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161.
B.A.W. Thompson P.M. Goldsworthy M.J. Riddle I. Snape J.S. Stark 《Journal of experimental marine biology and ecology》2007,340(2):213-226
To investigate the impacts of synthetic lubricants on Antarctic infaunal communities, a field experiment was setup near Australia's Casey Station, East Antarctica. Two types of synthetic lubricants were tested: an ‘Unused’ and ‘Used’ conventional synthetic lubricant, and an alternative marketed as ‘biodegradable’. Clean defaunated sediment was contaminated with the lubricants, decanted into trays, and deployed by divers onto the seabed in a randomised block design. Sediments were sampled 5 and 56 weeks after deployment. After 5 weeks, benthic assemblages that had recruited to the lubricant contaminated sediments were significantly different to those in ‘Control’ sediments, and differences were more pronounced after 56 weeks. Total number of individuals did not significantly differ between treatments after 5 weeks. However, after 56 weeks total individuals in the ‘Control’ sediments were significantly greater than in the contaminated sediments. Nototanais antarcticus (tanaid) and to a lesser extent Monoculodes sp. (gammarid), Tanaid sp. IV and Eudorella sp. (cumacean) had significantly higher abundances in the control sediments after 56 weeks compared to the contaminated sediments. Copepods numerically dominated the benthic assemblages at both sampling times; however, their abundance did not significantly differ across treatments. The community recruiting to the contaminated sediments remained different from that in the ‘Control’ sediments for the duration of the experiment (1 year). The ‘biodegradable’ lubricant was just as environmentally harmful to the Antarctic infauna as the ‘conventional’ lubricant currently used at Australia's Antarctic stations. Our results demonstrate that changes to recruitment are one of the potential environmental consequences of a lubricant spill to Antarctic benthic communities, and reinforce the importance of preventative oil spill management and effective clean-up procedures. Further monitoring of this field experiment will provide much needed information about the long-term impacts by synthetic lubricants in the Antarctic marine environment. 相似文献
162.
Simon Griffiths Luzie Wingen Julian Pietragalla Guillermo Garcia Ahmed Hasan Daniel Miralles Daniel F. Calderini Jignaben Bipinchandra Ankleshwaria Michelle Leverington Waite James Simmonds John Snape Matthew Reynolds 《PloS one》2015,10(3)
Grain weight (GW) and number per unit area of land (GN) are the primary components of grain yield in wheat. In segregating populations both yield components often show a negative correlation among themselves. Here we use a recombinant doubled haploid population of 105 individuals developed from the CIMMYT varieties Weebill and Bacanora to understand the relative contribution of these components to grain yield and their interaction with each other. Weebill was chosen for its high GW and Bacanora for high GN. The population was phenotyped in Mexico, Argentina, Chile and the UK. Two loci influencing grain yield were indicated on 1B and 7B after QTL analysis. Weebill contributed the increasing alleles. The 1B effect, which is probably caused by to the 1BL.1RS rye introgression in Bacanora, was a result of increased GN, whereas, the 7B QTL controls GW. We concluded that increased in GW from Weebill 7B allele is not accompanied by a significant reduction in grain number. The extent of the GW and GN trade-off is reduced. This makes this locus an attractive target for marker assisted selection to develop high yielding bold grain varieties like Weebill. AMMI analysis was used to show that the 7B Weebill allele appears to contribute to yield stability. 相似文献
163.
J. Baruah-Wolff W. A. Harwood D. A. Lonsdale A. Harvey R. Hull J. W. Snape 《Plant cell reports》1999,18(9):715-720
Transformed rice plants of var `TN1' were regenerated from immature embryos following particle bombardment with a construct
containing the firefly luciferase gene as a reporter gene and the hygromycin resistance gene as a selectable marker. Expression
of the luciferase gene in the presence of the substrate luciferin was visualised in the calli derived from bombarded immature
embryos and in the leaves and roots of the regenerated transformed plants using a low light imaging system (luminograph).
Embryogenic callus proliferation and plant regeneration were unaffected by luciferin treatment and luminograph screening.
The quantitative Luc assay using samples of leaf tissue from the segregating generations gave early information about the
homozygous and hemizygous state of the luc transgene.
Received: 25 August 1998 / Revision received: 2 November 1998 / Accepted: 13 November 1998 相似文献
164.
L. A. Sitch J. W. Snape S. J. Firman 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,70(3):309-314
Summary Intrachromosomal mapping studies were used to locate the positions of the genes Kr1 and Kr2, which control the crossability of wheat with Hordeum bulbosum, on chromosomes 5B and 5A, respectively. The location of Kr1 was established using the telocentric mapping technique and found to be on the long arm of chromosome 5B, distal to the centromere with a mean recombination frequency of 44.8±3.28%. Kr2 was located on the long arm of chromosome 5A by linkage with the major gene markers Vrn1, controlling vernalization requirement, and q, controlling ear morphology. Kr2 is closely linked to Vrn1, with a mean recombination frequency of 4.8±4.66%, and is distal to q with a mean recombination frequency of 38.1±10.60%. The similar locations of Kr1 and Kr2 on homoeologous chromosomes suggest that these two loci are homoeoallelic. Significant correlations between Hordeum bulbosum and rye crossability confirmed that Kr1 and Kr2 control the crossability of wheat with both species. 相似文献
165.
166.
Y. Z. Tao J. W. Snape H. Hu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,81(3):369-375
Summary Anther culture, when applied to hexaploid triticale×wheat hybrids, offers the opportunity to re-assort wheat D genome and rye R genome chromosomes into homozygous doubled haploid lines in a single generation. The characterisation of such lines is the first step in their utilisation in wheat improvement. Two lines, M24 and M25 from the cross of Beagle×Kedong 58, and one line, M27, from the cross Beagle×Jinghua No. 1 have been characterised using different methods including conventional cytology and chromosome banding, and by using marker systems for storage protein composition (glutenins and gliadins), isozymes (-amylase, aminopeptidase, glutamate oxaloacetic transaminase (GOT)) and RFLP markers. The results from all approaches were consistent in proving that M24 is a whole chromosome 6R/6D substitution line, while M25 and M27 are whole chromosome 1R/1D substitution lines. The relative advantages and disadvantages of each method of identification are also discussed. 相似文献
167.
The basolateral membrane of mouse duodenal enterocytes can be selectively labelled in vitro with 59Fe by incubating intact enterocytes with 59Fe(III)-nitrilotriacetate at 0-4 degrees C. It has been proposed that this labelling represents binding to a site important in the transfer of intracellular Fe to the portal plasma (Snape, S., Simpson, R.J. and Peters, T.J. (1990) Cell Biochem. Funct. 8, 107-115). Studies presented here show binding to intact enterocytes in vitro was complete within 1 h and was proportional to enterocyte protein concentration. Binding to enterocytes isolated from both normal and chronically hypoxic mice showed a hyperbolic dependence on medium Fe(III) concentration, consistent with a single class of binding sites. Neither apparent binding constant nor maximal binding were increased by hypoxic exposure of mice, suggesting that the increased in vivo labelling of this site in hypoxia is not due to an increase in affinity or capacity of this site for iron. Release of iron from intact enterocytes, labelled at 0-4 degrees C, was measured at 37 degrees C and 0-4 degrees C. Release of 59Fe was extensive and more rapid at 37 degrees C with highest release to mouse serum. Iron released to serum was found to be bound to transferrin. Prior dialysis of serum against buffer led to complete failure of enterocytes to release iron. Reconstituting serum by adding back the dialysate restores release to levels seen in fresh serum, suggesting that low molecular weight serum components, notably bicarbonate, mediate iron transfer from the basolateral membrane to serum transferrin. The properties of the basolateral membrane iron binding site described here are consistent with a role in the iron transfer process. 相似文献
168.
169.
J. W. Snape 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1982,62(2):127-134
Summary Genetical analysis of the F2 triple test cross design combined with conventional early generations was used to elucidate the genetical control of yield and yield components in two crosses of winter wheat. From estimates of the additive, {d}, and additive X additive, {i}, components of means, together with the additive genetical variance, D, predicted frequencies of recombinant inbred lines that would transgress the parental range were calculated for each cross. The accuracy of predictions was evaluated by comparing expected frequencies with observed numbers in populations of F6 lines previously developed by single seed descent.For both crosses and all characters where an adequate genetical model was found to explain the observed variation between the early generations, good agreement between predicted and observed frequencies of transgressive segregants was obtained. Furthermore, for characters exhibiting significant epistasis, allowance for additive X additive {i} epistasis in the prediction equations was sufficient to allow for skewness of the recombinant inbred population.These results demonstrate that cross performance in wheat can be predicted from genetical analysis of early generations, and the value of this approach in breeding new varieties is discussed. 相似文献
170.
Bayesian adaptive sequence alignment algorithms 总被引:3,自引:1,他引:2
The selection of a scoring matrix and gap penalty parameters continues to
be an important problem in sequence alignment. We describe here an
algorithm, the 'Bayes block aligner, which bypasses this requirement.
Instead of requiring a fixed set of parameter settings, this algorithm
returns the Bayesian posterior probability for the number of gaps and for
the scoring matrices in any series of interest. Furthermore, instead of
returning the single best alignment for the chosen parameter settings, this
algorithm returns the posterior distribution of all alignments considering
the full range of gapping and scoring matrices selected, weighing each in
proportion to its probability based on the data. We compared the Bayes
aligner with the popular Smith-Waterman algorithm with parameter settings
from the literature which had been optimized for the identification of
structural neighbors, and found that the Bayes aligner correctly identified
more structural neighbors. In a detailed examination of the alignment of a
pair of kinase and a pair of GTPase sequences, we illustrate the
algorithm's potential to identify subsequences that are conserved to
different degrees. In addition, this example shows that the Bayes aligner
returns an alignment-free assessment of the distance between a pair of
sequences.
相似文献