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排序方式: 共有86条查询结果,搜索用时 15 毫秒
1.
Marais HJ Nel P Bertschinger HJ Schoeman JP Zimmerman D 《Journal of the South African Veterinary Association》2007,78(3):145-148
There are no reports in the literature describing any tumours, and specifically sarcoids, in zebras. The equine sarcoid, a locally aggressive, fibroblastic skin tumour, is the most common dermatological neoplasm reported in horses. The Cape mountain zebra (CMZ) has been described as one of the most vulnerable mammals in South Africa with current populations existing in isolated units. All South African CMZ are descendants from no more than 30 individual animals originating from 3 populations, namely the Mountain Zebra National Park, and Kammanassie and Gamka Mountain Nature Reserves near Cradock. The possibility therefore exists that the existing populations arose from a very small gene pool and that they are considerably inbred. A reduction in major histocompatibility complex diversity due to genetic bottlenecks and subsequent inbreeding probably contributed to uniform population sensitivity and the subsequent development of sarcoid in two CMZ populations, namely in the Bontebok National Park and Gariep Nature Reserve. The entire population of CMZ in the Bontebok National Park was observed and sampled during 2002 to document the prevalence and body distribution of sarcoids. During the same year, a comparative study was carried out on an outbred population of Burchell's zebra in the Kruger National Park. The prevalence in CMZ in the Bontebok National Park was 53 %, while the Burchell's zebra in Kruger National Park had a prevalence of 1.9 %. The most common sites for sarcoid in CMZ were the ventral abdomen and limbs. Prevalence of sarcoids in horses recorded in the literature varies between 0.5 % and 2 %. The Gariep Nature Reserve recently reported a prevalence of almost 25 % in CMZ in the reserve. 相似文献
2.
This article considers the experiences of a Samoan female geographer undertaking community‐based field research in her home country, and identifies some lessons for researchers working in similar circumstances. The paper suggests that ethical behaviour in research is ‘place‐specific’, and there is therefore a need to employ culturally sensitive and ‘location‐specific’ methodologies when undertaking community‐based research fieldwork. For the lead researcher, growing up in Samoa played a significant role in gaining an understanding of a set of robust and effective procedures to evaluate citizens' resilience to climatic and other environmental challenges. Fluency in everyday and more formal local languages, and awareness of local differences, each with multi‐layered connections to local communities, understanding cultural nuances and practising respect for va tapuia [sacred space or relationships] protocols, together facilitated the process of knowledge acquisition and helped to confirm the validity of the conclusions derived from the study. 相似文献
3.
Woosnam’s desert rat, Zelotomys woosnami, occurs in the arid regions of southern Africa. It is sparsely distributed, asocial and nocturnal, and probably utilizes burrows of other rodents although it can dig well. It has a wide food spectrum ranging from seeds to flesh, and is an agile climber. The litter size of 4,7 and the rapid postnatal development are thought to be adaptations to a short breeding season in the summer months, and to capitalize on seasonally-rich resources in a potentially hostile environment. Minimum period between litters was 31 days. 相似文献
4.
The comparative hoarding behaviour of four rodent species,Saccostomus campeslris, Desmodillus auricula-is. Tatera brantsii and T. leucogaaer was studied under semi-natural conditions after prior determination of the seed preferences of each species.The results are consistent with all available ecological data. Desmodillus and Saccostomus are true larder-hoarders, although Desmodillus also scatter-hoards on occasion. The Tatera spp. did not hoard, but frequently covered seeds, a possible primitive form of scatter-hoarding. 相似文献
5.
6.
The potential of nonpathogenic Fusarium oxysporum and other biological control organisms for suppressing fusarium wilt of banana 总被引:3,自引:0,他引:3
The aim of this study was to evaluate the ability of nonpathogenic F. oxysporum and Trichoderma isolates from suppressive soils in South Africa to suppress fusarium wilt of banana in the glasshouse. Several biological control agents and commercial biological control products were included in the study. The isolates were first screened in vitro on potato dextrose agar. In glasshouse evaluations, the fungal and bacterial isolates were established on banana roots before they were replanted in pathogen-infested soil, while the commercial biocontrol agents were applied as directed by the supplier. Banana plantlets were evaluated for disease development after 7 weeks. In vitro tests showed none of the nonpathogenic isolates suppressed Fusarium oxysporum f.sp. cubense ( Foc ), while slight suppression was observed with the two Trichoderma isolates. Results of the glasshouse evaluations revealed that two of the nonpathogenic F. oxysporum isolates, CAV 255 and CAV 241, reduced fusarium wilt incidence by 87·4 and 75·0%, respectively. The known biological control agent Fo47 did not suppress Foc significantly. Pseudomonas fluorescens strain WCS 417, known for its ability to suppress other fusarium wilt diseases (WCS 417), reduced disease incidence by 87·4%. These isolates should be further evaluated for potential application in the field, independently and in combination. 相似文献
7.
Nel LH Bingham J Jacobs JA Jaftha JB 《The Onderstepoort journal of veterinary research》1998,65(4):297-303
Antigenic and nucleotide sequence analyses have shown that two distinct biotypes of rabies virus are circulating in South Africa. One of these typically infects members of the family Canidae, while the other comprises a heterogeneous group of apparently indigenous viruses, infecting members of the Viverridae family. In recent times, it has become evident that a considerable amount of cross-infection may occur and the manifestation of viverrid rabies in non-viverrid animals in particular appears to have become more commonplace. Consequently, the need to rapidly distinguish between rabies virus biotypes has become increasingly important in efforts to monitor the epidemiology of rabies in the southern African region. In this study, a nested polymerase chain reaction (PCR) assay was developed to distinguish between these two groups of rabies viruses. Consensus oligonucleotides were used to amplify the cytoplasmic domain of the rabies virus glycoprotein and the adjacent intergenic region. The resultant amplicon was subsequently used as template in second round heminested PCR in the presence of type-specific primers, thereby successfully generating amplicons of characteristic size for each biotype. 相似文献
8.
J. Roux B. Eisenberg A. Kanzler A. Nel V. Coetzee E. Kietzka M. J. Wingfield 《New Forests》2007,33(2):109-123
Plantations of Pinus spp. constitute approximately 50% of the South African forestry industry. The first aim of this study was to develop a reliable
inoculation technique to screen Pinus spp., for tolerance to infection by F. circinatum, which threatens pine forestry in South Africa. Inoculation of branches was compared with stem inoculations and we considered
the number of branches or trees required to obtain statistically significant results. Furthermore, variation in the susceptibility
of some Pinus families, clones and hybrids was considered. Results showed that branch inoculations were closely correlated with those from
stem inoculations, and that it is important to consider branch and stem diameters when assessing susceptibility of trees.
Subsequent trials using branch inoculations showed significant differences in F. circinatum tolerance amongst a range of pine species and hybrids of potential interest to forestry in South Africa. Significant differences
in susceptibility were also found among clones of two P. radiata families. The most tolerant trees were P. elliottii × caribaea and P. patula × oocarpa hybrids, while the most susceptible species were P. patula, P. greggii and hybrids of these two. This is the first trial considering the susceptibility of Pinus hybrids, Pinus clones and some P. patula provenances, and the results indicate excellent potential for breeding for tolerance to pitch canker in South Africa.
Application The accurate selection of disease tolerant planting stock for the South African forestry industry is crucially important
for the continued sustainability of this important industry. The work described here provides valuable information on an artificial
inoculation technique that will assist the industry in screening trees for tolerance to the pitch canker fungus, F. circinatum. It also provides some indication of the relative susceptibility of a number of Pinus spp., hybrids and families currently being evaluated in the country. 相似文献
9.
10.
P W Nel R A Schultz P Jordaan L A Anderson T S Kellerman C Reid 《The Onderstepoort journal of veterinary research》1987,54(4):641-644
Urginea physodes (Jacq.) Bak., a species closely related to or possibly synonymous with U. pusilla, is described and its distribution given. Four bufadienolides were isolated from U. physodes and the approximated LD50 and cumulative effect of some of them determined in guinea pigs. The most toxic one proved to be mildly cumulative. Typical signs of acute cardiac glycoside poisoning, involving the locomotory, gastro-intestinal, respiratory and cardiac system, were seen in the field cases and/or were experimentally induced by the plant. Similar signs could also be induced by injecting the isolated bufadienolide, physodine A, to a sheep. 相似文献