全文获取类型
收费全文 | 380篇 |
免费 | 16篇 |
专业分类
林业 | 13篇 |
农学 | 11篇 |
基础科学 | 2篇 |
64篇 | |
综合类 | 42篇 |
农作物 | 13篇 |
水产渔业 | 13篇 |
畜牧兽医 | 214篇 |
园艺 | 11篇 |
植物保护 | 13篇 |
出版年
2023年 | 8篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 12篇 |
2019年 | 16篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 11篇 |
2014年 | 14篇 |
2013年 | 20篇 |
2012年 | 27篇 |
2011年 | 35篇 |
2010年 | 19篇 |
2009年 | 9篇 |
2008年 | 24篇 |
2007年 | 23篇 |
2006年 | 25篇 |
2005年 | 32篇 |
2004年 | 17篇 |
2003年 | 29篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有396条查询结果,搜索用时 0 毫秒
101.
Transmission of equine influenza virus to dogs 总被引:1,自引:0,他引:1
Crawford PC Dubovi EJ Castleman WL Stephenson I Gibbs EP Chen L Smith C Hill RC Ferro P Pompey J Bright RA Medina MJ Johnson CM Olsen CW Cox NJ Klimov AI Katz JM Donis RO 《Science (New York, N.Y.)》2005,310(5747):482-485
Molecular and antigenic analyses of three influenza viruses isolated from outbreaks of severe respiratory disease in racing greyhounds revealed that they are closely related to H3N8 equine influenza virus. Phylogenetic analysis indicated that the canine influenza virus genomes form a monophyletic group, consistent with a single interspecies virus transfer. Molecular changes in the hemagglutinin suggested adaptive evolution in the new host. The etiologic role of this virus in respiratory disease was supported by the temporal association of rising antibody titers with disease and by experimental inoculation studies. The geographic expansion of the infection and its persistence for several years indicate efficient transmission of canine influenza virus among greyhounds. Evidence of infection in pet dogs suggests that this infection may also become enzootic in this population. 相似文献
102.
Jocelyn R Holt Lina Bernaola Kadie E Britt Chirs McCullough Morgan Roth Jennie Wagner Max Ragozzino Leslie Aviles Zhilin Li Forest Huval Manoj Pandey Benjamin W Lee Megan Asche Abigail Hayes Abigail Cohen Adrian Marshall Hannah E Quellhorst Rachel V Wilkins Valerie Nguyen Jacqueline Maille Rachel K Skinner John J Ternest Sarah Anderson Scott W Gula Kayleigh Hauri Julius Eason Megan Mulcahy Scott Lee James Michael Villegas Patricia Shorter 《Journal of insect science (Online)》2020,20(5)
Every year, the Student Debates Subcommittee (SDS) of the Student Affairs Committee (SAC) for the annual Entomological Society of America (ESA) meeting organizes the Student Debates. This year, the SAC selected topics based on their synergistic effect or ability to ignite exponential positive change when addressed as a whole. For the 2019 Student Debates, the SAC SDS identified these topic areas for teams to debate and unbiased introduction speakers to address: 1) how to better communicate science to engage the public, particularly in the area of integrated pest management (IPM), 2) the influential impacts of climate change on agriculturally and medically relevant insect pests, and 3) sustainable agriculture techniques that promote the use of IPM to promote food security. Three unbiased introduction speakers gave a foundation for our audience to understand each debate topic, while each of six debate teams provided a strong case to support their stance or perspective on a topic. Debate teams submitted for a competitive spot for the annual ESA Student Debates and trained for the better part of a year to showcase their talents in presenting logical arguments for a particular topic. Both the debate teams and unbiased introduction speakers provided their insight toward a better understanding of the complexities of each topic and established a foundation to delve further into the topics of science advocacy and communication, climate change, and the many facets of integrated pest management. 相似文献
103.
SeChin Chang Brian Condon Elena Graves Minori Uchimiya Chanel Fortier Michael Easson Phillip Wakelyn 《Fibers and Polymers》2011,12(3):334-339
The flame retardant behavior of cotton fabric treated with phosphorus-nitrogen containing triazine compound was evaluated.
It was found that cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) is an excellent starting material for the preparation
of phosphonate flame retardants that interact well with cotton to improve flame resistance (FR) performance. Tetraethyl 6-chloro-1,3,5-triazine-2,4-diyldiphosphonate
(TECTDP) has been prepared by a simple one-step reaction in high yield (98.0 %). Cotton fabrics treated with TECTDP result
in covalent bond formation between TECTDP and hydroxyl groups in cotton fabrics. This FR system provides an efficient flame
retardant for cotton textiles at low cost to meet government mandates. In this study, the FR material was synthesized and
characterized by 1H and 13C nuclear magnetic resonance (NMR), and LC-MS spectroscopy. The chemical structure of cotton twill fabric treated with TECTDP
by pad-dry-cure method was analyzed by FT-MIR and SEM. Furthermore, the thermal and flammability properties were evaluated
by thermogravimetric analysis (TGA), limiting oxygen index (LOI, ASTM D-2863-09), and a vertical flame test (ASTM D-6413-08). 相似文献
104.
Background
The rapid expansion in the availability of genome and DNA sequence information has opened up new possibilities for the development of methods for detecting free-living protozoa in environmental samples. The protozoan Blepharisma japonicum was used to investigate a rapid and simple detection system based on polymerase chain reaction amplification (PCR) from organisms immobilised on FTA paper. 相似文献105.
Tumpey TM Basler CF Aguilar PV Zeng H Solórzano A Swayne DE Cox NJ Katz JM Taubenberger JK Palese P García-Sastre A 《Science (New York, N.Y.)》2005,310(5745):77-80
The pandemic influenza virus of 1918-1919 killed an estimated 20 to 50 million people worldwide. With the recent availability of the complete 1918 influenza virus coding sequence, we used reverse genetics to generate an influenza virus bearing all eight gene segments of the pandemic virus to study the properties associated with its extraordinary virulence. In stark contrast to contemporary human influenza H1N1 viruses, the 1918 pandemic virus had the ability to replicate in the absence of trypsin, caused death in mice and embryonated chicken eggs, and displayed a high-growth phenotype in human bronchial epithelial cells. Moreover, the coordinated expression of the 1918 virus genes most certainly confers the unique high-virulence phenotype observed with this pandemic virus. 相似文献
106.
Loftus BJ Fung E Roncaglia P Rowley D Amedeo P Bruno D Vamathevan J Miranda M Anderson IJ Fraser JA Allen JE Bosdet IE Brent MR Chiu R Doering TL Donlin MJ D'Souza CA Fox DS Grinberg V Fu J Fukushima M Haas BJ Huang JC Janbon G Jones SJ Koo HL Krzywinski MI Kwon-Chung JK Lengeler KB Maiti R Marra MA Marra RE Mathewson CA Mitchell TG Pertea M Riggs FR Salzberg SL Schein JE Shvartsbeyn A Shin H Shumway M Specht CA Suh BB Tenney A Utterback TR Wickes BL Wortman JR Wye NH Kronstad JW Lodge JK 《Science (New York, N.Y.)》2005,307(5713):1321-1324
107.
Jacqueline dos Santos Oliveira Luis Depablos Bruno Grossi Costa Homem Igor Machado Ferreira Robert Michael Boddey Adenilson José Paiva Márcio André Stefanelli Lara Daniel Rume Casagrande 《Grass and Forage Science》2023,78(3):416-424
To define the best grazing management strategy, it is important to assess animals' responses to variations in the structure and composition of tropical forages. This 2-year study evaluated animal response to Marandu palisadegrass (Urochloa brizantha)-calopo (Calopogonium mucunoides) mixed pastures managed under rotational grazing. Treatments consisted of three defoliation frequencies defined by rest periods interrupted at 90% (90LI), 95% (95LI) and 100% (100LI) of photosynthetically active radiation interception (LI). The stubble post-grazing height target was 15 cm. Statistical difference was declared at p < .10. The 100LI had lowest crude protein (CP) and in vitro dry matter digestibility (IVDDM) for the Marandu palisadegrass (p = <.001 both) and calopo (p = .003 and p = .067, respectively). Also, the OM digestibility decreased 7.0% in the 100LI condition than 90LI and 95LI treatment (p = .005). There was no difference in forage, grass, and legume intakes between the treatments (p > .10). The 100LI treatment decreased CP intake from grass in 33.3% (p = <.001) compared to other treatments. Greatest production of microbial N (p = .093) occurred with the 90LI treatment. The CP/digestible organic matter (DOM) ratio, urinary N excretion and retained N were lowest in the 100LI treatment (p = <.001, p = .007 and p = .014, respectively). The recommendation for grazing between 90 and 95% of LI is recommended because of greater CP intake and N utilization for the animals and improved the nutritive value of Marandu palisadegrass and calopo mixed pastures. 相似文献
108.
Dominique Robert Jun Shoji Pascal Sirois Akinori Takasuka Ignacio A. Catalán Arild Folkvord Stuart A. Ludsin Myron A. Peck Su Sponaugle Patricia M. Ayón Richard D. Brodeur Emily Y. Campbell Evan K. D'Alessandro John F. Dower Louis Fortier Alberto G. García Klaus B. Huebert Marc Hufnagl Shin-ichi Ito Mikimasa Joh Francis Juanes Mitsuo Nyuji Yoshioki Oozeki Guido Plaza Motomitsu Takahashi Yosuke Tanaka Naoki Tojo Shingo Watari Naotaka Yasue Pierre Pepin 《Fish and Fisheries》2023,24(5):863-888
Early life survival is critical to successful replenishment of fish populations, and hypotheses developed under the Growth-Survival Paradigm (GSP) have guided investigations of controlling processes. The GSP postulates that recruitment depends on growth and mortality rates during early life stages, as well as their duration, after which the mortality declines substantially. The GSP predicts a shift in the frequency distribution of growth histories with age towards faster growth rates relative to the initial population because slow-growing individuals are subject to high mortality (via starvation and predation). However, mortality data compiled from 387 cases published in 153 studies (1971–2022) showed that the GSP was only supported in 56% of cases. Selection against slow growth occurred in two-thirds of field studies, leaving a non-negligible fraction of cases showing either an absence of or inverse growth-selective survival, suggesting the growth-survival relationship is more complex than currently considered within the GSP framework. Stochastic simulations allowed us to assess the influence of key intrinsic and extrinsic factors on the characteristics of surviving larvae and identify knowledge gaps on the drivers of variability in growth-selective survival. We suggest caution when interpreting patterns of growth selection because changes in variance and autocorrelation of individual growth rates among cohorts can invalidate fundamental GSP assumptions. We argue that breakthroughs in recruitment research require a comprehensive, population-specific characterization of the role of predation and intrinsic factors in driving variability in the distribution and autocorrelation of larval growth rates, and of the life stage corresponding to the endpoint of pre-recruited life. 相似文献
109.
Amanda M. Berrian Beatriz Martínez‐Lpez Vanessa Quan Patricia A. Conrad Jacques van Rooyen Gregory J. G. Simpson John Frean Jacqueline Weyer Jennifer Rossouw Darryn Knobel Lucille Blumberg 《Zoonoses and public health》2019,66(5):458-469
Endemic zoonoses, such as Q fever and spotted fever group (SFG) rickettsiosis, are prevalent in South Africa, yet often undiagnosed. In this study, we reviewed the demographics and animal exposure history of patients presenting with acute febrile illness to community health clinics in Mpumalanga Province to identify trends and risk factors associated with exposure to Coxiella burnetii, the causative agent of Q fever, and infection by SFG Rickettsia spp. Clinical and serological data and questionnaires elucidating exposure to animals and their products were obtained from 141 acutely febrile patients between 2012 and 2016. Exposure or infection status to C. burnetii and SFG Rickettsia spp. was determined by presence of IgG or IgM antibodies. Logistic regression models were built for risk factor analysis. Clinical presentation of patients infected by SFG rickettsiosis was described. There were 37/139 (27%) patients with a positive C. burnetii serology, indicative of Q fever exposure. Patients who had reported attending cattle inspection facilities (“dip tanks”) were 9.39 times more likely to be exposed to Q fever (95% CI: 2.9–30.4). Exposure risk also increased with age (OR: 1.03, 95% CI: 1.002–1.06). Twenty‐one per cent of febrile patients (24/118) had evidence of acute infection by SFG Rickettsia spp. Similarly, attending cattle inspection facilities was the most significant risk factor (OR: 8.48, 95% CI: 1.58–45.60). Seropositivity of females showed a significant OR of 8.0 when compared to males (95% CI: 1.49–43.0), and consumption of livestock was associated with a decreased risk (OR: 0.02, 95% CI: 0.001–0.54). A trend between domestic cat contact and SFG rickettsiosis was also noted, albeit borderline non‐significant. In this endemic region of South Africa, an understanding of risk factors for zoonotic pathogens, including exposure to domestic animals, can help clinic staff with diagnosis and appropriate therapeutic management of acutely febrile patients as well as identify target areas for education and prevention strategies. 相似文献
110.
Poot J 《Tijdschrift voor diergeneeskunde》2006,131(19):694-695