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91.
Lathe WC rd; Burke WD; Eickbush DG; Eickbush TH 《Molecular biology and evolution》1995,12(6):1094-1105
R1 is a non-long terminal repeat (non-LTR) retrotransposable element that
inserts into a specific sequence of insect 28S ribosomal RNA genes. We have
previously shown that this element has been maintained through vertical
transmission in the melanogaster species subgroup of Drosophila. To address
whether R1 elements have been vertically transmitted for longer periods of
evolutionary time, the analysis has been extended to 11 other species from
four species groups of the genus Drosophila (melanogaster, obscura,
testecea, and repleta). All sequenced elements appeared functional on the
basis of the preservation of their open-reading frames and consistently
higher rate of substitution at synonymous sites relative to replacement
sites. The phylogenetic relationships of the R1 elements from all species
analyzed were congruent with the species phylogenies, suggesting that the
R1 elements have been vertically transmitted since the inception of the
Drosophila genus, an estimated 50-70 Mya. The stable maintenance of R1
through the germ line appears to be the major mechanism for the widespread
distribution of these elements in Drosophila. In two species, D.
neotestecea of the testecea group and D. takahashii of the melanogaster
group, a second family of R1 elements was also present that differed in
sequence by 46% and 31%, respectively, from the family that was congruent
with the species phylogeny. These second families may represent occasional
horizontal transfers or, alternatively, they could reflect the ability of
R1 elements to diverge into new families within a species and evolve
independently.
相似文献
92.
The diversity and complexity of the uterine mRNA population has been compared at two different stages of uterine growth and development in the rat. Analysis by cDNA hybridization to homologous mRNA indicates that there are 8000 different sequences expressed in the immature rat uterus responding to just 4 h of oestradiol-17 beta-induced growth while the fully developed uterus expresses 36 000 sequences. As a check on our results, the complexity is re-analysed by hybridization of mercurated mRNA to total unique DNA. Analysis by this method indicates that the hormone-stimulated immature rat uterus contains 12 000 poly(A)-containing mRNA sequences while the fully differentiated adult tissue contains 53 000 diverse sequences. 相似文献
93.
The detection of messenger ribonucleic acid sequences in heterogeneous nuclear ribonucleic acid fractions of the oestrogen-stimulated rat uterus.
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Active xanthine oxidase was labelled specifically with 33S in the cyanide-labile site of the molybdenum centre. The Very Rapid molybdenum (V) e.p.r. signal, generated from this, shows strong coupling of 33S to molybdenum, providing unambiguous evidence that, at least in the signal-giving species, this sulphur atom is a ligand of molybdenum. The structure of the signal-giving species is discussed. 相似文献
94.
Collins-Schramm HE Phillips CM Operario DJ Lee JS Weber JL Hanson RL Knowler WC Cooper R Li H Seldin MF 《American journal of human genetics》2002,70(3):737-750
Mapping by admixture linkage disequilibrium (MALD) is a potentially powerful technique for the mapping of complex genetic diseases. The practical requirements of this method include (a) a set of markers spanning the genome that have large allele-frequency differences between the parental ethnicities contributing to the admixed population and (b) an understanding of the extent of admixture in the study population. To this end, a DNA-pooling technique was used to screen microsatellite and diallelic insertion/deletion markers for allele-frequency differences between putative representatives of the parental populations of the admixed Mexican American (MA) and African American (AA) populations. Markers with promising pooled differences were then confirmed by individual genotyping in both the parental and admixed populations. For the MA population, screening of >600 markers identified 151 ethnic-difference markers (EDMs) with delta>0.30 (where delta is the absolute value of each allele-frequency difference between two populations, summed over all marker alleles and divided by two) that are likely to be useful for MALD analysis. For the AA population, analysis of >400 markers identified 97 EDMs. In addition, individual genotyping of these markers in Pima Amerindians, Yavapai Amerindians, European American (EA) individuals, Africans from Zimbabwe, MA individuals, and AA individuals, as well as comparison to the CEPH genotyping set, suggests that the differences between subpopulations of an ethnicity are small for many markers with large interethnic differences. Estimates of admixture that are based on individual genotyping of these markers are consistent with a 60% EA:40% Amerindian contribution to MA populations and with a 20% EA:80% African contribution to AA populations. Taken together, these data suggest that EDMs with large interpopulation and small intrapopulation differences can be readily identified for MALD studies in both AA and MA populations. 相似文献
95.
Alka Malhotra Sayuko Kobes Clifton Bogardus William C. Knowler Leslie J. Baier Robert L. Hanson 《PloS one》2014,9(7)
Background
Genotype imputation is commonly used in genetic association studies to test untyped variants using information on linkage disequilibrium (LD) with typed markers. Imputing genotypes requires a suitable reference population in which the LD pattern is known, most often one selected from HapMap. However, some populations, such as American Indians, are not represented in HapMap. In the present study, we assessed accuracy of imputation using HapMap reference populations in a genome-wide association study in Pima Indians.Results
Data from six randomly selected chromosomes were used. Genotypes in the study population were masked (either 1% or 20% of SNPs available for a given chromosome). The masked genotypes were then imputed using the software Markov Chain Haplotyping Algorithm. Using four HapMap reference populations, average genotype error rates ranged from 7.86% for Mexican Americans to 22.30% for Yoruba. In contrast, use of the original Pima Indian data as a reference resulted in an average error rate of 1.73%.Conclusions
Our results suggest that the use of HapMap reference populations results in substantial inaccuracy in the imputation of genotypes in American Indians. A possible solution would be to densely genotype or sequence a reference American Indian population. 相似文献96.
4 h after a single precocious administration of oestrogen there was a considerable but short-lived surge in the uterine levels of myc-encoded polyadenylated mRNA. This was followed by a further peak 28 h after hormone administration. The expression of rasHa showed a totally different time course with a build up of hybridizable message that peaked 8 h after oestrogen administration. 相似文献
97.
Lifestyle Interventions Limit Gestational Weight Gain in Women with Overweight or Obesity: LIFE‐Moms Prospective Meta‐Analysis
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Alan M. Peaceman Rebecca G. Clifton Suzanne Phelan Dympna Gallagher Mary Evans Leanne M. Redman William C. Knowler Kaumudi Joshipura Debra Haire‐Joshu Susan Z. Yanovski Kimberly A. Couch Kimberly L. Drews Paul W. Franks Samuel Klein Corby K. Martin Xavier Pi‐Sunyer Elizabeth A. Thom Linda Van Horn Rena R. Wing Alison G. Cahill the LIFE‐Moms Research Group 《Obesity (Silver Spring, Md.)》2018,26(9):1396-1404
Objective
This study aimed to evaluate the effects of varied lifestyle intervention programs designed to ameliorate excess gestational weight gain (GWG) in pregnant women with overweight or obesity compared with standard care, including effects on pregnancy outcomes.Methods
Seven clinical centers conducted separate randomized clinical trials to test different lifestyle intervention strategies to modify GWG in diverse populations. Eligibility criteria, specific outcome measures, and assessment procedures were standardized across trials. The results of the separate trials were combined using an individual‐participant data meta‐analysis.Results
For the 1,150 women randomized, the percent with excess GWG per week was significantly lower in the intervention group compared with the standard care group (61.8% vs. 75.0%; odds ratio [95% CI]: 0.52 [0.40 to 0.67]). Total GWG from enrollment to 36 weeks' gestation was also lower in the intervention group (8.1 ± 5.2 vs. 9.7 ± 5.4 kg; mean difference: ?1.59 kg [95% CI:?2.18 to ?0.99 kg]). The results from the individual trials were similar. The intervention and standard care groups did not differ in preeclampsia, gestational diabetes, cesarean delivery, or birth weight.Conclusions
Behavioral lifestyle interventions focusing primarily on diet and physical activity among women with overweight and obesity resulted in a significantly lower proportion of women with excess GWG. This modest beneficial effect was consistent across diverse intervention modalities in a large, racially and socioeconomically diverse US population of pregnant women.98.
The phosphorylation of the proteins of rat liver heterogeneous ribonucleoprotein particles by an endogenous kinase activity 总被引:2,自引:0,他引:2
An endogenous protein kinase activity of liver heterogeneous nuclear ribonucleoprotein particles has been characterized and the particle proteins which it phosphorylates in vitro have been fractionated on two-dimensional polyacrylamide gels. The activity is dependent on Mg2+ and is further stimulated by cyclic AMP, polyamines and Mn2+. 相似文献
99.
Three methods were used to study the effect of oestrogen on the incorporation of radioactive precursor into uterine protein. Intact tissue was incubated in vitro. Isolated uterine epithelial, stromal and myometrial cells were labelled in vitro. Isolated polysomes were translated in cell free protein synthesising systems. In all of these systems, minor qualitative changes in protein synthesis were detected where the uteri were derived from oestrogen-treated rats. These changes were most dramatic in isolated stromal cells and were accompanied by a marked overall increase in protein synthesis. The translation of mRNA on isolated uterine polysomes revealed a sequence of minor, but reproducible, oestradiol-induced changes. It was difficult, however, to relate these changes to those detected in incubated tissue or cells, possibly because the cell free translation products were not subject to normal post-translational modification and processing. 相似文献
100.