed uptake and budget impact for compounds already on the market).Results
Differences between ICER's estimates and our own were largest for forecasted studies. Here, ICER's uptake estimates exceeded real-world estimates by factors ranging from 7.4 (sacubitril/valsartan) to 54 (hepatitis C treatments). The “unmanaged uptake” assumption (removed from ICER's approach in 2017) yields large deviations between BIM estimates and real-world consumption. Nevertheless, in some cases, ICER's BIMs that relied on current market estimates also deviated substantially from real-world sales data.Conclusions
This study highlights challenges with forecasting budget impact. In particular, assumptions about uptake and data source selection can greatly influence the accuracy of results. 相似文献46.
47.
Quang Ngoc Nguyen Linh Dieu Vuong Van-Long Truong To Van Ta Nam Trung Nguyen Hung Phi Nguyen Ha Hoang Chu 《Pathology, research and practice》2019,215(5):885-892
Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas. 相似文献
48.
49.
50.