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91.
设计与大豆叶片反射光谱相似的绿色诱盘,诱集大豆田迁飞降落的有翅蚜,结果所获蚜虫种类和数量与田间有翅蚜的动态变化相吻合。绿色诱盘诱集蚜量与田间百株有翅蚜量和大豆花叶病(SMV)侵染速率相关显著。黄皿诱蚜量接近绿色诱盘所获蚜量的2倍,但黄皿诱蚜与田间百株有翅蚜量和SMV侵染速率均无显著相关。SMV流行程度与田间百株有翅蚜量无显著相关,而决定于田间种传病株率的高低和病害盛发期田间着落蚜量的大小。 相似文献
92.
O. O. Banwo R. H. Makundi R. S. Abdallah J. C. Mbapila F. M. Kimmins 《Phytoparasitica》2002,30(1):96-104
Regular samplings were done of two important vectors in farmers’ fields during the 1999/2000 and 2000/01 rice seasons at crop
stages susceptible to rice yellow mottle virus (RYMV) on a traditional rice variety (‘Supa’) under rainfed lowland conditions
to provide information on the bionomics and importance of these vectors in the disease transmission. The population ofChaetocnema sp. (nr.varicornis Jacoby) (Coleoptera: Chrysomelidae) was significantly higher in hotspot than non-hotspot areas. However, there was no significant
difference in theC. pulla Chapuis population between these two areas. In general, theChaetocnema sp. population was higher than that ofC. pulla, and both vectors reached the peak of their population at 63 days after planting. Early planting in the hotspot areas is
suggested as a disease management strategy. Both vectors are naturally infective andChaetocnema sp. proved more efficient thanC. pulla in the transmission of RYMV. 相似文献
93.
AIM: To investigate the feasibility and infection efficiency of MSCs as the target cells of gene delivery mediated by adenoviral vector carrying CTLA4Ig gene, and to study the mechanism of transgenic MSC to inhibit immune response ex vivo. METHODS: The recombinant adenovirus containing CTLA4Ig gene was constructed, by which rat MSCs with various multiplicity of infection (MOI) were conducted. The infection efficiency was analyzed with FACS and fluorescence microscope. The expression of CTLA4Ig protein in transgenic MSCs was detected by FACS and western blot. Co-culturing the transgenic MSCs with mixed lymphocytes, the inhibitory effect of transgenic MSCs on lymphocyte proliferation was also observed. RESULTS: The adenoviral vector delivered CTLA4Ig gene with high efficiency to MSCs. The expression of CTLA4Ig protein was detected in transgenic MSCs. The gene modified MSCs inhibited the proliferation of mixed lymphocytes and maximal inhibition rate was observed on day 4 of MLR. The inhibition induced by CTLA4Ig was donor-specific. CONCLUSION: MSCs is a promising target cell for gene delivery. The expressed CTLA4Ig specifically inhibited the lymphocyte proliferation ex vivo. 相似文献
94.
95.
传染性胰腺坏死病毒VP3蛋白的干酪乳杆菌表达系统构建 总被引:1,自引:1,他引:1
根据传染性胰腺坏死病毒(IPNV)VP3蛋白的全基因序列,设计并合成引物,以IPNV(ATCC VR-1318)细胞培养毒提取的核酸为模板,对传染性胰腺坏死病毒VP3蛋白的干酪乳杆菌表达系统进行了构建研究。结果显示:进行RT-PCR扩增得到截短的VP3基因约615 bp目的片段,将其克隆到pMD18-T Simple载体,经酶切、PCR扩增和序列测定后显示目的片段正确;将目的片段分别亚克隆到乳酸菌细胞表面表达型载体和分泌表达型载体,电转化于干酪乳杆菌,获得了阳性重组菌株。结果表明,通过本实验方法可构建表达传染性胰腺坏死病毒VP3蛋白的干酪乳杆菌表达系统,为实现IPNV VP3蛋白在乳酸菌中的表达及免疫原性研究奠定了基础。 相似文献
96.
97.
Plant Viruses Transmitted by Thrips 总被引:8,自引:0,他引:8
Jones David R 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(2):119-157
All thrips (order Thysanoptera) that are known to be vectors of plant viruses are identified and described. Thrips transmit
plant viruses in the Tospovirus, Ilarvirus, Carmovirus, Sobemovirus and Machlomovirus genera. Tospoviruses are the cause of a number of significant emerging diseases, such as capsicum chlorosis and scape blight
of onion. They infect thrips as well as plant hosts and the relationship between pathogen and vector is intimate. Once infected
at the larval stage, adult thrips usually transmit tospovirsuses for life. Transmission to plant hosts occurs when thrips
feed. Information on the distribution and hosts of all recognised thrips vectors is provided. Fourteen tospovirus species
are described with information provided on other tospoviruses that have not yet been designated as species. The history of
the research that has led to present knowledge is reviewed in chronological order for each tospovirus. The possible origin
of tospoviruses is discussed. Information is presented on viruses, which are thrips-transmitted by mechanical processes, in
other genera. Pathways of spread of thrips vectors in relation to the threat of tospoviruses to European agriculture are discussed. 相似文献
98.
Envelope to a two-parameter family of point vectors method for surface swept by wheel during 5-axis gear form grinding 总被引:1,自引:0,他引:1 下载免费PDF全文
The wheel generating curve for gear grinding is always a composited curve which is composed of lines and arcs,and the calculation of the envelope surface is more complex than conventional rotary cutter. A method of envelope to a two-parametric family of point vectors is proposed,which defines the point and its normal vector on the wheel generating curve as a point vector. Each point vector corresponds to a virtual ball uniquely. The rotation of point vector forms latitude circle and the valid envelopment movement forms sectional circle. The intersection of latitude circle and sectional circle is grazing point. The analytical calculation model is established,in which the grazing point is determined by the geometry parameters of virtual ball and the velocity of virtual ball center,and the geometry parameters of virtual ball can be directly calculated from point vector. The kinematic geometry of 5-axis form gear grinder is analyzed. The coordinate transformation between fixed frame and moving frame is conducted,and the velocity of virtual ball center based on NC codes is obtained. An example is presented to demonstrate the effectiveness of the method which can be used for 5-axis gear grinding geometry simulation,accuracy evaluation and optimization of the wheel path. 相似文献
99.
施马伦贝格病毒病(Schmallenberg virus,SBV)是一种新发现的动物传染病,因于2011年底在德国施马伦贝格镇首次发现而临时得名,随后蔓延于西欧(包括比利时、法国、德国、荷兰、意大利、卢森堡、西班牙、英国和丹麦),并分别在奥地利、波兰、瑞典和芬兰等国的牛、山羊、绵羊中检测到抗体。遗传分析显示该病毒与布尼亚病毒科(Bunyaviridae)正布尼亚病毒属(Orthobunyavirus)西姆布血清群病毒(Simbu serogroup viruses)的亲缘关系最密切,西姆布血清群病毒是已知的反刍动物病原,可通过节肢动物媒介(蚊、蠓)传播。施马伦贝格病毒病有2种不同的临床症状:成年牛出现短暂轻微/温和的病症(产奶量减少、发热、腹泻)和新生哺乳动物(牛、羊)死产和先天缺陷。因为同群类似的病毒不是人畜共患病病原,也无该病毒致人发病的证据,但现阶段尚不能完全排除。尽管目前没有特效的药物和疫苗,但因已有类似病毒(赤羽病)的疫苗,疫苗接种应是控制该病的可能选项。因施马伦贝格病毒是一种新发现的病毒,许多方面尚不清楚,还有待于进一步研究。 相似文献
100.
N. Ioannou 《Potato Research》1989,32(1):33-47
Summary The infection pressure of two viruses, potato leafroll (PLRV) and potato virus Y (PVY), both common in seed potatoes grown
in Cyprus, was determined in three experiments in 1982–83. Virus-free bait plants, of potato and four other species, were
exposed weekly to field infection during the growing season (March–June), and then returned to an aphid-free glasshouse for
symptom expression. Only tobacco plants produced clear symptoms enabling reliable assessment of PVY infection pressure. When
assessed with ELISA or by tuber indexing, the potato plants were efficient baits for both viruses whose infection period commenced
at emergence (mid March to early April) and ended within 6–7 weeks. The seasonal trend of aphid populations, determined with
Moericke traps or 100-leaf counts, correspond to that of virus spread. Correlation and regression analysis of aphid and virus
data implicated the alate form ofMyzus persicae as the principal vector of both viruses. 相似文献