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31.
The extent of genetic diversity and the genetic relationships among 94 coconut varieties/populations (51 Talls and 43 Dwarfs)
representing the entire geographic range of cultivation/distribution of the coconut was assessed using 12 pairs of coconut
micro satellite primers. A high level of genetic diversity was observed in the collection with the mean gene diversity of
0.647±0.139, with that of the mean gene diversity of Talls 0.703±0.125 and 0.374±0.204 of Dwarfs. A phenetic tree based on
DAD genetic distances clustered all the 94 varieties/populations into two main groups, with one group composed of all the Talls
from southeast Asia, the Pacific, west coast of Panama, and all Dwarfs and the other of all Talls from south Asia, Africa,
and the Indian Ocean coast of Thailand. The allele distribution of Dwarfs highlighted a unique position of Dwarf palms from
the Philippines exhibiting as much variation as that in the Tall group. The grouping of all Dwarfs representing the entire
geographic distribution of the crop with Talls from southeast Asia and the Pacific and the allele distribution between the
Tall and Dwarf suggest that the Dwarfs originated from the Tall forms and that too from the Talls of southeast Asia and the
Pacific. Talls from Pacific Islands recorded the highest level of genetic diversity (0.6±0.26) with the highest number of
alleles (51) among all the regions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
32.
Assessment of EST- and genomic microsatellite markers for variety discrimination and genetic diversity studies in wheat 总被引:22,自引:0,他引:22
Fiona Leigh Vince Lea John Law Petra Wolters Wayne Powell Paolo Donini 《Euphytica》2003,133(3):359-366
It is likely that in the near future sequence information from sequencing programmes and EST libraries will generate an abundance
of genic microsatellite markers. This study is focused on the assessment of their likely impact and performance vis-à-vis
their genomic counterparts. Microsatellites from two sources were used to assess the genetic diversity in 56 old and new varieties
of bread wheat on the UK Recommended List. A set of 12 microsatellite markers generated from genomic libraries and 20 expressed
sequence tag (EST)-derived microsatellites were used in the study, and the performance of both marker sets assessed. The EST-derived
or genic microsatellites delivered fingerprints of superior quality, amplifying clear products with few stutter bands. Diversity
levels as revealed bygenic microsatellites are similar to the few published results. The PIC values for the genic markers
were generally lower than those calculated for the genomic microsatellites, though advantages of both marker classes for variety
identification applications are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
33.
A.H. Marshall T.P.T. Michaelson-Yeates M.T. Abberton A. Williams H.G. Powell 《Euphytica》2002,126(2):195-201
Interspecific hybridisation with Trifolium nigrescens Viv. is a possible strategy to improve the reproductive potential of white clover (Trifolium repens L.). Following the development of a fertile F1 hybrid, three generations of backcrossing have been carried out usingT. repens as the recurrent parent. Vegetative characteristics, stolon growth and seed yield components of the backcross (BC) 2 and
3 generations, as well as the parental species were measured on spaced plants grown in the field. Leaf size and plant spread
of the BC2 and BC3 generations were less than T. repens but there was no difference in plant fresh weight. Numbers of inflorescences per plant and florets per inflorescence of the
backcrosses were greater than T. repens however this was not reflected indifferences in seed yield per plant asT. repens had more seeds per floret and per plant than the backcrosses. Differences in stolon length, the proportion of flowering nodes
and the pattern of axillary bud development were observed between T. repens and the backcrosses. Significant variation among the BC 3 generation for vegetative and reproductive traits was observed.
Individual plants among the BC 3 generation were identified that combine high forage yield, substantial inflorescence production
and good fertility, and these will form the basis of further selection.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
34.
35.
Induction of HTLV-III/LAV from a nonvirus-producing T-cell line: implications for latency 总被引:42,自引:0,他引:42
T Folks D M Powell M M Lightfoote S Benn M A Martin A S Fauci 《Science (New York, N.Y.)》1986,231(4738):600-602
When the human T-cell line A3.01 is infected with HTLV-III/LAV, the virus associated with the acquired immune deficiency syndrome (AIDS), most of the cells are killed. However, a small number of cells that lack the Leu-3 surface marker survive. Under normal conditions these surviving cells do not produce virus, nor can they be infected by the virus, but they can be induced to produce virus by treatment with 5-iodo-2'-deoxyuridine. This response can be induced for as long as 3 months after the initial infection, suggesting that the cells may harbor a latent form of HTLV-III/LAV. 相似文献
36.
Powell JW 《Science (New York, N.Y.)》1884,3(64):511-513
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39.
Analysis of several well-documented specimens from each of the three volcanic series on Oahu gives the following mean ratios of Sr(87) to Sr(86): the Waianae series, 0.7030 +/- 0.00010 (sigma); the Koolau series, 0.70385+/- 0.00009 (sigma); and the Honolulu series, 0.7029 ++/- 0.00006 ( sigma). The mean ratio of Sr(87) to Sr(86) of the Koolau series specimens is significantly higher than the means of the other two series. With one exception, significant differences in Sr(87)/ Sr(86) within a series were not found, even though some large compositional differences existed. 相似文献
40.