全文获取类型
收费全文 | 184篇 |
免费 | 4篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 4篇 |
2014年 | 13篇 |
2013年 | 12篇 |
2012年 | 16篇 |
2011年 | 17篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 10篇 |
2006年 | 7篇 |
2005年 | 11篇 |
2004年 | 14篇 |
2003年 | 9篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有188条查询结果,搜索用时 296 毫秒
91.
Strang-Karlsson S Kajantie E Pesonen AK Räikkönen K Hovi P Lahti J Heinonen K Järvenpää AL Eriksson JG Andersson S Paavonen EJ 《Chronobiology international》2010,27(9-10):1829-1842
The authors explored morningness-eveningness propensity in adults born prematurely at very low birth weight (VLBW; 1500g) and in controls born at term. At age 21 to 29 yrs, 184 participants completed the Morningness-Eveningness Questionnaire (MEQ). Compared with controls, VLBW adults scored higher in morningness propensity (group difference: 2.8 scores, 95% confidence interval: 0.1 to 5.5; p?=?.042). This finding was confined to those VLBW adults whose birth weight was not small for gestational age, and remained similar when adjusting for age, sex, and working conditions. The finding is potentially important, since morningness is associated with beneficial health outcomes. 相似文献
92.
93.
Juha Taavela Outi Koskinen Heini Huhtala Marja-Leena L?hdeaho Alina Popp Kaija Laurila Pekka Collin Katri Kaukinen Kalle Kurppa Markku M?ki 《PloS one》2013,8(10)
Background
Assessment of the gluten-induced small-intestinal mucosal injury remains the cornerstone of celiac disease diagnosis. Usually the injury is evaluated using grouped classifications (e.g. Marsh groups), but this is often too imprecise and ignores minor but significant changes in the mucosa. Consequently, there is a need for validated continuous variables in everyday practice and in academic and pharmacological research.Methods
We studied the performance of our standard operating procedure (SOP) on 93 selected biopsy specimens from adult celiac disease patients and non-celiac disease controls. The specimens, which comprised different grades of gluten-induced mucosal injury, were evaluated by morphometric measurements. Specimens with tangential cutting resulting from poorly oriented biopsies were included. Two accredited evaluators performed the measurements in blinded fashion. The intraobserver and interobserver variations for villus height and crypt depth ratio (VH:CrD) and densities of intraepithelial lymphocytes (IELs) were analyzed by the Bland-Altman method and intraclass correlation.Results
Unevaluable biopsies according to our SOP were correctly identified. The intraobserver analysis of VH:CrD showed a mean difference of 0.087 with limits of agreement from −0.398 to 0.224; the standard deviation (SD) was 0.159. The mean difference in interobserver analysis was 0.070, limits of agreement −0.516 to 0.375, and SD 0.227. The intraclass correlation coefficient in intraobserver variation was 0.983 and that in interobserver variation 0.978. CD3+ IEL density countings in the paraffin-embedded and frozen biopsies showed SDs of 17.1% and 16.5%; the intraclass correlation coefficients were 0.961 and 0.956, respectively.Conclusions
Using our SOP, quantitative, reliable and reproducible morphometric results can be obtained on duodenal biopsy specimens with different grades of gluten-induced injury. Clinically significant changes were defined according to the error margins (2SD) of the analyses in VH:CrD as 0.4 and in CD3+-stained IELs as 30%. 相似文献94.
Katri Raikkonen Eero Kajantie Anu-Katriina Pesonen Kati Heinonen Hanna Alastalo Jukka T. Leskinen Kai Nyman Markus Henriksson Jari Lahti Marius Lahti Riikka Pyh?l? Soile Tuovinen Clive Osmond David J. P. Barker Johan G. Eriksson 《PloS one》2013,8(1)
Objectives
To examine whether the adverse effects of slow prenatal and postnatal growth on cognitive function persist to old age and predict age related cognitive decline.Design and Setting
A longitudinal birth cohort study of men born in Helsinki, Finland 1934-44.Participants
Nine-hundred-thirty-one men of the Helsinki Birth Cohort Study, with detailed data on growth from birth to adulthood, aged 20.1 (SD = 1.4) at the first and 67.9 (SD = 2.5) years at the second cognitive testing.Main Outcome Measures
The Finnish Defense Forces Basic Intellectual Ability Test assessed twice over nearly five decades apart.Results
Lower weight, length and head circumference at birth were associated with lower cognitive ability at 67.9 years (1.04–1.55 points lower ability per each standard deviation [SD] unit decrease in body size, 95% Confidence Interval [95%CI]: 0.05 to 2.72) and with cognitive decline after 20.1 years (0.07–0.11 SD decline over time per each SD decrease in body size, 95%CI:0.00 to 0.19). Men who were born larger were more likely to perform better in the cognitive ability test over time (1.22–1.43 increase in odds to remain in the top relative to the lower two thirds in ability over time per each SD increase in body size, 95%CI:1.04 to 1.79) and were more resilient to cognitive decline after 20.1 years (0.69 to 0.76 decrease in odds to decline from than remain in the top third of ability over time per each SD increase in body size, 95%CI:0.49 to 0.99). Slower growth between birth and two years in weight, height and body mass index was associated with lower cognitive ability at 67.9 years, but not with cognitive decline.Conclusions
Poorer lifetime cognitive ability is predicted by slower growth before and after birth. In predicting resilience to age related cognitive decline, the period before birth seems to be more critical. 相似文献95.
Anna-Maija K. Tiainen Satu M?nnist? Marius Lahti Paul A. Blomstedt Jari Lahti Mia-Maria Per?l? Katri R?ikk?nen Eero Kajantie Johan G. Eriksson 《PloS one》2013,8(7)
Background
Personality traits are associated with health outcomes including non-communicable diseases. This could be partly explained by lifestyle related factors including diet. The personality traits neuroticism, extraversion, openness, agreeableness, and conscientiousness are linked with resilience, meaning adaptability in challenging situations. Resilient people usually comply with favorable health behaviors.Objective
Our objective was to explore the associations between food and nutrient intake, personality traits and resilience.Design
A validated semi-quantitative food frequency questionnaire was used to measure diet and the NEO-personality inventory to assess personality in 1681 subjects. Linear regression analysis was used to explore diet-personality associations and cluster analysis to define resilient and non-resilient personality profiles.Results
Adjusting for age, education and energy intake, and applying Bonferroni corrections, openness in men was associated with higher vegetable (14.9 g/d for 1 SD increase in the personality score, PBonf <0.01) and lower confectionery and chocolate (−2.8 g/d, PBonf <0.01) intakes. In women, neuroticism was associated with lower fish (−4.9 g/d, PBonf <0.001) and vegetable (−18.9 g/d, PBonf <0.01) and higher soft drink (19.9 g/d, PBonf <0.001) intakes. Extraversion, in women, associated with higher meat (5.9 g/d, PBonf <0.05) and vegetable (24.8 g/d, PBonf<0.001) intakes, openness with higher vegetable (23.4 g/d, PBonf <0.001) and fruit (29.5 g/d, PBonf <0.01) intakes. Agreeableness was associated with a lower soft drink (−16.2 g/d, PBonf <0.01) and conscientiousness with a higher fruit (32.9 g/d, PBonf<0.01) intake in women. Comparing resilient and non-resilient subjects, we found resilience in women to be associated with higher intakes of vegetables (52.0 g/d, P<0.001), fruits (58.3 g/d, P<0.01), fish (8.6 g/d, P<0.01) and dietary fiber (1.6 g/d, P<0.01).Conclusion
Personality traits are associated with dietary intake and especially subjects with resilient personality profiles had healthier dietary intakes. These associations were stronger in women than in men. 相似文献96.
Katri Korpela Maria Delgado Heikki Henttonen Erkki Korpimäki Esa Koskela Otso Ovaskainen Hannu Pietiäinen Janne Sundell Nigel G Yoccoz Otso Huitu 《Global Change Biology》2013,19(3):697-710
Small rodents are key species in many ecosystems. In boreal and subarctic environments, their importance is heightened by pronounced multiannual population cycles. Alarmingly, the previously regular rodent cycles appear to be collapsing simultaneously in many areas. Climate change, particularly decreasing snow quality or quantity in winter, is hypothesized as a causal factor, but the evidence is contradictory. Reliable analysis of population dynamics and the influence of climate thereon necessitate spatially and temporally extensive data. We combined data on vole abundances and climate, collected at 33 locations throughout Finland from 1970 to 2011, to test the hypothesis that warming winters are causing a disappearance of multiannual vole cycles. We predicted that vole population dynamics exhibit geographic and temporal variation associated with variation in climate; reduced cyclicity should be observed when and where winter weather has become milder. We found that the temporal patterns in cyclicity varied between climatically different regions: a transient reduction in cycle amplitude in the coldest region, low‐amplitude cycles or irregular dynamics in the climatically intermediate regions, and strengthening cyclicity in the warmest region. Our results did not support the hypothesis that mild winters are uniformly leading to irregular dynamics in boreal vole populations. Long and cold winters were neither a prerequisite for high‐amplitude multiannual cycles, nor were mild winters with reduced snow cover associated with reduced winter growth rates. Population dynamics correlated more strongly with growing season than with winter conditions. Cyclicity was weakened by increasing growing season temperatures in the cold, but strengthened in the warm regions. High‐amplitude multiannual vole cycles emerge in two climatic regimes: a winter‐driven cycle in cold, and a summer‐driven cycle in warm climates. Finally, we show that geographic climatic gradients alone may not reliably predict biological responses to climate change. 相似文献
97.
Jokela TA Makkonen KM Oikari S Kärnä R Koli E Hart GW Tammi RH Carlberg C Tammi MI 《The Journal of biological chemistry》2011,286(38):33632-33640
98.
Savolainen O Kujala ST Sokol C Pyhäjärvi T Avia K Knürr T Kärkkäinen K Hicks S 《The Journal of heredity》2011,102(5):526-536
The adaptive potential of the northernmost Pinus sylvestris L. (and other northern tree) populations is considered by examining first the current patterns of quantitative genetic adaptive traits, which show high population differentiation and clines. We then consider the postglacial history of the populations using both paleobiological and genetic data. The current patterns of diversity at nuclear genes suggest that the traces of admixture are mostly visible in mitochondrial DNA variation patterns. There is little evidence of increased diversity due to admixture between an eastern and western colonization lineage, but no signal of reduced diversity (due to sequential bottlenecks) either. Quantitative trait variation in the north is not associated with the colonizing lineages. The current clines arose rapidly and may be based on standing genetic variation. The initial phenotypic response of Scots pine in the north is predicted to be increased survival and growth. The genetic responses are examined based on quantitative genetic predictions of sustained selection response and compared with earlier simulation results that have aimed at more ecological realism. The phenotypic responses of increased growth and survival reduce the opportunity for selection and delay the evolutionary responses. The lengthening of the thermal growing period also causes selection on the critical photoperiod in the different populations. Future studies should aim at including multiple ecological and genetic factors in evaluating potential responses. 相似文献
99.
Danielsson M Rosenthal-Aizman K Bergsson G Undén A 《Bioorganic & medicinal chemistry letters》2011,21(18):5262-5265
The antimicrobial activity of the peptide enantiomers cyclo[D-Tle-D-Lys-D-Tle-L-Ala-D-Tle-L-Ala-D-Tle-L-Ala] and cyclo[L-Tle-L-Lys-L-Tle-D-Ala-L-Tle-D-Ala-L-Tle-D-Ala] against Bacillus megaterium was investigated. Both these peptides showed very low activity in both an agar diffusion assay and a broth microdilution assay. However, when both peptides were present during the experiments a potent inhibition with an IC(50) value of 2 μM was observed. Furthermore, the peptides also showed low hemolytic activity. Neither peptide had any hemolytic activity in concentrations up to 1mM but when erythrocytes were exposed to both peptides a weak hemolytic activity could be observed with a HC(50) value of 316 μM. 相似文献
100.
Katri Krkkinen Helmi Kuittinen Rob van Treuren Claus Vogl Sami Oikarinen Outi Savolainen 《Evolution; international journal of organic evolution》1999,53(5):1354-1365
Inbreeding depression may be caused by (partially) recessive or overdominant gene action. The relative evolutionary importance of these two modes has been debated; the former mode is emphasized in the “dominance hypothesis,” the latter in the “overdominance hypothesis.” We analyzed the genetic basis of inbreeding depression in the self-incompatible herb Arabis petraea (L.) Lam.: In the selfed progeny of twelve parental plants, we studied the proportion of chlorophyll-deficient seedlings, the genotypic distributions of marker genes, and associations of marker genotypes with viability and quantitative traits. Early components of fitness were examined by scoring seed size, germination time, and early growth rate and by observing the proportion of chlorophyll-deficient seedlings. Later components of fitness, flowering, and root and aboveground biomass were also measured. Marker genotypes of young seedlings were scored for 11 enzyme loci and three microsatellite markers. We found a high proportion (about 70%) of families with chlorophyll-deficient seedlings, indicating a high mutational load. We found six significant deviations from 1:2:1 ratio at marker loci of 60 tests in seedlings, with three of these significant at the experimentwide level. Deviations from the expected ratio were assumed to be due to linked viability loci. A graphical and a Bayesian method were used to distinguish between the overdominance and dominance hypotheses. Most of the deviant segregation ratios suggested overdominance instead of recessivity of the deleterious allele. Neither the early (seed size, germination time, or early growth trait) nor the late quantitative traits (flowering, and root and aboveground biomass) showed significant linkage to markers at the experimentwide level. Presence of significant associations between markers and early viability, but lack thereof for quantitative traits expressed late, suggests either that there may be relatively low inbreeding depression in later life stages or that individual quantitative trait loci may have smaller effects than loci contributing to early viability. 相似文献