全文获取类型
收费全文 | 1126篇 |
免费 | 93篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 28篇 |
妇产科学 | 30篇 |
基础医学 | 193篇 |
口腔科学 | 34篇 |
临床医学 | 136篇 |
内科学 | 249篇 |
皮肤病学 | 25篇 |
神经病学 | 89篇 |
特种医学 | 16篇 |
外科学 | 91篇 |
综合类 | 39篇 |
一般理论 | 1篇 |
预防医学 | 143篇 |
眼科学 | 10篇 |
药学 | 72篇 |
中国医学 | 2篇 |
肿瘤学 | 58篇 |
出版年
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 15篇 |
2014年 | 25篇 |
2013年 | 35篇 |
2012年 | 43篇 |
2011年 | 49篇 |
2010年 | 24篇 |
2009年 | 21篇 |
2008年 | 29篇 |
2007年 | 48篇 |
2006年 | 46篇 |
2005年 | 66篇 |
2004年 | 48篇 |
2003年 | 45篇 |
2002年 | 43篇 |
2001年 | 48篇 |
2000年 | 42篇 |
1999年 | 40篇 |
1998年 | 15篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1994年 | 17篇 |
1993年 | 11篇 |
1992年 | 27篇 |
1991年 | 26篇 |
1990年 | 33篇 |
1989年 | 24篇 |
1988年 | 30篇 |
1987年 | 27篇 |
1986年 | 22篇 |
1985年 | 31篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 13篇 |
1981年 | 10篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1971年 | 9篇 |
1967年 | 6篇 |
排序方式: 共有1220条查询结果,搜索用时 31 毫秒
21.
Cummins RJ Mothersill C Seymour CB Johns H Joiner MC 《International journal of radiation biology》1999,75(2):225-232
PURPOSE: To investigate the effect of irradiating microcolonies of various sizes on their subsequent ability to form colonies. MATERIALS AND METHODS: The location of individual HPV-G cells in tissue culture flasks was recorded using computerized microscopy. This allowed the cells' positions to be continually revisited, which enabled manual sizing of individual microcolonies both at the time of irradiation (between 0-5 Gy) and following an incubation period during which the microcolonies were assessed for cologenic survival. RESULTS: The experiments indicate that when irradiated as microcolonies, cells have plating efficiencies (PE) that are lower than expected when compared with the prediction from the PE values of cells irradiated individually. CONCLUSION: These data support the conclusions of Mothersill and Seymour (1997b) which challenge the concept of independent survival of certain types of cells following irradiation. The results indicate that interactions between cells can occur even in small aggregates. 相似文献
22.
Studies of diabetic polyneuropathy using conduction velocity distribution (DCV) analysis 总被引:5,自引:0,他引:5
L J Dorfman K L Cummins G M Reaven J Ceranski M S Greenfield L Doberne 《Neurology》1983,33(6):773-779
The distributions of nerve fiber conduction velocities (DCVs) derived from the median nerves of 29 adult diabetic patients (mean age, 52.1 +/- 12.3 years) with mild or no symptoms or signs of polyneuropathy were compared with DCVs from 34 age-appropriate normal subjects. Ten patients (34%) had normal findings (type A DCVs). In the 19 patients (66%) with abnormal DCVs, defined as 10% or more of the DCV area falling outside the normal 95% confidence limits, two distinct patterns of DCV alteration were observed: type B DCVs (11 patients) showed reduced DCVmax, DCVmean, and DCVpeak, together with reduced DCVrange (narrow profile); whereas type C DCVs (8 patients) had reduced DCVmax, DCVmean, DCVpeak, and DCVmin, with normal DCVrange (broad profile). It is proposed that type C DCV represents a more advanced form of type B and that both reflect selective dysfunction of the fastest conducting (presumably largest-diameter) fibers in the nerve trunk. DCVmax was consistently greater than conventional measures of "maximal" CV in all patient subgroups. Patients with abnormal DCVs had higher incidence of mild neuropathic symptoms (15 of 19 versus 4 of 10, p less than 0.01) and greater insulin dependence (11 of 19 versus 1 of 10, p less than 0.001). Serial studies in 10 patients showed, at most, small degrees of change in conduction properties over relatively short intervals (1 to 9 months). 相似文献
23.
A randomized controlled study of luteal support therapy (using intramuscular injections of progesterone and/or human chorionic gonadotropin) was conducted in a trial designed to minimize variables that might adversely affect the change of pregnancy. After applying rigid selection criteria, 207 women were recruited into one of four groups. Mathematical modeling was applied to the results to determine if there were degrees of improvement in uterine receptivity relative to various grades of embryo quality ("E" factor). Although the trial size was insufficient to enable the detection of significant improvements in the pregnancy rates that ranged from 27.5% for non-treatment to 41.2% for those receiving combined treatment, the birth rates were significantly better with luteal support (11.8% versus 29.4%). Similarly, the overall implantation rate just failed to reach statistical significance for luteal support, but the ongoing implantations were significantly better (3.6% versus 9.0%). Data modeling indicated that luteal support, particularly with the combined regimen, could improve the ongoing implantation rate by up to 2.5-fold when the E factor was poorest. 相似文献
24.
Context Health plan utilization review rules are intended to enforce insurance contracts and can alter and constrain the services that physicians provide to their patients. Physicians can manipulate these rules, but how often they do so is unknown. Objective To determine the frequency with which physicians manipulate reimbursement rules to obtain coverage for services they perceive as necessary, and the physician attitudes and personal and practice characteristics associated with these manipulations. Design, Setting, and Participants A random national sample of 1124 practicing physicians was surveyed by mail in 1998; the response rate was 64% (n = 720). Main Outcome Measure Use of 3 different tactics "sometimes" or more often in the last year: (1) exaggerating the severity of patients' conditions; (2) changing patients' billing diagnoses; and/or (3) reporting signs or symptoms that patients did not have to help the patients secure coverage for needed care. Results Thirty-nine percent of physicians reported using at least 1 tactic "sometimes" or more often in the last year. In multivariate models comparing these physicians with physicians who "never" or "rarely" used any of these tactics, physicians using these tactics were more likely to (1) believe that "gaming the system" is necessary to provide high-quality care today (odds ratio [OR], 3.67; 95% confidence interval [CI], 2.54-5.29); (2) have received requests from patients to deceive insurers (OR, 2.44; 95% CI, 1.72-3.45); (3) feel pressed for time during patient visits (OR, 1.69; 95% CI, 1.21-2.37); and (4) have more than 25% of their patients covered by Medicaid (OR, 1.60; 95% CI, 1.08-2.38). Notably, greater worry about prosecution for fraud did not affect physicians' use of these tactics (P = .34). Of those reporting using these tactics, 54% reported doing so more often now than 5 years ago. Conclusions A sizable minority of physicians report manipulating reimbursement rules so patients can receive care that physicians perceive is necessary. Unless novel strategies are developed to address this, greater utilization restrictions in the health care system are likely to increase physicians' use of such manipulative "covert advocacy" tactics. 相似文献
25.
Suprascapular nerve entrapment 总被引:6,自引:0,他引:6
Cummins CA Messer TM Nuber GW 《The Journal of bone and joint surgery. American volume》2000,82(3):415-424
26.
Ashley Sharp Berit Muller-Pebody Andre Charlett Bharat Patel Rebecca Gorton Jonathan Lambourne Martina Cummins Adela Alcolea-Medina Mark Wilks Robin Smith Damien Mack Susan Hopkins Andrew Dodgson Phillipa Burns Nelun Perera Felicia Lim Gopal Rao Priya Khanna Elizabeth Johnson Andrew Borman Silke Schelenz Rebecca Guy Joanna Conneely Rohini J Manuel Colin S Brown 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2021,26(8)
Background Candida auris is an emerging multidrug-resistant fungal pathogen associated with bloodstream, wound and other infections, especially in critically ill patients. C. auris carriage is persistent and is difficult to eradicate from the hospital environment.AimWe aimed to pilot admission screening for C. auris in intensive care units (ICUs) in England to estimate prevalence in the ICU population and to inform public health guidance.MethodsBetween May 2017 and April 2018, we screened admissions to eight adult ICUs in hospitals with no previous cases of C. auris, in three major cities. Swabs were taken from the nose, throat, axilla, groin, perineum, rectum and catheter urine, then cultured and identified using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). Patient records were linked to routine ICU data to describe and compare the demographic and health indicators of the screened cohort with a national cohort of ICU patients admitted between 2016 and 2017.ResultsAll C. auris screens for 921 adults from 998 admissions were negative. The upper confidence limit of the pooled prevalence across all sites was 0.4%. Comparison of the screened cohort with the national cohort showed it was broadly similar to the national cohort with respect to demographics and co-morbidities.ConclusionThese findings imply that C. auris colonisation among patients admitted to ICUs in England is currently rare. We would not currently recommend widespread screening for C. auris in ICUs in England. Hospitals should continue to screen high-risk individuals based on local risk assessment. 相似文献
27.
28.
29.
30.
Meghan T. Hession M.D. Shannon M. Campbell D.O. Sophie J. Balk M.D. Deborah L. Cummins M.D. 《Pediatric dermatology》2013,30(5):626-627
This report presents results from an online survey of New York State pediatricians regarding their counseling habits and attitudes toward indoor tanning among adolescents, as well as their awareness of current legislation that restricts youth access to tanning beds. 相似文献