| 收费全文 | 1966994篇 |
| 免费 | 139006篇 |
| 国内免费 | 3296篇 |
| 耳鼻咽喉 | 27412篇 |
| 儿科学 | 62695篇 |
| 妇产科学 | 51759篇 |
| 基础医学 | 280503篇 |
| 口腔科学 | 54553篇 |
| 临床医学 | 187965篇 |
| 内科学 | 382833篇 |
| 皮肤病学 | 43808篇 |
| 神经病学 | 156733篇 |
| 特种医学 | 72677篇 |
| 外国民族医学 | 405篇 |
| 外科学 | 295320篇 |
| 综合类 | 38132篇 |
| 现状与发展 | 41篇 |
| 一般理论 | 684篇 |
| 预防医学 | 155426篇 |
| 眼科学 | 45100篇 |
| 药学 | 140847篇 |
| 48篇 | |
| 中国医学 | 3677篇 |
| 肿瘤学 | 108678篇 |
| 2021年 | 17298篇 |
| 2019年 | 17466篇 |
| 2018年 | 26397篇 |
| 2017年 | 21127篇 |
| 2016年 | 23479篇 |
| 2015年 | 25642篇 |
| 2014年 | 35797篇 |
| 2013年 | 51087篇 |
| 2012年 | 62138篇 |
| 2011年 | 65765篇 |
| 2010年 | 42247篇 |
| 2009年 | 41594篇 |
| 2008年 | 61965篇 |
| 2007年 | 65093篇 |
| 2006年 | 66523篇 |
| 2005年 | 63681篇 |
| 2004年 | 60573篇 |
| 2003年 | 57862篇 |
| 2002年 | 56213篇 |
| 2001年 | 88530篇 |
| 2000年 | 90106篇 |
| 1999年 | 76024篇 |
| 1998年 | 22937篇 |
| 1997年 | 20229篇 |
| 1996年 | 20633篇 |
| 1995年 | 19351篇 |
| 1994年 | 17480篇 |
| 1993年 | 16399篇 |
| 1992年 | 58163篇 |
| 1991年 | 56600篇 |
| 1990年 | 55180篇 |
| 1989年 | 52960篇 |
| 1988年 | 48709篇 |
| 1987年 | 47551篇 |
| 1986年 | 44415篇 |
| 1985年 | 42463篇 |
| 1984年 | 31463篇 |
| 1983年 | 26995篇 |
| 1982年 | 16197篇 |
| 1979年 | 28664篇 |
| 1978年 | 20528篇 |
| 1977年 | 17039篇 |
| 1976年 | 16351篇 |
| 1975年 | 17478篇 |
| 1974年 | 20927篇 |
| 1973年 | 19820篇 |
| 1972年 | 18653篇 |
| 1971年 | 17665篇 |
| 1970年 | 16316篇 |
| 1969年 | 15564篇 |
Patients and methods — All cemented stems with > 100 implantations were identified in the National Joint Registry of England and Wales from April 1, 2003 to September 31, 2013 and categorised as taper-slip or composite beam. Survival analyses using Kaplan–Meier and Cox regression were performed.
Results — We identified 292,987 cemented arthroplasties, of which 16% (47,586) were composite beam stems, with taper-slip stems making up the remainder (n = 245,401). There was a statistically significant increased chance of revision in the composite beam group compared with the taper-slip group (1.7% vs 1.3%, p < 0.001) but statistically no significant differences of survival estimates (p = 0.06). When the 2 groups were segregated to delineate the most implanted model in each category, the differences became more profound with the most implanted taper-slip stem (Exeter V40) showing statistically and clinically significant superior 8-year survival: 97.9% compared with 97.6% for all other taper-slip; 97.5% for the most implanted composite beam (Charnley cemented stem); and 97.7% for all other composite beam.
Interpretation — There was an increased incidence of revision for composite beam stems. The most implanted taper-slip stem demonstrated significant survival advantage vs. all other stems. 相似文献
Aims
To obtain an overview of the management and outcomes of children aged 18 years or younger diagnosed with differentiated thyroid carcinoma of follicular cell origin across the UK, by collecting and analysing data from the limited number of centres treating these patients. This multicentre data might provide a more realistic perspective than single-institution series.Materials and methods
Six centres submitted data extracted from historical records on patients aged 18 years or younger, diagnosed between 1964 and 2017. The univariate and multivariable Cox proportional hazard model was used to identify potential predictors of progression-free survival, using national data as a control.Results
Data on 166 patients were available for analysis. Females (74%) were predominant, and the age ranged from 3 to 19 years at diagnosis, mean 14.1 years. Nodal metastases were present in 51%; 12% had distant metastases. After surgery, 95% received radioactive iodine (39% on more than one occasion) and 4% received external beam radiotherapy. With a median follow-up duration of 5 years, 69% are alive with no evidence of disease; 20% are alive with a raised thyroglobulin level as the only evidence of residual disease; 6% have residual structural disease detectable on imaging; 2% have died, from cerebral metastases.Conclusion
Despite most patients having advanced disease at presentation, outcomes are very good. A national prospective registry should allow systematic collection of good-quality data and may facilitate research to further improve outcomes. 相似文献Introduction
Malignant pleural mesothelioma (MPM) is an uncommon cancer with a poor prognosis and heterogeneous survival. Surgery for MPM is offered in some specialist centers to highly selected patients. A previously described classification and regression tree (CART) model stratified survival in unselected MPM patients using routinely collected clinical data. This study aimed to examine the performance of this CART model on a highly selected surgical population.Methods
Data were collected from subjects undergoing cytoreductive surgery for MPM from specialist centers in Hyõgo, Japan, and Sydney, Australia, between 1991 and 2016. The CART model was applied using the combination of clinical variables to stratify subjects into risk groups (1 through 4); survival characteristics were then compared.Results
Two hundred eighty-nine cases were included (205 from Australia, 84 from Japan). Overall median survival was 34.6 (interquartile range: 17.5–56.1) months; median age was 63.0 (interquartile range: 57.0–67.8) years, and 83.0% (n = 240) were male. There were no clinically meaningful differences between the two cohorts. Survival across the four risk groups was significantly different (p < 0.0001); the model stratified survival well with a Harrell's concordance statistic of 0.62 (95% confidence interval: 0.57–0.66) at 36 months. The group with the longest survival (median, 82.5 months) had: no weight loss, hemoglobin > 153 g/L and serum albumin > 43 g/L at time of referral to the surgical center.Conclusions
Using routinely available clinical variables, the CART model was able to stratify surgical patients into risk groups with statistically different survival characteristics with fair to good performance. Presence of weight loss, anemia, and low albumin should confer caution when considering surgical therapy for MPM. 相似文献- Download : Download high-res image (134KB)
- Download : Download full-size image
- Download : Download high-res image (415KB)
- Download : Download full-size image