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41.
Harder DE 《Phytopathology》1999,89(12):1214-1217
ABSTRACT Infection types produced by Puccinia graminis f. sp. avenae on plants of Avena sativa with the stem rust resistance gene Pg10 are characterized by moderate-sized uredinia surrounded by an area of chlorosis and a larger variable zone of dark brown necrosis. This study was undertaken to assess the effectiveness of gene Pg10 as a source of resistance to stem rust and to determine the interactions of this gene with other common Pg genes. A derived Pg10 line was tested with 58 distinct pathotypes of P. graminis f. sp. avenae and was crossed to substituted single-gene lines carrying the resistance gene Pg1, Pg2, Pg3, Pg4, Pg8, Pg9, Pg13, Pg15, Pg16, or Pga. The Pg10 line showed moderate resistance to all 58 patho-types, and there was no indication of specificity in virulence by any isolate. Gene Pg10 was inherited independently of the other Pg genes and had a complementary effect on the expression of resistance by these genes. An effective level of resistance conferred by Pg10 was demonstrated in a field nursery artificially inoculated with P. graminis f. sp. avenae. It was concluded that Pg10 is a potentially useful source of stem rust resistance in oat breeding, with its main attributes being an apparent broad base of resistance, ease of combining with other Pg genes, and complementary effects on the expression of other Pg genes. 相似文献
42.
Harder MA Fowler D Pharr JW Tryon KA Shmon C 《The Canadian veterinary journal. La revue veterinaire canadienne》2002,43(5):365-368
Ultrasonography, angiography, magnetic resonance imaging, and exploratory laparotomy of a 2-year-old wheaten terrier with lethargy, exercise intolerance, and ascites revealed segmental aplasia of the caudal vena cava with azygos continuation, complicated by thrombus formation. Surgeries were performed on the blind-ended vessel to remove thrombi, enhancing shunting of blood through the azygos vein. 相似文献
43.
Lutaaya E Misztal I Mabry JW Short T Timm HH Holzbauer R 《Journal of animal science》2002,80(9):2263-2266
Data from two purebred swine lines A (n = 6,022) and B (n = 24,170), and their reciprocal, cross C (n = 6,135), were used to examine gains in reliability of combined purebred and crossbred evaluation over conventional within-line evaluations using crossbred and pureline models. Random effects in the pureline model included additive, parental dominance, and litter. In the crossbred model, effects were as in the pureline model except traits of each line were treated as separate traits and two additive effects were present. The approximate model was the same as the pureline except it was used for all lines disregarding breed differences. The traits in the evaluation were lifetime daily gain (LDG) and backfat. When separate line evaluations were replaced by evaluations with crossbreds, mean reliabilities of predicted breeding values increased by 2 to 9% for purebreds and by 21 to 72% for crossbreds. Rank correlations between these breeding values were > 0.99 for purebreds but 0.85 to 0.87 for crossbreds. Rank correlations between predicted breeding values obtained from crossbred and approximate models were 0.98 to 0.99 for purebreds and 0.96 to 0.98 for crossbreds. When the number of crossbreds was small in comparison to purebreds, the increase in reliability by using the crossbred data and the crossbred model as opposed to purebred models was small for purebreds but large for crossbreds. The approximate model provided very similar rankings to the crossbred model for purebreds but rankings were less consistent for crossbreds. 相似文献
44.
A tension band technique was used in conjunction with a transarticular pin to stabilise 24 sacroiliac separations in 19 cats. The authors suggest that this technique is simpler and safer than the transarticular screw technique, and as effective. 相似文献
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E Lutaaya I Misztal J W Mabry T Short H H Timm R Holzbauer 《Journal of animal science》2001,79(12):3002-3007
Records on lifetime daily gain and backfat from two purebred lines A (n = 6,022), B (n = 24,170), and their reciprocal crosses C (n = 6,135) were used to estimate genetic parameters using within-line and terminal-cross models. The models that were fitted included fixed (contemporary group and sex), random additive A and(or) random additive B, random dominance, and random litter effects. Model for purebreds included only one additive effect, whereas the model for crossbreds included two additive effects. End weight was included as a covariable for backfat. Heritability estimates for lifetime daily gain were 0.26, 0.28, and 0.23 with within-line models for lines A, B, and C, respectively, and 0.26, 0.30, and 0.27 with the crossbred model, respectively. Heritability estimates for backfat were 0.52, 0.35, and 0.29 with within-line models for lines A, B, and C, respectively, and 0.51, 0.38, and 0.29 with the crossbred model, respectively. The genetic correlations between purebreds and crossbreds (r(pc)) for lifetime daily gain were 0.99 (A-C) and 0.62 (B-C); for backfat the correlations were 0.32 (A-C) and 0.70 (B-C). The amount of dominance variance from the crossbred model expressed as a proportion of phenotypic variance for lifetime daily gain was 0.39, 0.16, and 0.29 for lines A, B, and C respectively. Dominance variance for backfat was estimated as 0. A joint evaluation of purebreds and crossbreds would be most efficient with the crossbred model. The dominance variation should be accounted for lifetime daily gain. 相似文献
47.
Observations of fout large groups of dolphins suggest that they are able to swim at a sustained speed of 14 to 18 knots. The blackfish are able to maintain speeds of about 22 knots, and one killer whale seemed able to swim somewhat faster. This implies that the apparent coefficient of surface friction remains approximately constant for dolphins from 6 to 22 ft long, as is the case for rigid bodies. 相似文献
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Prusinkiewicz P Erasmus Y Lane B Harder LD Coen E 《Science (New York, N.Y.)》2007,316(5830):1452-1456
To understand the constraints on biological diversity, we analyzed how selection and development interact to control the evolution of inflorescences, the branching structures that bear flowers. We show that a single developmental model accounts for the restricted range of inflorescence types observed in nature and that this model is supported by molecular genetic studies. The model predicts associations between inflorescence architecture, climate, and life history, which we validated empirically. Paths, or evolutionary wormholes, link different architectures in a multidimensional fitness space, but the rate of evolution along these paths is constrained by genetic and environmental factors, which explains why some evolutionary transitions are rare between closely related plant taxa. 相似文献