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51.
52.
Infrasound generated by the sonic boom from the inbound Concorde supersonic transport is recorded at Palisades, New York (Lamont-Doherty Geological Observatory), as a series of impulses from distances varying from 165 to about 1000 kilometers. Refraction effects determined by temperature and wind conditions return the signal to the surface from both stratospheric (40 to 50 kilometers) and thermospheric (100 to 130 kilometers) levels. The frequency of the recorded signal is a function of the level of reflection; the frequency decreases from impulse stretching as the atmosphere becomes more rarified relative to the sound pressure. The horizontal trace velocity of the signal across the array of instruments is equal to the acoustic velocity at the reflection level. The sonic boom can thus be used to provide temperature-wind parameters at reflection levels estimated from the signal frequency. Daily observed signal variations have indicated significant variations in these parameters. 相似文献
53.
Olga Andrievskaia James Algire Aru Balachandran Klaus Nielsen 《Journal of veterinary diagnostic investigation》2008,20(2):141-146
The misfolded form of cellular prion protein (PrP(C)) is the main component of the infectious agent of transmissible spongiform encephalopathies and the validated biomarker for these diseases. The expression of PrP(C) is highest in the central nervous system and has been found in peripheral tissues. Soluble PrP(C) has been detected in cerebrospinal fluid, urine, serum, milk, and seminal plasma. In this study, attempts were made to characterize prion protein in urine samples from normal and scrapie-infected sheep. Urine samples from scrapie-infected sheep and age-matched healthy sheep were collected and analyzed by Western blot following concentration. A protease K-sensitive protein band with a molecular weight of approximately 27-30 kDa was visualized after immunoblotting with anti-PrP monoclonal antibodies to a C-terminal part of PrP(C), but not after immunoblotting with monoclonal antibodies to an N-terminal epitope of PrP(C) or with secondary antibodies only. The amount of PrP(C) in the urine of 49 animals (control group: n = 16; naturally scrapie-infected group: n = 33) was estimated by comparison with known amounts of ovine recombinant PrP in the immunoblot. Background concentration of PrP(C) in urine was found to be 0-0.16 ng/ml (adjusted to the initial nonconcentrated volume of the urine samples). Seven out of 33 naturally scrapie-infected animals had an elevated level (0.3-4.7 ng/ml) of PrP(C) in urine. The origin of PrP(C) in urine and the reason for the increased level of PrP(C) in scrapie-infected sheep urine has yet to be explored. 相似文献
54.
Praveena PE Jayakumar R Balachandran C Thirumurugan G Raj GD Manohar BM 《Veterinary research communications》2007,31(6):775-781
Rabies is diagnosed by FAT in the impression smears of brain tissues. In this study, an attempt was made to diagnose rabies
using in situ polymerase chain reaction (ISPCR). A digoxigenin-labelled double-stranded probe specific for a portion of the ‘N’ gene of
rabies virus was used. Positive signals were identified as blue dots in the intraneuronal and neuropil areas. 相似文献
55.
本研究旨在克隆鸡淋巴细胞趋化因子(lymphotactin,XCL1)基因CDS区并探索其生物学特性。试验以固始鸡胸腺组织总RNA为模板,采用RT-PCR技术对该基因的CDS区进行扩增和克隆,并通过生物信息学软件进行相关生物信息学分析。结果表明,固始鸡XCL1基因CDS区长294 bp,编码97个氨基酸。相似性分析结果发现,鸡XCL1基因CDS区序列与牛、山羊、绵羊、人、小鼠、猪和大鼠的相似性分别为53.7%、53.0%、52.9%、51.8%、51.1%、50.9%和50.4%。进化树结果表明,鸡作为非哺乳动物,与哺乳动物亲缘关系较远。XCL1蛋白分子式为C491H822N150O132S6,理论等电点为10.95,属于碱性蛋白;分子质量为11.13 ku,脂肪系数为102.37,不稳定系数为51.44,属于不稳定蛋白,半衰期为30 h;具有跨膜结构(第5-27位氨基酸)和信号肽区域(第1-18位氨基酸),属于亲水性分泌型蛋白。XCL1蛋白存在8个潜在的磷酸化修饰位点和3个潜在的糖基化修饰位点。XCL1蛋白的二级结构由α-螺旋(35.05%)、β-转角(5.15%)、延伸链(26.80%)和无规则卷曲(32.99%)组成,三级结构预测结果与二级结构一致。亚细胞定位分析表明XCL1蛋白主要在细胞外发挥作用;该蛋白有1个位于第31—88氨基酸残基处的SCY保守性结构域;该蛋白能与OXT、PTAFR、GPR132和XCR1等分子形成互作网络。本试验结果为进一步研究鸡XCL1基因功能提供理论参考。 相似文献
56.
C. S. Balachandran 《Land Degradation \u0026amp; Development》1995,6(4):265-283
Knowledge about land conservation exists along a spatial continuum, represented at the broadest level (with least depth) by international-level experts who have international-level expertise, and at the narrowest level (with most depth) by the individual farmer with the most site-specific knowledge at the plot level. This continuum covers many different aspects of knowledge about land degradation and its amelioration, including technical and cultural knowledge. This paper reports an effort (one in a series of steps) to gather, formalize, codify, and operationalize knowledge about land conservation from two different levels of the continuum. Land conservation knowledge was elicited from farmers and extension agents in Vilathikulam taluk (an area of contiguous villages) in Tamil Nadu, southeastern India, using semi-structured interviews. The knowledge thus gained was combined with knowledge from the literature on soils and land conservation for the area. This information was organized into factual knowledge and process knowledge, and implemented in the form of general recommendations, constraints, and specific recommendations. The process of arriving at these categories was organized into several steps using a spatial anchor and soil type as keys. These were operationalized in a rule-based computer program (LAnd CONservation EXpert -LACONEX), which offers land conservation advice at the plot level for Vilathikulam taluk , using an expert system development environment. 相似文献