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Hemodynamic perturbations, partly resulting from abnormal vasoconstriction of digital vessels, have been implicated in the pathogenesis of bovine and equine laminitis. This study compared the responsiveness of isolated bovine (BDA) and equine (EDA) digital arteries to pharmacological agents that stimulate receptor systems involved in the regulation of normal vessel tone. The role of the endothelium and the short‐ and longer‐term effects of an experimentally induced endothelial damage were also evaluated. Species‐related differences were found in the vessel reactivity to all of the receptor agonists tested. In intact BDA, as compared to intact EDA, norepinephrine was a more effective vasoconstrictor, 5‐hydroxytryptamine a more effective but less potent vasoconstrictor, isoproterenol a less effective vasodilator and carbamylcholine a less potent vasodilator. In BDA, but not in EDA, the contractile responses to norepinephrine and 5‐hydroxytryptamine were enhanced immediately after endothelium removal. However, the contractile reactivity of denuded BDA returned to basal values following overnight incubation. The differences suggest species specificity for the pathophysiology of digital vasomotor tone and function in horses and cattle.  相似文献   
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REASONS FOR PERFORMING STUDY: The selective COX-2-inhibitor nimesulide is used extra-label in equine veterinary practice as an anti-inflammatory agent. However, there are no data on which to base the rational use of the drug in this species. OBJECTIVES: To determine the effective COX selectivity of nimesulide in the horse, and suggest a suitable dosing schedule. METHODS: The pharmacokinetics of nimesulide in the horse after oral administration (1 mg/kg bwt), and oral and i.v. administration (1.5 mg/kg bwt) were investigated, effects of feeding status on bioavailability determined, and plasma protein binding of the drug and its principal metabolites measured. Compartmental and noncompartmental pharmacokinetic analyses were performed. The plasma concentration-time profile was used, together with in vitro literature data on nimesulide inhibition of COX isoforms, to determine the effective COX selectivity of nimesulide in the horse, and suggest a suitable dosing schedule. RESULTS AND CONCLUSIONS: The findings suggest that 1.5 mg/kg bwt may produce adequate clinical effects, and the dosing interval should be 12-24 h depending on condition severity. However, at that dose, the concentration in the animal exceeds the in vitro IC50 for both isoforms, so that COX-1/COX-2 selectivity is lost and side-effects due to COX-1 inhibition are a possibility. Nimesulide should therefore be used with caution in equine clinical practice.  相似文献   
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A method for the separation of pure and viable lymphocytes and granulocytes from the same blood sample in horses was reported. By centrifuging equine heparinized blood at 100 xg for 10 min at room temperature (r.t.), the resulting supernatant plasma was an almost pure (97.71 +/- 0.30%; n = 15) suspension of highly viable (98.72 +/- 0.28%) lymphocytes. When sodium citrate was used as an anticoagulant, lymphocyte suspensions collected in the same manner showed lower purity (87.89 +/- 1.59%; n = 9) and higher yields (56.56 +/- 3.89%, n = 9 versus 36.11 +/- 2.23%, n = 15). Where needed, a further centrifugation at 250 xg for 3 min (r.t.) of heparinized lymphocyte preparations removed an average of 87.39% (n = 15) contaminating platelets. A suspension of 85.96 +/- 2.20% pure granulocytes (93.23 +/- 1.74% neutrophils; n = 14) with minimal contamination by erythrocytes and high viability (93.11 +/- 1.26%) was obtained by performing a flash red blood cell lysis on the white-greyish layer resulting from the centrifugation of the heparinized blood samples. Among the several methods available, the procedure described herein is easy, rapid, cheap and reproducible.  相似文献   
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We used isolated equine digital arteries to study the vasodilatory mechanism of isoxsuprine, and fowl caecum preparations to investigate the affinity of the drug for beta-adrenoceptors. Isoxsuprine is a potent vasodilator of arterial smooth muscle that has been precontracted by an alpha-adrenoceptor agonist such as noradrenaline (log EC50 = -6.33 [-5.98; -6.68]). The present study indicates that its effect is due to alpha-adrenoceptor blockade since: (1) after a long lasting exposure to cumulative doses of isoxsuprine the vasoconstricting action of noradrenaline cannot be restored; (2) isoxsuprine does not promote relaxation on preparations precontracted by PGF2alpha; (3) isoxsuprine shifts the dose-response curve of noradrenaline to the right; and (4) its affinity (pK(B) = 6.90 [6.60; 7.20]) in this experiment is comparable to that in noradrenaline-precontracted preparations and is 14 times lower than that of the selective alpha1-adrenergic antagonist prazosin [pK(B) = 8.04 (7.40; 8.68]). The affinity of isoxsuprine for beta-adrenoceptors was 100 times lower than that of isoprenaline when tested on fowl caecum. This preparation has a large beta-adrenoceptor and negligible alpha-adrenoceptor population concerned with the control of smooth muscle motility. Our data suggest that the alpha-mediated effect of isoxsuprine on horse arterial smooth muscle is due to higher affinity of the drug for alpha- than beta-adrenoceptors rather than low concentration or functionality of beta-sites at this site. According to these data, pure beta2-agonists seem to be more profitable tools to determine vasodilation of the arterial bed in horses legs.  相似文献   
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Acanthocephalan and spargana parasites were identified within a body wall mass during exploratory surgery in a wild green tree snake. Acanthocephalan parasites have not previously been reported in this species. Surgical excision, the treatment of choice, could not be achieved because of the extensive infiltration of the coelomic cavity.  相似文献   
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Objective To study the efficacy of multiple striate keratotomy for the treatment of persistent corneal erosions suspected to be caused by primary corneal epithelial basement membrane disease.
Design A retrospective study.
Animals 16 dogs, three cats and one Australian dingo.
Procedure A technique called multiple striate keratotomy was used to treat twenty animals suffering from persistent corneal erosions.
Results All persistent corneal erosions healed with only one treatment. Most cases healed within 2 weeks. One case developed a second erosion in the same eye but in a different position to the original erosion.
Conclusions Multiple striate keratotomy is a safe, effective and well tolerated technique for the treatment of persistent corneal erosions thought to be caused by corneal epithelial basement membrane disease.  相似文献   
10.
Femtosecond laser pulses and coherent two-phonon Raman scattering were used to excite KTaO3 into a squeezed state, nearly periodic in time, in which the variance of the atomic displacements dips below the standard quantum limit for half of a cycle. This nonclassical state involves a continuum of transverse acoustic modes that leads to oscillations in the refractive index associated with the frequency of a van Hove singularity in the phonon density of states.  相似文献   
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