全文获取类型
收费全文 | 941篇 |
免费 | 92篇 |
国内免费 | 2篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 14篇 |
2020年 | 7篇 |
2019年 | 13篇 |
2018年 | 11篇 |
2017年 | 9篇 |
2016年 | 30篇 |
2015年 | 37篇 |
2014年 | 39篇 |
2013年 | 55篇 |
2012年 | 84篇 |
2011年 | 82篇 |
2010年 | 51篇 |
2009年 | 45篇 |
2008年 | 60篇 |
2007年 | 53篇 |
2006年 | 56篇 |
2005年 | 55篇 |
2004年 | 73篇 |
2003年 | 65篇 |
2002年 | 34篇 |
2001年 | 12篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 17篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 13篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1035条查询结果,搜索用时 15 毫秒
191.
Lynette Lim Cathy Banwell Chris Bain Emily Banks Sam-ang Seubsman Matthew Kelly Vasoontara Yiengprugsawan Adrian Sleigh 《PloS one》2014,9(5)
Introduction
Sugar sweetened beverages (SSBs) are implicated in the rising prevalence of obesity and diet-related chronic diseases worldwide. However, little is known about their contribution to weight gain in Asian populations. This study aimed to investigate weight change associated with SSB consumption between 2005 and 2009 in a large national cohort of Thai university students.Methods
Questionnaire data were collected from a large Thai cohort (the Thai Health-Risk Transition: a National Cohort Study). The analysis was based on responses from 59 283 of the 60 569 (98%) cohort members who had valid SSB consumption and weight variables in 2005 and 2009. The relationship between SSB consumption in 2005 and self-reported weight change was analysed using multiple linear regression models controlled for socio-demographic, activity and (non-validated) dietary factors shown to influence weight.Results
Higher frequency of SSB consumption in 2005 was significantly associated with greater weight gain between 2005 and 2009 in all age groups and in both sexes (p<0.0001); persons who consumed SSBs at least once a day in 2005 gained 0.5 kg more than those who consumed SSBs less than once a month. The estimated weight gain for the average person in the sample was 1.9 kg (95% C I 1.95–1.96). The difference in weight gain between those who increased their consumption frequency (<once a month to > once per day) between 2005 and 2009 compared to those who maintained it was 0.3 kgs, while persons who reduced their consumption frequency (once a day to > once a month) gained 0.2 kgs less than those whose consumption remained unchanged.Conclusion
SSB consumption is independently associated with weight gain in the Thai population. Research and health promotion in Thailand and other economically transitioning countries should focus on reducing their contribution to population weight gain and to diet-related chronic diseases. 相似文献192.
193.
Carina Cesar Bryan E. Shepherd Cathy A. Jenkins Massimo Ghidinelli Jose Luis Castro Valdiléa Gon?alves Veloso Claudia P. Cortes Denis Padgett Brenda Crabtree-Ramirez Eduardo Gotuzzo Valeria Fink Adriana Duran Omar Sued Catherine C. McGowan Pedro Cahn for The Caribbean Central South America Network for HIV Epidemiology 《PloS one》2014,9(9)
Background
Access to highly active antiretroviral therapy (HAART) is expanding in Latin America. Many patients require second and third line therapy due to toxicity, tolerability, failure, or a combination of factors. The need for third line HAART, essential for program planning, is not known.Methods
Antiretroviral-naïve patients ≥18 years who started first HAART after January 1, 2000 in Caribbean, Central and South America Network (CCASAnet) sites in Argentina, Brazil, Honduras, Mexico, and Peru were included. Clinical trials participants were excluded. Third line HAART was defined as use of darunavir, tipranavir, etravirine, enfuvirtide, maraviroc or raltegravir. Need for third line HAART was defined as virologic failure while on second line HAART.Results
Of 5853 HAART initiators followed for a median of 3.5 years, 310 (5.3%) failed a second line regimen and 44 (0.8%) received a third line regimen. Cumulative incidence of failing a 2nd or starting a 3rd line regimen was 2.7% and 6.0% three and five years after HAART initiation, respectively. Predictors at HAART initiation for failing a second or starting a third line included female sex (hazard ratio [HR] = 1.54, 95% confidence interval [CI] 1.18–2.00, p = 0.001), younger age (HR = 2.76 for 20 vs. 40 years, 95% CI 1.86–4.10, p<0.001), and prior AIDS (HR = 2.17, 95% CI 1.62–2.90, p<0.001).Conclusions
Third line regimens may be needed for at least 6% of patients in Latin America within 5 years of starting HAART, a substantial proportion given the large numbers of patients on HAART in the region. Improved accessibility to third line regimens is warranted. 相似文献194.
Sarah H. Peterson Jason L. Hassrick Anne Lafontaine Jean-Pierre Thomé Daniel E. Crocker Cathy Debier Daniel P. Costa 《PloS one》2014,9(4)
Persistent organic pollutants, including polychlorinated biphenyls (PCBs), are widely distributed and detectable far from anthropogenic sources. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometers to forage in coastal and open-ocean regions of the northeast Pacific Ocean and then return to land where they fast while breeding and molting. Our study examined potential effects of age, adipose percent, and the difference between the breeding and molting fasts on PCB concentrations and congener profiles in blubber and serum of northern elephant seal females. Between 2005 and 2007, we sampled blubber and blood from 58 seals before and after a foraging trip, which were then analyzed for PCBs. Age did not significantly affect total PCB concentrations; however, the proportion of PCB congeners with different numbers of chlorine atoms was significantly affected by age, especially in the outer blubber. Younger adult females had a significantly greater proportion of low-chlorinated PCBs (tri-, tetra-, and penta-CBs) than older females, with the opposite trend observed for hepta-CBs, indicating that an age-associated process such as parity (birth) may significantly affect congener profiles. The percent of adipose tissue had a significant relationship with inner blubber PCB concentrations, with the highest mean concentrations observed at the end of the molting fast. These results highlight the importance of sampling across the entire blubber layer when assessing contaminant levels in phocid seals and taking into account the adipose stores and reproductive status of an animal when conducting contaminant research. 相似文献
195.
196.
197.
Anand Moodley William Rae Ahmed Bhigjee Cathy Connolly Natasha Devparsad Andrew Michowicz Thomas Harrison Angela Loyse 《PloS one》2012,7(12)
Cryptococcal induced visual loss is a devastating complication in survivors of cryptococcal meningitis (CM). Early detection is paramount in prevention and treatment. Subclinical optic nerve dysfunction in CM has not hitherto been investigated by electrophysiological means. We undertook a prospective study on 90 HIV sero-positive patients with culture confirmed CM. Seventy-four patients underwent visual evoked potential (VEP) testing and 47 patients underwent Humphrey''s visual field (HVF) testing. Decreased best corrected visual acuity (BCVA) was detected in 46.5% of patients. VEP was abnormal in 51/74 (68.9%) right eyes and 50/74 (67.6%) left eyes. VEP P100 latency was the main abnormality with mean latency values of 118.9 (±16.5) ms and 119.8 (±15.7) ms for the right and left eyes respectively, mildly prolonged when compared to our laboratory references of 104 (±10) ms (p<0.001). Subclinical VEP abnormality was detected in 56.5% of normal eyes and constituted mostly latency abnormality. VEP amplitude was also significantly reduced in this cohort but minimally so in the visually unimpaired. HVF was abnormal in 36/47 (76.6%) right eyes and 32/45 (71.1%) left eyes. The predominant field defect was peripheral constriction with an enlarged blind spot suggesting the greater impact by raised intracranial pressure over that of optic neuritis. Whether this was due to papilloedema or a compartment syndrome is open to further investigation. Subclinical HVF abnormalities were minimal and therefore a poor screening test for early optic nerve dysfunction. However, early optic nerve dysfunction can be detected by testing of VEP P100 latency, which may precede the onset of visual loss in CM. 相似文献
198.
Prevalence of ESR1 amplification in breast cancer is highly disputed and discrepancies have been related to different technical protocols and different scoring approaches. In addition, pre-mRNA artifacts have been proposed to influence outcome of ESR1 FISH analysis. We analyzed ESR1 gene copy number status combining an improved RNase FISH protocol with multiplex ligation-dependent probe amplification (MLPA) after laser microdissection. FISH showed a high prevalence of ESR1 gains and amplifications despite RNase treatment but MLPA did not confirm ESR1 copy number increases detected by FISH in more than half of cases. We suggest that the combination of the ESR1-specific intra-tumor heterogeneity and low-level copy number increase accounts for these discrepancies. 相似文献
199.
Cecilia Arighi Veronica Shamovsky Anna Maria Masci Alan Ruttenberg Barry Smith Darren A. Natale Cathy Wu Peter D’Eustachio 《PloS one》2015,10(4)
The Protein Ontology (PRO) provides terms for and supports annotation of species-specific protein complexes in an ontology framework that relates them both to their components and to species-independent families of complexes. Comprehensive curation of experimentally known forms and annotations thereof is expected to expose discrepancies, differences, and gaps in our knowledge. We have annotated the early events of innate immune signaling mediated by Toll-Like Receptor 3 and 4 complexes in human, mouse, and chicken. The resulting ontology and annotation data set has allowed us to identify species-specific gaps in experimental data and possible functional differences between species, and to employ inferred structural and functional relationships to suggest plausible resolutions of these discrepancies and gaps. 相似文献
200.