全文获取类型
收费全文 | 2547篇 |
免费 | 153篇 |
国内免费 | 35篇 |
出版年
2022年 | 26篇 |
2021年 | 58篇 |
2020年 | 11篇 |
2018年 | 35篇 |
2017年 | 24篇 |
2016年 | 102篇 |
2015年 | 224篇 |
2014年 | 225篇 |
2013年 | 246篇 |
2012年 | 297篇 |
2011年 | 229篇 |
2010年 | 120篇 |
2009年 | 96篇 |
2008年 | 113篇 |
2007年 | 84篇 |
2006年 | 57篇 |
2005年 | 93篇 |
2004年 | 84篇 |
2003年 | 91篇 |
2002年 | 65篇 |
2001年 | 48篇 |
2000年 | 29篇 |
1999年 | 14篇 |
1998年 | 16篇 |
1997年 | 11篇 |
1996年 | 14篇 |
1994年 | 6篇 |
1993年 | 12篇 |
1992年 | 10篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 11篇 |
1988年 | 15篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1968年 | 7篇 |
1961年 | 5篇 |
1957年 | 9篇 |
1953年 | 5篇 |
1951年 | 7篇 |
1950年 | 5篇 |
排序方式: 共有2735条查询结果,搜索用时 15 毫秒
151.
Marieke De Craemer Mina Lateva Violeta Iotova Ellen De Decker Ma?té Verloigne Ilse De Bourdeaudhuij Odysseas Androutsos Piotr Socha Zbigniew Kulaga Luis Moreno Berthold Koletzko Yannis Manios Greet Cardon the ToyBox-study group 《PloS one》2015,10(3)
Background
The aim of the current study was to compare levels of energy balance-related behaviours (physical activity, sedentary behaviour, and dietary behaviours (more specifically water consumption, sugar-sweetened beverage consumption and unhealthy snacking)) in four- to six-year-old preschoolers from six European countries (Belgium, Bulgaria, Germany, Greece, Poland, and Spain) within the ToyBox cross-sectional study.Methods
A sample of 4,045 preschoolers (4.77 ± 0.43 years; 52.2% boys) had valid physical activity data (steps per day), parents of 8,117 preschoolers (4.78 ± 0.46 years; 53.0% boys) completed a parental questionnaire with questions on sedentary behaviours (television viewing, computer use, and quiet play), and parents of 7,244 preschoolers (4.77 ± 0.44 years; 52.0% boys) completed a food frequency questionnaire with questions on water consumption, sugar-sweetened beverage consumption and unhealthy snacking.Results
The highest levels of physical activity were found in Spain (12,669 steps/day on weekdays), while the lowest levels were found in Bulgaria and Greece (9,777 and 9,656 steps/day on weekdays, respectively). German preschoolers spent the least amount of time in television viewing (43.3 min/day on weekdays), while Greek preschoolers spent the most time in television viewing (88.5 min/day on weekdays). A considerable amount of time was spent in quiet play in all countries, with the highest levels in Poland (104.9 min/day on weekdays), and the lowest levels in Spain (60.4 min/day on weekdays). Belgian, German, and Polish preschoolers had the lowest intakes of water and the highest intakes of sugar-sweetened beverages. The intake of snacks was the highest in Belgian preschoolers (73.1 g/day) and the lowest in Greek preschoolers (53.3 g/day).Conclusions
Across six European countries, differences in preschoolers’ energy balance-related behaviours were found. Future interventions should target European preschoolers’ energy balance-related behaviours simultaneously, but should apply country-specific adaptations. 相似文献152.
Sanjiv M. Baxi Ruth M. Greenblatt Peter Bacchetti Chengshi Jin Audrey L. French Marla J. Keller Michael H. Augenbraun Stephen J. Gange Chenglong Liu Wendy J. Mack Monica Gandhi Women’s Interagency HIV Study 《PloS one》2015,10(6)
Effective antiretroviral (ARV) therapy depends on adequate drug exposure, yet methods to assess ARV exposure are limited. Concentrations of ARV in hair are the product of steady-state pharmacokinetics factors and longitudinal adherence. We investigated nevirapine (NVP) concentrations in hair as a predictor of treatment response in women receiving ARVs. In participants of the Women’s Interagency HIV Study, who reported NVP use for >1 month from 2003–2008, NVP concentrations in hair were measured via liquid-chromatography-tandem mass-spectrometry. The outcome was virologic suppression (plasma HIV RNA below assay threshold) at the time of hair sampling and the primary predictor was nevirapine concentration categorized into quartiles. We controlled for age, race/ethnicity, pre-treatment HIV RNA, CD4 cell count, and self-reported adherence over the 6-month visit interval (categorized ≤ 74%, 75%–94% or ≥ 95%). We also assessed the relation of NVP concentration with changes in hepatic transaminase levels via multivariate random intercept logistic regression and linear regression analyses. 271 women contributed 1089 person-visits to the analysis (median 3 of semi-annual visits). Viral suppression was least frequent in concentration quartile 1 (86/178 (48.3%)) and increased in higher quartiles (to 158/204 (77.5%) for quartile 4). The odds of viral suppression in the highest concentration quartile were 9.17 times (95% CI 3.2–26, P < 0.0001) those in the lowest. African-American race was associated with lower rates of virologic suppression independent of NVP hair concentration. NVP concentration was not significantly associated with patterns of serum transaminases. Concentration of NVP in hair was a strong independent predictor of virologic suppression in women taking NVP, stronger than self-reported adherence, but did not appear to be strongly predictive of hepatotoxicity. 相似文献
153.
154.
Koldo Garcia-Etxebarria María Alma Bracho Juan Carlos Galán Tomàs Pumarola Jesús Castilla Raúl Ortiz de Lejarazu Mario Rodríguez-Dominguez Inés Quintela Núria Bonet Marc Garcia-Garcerà Angela Domínguez Fernando González-Candelas Francesc Calafell CIBERESP Cases Controls in Pandemic Influenza Working Group 《PloS one》2015,10(10)
155.
Metabolic syndrome is common and persistent in youth‐onset type 2 diabetes: Results from the TODAY clinical trial
下载免费PDF全文
![点击此处可从《Obesity (Silver Spring, Md.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
156.
Relationship between lifestyle behaviors and obesity in children ages 9–11: Results from a 12‐country study
下载免费PDF全文
![点击此处可从《Obesity (Silver Spring, Md.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Peter T. Katzmarzyk Tiago V. Barreira Stephanie T. Broyles Catherine M. Champagne Jean‐Philippe Chaput Mikael Fogelholm Gang Hu William D. Johnson Rebecca Kuriyan Anura Kurpad Estelle V. Lambert Carol Maher Jose Maia Victor Matsudo Timothy Olds Vincent Onywera Olga L. Sarmiento Martyn Standage Mark S. Tremblay Catrine Tudor‐Locke Pei Zhao Timothy S. Church for the ISCOLE Research Group 《Obesity (Silver Spring, Md.)》2015,23(8):1696-1702
157.
David Bann Don Hire Todd Manini Rachel Cooper Anda Botoseneanu Mary M. McDermott Marco Pahor Nancy W. Glynn Roger Fielding Abby C. King Timothy Church Walter T. Ambrosius Thomas Gill for the LIFE Study Group 《PloS one》2015,10(2)
BackgroundIdentifying modifiable determinants of fat mass and muscle strength in older adults is important given their impact on physical functioning and health. Light intensity physical activity and sedentary behavior are potential determinants, but their relations to these outcomes are poorly understood. We evaluated associations of light intensity physical activity and sedentary time—assessed both objectively and by self-report—with body mass index (BMI) and grip strength in a large sample of older adults.MethodsWe used cross-sectional baseline data from 1130 participants of the Lifestyle Interventions and Independence for Elders (LIFE) study, a community-dwelling sample of relatively sedentary older adults (70-89 years) at heightened risk of mobility disability. Time spent sedentary and in light intensity activity were assessed using an accelerometer worn for 3–7 days (Actigraph GT3X) and by self-report. Associations between these exposures and measured BMI and grip strength were evaluated using linear regression.ResultsGreater time spent in light intensity activity and lower sedentary times were both associated with lower BMI. This was evident using objective measures of lower-light intensity, and both objective and self-reported measures of higher-light intensity activity. Time spent watching television was positively associated with BMI, while reading and computer use were not. Greater time spent in higher but not lower intensities of light activity (assessed objectively) was associated with greater grip strength in men but not women, while neither objectively assessed nor self-reported sedentary time was associated with grip strength.ConclusionsIn this cross-sectional study, greater time spent in light intensity activity and lower sedentary times were associated with lower BMI. These results are consistent with the hypothesis that replacing sedentary activities with light intensity activities could lead to lower BMI levels and obesity prevalence among the population of older adults. However, longitudinal and experimental studies are needed to strengthen causal inferences. 相似文献
158.
Weight change in the first 2 months of a lifestyle intervention predicts weight changes 8 years later
下载免费PDF全文
![点击此处可从《Obesity (Silver Spring, Md.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
159.
Alessandra Bandera Andrea Gori Francesca Sabbatini Giordano Madeddu Stefano Bonora Raffaella Libertone Claudio Mastroianni Paolo Bonfanti Antonella d'Arminio Monforte Alessandro Cozzi-Lepri Icona Foundation Study Group 《PloS one》2015,10(5)
Whilst renal dysfunction, especially mild impairment (60<eGFR<90 ml/min), has been often described in HIV-infected population, its potential contribution to HIV evolution and risk of cerebro-cardiovascular disease (CCVD) has not been clarified. Data from HIV-1 infected patients enrolled in the Italian Cohort of Antiretroviral-Naïve (Icona) Foundation Study collected between January 2000 and February 2014 with at least two creatinine values available. eGFR (CKD-epi) and renal dysfunction defined using a priori cut-offs of 60 (severely impaired) and 90 ml/min/1.73m2 (mildly impaired). Characteristics of patients were described after stratification in these groups and compared using chi-square test (categorical variables) or Kruskal Wallis test comparing median values. Follow-up accrued from baseline up to the date of the CCVD or AIDS related events or death or last available visit. Kaplan Meier curves were used to estimate the cumulative probability of occurrence of the events over time. Adjusted analysis was performed using a proportional hazards Cox regression model. We included 7,385 patients, observed for a median follow-up of 43 months (inter-quartile range [IQR]: 21-93 months). Over this time, 130 cerebro-cardiovascular events (including 11 deaths due to CCVD) and 311 AIDS-related events (including 45 deaths) were observed. The rate of CCVD events among patients with eGFR >90, 60-89, <60 ml/min, was 2.91 (95% CI 2.30-3.67), 4.63 (95% CI 3.51-6.11) and 11.9 (95% CI 6.19-22.85) per 1,000 PYFU respectively, with an unadjusted hazard ratio (HR) of 4.14 (95%CI 2.07-8.29) for patients with eGFR <60 ml/min and 1.58 (95%CI 1.10-2.27) for eGFR 60-89 compared to those with eGFR ≥90. Of note, these estimates are adjusted for traditional cardio-vascular risk factors (e.g. smoking, diabetes, hypertension, dyslipidemia). Incidence of AIDS-related events was 9.51 (95%CI 8.35-10.83), 6.04 (95%CI 4.74-7.71) and 25.0 (95%CI 15.96-39.22) per 1,000 PYFU, among patients with eGFR >90, 60-89, <60 ml/min, respectively, with an unadjusted HR of 2.49 (95%CI 1.56-3.97) for patients with eGFR <60 ml/min and 0.68 (95%CI 0.52-0.90) for eGFR 60-89. The risk of AIDS events was significantly lower in mild renal dysfunction group even after adjustment for HIV-related characteristics. Our data confirm that impaired renal function is an important risk marker for CCVD events in the HIV-population; importantly, even those with mild renal impairment (90<eGFR<60) seem to be at increased risk of cerebro-cardiovascular morbidity and mortality. 相似文献
160.
Angelo Campanozzi Sonia Avallone Antonio Barbato Roberto Iacone Ornella Russo Gianpaolo De Filippo Giuseppina D’Angelo Licia Pensabene Basilio Malamisura Gaetano Cecere Maria Micillo Ruggiero Francavilla Anna Tetro Giuliano Lombardi Lisa Tonelli Giuseppe Castellucci Luigi Ferraro Rita Di Biase Antonella Lezo Silvia Salvatore Silvia Paoletti Alfonso Siani Daniela Galeone Pasquale Strazzullo MINISAL-GIRCSI Program Study Group 《PloS one》2015,10(4)