全文获取类型
收费全文 | 852篇 |
免费 | 65篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 38篇 |
基础医学 | 87篇 |
口腔科学 | 15篇 |
临床医学 | 74篇 |
内科学 | 139篇 |
皮肤病学 | 73篇 |
神经病学 | 23篇 |
特种医学 | 211篇 |
外科学 | 78篇 |
综合类 | 19篇 |
一般理论 | 1篇 |
预防医学 | 60篇 |
眼科学 | 9篇 |
药学 | 64篇 |
肿瘤学 | 46篇 |
出版年
2021年 | 8篇 |
2020年 | 4篇 |
2018年 | 11篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 16篇 |
2013年 | 19篇 |
2012年 | 15篇 |
2011年 | 19篇 |
2010年 | 15篇 |
2009年 | 16篇 |
2008年 | 26篇 |
2007年 | 44篇 |
2006年 | 29篇 |
2005年 | 30篇 |
2004年 | 18篇 |
2003年 | 18篇 |
2002年 | 12篇 |
2001年 | 22篇 |
2000年 | 16篇 |
1999年 | 18篇 |
1998年 | 43篇 |
1997年 | 57篇 |
1996年 | 38篇 |
1995年 | 32篇 |
1994年 | 25篇 |
1993年 | 18篇 |
1992年 | 16篇 |
1991年 | 19篇 |
1990年 | 22篇 |
1989年 | 31篇 |
1988年 | 34篇 |
1987年 | 24篇 |
1986年 | 26篇 |
1985年 | 28篇 |
1984年 | 18篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 8篇 |
1980年 | 16篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 16篇 |
1975年 | 5篇 |
1972年 | 5篇 |
1970年 | 4篇 |
1969年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有939条查询结果,搜索用时 15 毫秒
41.
42.
Patient dosage in computed tomography 总被引:1,自引:0,他引:1
43.
44.
Background
The purpose of this study was to determine the test-retest reliability of temporal and spatial gait measurements over a one-week period as measured using an instrumented walkway system (GAITRite®).Methods
Subjects were tested on two occasions one week apart. Measurements were made at preferred and fast walking speeds using the GAITRite® system. Measurements tested included walking speed, step length, stride length, base of support, step time, stride time, swing time, stance time, single and double support times, and toe in-toe out angle.Results
Twenty-one healthy subjects participated in this study. The group consisted of 12 men and 9 women, with an average age of 34 years (range: 19 – 59 years). At preferred walking speed, all gait measurements had ICC's of 0.92 and higher, except base of support which had an ICC of 0.80. At fast walking speed all gait measurements had ICC's above 0.89 except base of support (ICC = 0.79),Conclusions
Spatial-temporal gait measurements demonstrate good to excellent test-retest reliability over a one-week time span.45.
46.
OBJECTIVES:
To determine patterns of follow-up and prenatal education by family physicians and to assess whether practice patterns comply with the 1996 Canadian Paediatric Society/Society of Obstetricians and Gynecologists of Canada (CPS/SOGC) guidelines for early neonatal discharge.DESIGN:
Mail survey.SETTING:
A community of 300,000 people who were served exclusively for obstetrical care by a tertiary care hospital that performs 5000 deliveries per year and provides an early discharge program (EDP).PARTICIPANTS:
Family physicians who provide prenatal and/or newborn care.MAIN OUTCOME MEASURES:
The timing of neonatal follow-up and parental teaching by family physicians.RESULTS:
Thirty-two per cent of the respondents scheduled their first postnatal visits two or more weeks after early discharge. There was no significant difference (P=0.7) in scheduling of follow-up for babies who were part of an EDP compared with those who were not. Fewer than 20% of physician respondents provided antenatal education in preparation for early discharge.CONCLUSIONS:
The 1996 CPS/SOGC guidelines for physician follow-up after early neonatal discharge and for anticipatory parental education are not being followed consistently; however, these guidelines were disseminated without reinforcement. Until further study supports a change in practice guidelines, appropriate implementation strategies must be employed to ensure compliance. 相似文献47.
Targeted Mutation of the Gene for Cellular Glutathione Peroxidase (Gpx1) Increases Noise-Induced Hearing Loss in Mice 总被引:8,自引:2,他引:6
Kevin K. Ohlemiller Sandra L. McFadden Da-Lian Ding Patricia M. Lear Ye-Shih Ho 《Journal of the Association for Research in Otolaryngology》2000,1(3):243-254
Reactive oxygen species (ROS) and oxidative stress have been implicated in cochlear injury following loud noise and ototoxins.
Genetic mutations that impair antioxidant defenses would be expected to increase cochlear injury following acute insults and
to contribute to cumulative injury that presents as age-related hearing loss. We examined whether genetically based deficiency
of cellular glutathione peroxidase, a major antioxidant enzyme, increases noise-induced hearing loss in mice. Two-month-old
"knockout" mice with a targeted inactivating mutation of the gene coding for glutathione peroxidase (Gpx1) and wild type controls were exposed to broadband noise for one hour at 110 dB SPL. Auditory brainstem response (ABR) thresholds
at test frequencies ranging from 5 to 40 kHz were obtained two and four weeks after exposure to determine the stable permanent
component of the hearing loss. Depending on test frequency, Gpx1 knockout mice showed up to 16 dB higher ABR thresholds prior to noise exposure, and up to 15 dB greater noise-induced hearing
loss, compared with controls. Within the cochlear base, there was also a significant contribution of the knockout to inner
and outer hair cell loss, as well as nerve fiber loss. Our results support a link between genetic impairment of antioxidant
defenses, vulnerability of the cochlea injury, and cochlear degeneration. Such impairment produces characteristics expected
of some mutations associated with age-related hearing loss and offers one possible mechanism for their action. 相似文献
48.
Three sibs all presented in the early neonatal period with a salt-losing syndrome. The salt-losing form of congenital adrenal hyperplasia was diagnosed and appropriate treatment with glucocorticosteroids, mineralocorticosteroids, and additional dietary salt started. Although early life was maintained with difficulty, with age all 3 children required decreasing amounts of replacement steroids to maintain normal plasma electrolyte balance. They were reinvestigated at the ages of 15 years and 8 years (twins), when cortisol synthesis and metabolism proved normal, but aldosterone synthesis was blocked by deficiency of 18-dehydrogenase. Rational treatment of these cases of a salt-losing syndrome in which aldosterone synthesis alone is blocked due to lack of the enzyme 18-dehydrogenase requires the administration of a mineralocorticosteroid drug only. Since deoxycorticosterone (acetate or pivalate) requires intramuscular administration, as life-long therapy oral fludrocortisone is preferable. Although fludrocortisone has glucocorticoid activity, the "hydrocortisone equivalent" effect of the small dosage used was unlikely to inhibit either pituitary corticotrophin or growth hormone production. 相似文献
49.
Pauly RP Lear SA Hastings FC Birmingham CL 《The International journal of eating disorders》2000,28(2):231-234
OBJECTIVE: To examine changes in plasma leptin levels and resting energy expenditure (REE) during short-term refeeding of patients with anorexia nervosa (AN). METHOD: This was a longitudinal study of 21 women meeting the DSM-IV criteria for AN who were admitted to the hospital for renutrition. Height, weight, percent body fat (assessed by skin fold thickness), REE (measured by indirect calorimetry), and circulating plasma leptin concentration were assessed at the time of admission and 7 days later. RESULTS: Over the course of 1 week of refeeding, body mass index (BMI) increased 0.75 +/- 0.15 kg/m(2) (p <.0001), body fat increased 0.9 +/- 0.2% (p <.0001), and REE increased 107 +/- 33 kcal/24 hr (p =.0037). The change in mean leptin levels was not statistically significant (0.45 +/- 0.44 ng/ml; p =.32). DISCUSSION: Leptin is unlikely responsible for the increase in REE observed with short-term refeeding. 相似文献
50.
目的提高医院临时处方溃结Ⅰ号保留灌肠剂的稳定性,并对其中的主要成分含量进行控制。方法制备时加入助悬剂,用沉降容积比和再分散性选择适宜的助悬剂及其最佳助悬浓度,并用紫外分光光度法对主要成分柳氮磺吡啶的含量进行测定。结果在制剂中加入卡波母作为助悬剂0.15%就可以达到良好的助悬效果,而且制备的制剂再分散性好。结论加入卡波母作为助悬剂制备的制剂稳定,再分散性好,便于使用和保存。 相似文献