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311.
Sample size required for marker assisted selection in improving quantitative traits of self-fertilizing species 总被引:2,自引:0,他引:2
The efficiency of selection for desired trait genotypes in a molecular marker assisted selection for a quantitative trait
in self-fertilizing crop is considered. The QTLs controlling the trait were assumed to be unlinked. It was supposed that the
selection starts in F2, derived from a cross between inbred lines, and this selection will terminate if one or more plants with the desired trait
genotype is found. If no plant with the desired trait genotype is found in F2 then the selection is continued in the F3 progeny that is derived from a single selected F2 plant. Which F2 plant is to be selected was determined according to the rank which is related to the marker genotype of the F2 plants. And this rank was based on the expected frequency of the desired trait genotype in the progeny. The plant with the
top rank among all F2 plants is then selected with the first priority. Additionally the number of F3 plants in the progeny was set to be equal to the number of plants that are required for detecting one or more plants with
the desired trait genotype with a given probability. The probability of getting at least one plant with the desired trait
genotype is expressed as a function of the number of F2 plants (N).The required value for N and the total number of plants (T) in F2 and F3 for detecting at least one plant with the desired trait genotype were calculated for different situations. T was always smaller
for a single marker than for flanking markers. The minimum of T and monotonous decrease of N can be observed when the cumulative-expected-frequency
of selected marker genotypes of F2 plants increased.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
312.
Cistella japonica was inoculated onto the stems of youngChamaecyparis obtusa trees, and the development of external and internal symptoms was investigated for five years. Most lesions started exuding
resin from May to July during the first growing season after inoculation, while a few lesions started exuding resin during
the second growing season. Resin exudation lasted for two successive years on most lesions, and during successive three, four,
or five years on some lesions. Resin exuded excessively in the secondary phloem of the lesions and resin cysts frequently
developed there. The lesions where cambial tissue was necrosed occupied 18% of all the lesions and the resinous areas expanded
to a larger size than those where resin simply exuded in the phloem.Ci. japonica was reisolated from some inoculated lesion tissues at a high frequency. The isolation frequency of the fungus from some lesion
tissues two and more years later was zero or low and that ofCryptosporiopsis abietina was high.
This work was supported by a grant from the Forest Agency of the Japanese Government. 相似文献
313.
Yoshifumi Sawada Tsukasa Sasaki Keisuke Nishio Michio Kurata Tomoki Honryo Yasuo Agawa 《Aquaculture Research》2020,51(6):2261-2274
Jaw malformations are a serious problem in fingerlings of the greater amberjack, Seriola dumerili. To establish a countermeasure against these malformations, we conducted a larval behavioural test to identify their root cause, and we investigated the ability of low‐brightness rearing tank walls to control their occurrence. Larval distribution was examined in a horizontally illuminated rectangular transparent aquarium (20 cm × 100 cm × 25 cm), and their distribution was biased towards the light source after this lighting was provided from 3 to 13 days post hatching (dph), indicating positive phototaxis; this response disappeared on 22 dph (there are no data between 13 and 22 dph). Larvae were observed to swim phototactically towards the light source and repeatedly collided with the tank wall (walling behaviour). To investigate the ability of wall brightness to control the incidence of jaw malformations, we compared their incidence in a rearing trial with different Munsell colour values for the tank walls: 2.11 (black), 5.85 (grey) and 9.52 (white). The incidence rate of jaw malformations at 25 dph was significantly lower in the tanks with lower‐brightness walls, that is, 5.8%, 22.5% and 26.8% for black, grey and white respectively. Larval walling behaviour was most intense for white, followed in order by grey and black. These results indicate that positive phototaxis elicits larval walling behaviour, causing jaw malformations, and that low‐brightness tank walls control this process. 相似文献