首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8422篇
  免费   487篇
  国内免费   57篇
耳鼻咽喉   192篇
儿科学   178篇
妇产科学   131篇
基础医学   985篇
口腔科学   695篇
临床医学   677篇
内科学   2064篇
皮肤病学   169篇
神经病学   694篇
特种医学   222篇
外科学   1310篇
综合类   71篇
一般理论   1篇
预防医学   521篇
眼科学   185篇
药学   505篇
中国医学   21篇
肿瘤学   345篇
  2024年   5篇
  2023年   90篇
  2022年   189篇
  2021年   382篇
  2020年   201篇
  2019年   356篇
  2018年   374篇
  2017年   251篇
  2016年   280篇
  2015年   303篇
  2014年   443篇
  2013年   467篇
  2012年   758篇
  2011年   770篇
  2010年   416篇
  2009年   350篇
  2008年   494篇
  2007年   498篇
  2006年   420篇
  2005年   372篇
  2004年   357篇
  2003年   262篇
  2002年   246篇
  2001年   76篇
  2000年   72篇
  1999年   71篇
  1998年   42篇
  1997年   44篇
  1996年   29篇
  1995年   27篇
  1994年   26篇
  1993年   27篇
  1992年   19篇
  1991年   28篇
  1990年   27篇
  1989年   26篇
  1988年   24篇
  1987年   20篇
  1986年   26篇
  1985年   20篇
  1984年   10篇
  1983年   10篇
  1982年   12篇
  1981年   5篇
  1980年   4篇
  1979年   4篇
  1978年   4篇
  1977年   4篇
  1976年   6篇
  1975年   8篇
排序方式: 共有8966条查询结果,搜索用时 0 毫秒
61.

Objective

We aimed to study the cross-sectional area of levator ani muscle and the doppler velocimetric parameters of vessels its in premenopausal and postmenopausal women.

Study design

Sixty-four patients, divided into 3 groups, were assessed: group I (20 women—average age 28 years) premenopausal and nulliparous (control); group II (24 women—average age 38 years, vaginal delivery 1–4) premenopausal with vaginal deliveries; group III (20 women—average age 55 years, parity 0–4) postmenopausal without hormonal therapy. Doppler velocimetry of levator ani muscle vessels through resistance and pulsatility indices was used and the means of the groups compared by adjusting the weighed variance model with multiple comparisons, according to Tukey's method. Similarly, we measured the cross-sectional area of the muscle using ultrasonography.

Results

There was a significant increase in resistance and pulsatility indices in postmenopausal patients as compared to the other two groups. We also observed a significant decrease in the cross-sectional area of the muscle of postmenopausal patients when compared to those in premenopausal.

Conclusion

The obtained results allow us to conclude that levator ani muscle vascularization significantly decreases after menopause (age and/or hipoestrogenism) and that it can be assumed that vaginal delivery does not promote long-term alterations in levator ani muscle vascularization. We also observed a significant decrease in the cross-sectional area of the muscle in postmenopausal women when compared to those in premenopausal.  相似文献   
62.
63.
64.
Background:Autonomic nervous system balance is altered in cystic fibrosis (CF), although its influence on physical fitness has been poorly explored.Objective:This study aimed to evaluate the association of heart rate variability (HRV) with exercise capacity and levels of daily physical activity in children and adolescents with mild-to-moderate CF.Methods:A cross-sectional study including individuals with CF aged 6–18 years, not under CFTR modulator therapy, was performed. Sociodemographic (age, sex) and clinical information (airway colonization, pancreatic insufficiency, and genotyping) were collected. In addition, exercise capacity (modified shuttle test — MST), lung function (spirometry), body composition (bioimpedance), levels of daily physical activity (5-day accelerometer), and HRV (both at rest and during the MST) were evaluated.Results:30 individuals (20 females) aged 11.2±3.7 years, mean FEV162.8±27.6%, were included. A sympathovagal balance (LF/HF) increase (p<0.001) during the MST was shown, indicating a predominance of sympathetic modulation. The standard deviation of all RR intervals (SDNN) and the high frequency (HF) index during exercise correlated significantly with FEV1 (r=0.45, p=0.01 and r=0.46, p=0.01; respectively). MST distance also correlated positively and significantly with SDNN (r=0.43, p=0.01), square root of the mean of the sums of squares of frequencies between RR intervals greater than 50 ms — RMSSD (r=0.53, p<0.01), low frequency — LF (r=0.48, p<0.01), HF (r=0.64, p<0.01), dispersion of points perpendicular to the short-term identity line — SD1 (r=0.40, p=0.02) and negatively with LF/HF (r=−0.57, p<0.01). Regarding daily physical activity, SDNN at rest (r=0.37, p=0.04) and exercise (r=0.41, p=0.02) showed positive correlations with time in moderate-to-vigorous activities. When normalizing the SDNN and classifying individuals as normal or altered, those presenting altered SDNN showed poorest FEV1 (p=0.001) and lower exercise capacity (p=0.027).Conclusion:HRV correlates with lung function, exercise capacity and levels of daily physical activity in children and adolescents with CF. The study highlights the influence of CF on autonomic function and suggests HRV measurement as an easy tool to be used in clinical settings as an alternative marker to monitor CF individuals.  相似文献   
65.
The transdermal permeation of curcumin aided by choline and geranic acid ionic liquid (CAGE-IL) was addressed as a potential treatment for skin diseases. An in-depth analysis of the effect of CAGE-IL concentration in the enhancement of transdermal permeation of curcumin was performed, and the results were modelled via nonlinear regression analysis. The results obtained showed that a low percentage of CAGE-IL (viz. 2.0%, w/w) was effective in disrupting the skin structure in a transient fashion, facilitating the passage of curcumin dissolved in it.  相似文献   
66.
The novel severe acute respiratory syndrome (SARS) coronavirus, SARS-CoV-2, is responsible for the global COVID-19 pandemic. Effective interventions are urgently needed to mitigate the effects of COVID-19 and likely require multiple strategies. Egg-extracted antibody therapies are a low-cost and scalable strategy to protect at-risk individuals from SARS-CoV-2 infection. Commercial laying hens were hyperimmunized against the SARS-CoV-2 S1 protein using three different S1 recombinant proteins and three different doses. Sera and egg yolk were collected at three and six weeks after the second immunization for enzyme-linked immunosorbent assay and plaque-reduction neutralization assay to determine antigen-specific antibody titers and neutralizing antibody titers, respectively. In this study we demonstrate that hens hyperimmunized against the SARS-CoV-2 recombinant S1 and receptor binding domain (RBD) proteins produced neutralizing antibodies against SARS-CoV-2. We further demonstrate that antibody production was dependent on the dose and type of antigen administered. Our data suggests that antibodies purified from the egg yolk of hyperimmunized hens can be used as immunoprophylaxis in humans at risk of exposure to SARS-CoV-2.  相似文献   
67.
La morbilidad asociada al consumo de alcohol incluye patología digestiva, psiquiátrica, neurológica, infecciosa, cáncer de diversos tipos, enfermedades cardiovasculares, lesiones intencionales, no intencionales, patología social y problemas familiares. Las evidencias más recientes no indican que el consumo «moderado» sea beneficioso para la salud. Por lo tanto, debe enfatizarse más bien la idea de evitar los consumos de riego y transmitir a los pacientes que lo más beneficioso para la salud sería no consumir alcohol o hacerlo en dosis de bajo riesgo. El instrumento más adecuado de cribado es el AUDIT-C. Las bases de la intervención breve consisten en estrategias cognitivo-conductuales y motivacionales. Hay que dar una información positiva sobre los beneficios de la moderación e informar sobre el peligro de la ingesta de alcohol. En fases precoces de la dependencia se contempla la oferta de tratamiento farmacológico de desintoxicación, deshabituación y seguimiento. Los casos más graves requieren coordinación con los servicios de adicciones. En España se ha podido comprobar que la intervención breve es efectiva y que disminuye el consumo 100 gramos de alcohol a la semana. Las estrategias comunitarias son el marco normativo adecuado para lograr los mejores resultados de la intervención breve. Estas deberán ir encaminadas a reducir la oferta y la disponibilidad para el consumo, mediante la adopción de medidas legislativas, de manera que se limite tanto la accesibilidad económica como la física. Por otra parte, habrá que implementar medidas para disminuir la demanda del alcohol mediante la educación para la salud a determinados grupos de riesgo.Palabras clave: Alcohol, Intervención breve, Prevención, Atención Primaria  相似文献   
68.
69.
70.
The recent history of French and Brazilian medicine goes back to the first decades of the xixth century. As regards nephrology, the first links were established starting in the 1950s of the xxth century. Over the past 60 years, the scientific production of the Franco-Brazilian school of nephrology totalized more than a thousand scientific papers and created a new generation of more than two hundred disciples, formed in Brazil by nephrologists who had completed their studies in France. In this article, we would like to memorize the successive exchanges between French and Brazilian physicians, mainly in the field of nephrology.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号