全文获取类型
收费全文 | 126篇 |
免费 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 7篇 |
2012年 | 6篇 |
2011年 | 8篇 |
2010年 | 10篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 3篇 |
2005年 | 7篇 |
2004年 | 12篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1994年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有127条查询结果,搜索用时 33 毫秒
41.
Hereditary variation of 5 immunological systems coded by 8 loci was compared in 148 couples and 100 women with repeated spontaneous abortions in anamnesis (experimental group) and 141 couples and 100 women with normal fertility (control group). Marked differences in distributions of genotypes and frequencies of 3 systems (MNSs, Rhesus, Duffy) and frequency of AB0-incompatible couples were found between control and experimental groups. An average value of observed heterozygosity in experimental group was lower, as compared to the expected value. Possible influence of immunological factors on recurrent fetal wastage is discussed. 相似文献
42.
The sex, age, tribal, and surname compositions of the populations of three villages of Altai Republic, Kulada (Ongudaisk raion), Beshpeltir (Chemal raion), and Kurmach-Baigol (Turochak raion) have been studied. Altaian populations are characterized by a high proportion of persons under 20 years of age (35.3-46.1%); however, there is a tendency towards a narrow base of the sex-age pyramid. The sex ratios in the total populations and in individual age groups are unfavorable. The rural populations studied differ in the spectrum and pattern of surname accumulation. The Kurmach-Baigol population (which consists of Northern Altaians) considerably differs from the Beshpeltir and Kulada populations (which are mostly Southern Altaian) with respect to the calculated parameters characterizing the population structure (random isonymy, migration index, the parameter of tribe diversity, entropy, and the redundancy of surname distribution). Isonymy coefficients of relationship between individual populations have been calculated from the data on tribes (surnames). These coefficients for pairs of populations are the following: for the Beshpeltir and Kulada populations, 0.3035938 (0.0000443 and 0.0000378 for the Altaian and total populations, respectively); for the Beshpeltir and Kurmach-Baigol populations, 0.0026788 (0.0000172 and 0.0000121 for the Altaian and total populations, respectively); and for the Kulada and Kurmach-Baigol populations, 0.0054811 (no common surnames have been found). 相似文献
43.
The dynamics of population marriage structure in the period from 1951 to 1997 has been studied in three villages of Altai Republic: Kulada (Ongudaisk raion), Beshpeltir (Chemal raion), and Kurmach-Baigol (Turochak raion). These populations have been found to differ from one another in the intensity and direction of migration, as well a its temporal pattern with respect to the birthplaces and ethnicity of persons contracting marriages. Periods of active incorporation of non-Altaian (mostly Slavic) ethnic components into the gene pools of the Beshpeltir and Kurmach-Baigol populations have been detected. The geographic distributions of the birthplaces of men and women contracting marriages are different. Therefore, migration has different effects on the genetic diversity of the Y-chromosomal and mitochondrial-DNA pools. No isonymic marriages have been found in the Altaian populations studied; however, an increase in the random component of inbreeding has been observed. 相似文献
44.
ACE and AGTR1 genes polymorphisms in left ventricular hypertrophy pathogenesis in humans 总被引:2,自引:0,他引:2
Makeeva OA Puzyrev KV Pavliukova EN Koshel'skaia OA Golubenko MV Efimova EV Kucher AN Tsimbaliuk IV Karpov RS Puzyrev VP 《Molekuliarnaia biologiia》2004,38(6):990-996
The role of A2350G polymorphism in exon 17 of the ACE gene and A1166C - in 3'-UTR of the AGTR1 in the pathogenesis of left ventricular hypertrophy was studied in patients with essential hypertension (EH) and arterial hypertension combined with diabetes mellitus type 2 (AH + DM2). Patients with EH and AH + DM2 did not differ from the control sample of healthy individuals by allele or genotype frequencies. However, an association of both polymorphisms with LVH was detected in EH patients. The frequency of 1166C allele was higher in patients with LVH (33.6% vs 20.7% without LVH). A1166C polymorphism determined the magnitude of left ventricular mass index (LVMI) in EH patients as well (p = 0.007). 2350G allele frequency of the ACE gene was in 1.5, and GG genotype--in 3.5-fold higher in EH patients with LVH, as compared without LVH. LVMI was significantly higher in patients with GG genotype as compared with heterozygotes and AA homozygotes (p = 0.002). Thus the presence of 1166C allele of AGTR1 and 2350G allele of ACE can be considered as predisposing factors for LVH development in EH. In contrast, association of studied polymorphisms with presence or LVH degree was not detected in patients with arterial hypertension combined with DM2. This may indicate another structure of genetic component of predisposition to LVH in different causes. 相似文献
45.
Loss of phylogenetic information in chorion gene families of Bombyx mori gene conversion 总被引:1,自引:0,他引:1
Regier JC; Weigmann BM; Leclerc RF; Friedlander TP 《Molecular biology and evolution》1994,11(1):72-87
The silkmoth chorion has provided a stimulating model for the study of
evolution and developmental regulation of gene families. Previous attempts
at inferring relationships among chorion sequences have been based on
pairwise comparisons of overall similarity, a potentially problematic
approach. To remedy this, we identified the alignable regions of low
sequence variability and then analyzed this restricted database by
parsimony and neighbor-joining methods. At the deepest level, the chorion
sequence tree is split into two branches, called "alpha" and "beta." Within
each branch, early- and late-expressing genes each constitute monophyletic
groups, while the situation with middle-expressing genes remains uncertain.
The HcB gene family appears to be the most basal beta-branch group, but
this conclusion is qualified because the effect of gene conversion on
branching order is unknown. Previous studies by Eickbush and colleagues
have strongly suggested that ErA, HcA, and HcB families undergo gene
conversion within a gene family, whereas the ErB family does not. The
occurrence of conversion correlates with a particular tree structure;
namely, branch lengths are much greater at the base of the family than at
higher internodes and terminal branches. These observations raise the
possibility that chorion gene families are defined by gene conversion
events (reticulate evolution) rather than by descent with modification
(synapomorphy).
相似文献
46.
It was shown that women from the studied group of married couples, suffering from repeated spontaneous abortions (the main group), have earlier menarche and their husbands are taller, as compared with the control group of couples with normal reproductive performance. The degree of similarity between mates in age and stature appeared to be lower in the main group than in the control group. The variation of the characters under study is supposed to provide an auxiliary criterion in selecting couples at high risk of repeated spontaneous abortions. 相似文献
47.
This article is a review of scientific publications, in which issues of pathogenetics of multifactorial diseases (MFDs) are
considered from the viewpoint of evolution and ontogeny. Concepts explaining significance of evolutionary processes in the
formation of genetic architecture of human chronic diseases (“thrifty” genomes and phenotypes, “drifty genes,” decanalization)
are analyzed. The roles of natural selection and genetic drift in the formation of hereditary diversity of genes for susceptibility
to MFDs are considered. The modern concept of “disease ontogeny” (somatic mosaicism, loss of heterozygosity, paradominant
inheritance, epigenetic variability) is discussed. It is demonstrated that the evolutionary and ontogenetic approaches to
analysis of genimuc and other “-omic” data are essential for understanding the biology of diseases. 相似文献
48.
Ingar M Zielinski Marijtje LA Jongsma C Marjolein Baas Pauline BM Aarts Bert Steenbergen 《BMC neurology》2014,14(1):1-9
Background
In a subset of children with unilateral Cerebral Palsy (CP) a discrepancy between capacity and performance of the affected upper limb can be observed. This discrepancy is known as Developmental Disregard (DD). Though the phenomenon of DD has been well documented, its underlying cause is still under debate. DD has originally been explained based on principles of operant conditioning. Alternatively, it has been proposed that DD results from a diminished automaticity of movements, resulting in an increased cognitive load when using the affected hand. To investigate the amount of involved cognitive load we studied Event-Related Potentials (ERPs) preceding task-related motor responses during a single-hand capacity and a dual-hand performance task. It was hypothesised that children with DD show alterations related to long-latency ERP components when selecting a response with the affected upper limb, reflecting increased cognitive load in order to generate an adequate response and especially so within the dual-hand task.Methods
Fifteen children with unilateral CP participated in the study. One of the participants was excluded due to major visual impairments. Seven of the remaining participants displayed DD. The other seven children served as a control group. All participants performed two versions of a cue-target paradigm, a single-hand capacity and a dual-hand performance task. The ERP components linked to target presentation were inspected: the mid-latency P2 component and the consecutive long-latency N2b component.Results
In the dual-hand performance task children with DD showed an enhancement in mean amplitude of the long-latency N2b component when selecting a response with their affected hand. No differences were found regarding the amplitude of the mid-latency P2 component. No differences were observed regarding the single-hand capacity task. The control group did not display any differences in ERPs linked to target evaluation processes between both hands.Conclusion
These electrophysiological findings show that DD is associated with increased cognitive load when movements are prepared with the affected hand during a dual-hand performance task. These findings confirm behavioural observations, advance our insights on the neural substrate of DD and have implications for therapy. 相似文献49.
Nicoline BM Voet Gijs Bleijenberg George W Padberg Baziel GM van Engelen Alexander CH Geurts 《BMC neurology》2010,10(1):56
Background
In facioscapulohumeral dystrophy (FSHD) muscle function is impaired and declines over time. Currently there is no effective treatment available to slow down this decline. We have previously reported that loss of muscle strength contributes to chronic fatigue through a decreased level of physical activity, while fatigue and physical inactivity both determine loss of societal participation. To decrease chronic fatigue, two distinctly different therapeutic approaches can be proposed: aerobic exercise training (AET) to improve physical capacity and cognitive behavioural therapy (CBT) to stimulate an active life-style yet avoiding excessive physical strain. The primary aim of the FACTS-2-FSHD (acronym for Fitness And Cognitive behavioural TherapieS/for Fatigue and ACTivitieS in FSHD) trial is to study the effect of AET and CBT on the reduction of chronic fatigue as assessed with the Checklist Individual Strength subscale fatigue (CIS-fatigue) in patients with FSHD. Additionally, possible working mechanisms and the effects on various secondary outcome measures at all levels of the International Classification of Functioning, Disability and Health (ICF) are evaluated.Methods/Design
A multi-centre, assessor-blinded, randomized controlled trial is conducted. A sample of 75 FSHD patients with severe chronic fatigue (CIS-fatigue ≥ 35) will be recruited and randomized to one of three groups: (1) AET + usual care, (2) CBT + usual care or (3) usual care alone, which consists of no therapy at all or occasional (conventional) physical therapy. After an intervention period of 16 weeks and a follow-up of 3 months, the third (control) group will as yet be randomized to either AET or CBT (approximately 7 months after inclusion). Outcomes will be assessed at baseline, immediately post intervention and at 3 and 6 months follow up.Discussion
The FACTS-2-FSHD study is the first theory-based randomized clinical trial which evaluates the effect and the maintenance of effects of AET and CBT on the reduction of chronic fatigue in patients with FSHD. The interventions are based on a theoretical model of chronic fatigue in patients with FSHD. The study will provide a unique set of data with which the relationships between outcome measures at all levels of the ICF could be assessed.Trial registration
Dutch Trial Register, NTR1447.50.
A. N. Kucher A. L. Danilova L. A. Koneva A. N. Nogovitsina 《Russian Journal of Genetics》2006,42(12):1452-1459
The genetic demographic structure of 12 rural populations from eight uluses of Sakha Republic (Yakutia) has been analyzed. The ethnic, sex, and age composition of the population and the reproductive parameters of women that have completed and have not completed the reproductive period are reported. Crow’s indices have been estimated in representatives of three indigenous ethnic groups (Yakuts, Evens, and Evenks). 相似文献