全文获取类型
收费全文 | 1534篇 |
免费 | 438篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 33篇 |
妇产科学 | 46篇 |
基础医学 | 11篇 |
口腔科学 | 41篇 |
临床医学 | 267篇 |
内科学 | 569篇 |
皮肤病学 | 11篇 |
神经病学 | 105篇 |
特种医学 | 25篇 |
外科学 | 111篇 |
综合类 | 1篇 |
预防医学 | 441篇 |
眼科学 | 4篇 |
药学 | 27篇 |
肿瘤学 | 265篇 |
出版年
2024年 | 8篇 |
2023年 | 68篇 |
2022年 | 35篇 |
2021年 | 68篇 |
2020年 | 102篇 |
2019年 | 52篇 |
2018年 | 80篇 |
2017年 | 82篇 |
2016年 | 110篇 |
2015年 | 107篇 |
2014年 | 149篇 |
2013年 | 206篇 |
2012年 | 57篇 |
2011年 | 42篇 |
2010年 | 108篇 |
2009年 | 166篇 |
2008年 | 57篇 |
2007年 | 32篇 |
2006年 | 60篇 |
2005年 | 19篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 16篇 |
2001年 | 34篇 |
2000年 | 26篇 |
1999年 | 28篇 |
1998年 | 42篇 |
1997年 | 29篇 |
1996年 | 25篇 |
1995年 | 18篇 |
1994年 | 20篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 15篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 9篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1964年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有1976条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
Diabetic neuropathic foot ulcers and amputation 总被引:2,自引:0,他引:2
David J. Margolis MD PhD ; Lynne Allen-Taylor PhD ; Ole Hoffstad MA ; Jesse A. Berlin ScD 《Wound repair and regeneration》2005,13(3):230-236
A neuropathic foot ulcer is a severe complication of diabetes that can result in a more severe complication, a lower extremity amputation. We conducted a cohort study of 24,616 individuals with a diabetic neuropathic foot ulcer treated within a multicenter wound care network. A total of 1653 (6.7%) individuals had an amputation and 46.3% of these amputations were of a toe or ray (minor amputation). In the more than 10-year follow-up period that we studied, the percentage of those who had an amputation varied between 5.6% and 8.4%. Of those who had an amputation, the percentage that had a minor amputation increased over time from 4.0% in the earliest years to more than 60% in the later years of observation. The single most important determinant of amputation was the observation of fascia, tendon, and bone at the initial assessment. In conclusion, about 7% of those with a diabetic neuropathic foot ulcer will have an amputation and in the past 10 years there has been a remarkable increase in the number of minor as compared to major amputations. 相似文献
8.
9.
Dr James Charles Robin Turner MA PhD ScD 《Journal of clinical monitoring and computing》1991,7(3):237-240
Anesthetic gases from several patients can be monitored simultaneously with a centrally located mass spectrometer. Such monitoring requires catheters from patient to spectrometer that are several meters long. Scamman (J Clin Monit 1988;4:227–229) found that when the respiratory frequency is high, as with infants, the CO2 signal from the patient is unacceptably distorted during passage down the catheter. This is due to Taylor dispersion of the input signal. An outline of the theory of Taylor dispersion is given. The equations describe the interaction between the velocity distribution (which, in laminar flow, is parabolic) and the radial diffusion of CO2. This interaction keeps a tracer signal together in a pulse, as it moves down the tube with themean velocity, spreading somewhat as it proceeds. How much does an initially sharp signal become blurred? The spread of such a signal when it reaches the detector, measured in time, can be expressed in various ways. Measurement is complicated, however, by the fact that the gas pressure may fall by as much as a factor of 10 along the line. The resultant expansion and acceleration of the gas cannot be ignored. A full treatment of this complication is given elsewhere, but the following simple equation is described: {ie237-1} Typically, the spread time is up to a quarter of a second for catheters of 50 m, such as used by Scamman. This is comparable with the period of CO2 rise and fall for infants and explains the serious distortion in wave form that Scamman found. Some distortion can be eliminated by reducing R to 0.1 or less, but the extent of this improvement is small. Ideally, for fast-breathing patients, the catheter length should be reduced to 20 m or less, if possible. 相似文献
10.
CANDYCE M. ROBERTS MS KATHRYN SUCHER ScD RD DONALD G. PERRIN PhD STEPHEN RODRIGUEZ PhD 《Journal of the American Dietetic Association》1995,95(8)
Concept mapping is an instructional strategy that requires learners to identify, graphically display, and link key concepts in instructional reading material. Although proven effective in numerous disciplines as a means to promote critical thinking and self-directed learning, concept mapping has not been tested in diet therapy. The objective of this study was to implement concept mapping as a small-group, cooperative learning strategy in an upper-division diet therapy course and to evaluate student attitudes about the effect of concept mapping on knowledge, self-directed learning, problem-solving, and collaborative skills. Students in the first semester (n=27) initially learned course material by lecture (4 weeks) followed by an integrated mapping/lecture format (12 weeks); the second semester (n=25) used an integrated mapping lecture format for the full 16 weeks. At the end of both semesters, students completed a 10-item original survey questionnaire. Responses for first (n=25) and second (n=21) semesters were analyzed independently. Results indicated that a majority of students thought participation in concept mapping enhanced knowledge of diet therapy principles (n=19 of 25; 18 of 21), self-directed learning (n=14 of 25; 18 of 21), critical thinking (n=21 of 25; 14 of 21), problem-solving (n=22 of 25; 16 of 21), and collaboration (n=24 of 25; 20 of 21) skills. When noncooperation of teammates was a factor, concept mapping was viewed as more frustrating and time consuming than lecture. This study demonstrated concept mapping as an effective learning strategy for diet therapy; it improves students’ ability to engage in self-directed learning, critical thinking, collaboration, and creative problem solving. Results suggest that concept mapping is most effective when accompanied with comprehensive training, coordinated lectures, instructor guidance, and long-term practice. J Am Diet Assoc. 1995; 95:908–911. 相似文献