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21.
At a time of increasing demand for rapeseed oil for biofuel and food use and as increasing areas are grown, the risk of pollen beetle resistance to pyrethroids presents a significant threat to the sustainability of the oilseed rape crop and to farm incomes. Measures are urgently required to reduce the use of insecticides against pollen beetles, to preserve activity of the limited armoury of insecticides and minimise environmental pollution. In this paper, the status of pollen beetle resistance to pyrethroid insecticides and current control methods are presented from a UK perspective. Three ecological approaches to the control of pollen beetles that are based on research into their behaviour and ecology and that of their natural enemies are highlighted: use of monitoring, trap cropping and conservation biological control. These approaches have the potential to significantly reduce insecticide use against pollen beetles by helping to identify when spray thresholds have been breached, reducing pest incidence in the crop and increasing populations of natural enemies, respectively.  相似文献   
22.
Disclosure of affected breed without disclosure of major progenitors has been the usual practice in scientific papers reporting recessive heritable disorders of cattle. Before molecular genetics, carrier identity could not be used by breeders to control causal mutations because phenotypically normal heterozygotes among genetically related animals could not be detected other than by test mating. Accurate, low‐cost DNA tests fundamentally changed this situation. Genomics can provide relief from the old problem of emerging recessive disorders in cattle breeding, but greater transparency of genotype data between breeders is necessary to fully exploit the opportunities for cost‐efficient genetic disease control. Effective control of several recessive disorders has been demonstrated in Angus cattle, based entirely on voluntary DNA testing by breeders but mandatory public disclosure of test results and genotype probabilities for all registered animals. When a DNA test is available, major progenitors (particularly bulls from which semen has been distributed) should be identified and disclosed concurrently with the affected breed. As a minimum, whenever possible the closest common ancestors in the pedigrees of the parents of homozygous mutants should be disclosed after confirmation of carrier status. Progenitor disclosure in scientific publications should occur in cooperation with breed societies, which should have the opportunity to advise breeders and initiate management programs before scientific publication. Unless properly managed, genomic enhancement of animal selection using SNP markers may increase inbreeding, co‐ancestry and emergence of recessive disorders. The information systems and genotype disclosure policies of some breed societies will be increasingly challenged, particularly with accelerating mutation discovery using next‐generation sequencing.  相似文献   
23.
The penetration and metabolism of [14C]deltamethrin was studied in susceptible and resistant Chinese and Pakistani strains of Helicoverpa armigera (Hübner), which were resistant to deltamethrin by 330- and 670-fold, respectively. The penetration of deltamethrin into resistant individuals was significantly slower than into susceptible individuals over a 24-h period. The time taken for 50% penetration of the applied deltamethrin was 1 h for the susceptible strain and 6 h for both of the resistant strains. The internal radioactivity was reduced by the larvae of resistant strains much faster than by the susceptible larvae. After 48 h, 40% of the penetrated deltamethrin was still inside the larvae of the susceptible strain, in comparison with 1.5-5% in the Pakistani strain and 8-14% in the Chinese strain. Both of the resistant strains produced methanol-soluble and water-soluble metabolites, but the susceptible strain produced methanol-soluble metabolites only. By 12, 24 and 48 h after dosing, the amount of methanol-soluble metabolites excreted by the resistant strains was almost double that of the susceptible strain. Both of the resistant strains also excreted 5-7% of the penetrated dose as a water-soluble metabolite after 48 h. In comparison with the Chinese strain, the Pakistani strain exhibited slower penetration, lower internal content and faster excretion of deltamethrin, which correlated with the higher resistance of the Pakistani strain. These findings show that the resistant Pakistani and Chinese strains of H. armigera possess mechanisms of reduced cuticular penetration and enhanced metabolism of deltamethrin and perhaps other pyrethroids.  相似文献   
24.
GRIEVE  IAN C. 《Forestry》1978,51(1):21-28
Acid brown soils under 50-year-old conifer plantations are comparedwith those at a control site under the previous vegetation ofmixed deciduous woodland. The soils under the conifers showsignificant signs of podzolization and associated with this,evidence of structural breakdown. The implications of thesechanges are briefly discussed.  相似文献   
25.
Equine Large Intestinal Volvulus A Review of 124 Cases   总被引:2,自引:0,他引:2  
The average age of 122 horses with ascending colon volvulus was 6.6 +/- 0.4 years. Gastric reflux was a presenting sign in 35% of the cases. Peritoneal fluid protein levels had a mean of 2.54 +/- 0.14 g/dl and 20 horses had grossly normal peritoneal fluid at the time of presentation. Ascending colon volvulus was most commonly found at the level of the cecocolic fold with the initial ventral colon movement in a dorsomedial direction about the ascending mesocolic axis. The overall survival rate was 34.7% with a recurrence rate of only 4.9%.  相似文献   
26.
SUMMARY Most stock losses caused by annual ryegrass toxicity occur because stockowners unknowingly allow their stock to graze annual ryegrass (Lollum rigidum) Infected with the bacterium Clavlbacter toxicus. To help stockowners avoid losses we have developed criteria for a testing service to determine the risk of poisoning before the pasture is grazed. Low, medium and high risk categories were selected using samples of dry, mature ryegrass seedheads collected by stockowners from untreated, Infected pastures In South Australia. The proportion of toxic paddocks in each risk category over all the seasons tested was 11%;, 32%; and 76%;, respectively, and these accounted for 7%;, 14%; and 79%; of total stock losses. The proportion of paddocks in which stock were poisoned did not vary significantly between years, was not affected by variation in sample weight, and did not vary between South Australia and Western Australia.  相似文献   
27.
Abstract— Intradermal injection of staphylococcal protein A, and crude extracts of Staphylococcus intermedius and Staphylococcus aureus in normal dogs elicited dose-dependent increases in skin fold thickness. The most concentrated doses of S. inlermedius elicited a significantly greater response than the equivalent dose of S. aureus between 30 min and 4 h after injection (p < 0.05). This may be due to prior sensitisation or may indicate that S. intermedius is more virulent. At all other times and doses there was no significant difference between the two crude staphylococcal extracts. Histological examination indicated that while there were differences between the responses to the three extracts, all three elicited similar epidermal lesions (sub-corneal pustules, spongiosis and hyperplasia) and superficial perivascular dermatitis. A similar pattern of changes has been recorded in canine superficial pyoderma supporting the hypothesis that penetration of staphylococcal products into the dermis is involved in the pathogenesis of the lesions of pyoderma. Résumé— Des injections de Protéine A et d'extraits totaux de Staphylococcus intermedius et Staphylococcus aureus sur des chiens normaux entrainent des augmentations dose dépendantes du pli de peau et de l'érythème. La does plus concentrée de Staphycolococcus intermedius entrainent une réponse plus importante statistiquement significative que la réponse obtenue avec une concentration équivalente de Staphylococcus aureus entre 30 minutes et 4 heures après l'injection (p < 0,05). Ceci peut être due à une sensibilisation antérieure ou peut indiquer que Staphylococcus intermedius est plus virulent. Par contre, il n'existe pas de differences significatives entre les deux types d'extraits staphylocoques totaux à d'autres temps et concentrations. Les lesions histopathologiques montrent que tandis qu'il existe des differences entre les réponses aux trois extraits, tous les trois montrent des lesions épidermiques similaires (pustules sous cornées, spongiose et hyperplasie) et de dermatite périvasculaire superficielle. Des lesions semblables sont observées dans les pyodermites superficielles canines. Ceci conforte l'hypothèse que la penetration des produits staphylococciques dans le derme joue en role dans la pathogénie des lesions de pyodermite. [Mason, I. S., LLOyD, D. H. The macroscopic and microscopic effects of intradermal injection of crude and purified staphylococcal extracts on canine skin (Effects macroscopiques et microscopiques de l'injection intradermique d'extraits totaux et purifies staphylococciques sur la peau du chien.  相似文献   
28.
The clinical findings in a series of eighteen dogs with brachial plexus avulsion are presented. It is suggested that both motor and sensory loss reflects damage in nerve roots and ventral branches, rather than the peripheral nerves. Ipsilateral loss of the panniculus reflex with a consensual response was a common finding. Fifty-five per cent of the dogs also showed sympathetic dysfunction with an ipsilateral myosis. Further methods for investigating these cases are also discussed.
Résumé. Sont présentées les observations cliniques sur une série de 18 chiens attents d'avulsion du plexus brachial. Il est suggéré que les pertes moteur comme sensorielles proviennent de dommages causés aux racines nerveuses et aux branches ventrales, plutôt qu'aux nerfs péri-phériques. La perte du réflexe pannicule avec réponse consensuelle fut communément observée. Chez 55% des chiens il existait aussi une dysfonction sympathique avec myosis ipsilatéral. Autres méthodes d'investigation de ces cas sont également discutées.
Zusammenfassung. Die klinischen Befunde einer Serie von achtzehn Hunden mit Ausreissung des Plexus brachialis sind wiederlegt. Es ist vorgeschlagen, dass der Bewegungs- und Empfin-dungs- Verlust eine Beschädigung der Nervenwurzeln und ventralen Nervenästen, nicht der peripheralen Nerven, reflektiert. Selbseitiger Verlust des Pannicules Reflexes, mit gleichsinniger Respondierung, wurde allgemein erwiesen. An 55% der Hunde konnte sympathetische Dysfunktion, mit selbseitiger Myose, beobachtet werden. Weitere Untersuchungsmethoden dieser Fälle, sind ebenfalls ausgeführt.  相似文献   
29.
Crown width (CW) and breast height diameter (D) were measuredfor 73 open grown Sitka spruce trees. A highly significant linearrelationship was found between these two characteristics, withmore variation at large values of D. After applying weightingto compensate for this and eliminating the largest tree whichdid not follow the main trend, the equation CW=188. 30 + 15.27Dand D = 0.05865 CW - 8.31 were fitted where CW and D are expressedin centimetres. A comparison is made with equations derivedby other workers. The relationship may be used to predict the time of canopy closurefrom a knowledge of the development of D with age for a givenstand, after defining canopy closure in terms of mean crownwidth and spacing, or mean crown area and the available growingspace.  相似文献   
30.
Objectives— To report the technique, observations on fracture configurations and results of treatment by fixation lag screw following the fracture plane determined by an approach to the third metacarpal/metatarsal bone (MC3/MT3) that begins laterally over the metacarpo(metatarso)phalangeal joint and extends dorsally over the diaphysis of the bone.
Study Design— Case series.
Animals— Thoroughbred horses (n=18) with propagating fractures of the medial condyle of MC3/MT3.
Methods— Retrospective analysis of case records of horses with fractures of the medial condyle of MC3/MT3 that propagated sagittaly or in a spiral configuration into the diaphysis, repaired surgically under general anesthesia by screw fixation in lag fashion through a lateral approach with periosteal reflection.
Results— Fractures were readily identified at surgery, enabling screw fixation in lag fashion following the fracture plane. Fracture configurations varied and could be classified as sagittal and spiral fractures with fractures within each group generally following a similar course. All horses recovered relatively uneventfully from general anesthesia and surgery, and all fractures healed well. Thirteen horses returned to training; 5 subsequently raced.
Conclusions— Repair of propagating sagittal and spiral fractures of the medial condyle of MC3/MT3 with diaphyseal involvement, through a lateral approach with periosteal reflection permits stable fixation with minimal complications. In this series there were no catastrophic failures.
Clinical relevance— Fractures of the medial condyle of MC3/MT3 that propagate either sagittaly or in a spiral configuration into the diaphysis can be successfully repaired with screw fixation in lag fashion using a lateral approach with periosteal reflection.  相似文献   
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