全文获取类型
收费全文 | 244篇 |
免费 | 8篇 |
专业分类
252篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 12篇 |
2013年 | 24篇 |
2012年 | 13篇 |
2011年 | 19篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 13篇 |
2007年 | 15篇 |
2006年 | 16篇 |
2005年 | 19篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 11篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有252条查询结果,搜索用时 15 毫秒
51.
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52.
Thermal denaturation of the BRCT tandem repeat region of human tumour suppressor gene product BRCA1 总被引:2,自引:0,他引:2
Pyrpassopoulos S Ladopoulou A Vlassi M Papanikolau Y Vorgias CE Yannoukakos D Nounesis G 《Biophysical chemistry》2005,114(1):1-12
Reduced stability of the tandem BRCT domains of human BReast CAncer 1 (BRCA1) due to missense mutations may be critical for loss of function in DNA repair and damage-induced checkpoint control. In the present thermal denaturation study of the BRCA1 BRCT region, high-precision differential scanning calorimetry (DSC) and circular dichroism (CD) spectroscopy provide evidence for the existence of a denatured state that is structurally very similar to the native. Consistency between theoretical structure-based estimates of the enthalpy (DeltaH) and heat capacity change (DeltaCp) and the calorimetric results is obtained when considering partial thermal unfolding contained in the region of the conserved hydrophobic pocket formed at the interface of the two BRCT repeats. The structural integrity of this region has been shown to be crucial for the interaction of BRCA1 with phosphorylated peptides. In addition, cancer-causing missense mutations located at the inter-BRCT-repeat interface have been linked to the destabilization of the tandem BRCT structure. 相似文献
53.
54.
Sylvain Bourgerie Yannis Karamanos Sylvie Berger Raymond Julien 《Glycoconjugate journal》1992,9(4):162-167
Peptide-N
4-(N-acetyl--glucosaminyl) asparagine amidase F (PNGase F) and endo--N-acetyl glucosaminidase F (Endo F) activities were monitored during cultivation ofFlavobacterium meningosepticum using a new fluorescence-HPLC procedure based on a commercially available substrate. The PNGase F activity reached a maximum level at the end of the log phase and remained constant during the stationary phase, while Endo F continuously increased until late stationary phase. PNGase F obtained at the end of the log phase was less contaminated by other proteins compared with late stationary phase.Abbreviations Con A
concanavalin A
- Endo F
endo--N-acetyl glucosaminidase F (EC 3.2.1.96)
- GlcNAc
N-acetylglucosamine
- PNGase F
peptide-N
4-(N-acetyl--glucosaminyl) asparagine amidase F (EC 3.5.1.52). 相似文献
55.
Clothilde Esteve Ludmila Francescatto Perciliz L. Tan Aurélie Bourchany Cécile De Leusse Evelyne Marinier Arnaud Blanchard Patrice Bourgeois Céline Brochier-Armanet Ange-Line Bruel Arnauld Delarue Yannis Duffourd Emmanuelle Ecochard-Dugelay Géraldine Hery Frédéric Huet Philippe Gauchez Emmanuel Gonzales Catherine Guettier-Bouttier Alexandre Fabre 《American journal of human genetics》2018,102(3):364-374
56.
Physiological responses of beech and sessile oak in a natural mixed stand during a dry summer 总被引:1,自引:0,他引:1
Responses of CO2 assimilation and stomatal conductance to decreasing leaf water potential, and to environmental factors, were analysed in a mixed natural stand of sessile oak (Quercus petraea ssp. medwediewii) and beech (Fagus svlvatica L.) in Greece during the exceptionally dry summer of 1998. Seasonal courses of leaf water potential were similar for both species, whereas mean net photosynthesis and stomatal conductance were always higher in sessile oak than in beech. The relationship between net photosynthesis and stomatal conductance was strong for both species. Sessile oak had high rates of photosynthesis even under very low leaf water potentials and high air temperatures, whereas the photosynthetic rate of beech decreased at low water potentials. Diurnal patterns were similar in both species but sessile oak had higher rates of CO2 assimilation than beech. Our results indicate that sessile oak is more tolerant of drought than beech, due, in part, to its maintenance of photosynthesis at low water potential. 相似文献
57.
Yannis A. Phillis 《Journal of theoretical biology》1981,93(3):541-546
Exponentially growing pollution systems are examined from the point of view of control. A simplified mathematical model is used. Employing optimal control theory, we show that it is not always possible to drive the state (level of pollution) of such a system to a desired level. We prove that the state has to be smaller than certain bound for the system to be controllable. A specific example illustrates these ideas. The importance of this research lies in the fact that it shows the existence of certain state, and, consequently, time limits in the process of controlling the system. 相似文献
58.
Samoilis G Psaroulaki A Vougas K Tselentis Y Tsiotis G 《Journal of proteome research》2007,6(8):3032-3041
Coxiella burnetii, the causative agent of Q fever, is an obligate intracellular gamma-proteobacterium, which replicates within large phagolysosome-like compartments formed in the host cell. The global protein profile of intracellular C. burnetii strain Nine Mile phase II was analyzed by two gel-based approaches coupled to MALDI-TOF MS. Colloidal Coomassie brilliant blue-stained 2-DE gels at the pH range 3-10 resolved over 600 protein spots and 125 spots in doubled-SDS-PAGE gels. Mass spectra obtained for each trypsin-digested protein-spot were compared to the C. burnetii genome database, and a total number of 185 different C. burnetii proteins were identified by both techniques. 2-DE in combination with MALDI-TOF MS, as a high-throughput method, allowed the identification of 172 proteins. On the other hand, the application of doubled-SDS-PAGE allowed the identification of 38 proteins, with some of them being very alkaline and membrane proteins not identified in the 2-DE approach. Most identified proteins were predicted to be involved in metabolism and biosynthesis. Several identified proteins are speculated to have a distinct and vital role in the pathogenesis and survival of C. burnetii within the harsh phagolysosomal environment. 相似文献
59.
60.
Kasper Thorup Yannis Vardanis Anders P. Tøttrup Mikkel Willemoes Kristensen Thomas Alerstam 《Journal of avian biology》2013,44(5):486-494
The timing of migration is generally considered of utmost importance for reproduction and survival, and timing is furthermore considered to be under strong genetic control. The individual timing of migration is presumably a result of a combination of genetic, phenotypic and environmental factors as well as some degree of randomness. However, potential differences in consistency of timing between spring and autumn and between migration strategies are not well studied. Using long‐term Danish ringing data, we study such differences by correlating date of ringing with date of recaptures for a suite of common migrating passerines in Denmark. We found that individuals marked early in one year tended to be recaptured early in the same season in a following year indicating that individuals time their migration in spring or autumn similarly between years. The relationship between spring and autumn migration was overall slightly negative, suggesting that birds arriving early in spring tended to depart late in autumn and vice versa. There were only weak effects of geographical location on timing, suggesting that the patterns found are not primarily caused by different populations being involved. Knowledge of individual consistency in migration timing is needed for understanding changes in migration timing. The consistent patterns of repeatabilities within and between seasons found here highlight the importance of timing of migration in songbirds. 相似文献