全文获取类型
收费全文 | 54489篇 |
免费 | 4252篇 |
国内免费 | 119篇 |
学科分类
医药卫生 | 58860篇 |
出版年
2023年 | 506篇 |
2022年 | 748篇 |
2021年 | 1600篇 |
2020年 | 965篇 |
2019年 | 1507篇 |
2018年 | 1762篇 |
2017年 | 1290篇 |
2016年 | 1362篇 |
2015年 | 1447篇 |
2014年 | 2028篇 |
2013年 | 2966篇 |
2012年 | 4195篇 |
2011年 | 4301篇 |
2010年 | 2278篇 |
2009年 | 1994篇 |
2008年 | 3603篇 |
2007年 | 3562篇 |
2006年 | 3322篇 |
2005年 | 3230篇 |
2004年 | 2927篇 |
2003年 | 2608篇 |
2002年 | 2488篇 |
2001年 | 461篇 |
2000年 | 358篇 |
1999年 | 432篇 |
1998年 | 519篇 |
1997年 | 395篇 |
1996年 | 343篇 |
1995年 | 356篇 |
1994年 | 302篇 |
1993年 | 267篇 |
1992年 | 256篇 |
1991年 | 261篇 |
1990年 | 229篇 |
1989年 | 227篇 |
1988年 | 223篇 |
1987年 | 201篇 |
1986年 | 215篇 |
1985年 | 237篇 |
1984年 | 221篇 |
1983年 | 183篇 |
1982年 | 190篇 |
1981年 | 208篇 |
1980年 | 166篇 |
1979年 | 161篇 |
1978年 | 129篇 |
1977年 | 107篇 |
1974年 | 129篇 |
1973年 | 99篇 |
1972年 | 121篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Philip Harber Laura Pea Paul Hsu Elizabeth Billet Deborah Greer Katty Kim 《American journal of industrial medicine》1994,25(4):519-526
Back pain among nurses is a common problem. Prior studies of this problem have been based on cross-sectional or retrospective data. This 18-month prospective study involving nurses newly graduated from nursing school investigated personal, worksite, and training factors associated with future risk of back pain. Each nurse underwent a preliminary interview and periodic follow-ups to identify those with back injuries. Contingency tables and logistic regression analyses demonstrated that prior significant back pain episodes (evidenced by previous job changes because of back pain, frequent medication use, etc.) were associated with increased future risk. Training at nursing school or on the job did not have a protective effect. This pilot study therefore suggests factors useful in placement and counseling of new nurses and indicates the need for further implementation of mechanical lift assist device use. © 1994 Wiley-Liss, Inc. 相似文献
82.
Upregulation of interleukin-1 receptors in mouse AtT-20 pituitary tumor cells following treatment with corticotropin-releasing factor. 总被引:1,自引:0,他引:1
Treatment of AtT-20 cell cultures with increasing concentrations of rat/human corticotropin-releasing factor (r/hCRF) for 24 h resulted in a dose-dependent 2-3 fold increase in specific 125I-labelled recombinant human IL-1 alpha (125I-IL-1 alpha) binding that was paralleled by a 70-80% decrease in 125I-Tyro-ovine CRF binding. Saturation analysis of 125I-IL-1 alpha binding in control and CRF-treated cultures indicated that CRF produced an increase in the density (Bmax) of IL-1 receptors without altering their affinity (KD). The CRF-induced upregulation of IL-1 receptors appears to be mediated through specific membrane receptors for CRF since the CRF receptor antagonist, alpha-helical oCRF (9-41), blocked the CRF-induced upregulation of IL-1 receptors without producing any effect on 125I-IL-1 alpha binding by itself. In summary, these data demonstrate complex interactions between CRF and IL-1 at the pituitary level and identify potential novel mechanisms for cytokines to alter neuroendocrine function. 相似文献
83.
OBJECTIVE: To describe the rationale, methodology, and general sample characteristics of the Canadian Psychiatric Association (CPA) practice profile survey, a national survey of psychiatrists and psychiatric practice. METHOD: Mail-in interviews were sent to all Canadian psychiatrists listed in their provincial registers and to all active CPA members (total = 3628). Respondents provided general information about their professional activities for one 24-hour day and detailed information for 1 randomly selected hour. Patient information--including sociodemographics, diagnostic profiles, functioning levels, risk of harm to self or others, and disposition--was elicited for 1 patient seen during the random hour as well as for the most seriously ill patient receiving clinical services that day. RESULTS: There was a 45.5% response rate. Questionnaires completed by nonpsychiatrists or with a large percentage of missing or incorrect data were eliminated (107 surveys), resulting in a final sample size of 1570. CPA members and those from Western Canada responded at a higher rate to the survey. The results suggest some cause for concern about future manpower shortages. Most psychiatrists practise eclectically, seeing patients across the life-span, and working in both community and institutional settings. The old and the young appear to be underserviced, compared with adults. CONCLUSIONS: This study represents an important step forward in evaluating the profile and activities of the profession. 相似文献
84.
85.
86.
N S Fuleihan M A Natout R C Webster N A Hariri M A Samara R C Smith 《Otolaryngology--head and neck surgery》1987,97(1):18-23
Amputations of the nose and of the auricle present difficult management problems. Application of simple reattachment techniques, followed by aggressive medical therapy which consists of cooling, anticoagulation, antibiotic coverage, and multiple stab incisions in the amputated tissues, have resulted in the successful replantation of major portions of an amputated nose and an amputated auricle with satisfactory cosmetic results. 相似文献
87.
Elizabeth Roberts Steven D Void Robert H Rosa David C Dries 《Ophthalmic surgery, lasers & imaging》2007,38(4):326-327
The presence of collateral vessels in a young child with glaucoma is rare. The authors describe a case of collateral vessel regression with intraocular pressure reduction in a child with primary congenital glaucoma. Six months following 180 degrees goniotomies in each eye, the intraocular pressure was reduced, dilation of the retinal arteries and veins resolved, and collateral vessels in both eyes regressed. Intraocular pressure reduction may lead to the regression of collateral vessels in children with primary congenital glaucoma. 相似文献
88.
Joseph C. Alper M.D. Elizabeth A. Welch M.D. Patricia Maguire R.N. 《Age (Dordrecht, Netherlands)》1986,9(4):105-109
During a five year period, approximately 150 elderly patients were treated with a water vapor and oxygen permeable membrane
(VPM) in an open fashion.
The following is important when treating elderly patients with VPM: xerosis or irritant dermatitis must be thoroughly treated
before use of VPM as it will not adhere to abnormal skin; alcohol or acetone should not be used to prepare the treatment site
as they cause irritation; VPM must not be stretched prior to placement as friction blisters occur in fragile, elderly skin;
prior to removal, VPM should be soaked in soapy water or its surface rubbed lightly with alconol to break the adhesive bond
to prevent stripping off epidermis; in patients with protein-calorie malnutrition, serum albumin should be monitored as large
amounts of protein-rich fluid collect under VPM. VPM is a useful non-surgical approach to treating many ulcers in the elderly.
Certain precautions must be taken to achieve optimum success in this population. 相似文献
89.
90.
1. A heat-sink calorimeter, suitable for the measurement of energy expenditure in human subjects over periods up to 26 h, is described. 2. The performance of the calorimeter is illustrated by a study of four normal subjects at rest or performing clerical work for a period of 7.5 h. Each condition was measured in duplicate in each subject. On the resting days the subjects were recumbent, and on the working days they were seated throughout the measurement period. Heart rate was monitored by infra-red telemetry and physical activity by an ultrasound movement detector. Urinary cortisol excretion was also measured as an indicator of stress. 3. In each subject the mean heat loss on working days was higher than that on resting days: the increase ranged from 5.1% to 16.7%, with a mean value of 10.0% (P = 0.015). There was no significant difference between resting and working days in heart rate, physical activity or urinary cortisol excretion. 4. The present study confirms that tiring clerical work has very little effect on 24 h energy expenditure. 相似文献