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61.
Abstract

CASE HISTORY: Outbreaks of mortality in South Island saddlebacks (Philesturnus carunculatus carunculatus) that had been translocated to two offshore islands in the Marlborough Sounds of New Zealand were investigated during the summer of 2002 and 2007. Both outbreaks were associated with a severe decrease in numbers of saddlebacks of up to 60% of approximately 200 birds.

CLINICAL AND PATHOLOGICAL FINDINGS: Many of the surviving birds were in poor condition, and had skin lesions on the legs and head. Necropsy showed pale liver and lungs, and a swollen spleen. Histopathology revealed schizonts resembling Plasmodium spp. within the cytoplasm of many hepatocytes and splenic histiocytes. The skin lesions consisted of epithelial proliferations containing numerous Bollinger bodies typical of avipox virus (APV) infection. Two different APV were isolated, using PCR, from two different birds exhibiting skin lesions. Each isolate had 100% sequence homology with APV members from either Clade A or Clade B. In addition, PCR analysis revealed that the Plasmodium elongatum present in infected birdsbelonged to a strain that was endemic in the population of North Island saddlebacks (Philesturnus carunculatus rufusater).

DIAGNOSIS: Concurrent infections with Plasmodium spp. haemoparasites and APV were identified as the likely cause of death in the birds examined.

CONCLUSIONS AND CLINICAL RELEVANCE: Although the Plasmodium spp. identified is thought to be endemic to saddlebacks in New Zealand, the affected birds were likely to be immunocompromised by concurrent APV infection or through lack of genetic diversity. Both the introduced mosquito Culex quinquefasicatus and the native mosquito Culex pervigilans are likely vectors for both these diseases, and the provision of water supplies less favourable to mosquito-breeding is recommended.  相似文献   
62.
AIMS: To study the development and progression of lesions produced following experimental inoculations of possums with Bacille Calmette-Guérin (BCG) Pasteur Strain 1173P2 and to compare these with lesions that occurred following natural Mycobacterium bovis infection.

METHODS: Possums were inoculated with 5 x 106 colony forming units (cfu) of BCG via the intra-dermal (I/D) route into the dorsum of the neck (n=38) or the left brachium (n=7), orally (n=10), via the endo-bronchial (E/B) route (n=12), or intravenously (I/V) (n=10, half of which received 5 x 106 cfu and half of which received 5 x 107 cfu of BCG). The possums were humanely killed between 1–4 weeks post inoculation (p.i.), and the nature and distribution of lesions examined grossly and histopathologically.

RESULTS: The distribution of lesions following I/D inoculation via either route was similar to that of the natural disease, but there were few lesions in the lung. Endo-bronchial inoculation resulted in pulmonary disease but produced few lesions outside the respiratory tract. Lesions produced by I/V inoculation were similar in distribution to those seen in terminally ill tuberculous possums. No lesions were produced following oral inoculation. Regression of lesions commenced after 3 weeks p.i.

CONCLUSIONS: Although the phenomenon of lesion resolution restricts the use of BCG to the study of early lesion development, it avoids the overwhelming disease induced using M. bovis and thus allows the early phases of the development and progression of tuberculosis in this species to be observed. Intra-dermal inoculation produced evidence that infection through the skin is associated with lesions in superficial lymph nodes, whereas pulmonary disease was associated with E/B inoculation. The results are consistent with the hypothesis that both percutaneous and respiratory routes are important in natural infection of possums with M. bovis.  相似文献   
63.
Abstract

Compared to mammals, twinning in birds is rare. The reported incidence in domestic chickens (Gallus gallus) is 0.11 % (Byerly and Olsen 1934 Byerly, TC and Olsen, MW. 1934. Polyembryology in the domestic fowl. Science, 80: 247248.  [Google Scholar]) and in pigeons (Columba livia) only 0.07% (Riddle 1923 Riddle, O. 1923. The causes of twinning and abnormal development in birds. American Journal of Anatomy, 32: 199252.  [Google Scholar]). Monozygotic twins occur following the fission of an early embryo and may or may not share the same yolk. Dizygotic twins are thought to occur following 2 simultaneous ovulations or perhaps by the slow passage of an ovum down the oviduct, resulting in it being caught by a succeeding yolk and then being incorporated into the same membrane and shell (Harrison 1986 Harrison, GJ. 1986. “Reproductive Medicine”. In Clinical Avian Medicine and Surgery, Edited by: Harrison, GJ and Harrison, LR. 620633. Philadelphia: WB Saunders.  [Google Scholar]). Regardless of their origin most avian twins do not survive beyond hatching.  相似文献   
64.
A prospective observational study was conducted in two Australian dairy herds to assess the potential for improving pregnancy rates (proportions of inseminations that result in pregnancy) to artificial insemination (AI) if the time of ovulation could be predicted with more certainty. Herd 1 calved year‐round and inseminations were performed during two periods each day. Herd 2 calved during autumn–winter and inseminations were performed only after the morning milking each day. In both herds, the AI to ovulation interval of enrolled cows was determined by trans‐rectal ovarian ultrasonography approximately 0, 12, 24 and 36 h after AI, and pregnancy was assessed by palpation per rectum 35–56 days after AI. Also, in Herd 1 vaginal electrical resistance (VER) measurements were taken at approximately 0, 12, 24 and 36 h after AI, and in Herd 2 cows were fitted with neck mounted activity meters that monitored cow activity count in 2‐h periods. There was substantial variation in the intervals from AI to ovulation within and between herds (mean ± SD 21.2 ± 10.7, n = 102; 14.7 ± 10.4, n = 100 in herds 1 and 2, respectively). Pregnancy rates were higher for inseminations close to, but preceding, ovulation. Using combined herd data (n = 202), the highest pregnancy rate (50.8%) was observed for inseminations between 0 and 16 h before ovulation, a period in which only a modest proportion of inseminations (31.2%) occurred. In contrast, pregnancy rate was significantly lower (28.7%; risk ratio 0.6; 95% CI 0.4–1.0; p = 0.039) for inseminations between 16 and 32 h before ovulation, a period where the highest proportion of inseminations (53.2%) occurred. Thus pregnancy rates could potentially be improved if a greater proportion of inseminations were conducted shortly before ovulation. In Herd 1, mean VER during the peri‐ovulatory period varied with time from ovulation. Lowest values (mean ± SEM, VER = 64.8 ± 1.2, n = 55) occurred approximately 18 h before ovulation and were significantly lower than measurements approximately 6 h before ovulation (67.4 ± 1.0; n = 73; p = 0.003). Further work is required to determine if VER can be used to identify ovulation time and hence the optimal time to inseminate in individual animals. In Herd 2 a modest proportion of inseminations (26.9%) occurred between 24 and 40 h after the onset of increased cow activity where the highest pregnancy rate (67.9%) was observed, whereas a significantly lower pregnancy rate (42.4%; risk ratio 0.6; 95% CI 0.4–0.9; p = 0.036) was observed for inseminations between 8 and 24 h after the onset of increased cow activity where the highest proportion of inseminations (56.7%) occurred. Thus cow activity monitoring may be useful to identify the optimal time to inseminate cows. Results from this study indicate that improved methods of ovulation prediction may allow better insemination timing relative to ovulation and consequently increased pregnancy rates.  相似文献   
65.
Objectives To define the prevalence of Bartonella spp., Rickettsia felis, Mycoplasma haemofelis, ‘Candidatus Mycoplasma haemominutum’ (Mhm) and ‘Candidatus Mycoplasma turicensis’ (Mtc) in cats and their fleas in eastern Australia. Design and procedure Conventional PCR assays that detect Bartonella spp., M. haemofelis, Mhm, Mtc, Rickettsia spp., Ehrlichia spp., Anaplasma spp. and Neorickettsia spp. were performed on DNA extracted from blood and fleas collected from 111 cats. Cat sera were assayed by ELISA for IgG of Bartonella spp. Results DNA of M. haemofelis, Mtc and Mhm was amplified from 1 (0.9%), 1 (0.9%) and 17 cats (15.3%), respectively. Only DNA of Mhm was amplified from the 62 of 111 pooled flea samples (flea sets; 55.9%). Overall, the prevalence rates for Bartonella spp. DNA in the cats and the flea sets was 16.2% (18 cats) and 28.8% (32 flea sets), respectively. Bartonella spp. IgG was detected in 42 cats (37.8%), of which 11 (26.2%) were positive for Bartonella spp. DNA in their blood. R. felis DNA was amplified from 22 flea sets (19.8%), but not from cats. Overall, DNA of one or more of the organisms was amplified from 27% (30) of cats and 67.6% (75) of the flea sets. Conclusions This is the first Australian study to determine the prevalence of R. felis and B. clarridgeiae in both fleas and the cats from which they were collected. Flea-associated infectious agents are common in cats and fleas in eastern Australia and support the recommendation that stringent flea control be maintained on cats.  相似文献   
66.
We investigated the effects of concentration of the microalga Dunaliella tertiolecta on the growth and survival of fairy shrimp, Phallocryptus spinosa. Newly hatched nauplii were stocked into containers, maintained at different concentrations of D. tertiolecta (at 18, 36, 54, 72 and 90 × 106 cells mL?1). All treatments were in quadruplicate and each replicate was stocked with 100 larvae in a 2‐L cylindrical bowl. We studied the survival and growth of the fairy shrimp after 3, 6, 9, 12 and 15 days of culture. The results indicated significant differences, in terms of growth and survival, of fairy shrimps fed at different algal densities. The highest and lowest growth and survival among the treatments were observed on Day 15, the highest in animals fed at a concentration of 90 × 106 cells mL?1 and the lowest in animals fed at a concentration of 18 × 106 cells mL?1. We conclude that the growth and survival of the P. spinosa increased with increasing density of algae, to a threshold level. Within certain concentration limits, the addition of D. tertiolecta substantially improved the performance of larval culture of P. spinosa, suggesting that this fairy shrimp has potential in terms of aquaculture development.  相似文献   
67.
The pharmacokinetic profile of posaconazole in clinically normal koalas (n = 8) was investigated. Single doses of posaconazole were administered intravenously (i.v.; 3 mg/kg; n = 2) or orally (p.o.; 6 mg/kg; n = 6) with serial plasma samples collected over 24 and 36 hr, respectively. Plasma concentrations of posaconazole were quantified by validated high‐performance liquid chromatography. A noncompartmental pharmacokinetic analysis of data was performed. Following i.v. administration, estimates of the median (range) of plasma clearance (CL) and steady‐state volume of distribution (Vss) were 0.15 (0.13–0.18) L hr?1 kg?1 and 1.23 (0.93–1.53) L/kg, respectively. The median (range) elimination half‐life (t1/2) after i.v. and p.o. administration was 7.90 (7.62–8.18) and 12.79 (11.22–16.24) hr, respectively. Oral bioavailability varied from 0.43 to 0.99 (median: 0.66). Following oral administration, maximum plasma concentration (Cmax; median: 0.72, range: 0.55–0.93 μg/ml) was achieved in 8 (range 6–12) hr. The in vitro plasma protein binding of posaconazole incubated at 37°C was 99.25 ± 0.29%. Consideration of posaconazole pharmacokinetic/pharmacodynamic (PK/PD) targets for some yeasts such as disseminated candidiasis suggests that posaconazole could be an efficacious treatment for cryptococcosis in koalas.  相似文献   
68.
The primary objective of this study was to investigate the impact of animal‐level factors including energy balance and environmental/management stress, on the ovarian function of Bos indicus heifers treated to synchronize ovulation. Two‐year‐old Brahman (BN) (n = 30) and BN‐cross (n = 34) heifers were randomly allocated to three intravaginal progesterone‐releasing device (IPRD) treatment groups: (i) standard‐dose IPRD [Cue‐Mate® (CM) 1.56 g; n = 17]; (ii) half‐dose IPRD [0.78 g progesterone (P4); CM 0.78 g; n = 15]; (iii) half‐dose IPRD + 300 IU equine chorionic gonadotrophin at IPRD removal (CM 0.78 g + G; n = 14); (iv) and a control group, 2× PGF [500 μg prostaglandin F (PGF)] on Day ?16 and ?2 (n = 18). Intravaginal progesterone‐releasing device‐treated heifers received 250 μg PGF at IPRD insertion (Day ?10) and IPRD removal (Day ?2) and 1 mg oestradiol benzoate on Day ?10 and ?1. Heifers were managed in a small feedlot and fed a defined ration. Ovarian function was evaluated by ultrasonography and plasma P4 throughout the synchronized and return cycles. Energy balance was evaluated using plasma insulin‐like growth factor 1 (IGF‐I) and glucose concentrations. The impact of environmental stressors was evaluated using plasma cortisol concentration. Heifers that had normal ovarian function had significantly higher IGF‐I concentrations at commencement of the experiment (p = 0.008) and significantly higher plasma glucose concentrations at Day ?2 (p = 0.040) and Day 4 (p = 0.043), than heifers with abnormal ovarian function. There was no difference between the mean pre‐ovulatory cortisol concentrations of heifers that ovulated or did not ovulate. However, heifers that ovulated had higher cortisol concentrations at Day 4 (p = 0.056) and 6 (p = 0.026) after ovulation than heifers that did not ovulate.  相似文献   
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