全文获取类型
收费全文 | 3022篇 |
免费 | 242篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 98篇 |
妇产科学 | 39篇 |
基础医学 | 420篇 |
口腔科学 | 53篇 |
临床医学 | 250篇 |
内科学 | 841篇 |
皮肤病学 | 45篇 |
神经病学 | 240篇 |
特种医学 | 201篇 |
外科学 | 512篇 |
综合类 | 49篇 |
一般理论 | 1篇 |
预防医学 | 203篇 |
眼科学 | 13篇 |
药学 | 140篇 |
肿瘤学 | 103篇 |
出版年
2021年 | 41篇 |
2020年 | 22篇 |
2019年 | 25篇 |
2018年 | 31篇 |
2017年 | 37篇 |
2016年 | 39篇 |
2015年 | 47篇 |
2014年 | 77篇 |
2013年 | 103篇 |
2012年 | 118篇 |
2011年 | 133篇 |
2010年 | 101篇 |
2009年 | 97篇 |
2008年 | 126篇 |
2007年 | 133篇 |
2006年 | 145篇 |
2005年 | 123篇 |
2004年 | 128篇 |
2003年 | 80篇 |
2002年 | 102篇 |
2001年 | 92篇 |
2000年 | 81篇 |
1999年 | 85篇 |
1998年 | 71篇 |
1997年 | 60篇 |
1996年 | 54篇 |
1995年 | 52篇 |
1994年 | 34篇 |
1993年 | 45篇 |
1992年 | 59篇 |
1991年 | 51篇 |
1990年 | 45篇 |
1989年 | 70篇 |
1988年 | 74篇 |
1987年 | 53篇 |
1986年 | 41篇 |
1985年 | 48篇 |
1984年 | 52篇 |
1983年 | 33篇 |
1982年 | 30篇 |
1981年 | 20篇 |
1980年 | 31篇 |
1979年 | 29篇 |
1978年 | 35篇 |
1977年 | 41篇 |
1976年 | 25篇 |
1975年 | 37篇 |
1974年 | 33篇 |
1973年 | 35篇 |
1970年 | 24篇 |
排序方式: 共有3288条查询结果,搜索用时 453 毫秒
1.
2.
Work therapy and return to work 总被引:2,自引:0,他引:2
In summary, data were selected for 1 year on patients treated in the Work Tolerance Program at the Hand Rehabilitation Center in Philadelphia. The type of information obtained has been used to obtain a profile of the patient population in the Work Tolerance Program. Statistical analysis was used, not only to formulate patient demographics, but also to evaluate the length of treatment of patients in the Work Tolerance Program. This period averaged 6 weeks. The statistical analysis also revealed there was significant interaction between the type of injury and the patient's diagnosis, and the rate of return to work. The patients with injuries to bone and nerve required longer periods of treatment until they returned to work than did patients with injuries to soft tissue or combination injuries. Our statistical analysis revealed that in 1982, 75 per cent of the patients in the Work Tolerance Program returned to work to regular or modified jobs. The length of time from injury to return to work was 63 per cent longer for patients with Workers' Compensation coverage than for patients with private insurance coverage. Because the statistical analysis that 60 per cent of the patients treated in the Work Tolerance Program were Workers' Compensation insured, and 80 per cent of the patients treated in the Work Tolerance Program were secondarily referred, it should be recognized that all patients with severe hand injuries would benefit from an immediate referral to a Hand Rehabilitation Center of excellence to facilitate their therapeutic management and expedite their recovery from time of injury to return to work. This study was restricted to the analysis of length of treatment and rate of return to work. Future studies should study the effect of early referral and the application of specific treatments. 相似文献
3.
4.
5.
6.
7.
8.
Reto Treier Andreas Steingoetter Michael Fried Werner Schwizer Peter Boesiger 《Magnetic resonance in medicine》2007,57(3):568-576
Fast T(1) mapping techniques are a valuable means of quantitatively assessing the distribution and dynamics of intravenously or orally applied paramagnetic contrast agents (CAs) by noninvasive imaging. In this study a fast T(1) mapping technique based on the variable flip angle (VFA) approach was optimized for accurate T(1) quantification in abdominal contrast-enhanced (CE) MRI. Optimization methods were developed to maximize the signal-to-noise ratio (SNR) and ensure effective RF and gradient spoiling, as well as a steady state, for a defined T(1) range of 100-800 ms and a limited acquisition time. We corrected B(1) field inhomogeneities by performing an additional measurement using an optimized fast B(1) mapping technique. High-precision in vitro and abdominal in vivo T(1) maps were successfully generated at a voxel size of 2.8 x 2.8 x 15 mm(3) and a temporal resolution of 2.3 s per T(1) map on 1.5T and 3T MRI systems. The application of the proposed fast T(1) mapping technique in abdominal CE-MRI enables noninvasive quantification of abdominal tissue perfusion and vascular permeability, and offers the possibility of quantitatively assessing dilution, distribution, and mixing processes of labeled solutions or drugs in the gastrointestinal tract. 相似文献
9.
10.
BACKGROUND: The QT interval on the ECG is prolonged by more than 50 marketed drugs, an effect that has been associated with syncope and/or sudden cardiac death due to an arrhythmia. Because changes in heart rate also change the QT interval, it has become standard practice to use a correction formula, such as the Bazett formula, to normalize the QT interval to a heart rate of 60 bpm, that is, the rate-corrected QT or QTc. Numerous other formulas have been devised to make this correction, including the Fridericia, Hodges, and Framingham formulas. OBJECTIVES: The purpose of this study was to investigate how the Bazett formula and three other formulas influence assessment of the QT-prolonging effect of the potassium channel-blocking drug ibutilide. METHODS: Using a standardized physical activity protocol, the QT interval was assessed over a broad range of heart rates before and after an infusion of ibutilide (4.75 microg/kg) that produced a stable 15- to 20-ms QT prolongation in consenting normal subjects (9 men and 9 women). The QT interval was measured digitally over a range of heart rates from 60 to 120 bpm, and then four correction formulas (Bazett, Fridericia, Framingham, or Hodges) were applied. The uncorrected change in QT interval due to ibutilide was compared with the change using each of the formulas by repeated measures analysis of variance. RESULTS: At heart rates from 60 to 120 bpm, the Bazett and Fridericia correction formulas overestimated the change in QT in both men and women (P <.001). However, the Framingham and Hodges formulas did not alter the accuracy of the assessment of QT interval change. CONCLUSION: Rate correction of QT intervals using the standard Bazett and Fridericia formulas can introduce significant errors in the assessment of drug effects on the QT interval. This has implications for the clinical assessment of drug effects and for the safety assessment of new drugs under development. 相似文献