全文获取类型
收费全文 | 8644篇 |
免费 | 657篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 56篇 |
儿科学 | 259篇 |
妇产科学 | 238篇 |
基础医学 | 1463篇 |
口腔科学 | 189篇 |
临床医学 | 1018篇 |
内科学 | 1695篇 |
皮肤病学 | 184篇 |
神经病学 | 864篇 |
特种医学 | 488篇 |
外科学 | 1050篇 |
综合类 | 95篇 |
一般理论 | 3篇 |
预防医学 | 680篇 |
眼科学 | 89篇 |
药学 | 462篇 |
中国医学 | 12篇 |
肿瘤学 | 479篇 |
出版年
2023年 | 43篇 |
2022年 | 56篇 |
2021年 | 124篇 |
2020年 | 98篇 |
2019年 | 162篇 |
2018年 | 175篇 |
2017年 | 138篇 |
2016年 | 187篇 |
2015年 | 171篇 |
2014年 | 216篇 |
2013年 | 360篇 |
2012年 | 446篇 |
2011年 | 422篇 |
2010年 | 247篇 |
2009年 | 240篇 |
2008年 | 372篇 |
2007年 | 431篇 |
2006年 | 424篇 |
2005年 | 387篇 |
2004年 | 347篇 |
2003年 | 343篇 |
2002年 | 348篇 |
2001年 | 286篇 |
2000年 | 289篇 |
1999年 | 275篇 |
1998年 | 158篇 |
1997年 | 114篇 |
1996年 | 99篇 |
1995年 | 76篇 |
1994年 | 84篇 |
1993年 | 71篇 |
1992年 | 183篇 |
1991年 | 155篇 |
1990年 | 144篇 |
1989年 | 168篇 |
1988年 | 133篇 |
1987年 | 134篇 |
1986年 | 120篇 |
1985年 | 121篇 |
1984年 | 100篇 |
1983年 | 76篇 |
1982年 | 56篇 |
1981年 | 48篇 |
1980年 | 39篇 |
1979年 | 68篇 |
1978年 | 45篇 |
1977年 | 55篇 |
1974年 | 44篇 |
1973年 | 37篇 |
1971年 | 37篇 |
排序方式: 共有9324条查询结果,搜索用时 15 毫秒
1.
2.
3.
Marie Warrer Petersen Tine Sylvest Meyhoff Marie Helleberg Maj-Brit Nørregaard Kjær Anders Granholm Carl Johan Steensen Hjortsø Thomas Steen Jensen Morten Hylander Møller Peter Buhl Hjortrup Mik Wetterslev Gitte Kingo Vesterlund Lene Russell Vibeke Lind Jørgensen Klaus Tjelle Thomas Benfield Charlotte Suppli Ulrik Anne Sofie Andreasen Thomas Mohr Morten H. Bestle Lone Musaeus Poulsen Mette Friberg Hitz Thomas Hildebrandt Lene Surland Knudsen Anders Møller Christoffer Grant Sølling Anne Craveiro Brøchner Bodil Steen Rasmussen Henrik Nielsen Steffen Christensen Thomas Strøm Maria Cronhjort Rebecka Rubenson Wahlin Stephan Jakob Luca Cioccari Balasubramanian Venkatesh Naomi Hammond Vivekanand Jha Sheila Nainan Myatra Christian Gluud Theis Lange Anders Perner 《Acta anaesthesiologica Scandinavica》2020,64(9):1365-1375
Introduction
Severe acute respiratory syndrome coronavirus-2 has caused a pandemic of coronavirus disease (COVID-19) with many patients developing hypoxic respiratory failure. Corticosteroids reduce the time on mechanical ventilation, length of stay in the intensive care unit and potentially also mortality in similar patient populations. However, corticosteroids have undesirable effects, including longer time to viral clearance. Clinical equipoise on the use of corticosteroids for COVID-19 exists.Methods
The COVID STEROID trial is an international, randomised, stratified, blinded clinical trial. We will allocate 1000 adult patients with COVID-19 receiving ≥10 L/min of oxygen or on mechanical ventilation to intravenous hydrocortisone 200 mg daily vs placebo (0.9% saline) for 7 days. The primary outcome is days alive without life support (ie mechanical ventilation, circulatory support, and renal replacement therapy) at day 28. Secondary outcomes are serious adverse reactions at day 14; days alive without life support at day 90; days alive and out of hospital at day 90; all-cause mortality at day 28, day 90, and 1 year; and health-related quality of life at 1 year. We will conduct the statistical analyses according to this protocol, including interim analyses for every 250 patients followed for 28 days. The primary outcome will be compared using the Kryger Jensen and Lange test in the intention to treat population and reported as differences in means and medians with 95% confidence intervals.Discussion
The COVID STEROID trial will provide important evidence to guide the use of corticosteroids in COVID-19 and severe hypoxia.4.
5.
Dr. Annette Raabe Cordula Petersen Andreas Krüll 《Strahlentherapie und Onkologie》2007,183(7):360-365
PURPOSE: To study the effect of treatment time prolongation following initial dose acceleration on the response of subcutaneously growing R1H tumor. MATERIAL AND METHODS: Continuous standard fractionation (30 fractions/40 days) was compared to initially accelerated treatment (30 fractions/21 days) followed by five to two fractions per week yielding total treatment times from 40 to 72 days. Local tumor control was assessed as endpoint. RESULTS: Radiation dose to control 50% of the tumors (TCD50%) decreased statistically significant from 83.5 Gy (95% confidence interval [CI]: 78.6 .. 88.4) for standard fractionation to 74.1 Gy (95% CI: 72.7 .. 75.5) determined for all accelerated treatment arms (p = 0.003). Prolongation of treatment time after initial acceleration from 40 to 72 days led to a small but statistically not significant increase in TCD50% from 72.0 Gy (95% CI: 71.0 .. 72.9) to 76.2 Gy (95% CI: 69.9 .. 82.4) corresponding to a repopulated dose of 0.9 Gy per week. This time factor is considerably smaller than for conventional radiation treatment as determined in previous experiments. CONCLUSION: The results indicate that initially accelerated irradiation not only improves local tumor control but also minimizes the negative effect of treatment time prolongation. This might be due to changes in tumor cell repopulation kinetics. 相似文献
6.
The purpose of the study was to compare skin blood flow by laser Doppler flowmetry (LDF) and the 133-Xenon washout technique in UVB-inflamed human skin. Six healthy subjects participated in the study. Forearm skin blood flow was measured prior to irradiation and then 8, 24, 48 and 72 h after the exposure to twice the minimal erythema dose of UVB. Baseline blood flow as measured by the 133-Xenon washout method was 5.2 (range 3.0 to 10.4) ml/100g/min and LDF flux was 3.1 (range 2.7 to 5.7) arbitrary units. Following irradiation, maximum blood flow increase as evaluated by the 133-Xenon washout was 10.8 (95% confidence interval 3.7 to 11.3) times baseline blood flow, corresponding to an absolute blood flow of 47.5 (range 33.8 to 56.3) ml/100g/min. Maximum increase after induction of inflammation as assessed by LDF was 34.6 (95% confidence interval 24.6 to 56.5) times baseline flux. The two methods showed comparable time courses in all subjects. A significant correlation between the two methods was found, Spearman's rho = 0.54, p = 0.006. The relative LDF blood flow increase was 4.2-fold (95% confidence interval 2.7 to 5.0) greater than the increase measured by the 133-Xenon washout method. These results are at variance with previous comparative studies of the two methods. Some explanations are discussed. 相似文献
7.
Mario C. Petersen David A. Kube Frederick B. Palmer 《Journal of developmental and physical disabilities》2006,18(3):307-318
Objective: Evaluate a) the prevalence of developmental disabilities (DD) in children admitted to a general pediatrics inpatient unit, and b) the number of children admitted to the unit with previously undiagnosed developmental disability. Methods: Prevalence was evaluated through retrospective record review. Subjects: One hundred ninety children older than five months of age admitted to a general pediatric unit. Results: Of 190 children admitted, 155 (81.6%) had adequate developmental screening documented in the record. Forty-nine (25.7% of total, 31.6% of screened) had a developmental disability, 22 (12.1% of total, 14.8% of screened) had a previously unrecognized disability. Sample prevalence of DD was: cerebral palsy (6.8%), developmental delay or mental retardation (8.4%), language delay (4.6%), learning disability (8.2%), and hearing loss (1.5%). New diagnoses included: three children with probable mental retardation (MR), nine with learning disability (may include mild MR), seven with language delay, three with abnormal motor skills (fine and/or gross motor), one each of: neurofibromatosis type I, hearing loss, cerebral palsy, dysphagia. Some children had more than one new diagnosis. Conclusion: The prevalence of disabilities in a general pediatrics inpatient unit is much higher than the prevalence in the community. Because almost half of the disabilities were previously unrecognized, acute hospitalization is an excellent opportunity to conduct developmental screening. 相似文献
8.
Human immunodeficiency virus infection in disadvantaged adolescents. Findings from the US Job Corps 总被引:3,自引:0,他引:3
OBJECTIVE--To describe the human immunodeficiency virus (HIV) epidemic among socially and educationally disadvantaged young persons in the United States. DESIGN.-We analyzed demographic and geographic findings from the screening of Job Corps students for antibody to HIV. SETTING--The Job Corps is a federal training program for disadvantaged, out-of-school youth. POPULATION SCREENED--Residential students aged 16 to 21 years who entered the Job Corps from October 1987 through February 1990. MAIN OUTCOME MEASURE--Rates of observed HIV infection in entering students, stratified by demographic and geographic features. RESULTS--Of 137,209 Job Corps students screened, 488 were HIV seropositive (3.6 per 1000), a seroprevalence rate higher than that among military applicants of the same age. Overall seroprevalence was slightly higher in male (3.7 per 1000) than in female (3.2 per 1000) Job Corps students, but among those students aged 16 and 17 years, seroprevalence was higher among females (2.3 per 1000) than among males (1.5 per 1000) (P less than .05). For students aged 16 to 21 years, seroprevalence increased with year of age: 1.8 per 1000 per year for males and 0.7 per 1000 per year for females. Among those aged 21 years, HIV prevalence was 8.9 per 1000. For black and Hispanic students from large Northeastern cities, seroprevalence increased by 4.3 per 1000 per year of age and reached 24.8 per 1000 (one of 40) in students aged 21 years. However, among students from rural areas and small towns, HIV seroprevalence was disproportionately high in the Southeast. Compared with recently described US patients with the acquired immunodeficiency syndrome, HIV-infected students who entered the Job Corps were much more likely to be female. CONCLUSIONS--These findings show that disadvantaged, out-of-school adolescents are at high risk for HIV infection. The screening results identified surprisingly high seroprevalence in the southeastern United States and demonstrated a marked shift in the HIV epidemic to young women. Controlling the HIV epidemic among teenagers must include interventions that will reach adolescents early and outside of the formal educational system. 相似文献
9.
Between 1944 and 1947 the mortality statistics for the Danish population show an epidemic increase of liver diseases: subacute necrosis and cirrhosis. The epidemic only affected female mortality rates. Mortality due to cirrhosis remained at a higher rate for women than men until 1970 as a result of an excess mortality in the cohort of women who in 1945 were over the age of 45. Up to 1981 this group showed an excess of 4,000 fatalities. A reevaluation of medico-statistical data shows that the disease cannot be explained by the epidemic hepatitis occurring in 1942-1944 or by increased consumption of alcohol. Possible causes could be pharmaceutical products or additives, perhaps hormone preparations. 相似文献