全文获取类型
收费全文 | 27944篇 |
免费 | 2355篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 300篇 |
儿科学 | 898篇 |
妇产科学 | 642篇 |
基础医学 | 3689篇 |
口腔科学 | 655篇 |
临床医学 | 2887篇 |
内科学 | 5068篇 |
皮肤病学 | 579篇 |
神经病学 | 2747篇 |
特种医学 | 940篇 |
外科学 | 3884篇 |
综合类 | 495篇 |
一般理论 | 36篇 |
预防医学 | 2796篇 |
眼科学 | 578篇 |
药学 | 1864篇 |
中国医学 | 27篇 |
肿瘤学 | 2269篇 |
出版年
2021年 | 333篇 |
2020年 | 254篇 |
2019年 | 424篇 |
2018年 | 488篇 |
2017年 | 395篇 |
2016年 | 429篇 |
2015年 | 485篇 |
2014年 | 664篇 |
2013年 | 1284篇 |
2012年 | 1486篇 |
2011年 | 1624篇 |
2010年 | 947篇 |
2009年 | 868篇 |
2008年 | 1586篇 |
2007年 | 1639篇 |
2006年 | 1610篇 |
2005年 | 1563篇 |
2004年 | 1448篇 |
2003年 | 1375篇 |
2002年 | 1320篇 |
2001年 | 505篇 |
2000年 | 454篇 |
1999年 | 503篇 |
1998年 | 373篇 |
1997年 | 292篇 |
1996年 | 278篇 |
1995年 | 256篇 |
1994年 | 264篇 |
1993年 | 269篇 |
1992年 | 394篇 |
1991年 | 372篇 |
1990年 | 372篇 |
1989年 | 345篇 |
1988年 | 299篇 |
1987年 | 246篇 |
1986年 | 322篇 |
1985年 | 257篇 |
1984年 | 276篇 |
1983年 | 240篇 |
1982年 | 277篇 |
1981年 | 247篇 |
1980年 | 207篇 |
1979年 | 222篇 |
1978年 | 166篇 |
1977年 | 167篇 |
1976年 | 175篇 |
1975年 | 162篇 |
1974年 | 191篇 |
1973年 | 167篇 |
1972年 | 169篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
Philip Peng FRCPC Manon Choiniere PhD Dominique Dion MD MSc Howard Intrater FRCPC Sandra LeFort PhD Mary Lynch FRCPC May Ong FRCPC Saifee Rashiq MSc DA FRCPC Gregg Tkachuk PhD Yves Veillette FRCPC 《Journal canadien d'anesthésie》2007,54(12):977-984
PURPOSE: The objective of this survey was to examine the services offered by multidisciplinary pain treatment facilities (MPTFs) across Canada and to compare access to care at these MPTFs. METHODS: A MPTF was defined as a clinic that advertised specialized multidisciplinary services for the diagnosis and management of patients with chronic pain, having a minimum of three different health care disciplines (including at least one medical speciality) available and integrated within the facility. The search method included approaching all hospital and rehabilitation centre administrators in Canada, the Insurance Bureau of Canada, the Workplace Safety and Insurance Board or similar body in each province. Designated investigators were responsible for confirming and supplementing MPTFs from the preliminary list for each province. Administrative leads at each eligible MPTF were asked to complete a detailed questionnaire regarding their MPTF infrastructure, clinical, research, teaching and administrative activities. RESULTS: Completed survey forms were received from 102 MPTFs (response rate 85%) with 80% concentrated in major cities, and none in Prince Edward Island and the Territories. The MPTFs offer a wide variety of treatments including non-pharmacological modalities such as interventional, physical and psychological therapy. The median wait time for a first appointment in public MPTFs is six months, which is approximately 12 times longer than non-public MPTFs. Eighteen pain fellowship programs exist in Canadian MPTFs and 64% engage in some form of research activities CONCLUSION: Canadian MPTFs are unable to meet clinical demands of patients suffering from chronic pain, both in terms of regional accessibility and reasonable wait time for patients' first appointment. 相似文献
63.
Cora E Lewis Susan K Ewing Brent C Taylor James M Shikany Howard A Fink Kristine E Ensrud Elizabeth Barrett-Connor Steven R Cummings Eric Orwoll 《Journal of bone and mineral research》2007,22(2):211-219
We examined determinants of nonvertebral fracture in elderly men from six U.S. communities followed an average of 4.1 years. Six clinical risk factors predicted fracture risk independent of hip BMD: tricyclic antidepressant use, previous fracture, inability to complete a narrow walk trial, falls in previous year, age > or =80 years, and depressed mood. INTRODUCTION: There are few prospective studies of fracture determinants in men. We examined the associations between a comprehensive set of clinical risk factors and risk of nonspine fracture in older men and whether determinants of fracture risk were independent of total hip BMD. MATERIALS AND METHODS: A total of 5995 men > or =65 years of age were recruited from six communities in the Unites States and followed prospectively for an average of 4.1 years. Baseline assessments of demographic, lifestyle, medical history, functional status, anthropometry, and cognitive, visual, and neuromuscular function were assessed by questionnaire or examination. Triannual mailed questionnaires ascertained incident fracture; reported fractures were adjudicated by physicians using medical records and X-ray reports. Proportional hazards models were used to develop multivariable models, selecting variables and controlling for BMD. RESULTS: Of 5876 men, 4.7% (N = 275) reported an incident nonspine fracture during follow-up (11.46/1000 person-years). Tricyclic antidepressant use (hazard ratio [HR], 2.36; 95% CI, 1.25-4.46), history of fracture at or after age 50 (HR, 2.07; 95% CI, 1.62-2.65), inability to complete a narrow walk trial (HR, 1.70; 95% CI, 1.23-2.34), falls in previous year (HR, 1.59; 95% CI, 1.23-2.05), age > or =80 years (HR, 1.33; 95% CI, 1.01-1.76), depressed mood (HR, 1.72; 95% CI, 1.00-2.95), and decreased total hip BMD (HR, 1.53; 95% CI, 1.34-1.74) were independently related to increased risk. Compared with having none (48.0% of men), having three or more of the clinical risk factors (4.9% of men) increased fracture risk 5-fold, independent of BMD. Having three or more risk factors and being in the lowest tertile of BMD was associated with a 15-fold greater risk than having no risk factors and being in the highest BMD tertile. CONCLUSIONS: Several clinical risk factors were independently associated with nonspine fractures in elderly men. The combination of multiple risk factors and low BMD was a very powerful indicator of fracture risk. 相似文献
64.
65.
Howard Litwin 《European journal of ageing》2007,4(2):71-82
The aim of the inquiry was to examine the social network–mortality association within a wider multivariate context that accounts
for the effects of background framing forces and psychobiological pathways. The inquiry was based upon the Berkman et al.
(2000) conceptual model of the determinants of health. Its main purpose was to identify the salient network correlates of 7-year
all cause mortality among Jewish men and women, aged 70 and over, in Israel (n = 1,811). The investigation utilized baseline data from a national household survey of older adults from 1997 that was linked
to records from the National Death Registry, updated through 2004. At the time of the study, 38% of the sample had died. Multivariate
Cox hazard regressions identified two main network-related components as predictors of survival: contact with friends, a social
network interaction variable, and attendance at a synagogue, a social engagement variable. Friendship ties are seen to uniquely
reduce mortality risk because they are based on choice in nature, and reflect a sense of personal control. Synagogue attendance
is seen to promote survival mainly through its function as a source of communal attachment and, perhaps, as a reflection of
spirituality as well. Other possibly network-related correlates of mortality were also noted in the current analysis—the receipt
of instrumental support and the state of childlessness.
The study on which this article is based was made possible by grants from the Israel Ministry of Science and Technology to
the Israel Gerontological Data Center. 相似文献
66.
Regina P Walker Howard L Levine Martin L Hopp David Greene Kenny Pang 《Otolaryngology--head and neck surgery》2006,135(4):549-554
OBJECTIVE: To evaluate the short-term safety and efficacy of palatal implants in patients with mild and moderate obstructive sleep apnea (OSA). STUDY DESIGN AND SETTING: A prospective, non-randomized study conducted at 5 clinical sites. Three polyester implants were placed in the soft palate under local anesthesia during a single-stage office procedure. Polysomnography was conducted at baseline and 90 days post-procedure. Subjective quality of life data were collected. RESULTS: Fifty-three patients were evaluated; the apnea hypopnea index (AHI) decreased from 25.0 +/- 13.9 to 22.0 +/- 14.8 events/hour (P = 0.05). The Epworth Sleepiness Scale (ESS) decreased from 11.0 +/- 5.1 to 6.9 +/- 4.5 (P < 0.001), and the snore score decreased from 7.9 +/- 2.1 to 4.0 +/- 3.0 (P < 0.001). No serious complications occurred during the study. CONCLUSION: Palatal implants can be an effective initial low morbidity treatment option for patients diagnosed with mild to moderate OSA. 相似文献
67.
68.
69.
70.
Karen A. Baskerville Howard T. Chang Paul Herron 《The Journal of comparative neurology》1993,335(4):552-562
We investigated (1) the topography of projection neurons in the nucleus basalis of Meynert (NBM) with efferents to restricted regions of the primary somatosensory (SI), the second somatosensory (SII), and the primary motor (MI) cortices in the rat; (2) the percentage of these NBM projection neurons that were cholinergic; and (3) the collateralization, if any, of single NBM neurons to different subdivisions within SI, to homotopic areas of SI and SII, and to homotopic areas of SI and MI. Retrograde single-and double-labeling techniques were used to study NBM projections to electrophysiologically identified subdivisions of SI and to homotopic representational areas of SI and SII, and of SI and MI. Choline acetyltransferase immunocytochemistry was done to identify cholinergic NBM neurons. Of the retrogradely labeled NBM neurons that projected to selective subdivisions of SI, SII, and MI, 89%, 87%, and 88%, respectively, were cholinergic. We found a rostral-to-caudal progression of retrogradely labeled NBM neurons following a medial-to-lateral sequence of injections into subdivisions of SI. Overlapping groups of single-labeled NBM neurons were observed after injections of different tracers into adjacent subdivisions within SI or homotopic areas of SI and SII, and of SI and MI. We conclude that NBM innervation to SI, SII, and MI is mostly cholinergic in the rat, that each cortical area receives cholinergic afferents from neurons widely distributed within the NBM, and that each NBM neuron projects to a restricted cortical area without significant collateralization to adjacent subdivisions within SI or to homotopic areas of SI and SII, or SI and MI. © 1993 Wiley-Liss, Inc. 相似文献