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41.
The disease produced by feeding chickens and ducks a commercial poultry feed containing heliotrine and lasiocarpine, pyrrolizidine alkaloids of Heliotropium europaeum, is described. Illthrift, ascites and degenerative lesions in the liver were the major findings. Similar lesions occurred in chickens fed a diet containing H. europaeum. The source of the alkaloids in commercial poultry feed was probably the seeds of H. europaeum harvested with wheat.  相似文献   
42.
The objective of this study was to establish representative treadmill ground reaction force (GRF) and interlimb co-ordination time data of clinically sound horses at the trot. It was anticipated that these normative standards would provide a reference data base against which lame horses could be compared. GRF-time histories were collected from 30 Warmblood riding horses with easy, wide natural gaits. Data were recorded of all four limbs simultaneously by the use of an instrumented treadmill. A total of 912 stride cycles per limb were analysed for force, time and spatial parameters and were averaged. The shape and amplitude of the treadmill force curves were very similar to force traces recorded with a stationary force plate. The horses showed a high degree of symmetry in all investigated parameters (95% reference interval of left-right asymmetry +/-1.8-6.8%). No significant differences were found between left and right mean values. Intra-individual coefficients of variance of the various parameters did not exceed 2.7%. Inter-individual coefficients of variance were 2.5-3.5 times larger than the respective intra-individual coefficients. An instrumented treadmill provides a number of decisive advantages, such as time-efficient data acquisition of all four feet simultaneously over successive strides, or the high regularity of the horse's gait pattern at controlled velocities, which allow the clinical assessment of locomotor performance of horses.  相似文献   
43.
Wheat (Triticum aestivum) end‐product quality is impacted by grain hardness, which is determined by the Hardness locus consisting of the Puroindoline a and Puroindoline b genes, Pina and Pinb, respectively. Hard wheats commonly contain just one of two Pin mutations. We previously demonstrated the creation and preliminary hardness testing of 46 Pin missense alleles. In this study we examine the degree that individual Pin missense alleles confer unique milling and bread quality traits. Three Pina (PINA‐R103K, ‐G47S, and ‐P35S) and four Pinb (PINB‐D34N, ‐T38I, ‐G46D, and ‐E51K) missense alleles were chosen because they impart variable grain hardness levels, with one allele conferring soft seed texture, three conferring intermediate hardness (single‐kernel characterization system [SKCS] hardness approximately 50), and three conferring hard grain texture (SKCS hardness greater than 60). All but two of the alleles (PINA‐R103K and PINA‐G47S) resulted in higher total flour yield when compared with wild‐type controls. All hard and intermediate hardness alleles had decreased break flour yield, but intermediate hardness allele PINA‐P35S had higher break flour yield than common hard allele Pinb‐D1b. Intermediate and hard alleles resulted in increased abundance of larger and reduced levels of smaller flour particles. None of the missense alleles differed from their controls for loaf volume. The seven selected Pin alleles imparted defined levels of grain hardness and milling properties not previously available that may prove useful in wheat improvement.  相似文献   
44.
The circumstellar silicon carbide (SiC) grain X57 from the Murchison meteorite contains large amounts of radiogenic calcium-44 (20 times its solar system abundance) and has an anomalous silicon isotopic composition, different from other circumstellar SiC grains. Its inferred initial 44Ti/Si and 44Ti/48Ti ratios are 1.6 x 10(-4) and 0.37. In addition, it contains radiogenic magnesium-26; the inferred initial 26Al/27Al ratio is 0.11. The isotopic and elemental data of X57 can be explained by selective mixing of matter from different zones of a typical type II supernova of 25 solar masses during its explosion. The high 44Ti/Si ratio requires contributions from the innermost nickel zone of the supernova to the SiC condensation site, as similarly suggested by astronomical observations.  相似文献   
45.
A general method for combining existing algorithms into new programs that are unequivocally preferable to any of the component algorithms is presented. This method, based on notions of risk in economics, offers a computational portfolio design procedure that can be used for a wide range of problems. Tested by solving a canonical NP-complete problem, the method can be used for problems ranging from the combinatorics of DNA sequencing to the completion of tasks in environments with resource contention, such as the World Wide Web.  相似文献   
46.
Carotenoid compounds in grapes and their relationship to plant water status   总被引:1,自引:0,他引:1  
The aim of this work was to study the relationship between carotenoid contents in grapevine berries and plant water status. For this purpose, a black grapevine variety, Vitis vinifera L. cv. Touriga Nacional, was studied. The experiments were carried out in the same Douro vineyards, with plants of the same age, in two different water retention soils. A higher water retention capacity soil, soil A, and a lower water retention capacity soil, soil B, were both in a 1.2 m deep silt-loam schist-derived soil. The training system was the double cordon trained and spur pruned. A first range was nonirrigated (NI) and a second one was irrigated (I), 60% of evapotranspiration (ET(0)). For soil B, a 30% of ET(0) treatment was also applied. The plant water status was estimated by predawn leaf water potential. The effects of plant water status on berry growth were studied by measurement of the berry weight and total soluble solids (degrees Brix). The carotenoid profile was quantitatively determined by high-performance liquid chromatography/diode array. Carotenoids determined were beta-carotene, lutein, neoxanthin, violaxanthin, and luteoxanthin. The comparison between irrigated and nonirrigated grapes was followed from 2 weeks before veraison until the ripe stage. Results showed that at harvest time, berries exposed to the NI had a lower weight than those exposed to the irrigated treatment (60% of ET(0)), 0.89 vs 1.36 g/berry and 0.94 vs 1.34 g/berry, for soils A and B, respectively. The irrigated treatment contributed to a higher sugar concentration in both soils. However, depending on the soil water retention capacity, the carotenoid contents were different in soils A and B. For soil A, the total carotenoid content was similar for both NI and I treatments. However, with regard to soil B, in irrigated treatment, levels of carotenoids were approximately 60% lower than those found for the NI. It seems to be possible to produce higher weight berries (with higher sugar levels) with similar carotenoid contents. On the other hand, soil characteristics had a larger influence than irrigation on the concentration of carotenoids in grapes, resulting in an important viticultural parameter to take into account in aroma precursor formation.  相似文献   
47.
We carried out a comparative study using mtDNA (COI) for two free-living, endemic, terrestrial invertebrate taxa—the springtail Gomphiocephalus hodgsoni (Hypogastruridae) and the mite Stereotydeus mollis (Penthalodidae) collected from sites throughout Victoria Land and the Queen Maud Mountains, Antarctica. Maximum likelihood (ML) analyses revealed low levels of intraspecific substructuring for G. hodgsoni (?2% sequence divergence) with groups mostly corresponding to geographic location. Other well-defined (morphological) species within the Hypogastruridae ranged from 15% to 22% sequence divergence relative to G. hodgsoni. In contrast, ML analyses for S. mollis showed considerably higher levels of intraspecific divergence (up to 18% sequence divergence), suggesting the presence of morphologically cryptic species. Other presently described mite species were also readily discernible (14-18% sequence divergence). Within both G. hodgsoni and S. mollis there were three main groups corresponding to: (1) Taylor Valley; (2) Beaufort Island; and (3) Ross Island together with the adjacent continental sites. We suggest that a common pattern of climatic and geological history over long-term glacial habitat fragmentation have determined the similar geographic and haplotype distributions found for both species. However, a large variation in substitution rate, around eight times slower for G. hodgsoni, compared to S. mollis, may be due to their different life history strategies on the Antarctic continent.  相似文献   
48.
Recent studies suggest associations exist between foetal size and sex, and gene expression at the porcine feto-maternal interface. It is essential to identify reference genes which have stable expression throughout gestation in feto-placental units associated with foetuses of different size and sex. qPCR was performed for 11 genes within porcine placentae and endometria at gestational days (GD) 30, 60 and 90. Several reference genes were found to have stable expression in these samples. The combination of B2m1 and Tbp1, and Hprt1 and Tbp1 had the most stable expression in endometria and placentae, respectively. Reference genes identified as having stable expression were utilized in a larger experiment with placentae and endometria associated with foetuses of different size and sex at four GD. The average expression of B2m1 and Tbp1 mRNAs was suitable for the normalization of temporal changes in endometria, and comparison between endometria supplying foetuses of different size throughout gestation. The average expression of Hprt1 and Tbp1 mRNAs was suitable for the normalization of placental mRNA expression for comparison of temporal changes and sex differences between placentae supplying foetuses of different sex throughout gestation. This combination was suitable for the normalization of mRNA expression in placentas supplying GD30, GD60 and GD90 foetuses of different size. This study has identified reference genes with stable expression in placentae and endometria across multiple gestational days, in tissues associated with foetuses of different size and sex. The results of these experiments highlight the importance of selecting appropriate reference genes for the biological comparison under investigation.  相似文献   
49.
A midwestern producer reported high incidence of conjunctivitis and keratoconjunctivitis in a herd of crossbred finishing swine. Complete necropsy was performed on 3 pigs with bilateral mucopurulent conjunctivitis and chemosis; other gross lesions were not seen. Mycoplasma sp was isolated from conjunctival swab specimens obtained from 1 pig; small numbers of streptococci and coagulase-negative staphylococci were isolated from conjunctival swab specimens from all 3 pigs. Neither swine influenza virus nor pseudorabies virus was isolated from conjunctival swab specimens. Histologically, the 3 pigs had chronic lymphoplasmacytic conjunctivitis with lymphofollicular hyperplasia and foci of epithelial and goblet cell hyperplasia. Ultrastructural examination of conjunctival specimens from the 3 pigs revealed large numbers of Mycoplasma-like organisms adhered to superficial conjunctival cells. Mycoplasma-like organisms also were seen in membrane-bound vacuoles in superficial conjunctival cells. Bacteria (including chlamydiae) or viruses were not seen ultrastructurally. The lymphoproliferative nature of the conjunctival lesion and the evidence of adhered and intracellular organisms suggested an etiologic role for a Mycoplasma-like organism in the disease in these pigs.  相似文献   
50.
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