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2.
Incorrect labelling of plants in trade and misidentification are widespread. Likewise, in trade numerous names are being used for the ornamental aquatic plant known as ‘Kariba weed’, but rarely the correct scientific name Salvinia molesta Mitch. For inspection services of EPPO member countries, correct identification of S. molesta has become important since the species was added to the EPPO A2 List and the List of Union concern in accordance with EU regulation 1143/2014 based on an EPPO Pest Risk Analysis (PRA) for the species. Inspections and a targetted survey of Salvinia plants in trade in the Netherlands were performed and additional material was obtained from wild sources in South Africa, Hungary and the United States. Specimen identification was verified by comparison with the herbarium collection at Naturalis Biodiversity Center in Leiden and with the sequences available in NCBI GenBank database. This paper provides the tools to correctly identity the relevant Salvinia species. 相似文献
3.
Piet?C.?N.?GroenewaldEmail author Carin?S.?Viljoen 《Journal of Agricultural, Biological & Environmental Statistics》2003,8(1):75-83
This article aims to determine the effect of certain covariates, such as season of kidding, parity, and time of kidding on
the characteristics of the lactation curve of Saanen dairy goats. Characteristics investigated are peak milk yield, time of
peak milk yield, total milk production, persistency, and the relationship between fat and protein in milk composition, as
well as between lactation curves of the same animal in successive years. The analysis is carried out using a hierarchical
Bayesian approach, together with Wood’s model, to model lactation. Posterior distributions of quantities of interest are obtained
by means of the Markov chain Monte Carlo (MCMC) methods. These clearly illustrate the significant effect of especially parity,
but also season and time of kidding on the characteristics of the lactation curve. Total and peak milk yield increase with
increasing parity up to about the third or fourth parity, while peak yield is later for first than for later parities. The
analysis also enables estimation of lactation characteristics of untested animals, prediction of future characteristics and
identification of exceptional animals. 相似文献
4.
Zifu Yan Oene Dolstra Theo W. Prins Piet Stam Peter B. Visser 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(3):301-308
Powdery mildew (Podosphaera pannosa) is the most important fungal disease in greenhouse roses and is in practice controlled by fungicides. The creation of novel
cultivars with durable resistance to powdery mildew is highly desirable. To understand the inheritance of mildew resistance,
a tetraploid rose population with a size of 181 seedlings was obtained by crossing two tetraploid genotypes each having partial
resistance. The population and its parents were tested under greenhouse conditions with two well-defined monospore isolates
(2 and F1) using artificial inoculation with spore suspensions. Disease score at 11 days post-inoculation, latent period and
rate of symptom development were used to describe seedling resistance. The tests for both isolates exhibited a wide and significant
variation among genotypes for resistance. The distribution of the genotypic means of the disease scores was continuous and
showed a considerable transgression. Statistical analysis, scatter plot of disease scores for the isolates, and correlation
analyses indicated that the two isolates differed in pathogenicity. The outcome of the tests showed that the inoculation assay
with spore suspensions was a reliable and effective way to screen large numbers of genotypes under greenhouse conditions for
genetic and breeding studies. This is the first report on spore-suspension inoculation to be used successfully in rose. 相似文献
5.
Growth and photosynthetic performance were analyzed in alloplasmic tomato at a high- (25/17 °C; HTR) and low-temperature regime (12/6 °C; LTR) in order to establish the role of cytoplasmic variation on low-temperature tolerance of tomato (Lycopersicon esculentum Mill.). Four alloplasmic tomato lines, containing the nuclear genome of tomato and the plastome of L. hirsutum LA 1777 Humb. & Bonpl., an accession collected at high-altitude in Peru, were reciprocally crossed with 11 tomato entries
with a high inbreeding level and a wide genetic variation, resulting in a set of 44 reciprocal crosses. Irrespective of growth
temperature, alloplasmic families with alien chloroplasts of L. hirsutum (h) were on average characterized by a high shoot biomass, a large leaf area, and a low specific leaf area in comparison with
their euplasmic counterparts. These results do not directly point to an advantageous effect of h-chloroplasts on biomass accumulation at low temperature but rather towards a small general beneficial effect on growth and/or
distribution of assimilates. Significant chloroplast-related differences in photosynthetic performance, however, were not
detected at both temperature regimes, indicating that h-chloroplasts can properly function in a variable nuclear background of L. esculentum. It is concluded that chloroplast substitution is not an effective method for breeding tomato plants with improved low-temperature
tolerance.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
Daas PJ Grolle K Van Vliet T Schols HA De Jongh HH 《Journal of agricultural and food chemistry》2002,50(15):4282-4289
In this paper the determination of the physical/rheological characteristics is described for a series of commercial galactomannans of which the structural details have been reported previously. Both solubility of the galactomannans and rheological properties of galactomannan solutions and galactomannan/xanthan mixtures were determined. Using a statistical analysis approach an attempt was undertaken to recognize correlations between structural and rheological data. The best correlation found was between the abundance of galactose substituents at a regular distance (type of galactomannan) and the storage modulus (G') of mixed galactomannan/xanthan gels, underscoring the hypothesis that branching hinders the formation of a network with xanthan gum. Also, the G' for the group of locust bean gums correlated with the degree of blockiness, that is, the size and occurrence of nonsubstituted regions on the mannose backbone. In addition, galactomannans displayed an apparent decrease in gelling ability with increasing average molecular weight. That G' also relates to the type of galactomannan can therefore partly be attributed to differences in average molecular weight for the various galactomannan types. However, within the series of locust bean gums tested, also an increase of G' with molecular weight was observed. This can be explained by the decreasing number of loose ends of the polymers and the concomitant increasing efficiency in network participation with increasing molecular weight. 相似文献
7.
8.
(+/-)-3,4-Methylenedioxyamphetamine (MDA), an amphetamine analog with hallucinogenic activity, produced selective long-lasting reductions in the level of serotonin, the number of serotonin uptake sites, and the concentration of 5-hydroxyindoleacetic acid in rat brain. Morphological studies suggested that these neurochemical deficits were due to serotonin nerve terminal degeneration. These results show that MDA has toxic activity for serotonin neurons in rats and raise the question of whether exposure to MDA and related hallucinogenic amphetamines can produce serotonin neurotoxicity in the human brain. 相似文献
9.
A theory is presented in which much of the structure of spiral galaxies arises from a percolation phase transition that underlies the phenomenon of propagating star formation. According to this view, the appearance of spiral arms is a consequence of the differential rotation of the galaxy and the characteristic divergence of correlation lengths for continuous phase transitions. Other structural properties of spiral galaxies, such as the distribution of the gaseous components and the luminosity, arise directly from a feedback mechanism that pins the star formation rate close to the critical point of the phase transition. The approach taken in this article differs from traditional dynamical views. The argument is presented that, at least for some galaxies, morphological and other features are already fixed by general properties of phase transitions, irrespective of detailed dynamic or other considerations. 相似文献
10.
ObjectiveTo characterize the cardiorespiratory and electrocardiographic effects of the combined administration of phenylbutazone and romifidine.Study designProspective four-period, four-treatment, blinded, randomized, crossover trial.AnimalsFive, healthy, mixed breed horses.MethodsPrior to treatment administration, a catheter was introduced into the intra-thoracic cranial vena cava via the jugular vein and a subcutaneously located carotid artery was catheterised. All treatments were administered intravenously (IV) and consisted of saline placebo (PLC), phenylbutazone (PBZ, 4.4 mg kg?1) romifidine (ROM, 80 μg kg?1) and a combination of phenylbutazone (4.4 mg kg?1) and romifidine (80 μg kg?1). There was at least a 1 week washout period between treatments. Heart rate (HR), respiratory rate (fR), systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures and central venous pressure (CVP) were recorded for baseline (prior to drug administration) and at 5 minute intervals thereafter for 30 minutes. Electrocardiographic abnormalities were recorded. Data were analyzed by anova.ResultsFor the cardiovascular variables there were no statistically significant (p > 0.05) differences between horses treated with ROM and PBZ_ROM. Statistically significant (p < 0.05) differences only occurred between treatments with romifidine (ROM and PBZ_ROM) and without romifidine (PLC and PBZ). Within treatments, for ROM, changes over time were statistically significant (p < 0.05) for HR, SAP, DAP, MAP and CVP. For PBZ_ROM, changes over time were statistically significant (p < 0.05) for CVP. Sino-atrial and atrio-ventricular blocks occurred in horses treated with ROM and PBZ_ROM.Conclusions and clinical relevanceThe combined IV administration of phenylbutazone and romifidine had no statistically significant effect on cardiorespiratory variables. These limited data suggest no evidence why both agents should not be included in a preoperative medication protocol for healthy horses but do not exclude the possibility of interactions occurring in a larger population. 相似文献