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排序方式: 共有183条查询结果,搜索用时 15 毫秒
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AIM: To determine the aetiolog y of a recurring and severe form of infectious keratoconjunctivitis (IKC) in sheep. METHODS: Five sheep flocks that had experienced a severe form of IKC were examined. Clinical history, conjunctival swabs and blood samples were collected from affected animals. Culture for bacteria, and also specifically for Mycoplasma and Chlamydophila spp, and detection of Mycoplasma conjunctivae DNA by polymerase chain reaction (PCR) were attempted. Serum samples were tested for antibodies to M. agalactiae, M. capricolum, M. conjunctivae and Chlamydophila spp. RESULTS: Mycoplasma conjunctivae DNA was detected using PCR in 3/5 flocks, and in all flocks antibodies to M. conjunctivae were detected in sera. A pure growth of Branhamella ovis was cultured from conjunctival swabs from a small proportion of sheep in two flocks. No other pathogens were detected. CONCLUSIONS: This investigation demonstrated that M. conjunctivae was a primary pathogen causing severe IKC in sheep, and is the first report of detection of this organism in sheep in New Zealand. Introduction of clinically normal carrier sheep appeared to have caused the outbreaks. 相似文献
94.
SUMMARY Three groups of 15 to 17 adult fallow does with some additional yearling does in 2 of the groups were treated to synchronise oestrous cycles, and mated. All does were scanned by ultrasound at 4 weeks of gestation and at weekly intervals from week 7 to week 14 of gestation. Growth rates of 13 foetal and uterine characters, which have been used for ageing foetuses of red deer, were similar for adult and yearling does and among the 3 groups. Transrectal ultrasound scanning was a reliable and accurate means of detecting pregnancy and of ageing foetuses of fallow deer during weeks 7 to 17 of pregnancy. 相似文献
95.
Mapping of leaf and neck blast resistance genes with resistance gene analog, RAPD and RFLP in rice 总被引:17,自引:1,他引:17
Jie-Yun Zhuang Wen-Bin Ma Jian-Li Wu Rong-Yao Chai Jun Lu Ye-Yang Fan Min-Zhong Jin Hei Leung Kang-Le Zheng 《Euphytica》2002,128(3):363-370
An F8 recombinant inbred population was constructed using a commercial indica rice variety Zhong 156 as the female parent and a semidwarf indica variety Gumei 2 with durable resistance to rice blast as the male parent. Zhong 156 is resistant to the fungus race ZC15 at the seedling stage but susceptible to the same race at the flowering stage. Gumei 2 is resistant to ZC15 at both stages. The blast resistance of 148 recombinant inbred lines was evaluated using the blast race ZC15. Genetic analysis indicated that the resistance to leaf blast was controlled by three genes and the presence of resistant
alleles at any loci would result in resistance. One of the three genes did not have effects at the flowering stage. Two genes,
tentatively assigned as Pi24(t) and Pi25(t), were mapped onto chromosome 12 and 6,respectively, based on RGA (resistance gene analog), RFLP and RAPD markers. Pi24(t) conferred resistance to leaf blast only, and its resistance allele was from Zhong 156. Pi25(t) conferred resistance to both leaf and neck blast, and its resistance allele was from Gumei 2. In a natural infection test
in a blast hot-spot, Pi25(t) exhibited high resistance to neck blast, while Pi24(t) showed little effect.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
96.
Geoffrey Jones Joyce Leung Hugh Robertson 《Journal of Agricultural, Biological & Environmental Statistics》2009,14(1):66-78
We introduce a new method for modeling a population of growth curves with B-splines, adapting the usual regression spline basis to ensure a horizontal upper asymptote in all fitted curves. The new
method is easily implemented in standard statistical software. We motivate and illustrate our method using data on the growth
of Brown Kiwi (Apteryx mantelli) in the North Island of New Zealand, including a time-dependent covariate to investigate the effects of different rearing
environments on patterns of weight increase. 相似文献
97.
98.
Xiao WL Motley TJ Unachukwu UJ Lau CB Jiang B Hong F Leung PC Wang QF Livingston PO Cassileth BR Kennelly EJ 《Journal of agricultural and food chemistry》2011,59(5):1548-1556
Radix Astragali (Huangqi) has been demonstrated to have a wide range of immunopotentiating effects and has been used as an adjuvant medicine during cancer therapy. Identity issues in the collection of Radix Astragali exist because many sympatric species of Astragalus occur in the northern regions of China. In order to assess the quality, purity, and uniformity of commercial Radix Astragali, 44 samples were purchased from herbal stores in Hong Kong and New York City. The main constituents, including four isoflavonoids and three saponins, were quantitatively determined by liquid chromatography mass spectrometry (LC-MS). There was significant sample-to-sample variability in the amounts of the saponins and isoflavonoids measured. Furthermore, DNA barcoding utilizing the variable nuclear ITS spacer regions of the 44 purchased Radix Astragali samples were sequenced, aligned and compared. Eight polymorphic point mutations were identified which separated the Radix Astragali samples into three groups. These results indicate that the chemical and genetic variability that exists among Radix Astragali medicinal products is still a consistency and quality issue for this herbal. Two-way ANOVA analysis showed significant effects on the contents of the seven tested compounds when both phylogenetic and geographic (i.e., point of purchase) factors were considered. Therefore, chemical profiles determined by LC-MS and DNA profiles in ITS spacer domains could serve as barcode markers for quality control of Radix Astragali. 相似文献
99.
A Review on Ozone Evolution and Its Relationship with Boundary Layer Characteristics in Urban Environments 总被引:1,自引:0,他引:1
Nelson Y. O. Tong Dennis Y. C. Leung Chun-Ho Liu 《Water, air, and soil pollution》2011,214(1-4):13-36
This paper reviews the interrelationship among boundary layer, urbanization, and evolution of ozone, with particular emphasis on how boundary layer dynamics and urbanization affects the evolution of ozone under different meteorological and climatological conditions. The aim of this work is not only to provide an exhaustive investigation of individual ozone episodes but to look at the underlying issues and hypotheses that are available for understanding the evolution of ozone. The review concludes with a summary of the current state of knowledge and outlines some of the remaining questions. It is the intention of this paper to serve as an ecumenical reference to the community for reappraising the relation of boundary layer climate to the evolution of ozone in an urban setting, especially on a peculiar feature of ozone dynamic, nocturnal ozone maxima. To date, there is still no overarching consensus on the mechanisms that lead to its formation. The importance of levels of urbanization and advantage of ascertaining the substantial weights of the respective mixing height and emission structure in exploring the relationship between ozone evolutions should not be overlooked. 相似文献
100.
Using GIS to measure changes in the temporal and spatial dynamics of forestland: experiences from north-west Spain 总被引:2,自引:0,他引:2
Forestry variables are usually calculated at a forest managementunit scale. However, a region's forestry sector is affectedby various other factors that interact over space and time,many of which are not directly associated to silvicultural activitiesbut nonetheless play an important part in its development froma socio-economic or environmental point of view. To understanda region's forestry dynamics, and especially to predict itsfuture tendencies, we must include all the necessary variablesin a single database, calculated for spatial units that arestable over time and adequate for planning purposes. In ourstudy, we developed a Forest Geographic Information System forGalicia called SIFGa. We used it to examine 310variables describing the environment, population tendencies,land tenure and forest management in the Spanish autonomousregion of Galicia, at both council and parish levels. Resultsreveal the connections between our variables, which reflectthe changes the regional forestry sector has experienced inthe past, and explain its current situation. They also confirmthe heterogeneity of forestry in the area and the need to adaptforest-planning strategies to each study unit, as well as tothe entire region. 相似文献