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41.
Summary
Phytophthora infestans isolates collected in Poland in 1987–1995 were evaluated on detached leaflets of a differential series consisting of potato
genotypes possessing resistance genes R1–R11. On the same differentials was evaluated over three years a highly virulentP. infestans isolate MP 245.
Isolate MP 245 and those from natural populations ofP. infestans were seldom or inconsistently pathogenic to R5, R8 and R9. When leaflets of the differentials were infected with MP 245 the
lesions were often small and sporulation weak. A statistically significant interaction was found between years and pathogenicity
of MP 245 to individual differentials. Attempts to train the isolate MP 245 for pathogenicity to R9 were unsuccessful.
The variation in specific resistance of potato genotypes may complicate the evaluation of their resistance toP. infestans, as well as the evaluation of the virulence spectrum of natural fungus populations. This variation may be due to changes
in specific pathogenicity of the fungus or in specific resistance of the potato. Some differentials have a possibly useful
resistance toP. infestans. 相似文献
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The serum antibody titers to diphtheria toxoid and human serum albumin were determined in 103 goat kids from lines selected for 12 yr for high or low antibody response to diphtheria toxoid. In the 12th yr, six groups of kids were immunized with different preparations of the antigens. In all groups but one, the antigens were emulsified in Freund's incomplete adjuvant with added sonicated Mycobacterium paratuberculosis. The groups received the following treatments: Group 1 was immunized with both antigens mixed in the same syringe, Group 2 got both antigens injected separately, Group 3 got both antigens injected separately, but with a lower concentration of M. paratuberculosis, Group 4 was immunized with diphtheria toxoid only, Group 5 was immunized with human serum albumin only, and Group 6 was immunized with both antigens mixed, but without any M. paratuberculosis. The animals were immunized at 4 wk of age, and the antibody titers were determined 3 wk later by ELISA and passive hemagglutination. The mean antibody titers to both antigens were different between the selected lines (P less than .03). There was no effect of separate vs combined injections of antigens. However, there were indications of antigen suppression or competition between the antigens. Animals receiving only one antigen seemed to mount a higher antibody response to that antigen than did animals immunized with two antigens. 相似文献
45.
Beyzi Selma Büyükkılıç Konca Yusuf Köknur Özlem Köknur Sebahattin Yalçın Hasan Uddin Muhammad Jasim Çınar Mehmet Ulaş 《Tropical animal health and production》2019,51(7):1919-1925
Tropical Animal Health and Production - The primary objective of the present study was to assess the effects of vitamin and mineral premix (VMP) withdrawal from the diets 30 and 60 days... 相似文献
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Study on Surface Noise Distribution of Three ring Reducer 总被引:1,自引:0,他引:1
The three ring reducer is a kind of gear drive developed in the past decade. Adopting the new conception of "parallel and movable axis" of multiple mechanisms, this kind of gear drive has many characteristics such as large transmission ratio, high efficiency and so on. As the three ring reducer has been invented only for ten years, up to date the design of the gear drive is only made with analogue method, no design theory can be followed, there exist serious vibration and noise in transmission, which limit its wide application in industry. In this paper, the transmission principle of SHQ50 reducer is studied, the surface noise distribution of the reducer, transmission ratio 49.5 , is measured and analyzed by means of sound intensity method. The 3D distribution maps of noise on top of reducer, input side and output side of reducer, and left side and right side of reducer are drawn. With the sound intensity frequency maps of each measuring point, the sources of giving out noise are analyzed. The reducer of low vibration and noise can be designed rightly according to the analysis. 相似文献
49.
Francisco Rodríguez y Silva Juan Ramón Molina-Martínez 《European Journal of Forest Research》2012,131(3):571-582
Fire behavior modeling systems are important in predicting wildfire risk, fire growth, and fire effects. However, simulation
software requires a new fuel modeling to include fuel treatments, prescribed fire and the transition to crown fire. The thirteen
Rothermel models are insufficient in completely representing Mediterranean ecosystems. In this sense, the new American modeling
includes five fuel types, requiring the acquisition of hybrid models made up of the mixture of grass and shrub and the grass
or shrub mixed with litter from forest canopy. Respecting meteorological conditions and shrub characteristics, field studies
have shown significant differences between American and Mediterranean models. As a consequence, the definition of new Mediterranean
models requires the adjustment of specific parameters such as fuel load by category (live and dead) and particle size class
(1-, 10- and 100-h time-lag), fuelbed depth and surface area-to-volume ratio. These new parameters were obtained in situ of
sample itineraries, prescribed fires, and forest fires. The availability of this new modeling, validated on a field of regional
scale, will facilitate preventive planning and management as well as an efficient application of suppression techniques, both
ground and aerial operations, required in defending a territory against forest fires. 相似文献
50.
A field trial was performed in order to evaluate the effect on fertility of different straw types, freezing protocols (one- or two-step) and thawing procedures (35°C and 70°C) using frozen–thawed ram semen. A total of 791 Norwegian Crossbred ewes were artificially inseminated during natural oestrus with semen collected from nine mature and proven Norwegian Crossbred rams. A milk-based extender was used for dilution. The ewes were allocated into one of the following three groups based on the different straw types and thawing temperatures: medium straw (0.5 ml) thawed at 35°C for 20 s (Med35), medium straw thawed at 70°C for 8 s (Med70) and mini straw (0.25 ml) thawed at 35°C for 15 s (Mini35). The semen to be frozen in mini straws was re-concentrated by centrifugation. Sperm number in each insemination dose was approximately 200 × 106 spermatozoa. The fertility results [as 25-day non-return rate (NRR)] for Med35, Med70 and Mini35 were 53.1%, 50.8% and 58.3%, respectively, and the lambing rates 49.8%, 46.8% and 53.8%, respectively. No significant main effects were seen for straw type/thawing temperature (p = 0.17), ram (p = 0.06) or age of the ewe (p = 0.18) on NRR or lambing rates (p = 0.19, p = 0.16 and p = 0.27, respectively). Both NRR and lambing rate differed significantly among farms (p < 0.0001). 相似文献