全文获取类型
收费全文 | 451篇 |
免费 | 18篇 |
专业分类
林业 | 31篇 |
农学 | 1篇 |
基础科学 | 14篇 |
17篇 | |
综合类 | 69篇 |
农作物 | 9篇 |
水产渔业 | 29篇 |
畜牧兽医 | 271篇 |
园艺 | 5篇 |
植物保护 | 23篇 |
出版年
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 18篇 |
2012年 | 11篇 |
2011年 | 21篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 15篇 |
2007年 | 19篇 |
2006年 | 21篇 |
2005年 | 23篇 |
2004年 | 10篇 |
2003年 | 17篇 |
2002年 | 24篇 |
2001年 | 11篇 |
2000年 | 15篇 |
1999年 | 24篇 |
1998年 | 13篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1993年 | 2篇 |
1992年 | 13篇 |
1991年 | 5篇 |
1990年 | 11篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1965年 | 2篇 |
1943年 | 2篇 |
排序方式: 共有469条查询结果,搜索用时 109 毫秒
141.
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
142.
The genome sequence of Drosophila melanogaster 总被引:2,自引:0,他引:2
Adams MD Celniker SE Holt RA Evans CA Gocayne JD Amanatides PG Scherer SE Li PW Hoskins RA Galle RF George RA Lewis SE Richards S Ashburner M Henderson SN Sutton GG Wortman JR Yandell MD Zhang Q Chen LX Brandon RC Rogers YH Blazej RG Champe M Pfeiffer BD Wan KH Doyle C Baxter EG Helt G Nelson CR Gabor GL Abril JF Agbayani A An HJ Andrews-Pfannkoch C Baldwin D Ballew RM Basu A Baxendale J Bayraktaroglu L Beasley EM Beeson KY Benos PV Berman BP Bhandari D Bolshakov S Borkova D Botchan MR Bouck J 《Science (New York, N.Y.)》2000,287(5461):2185-2195
The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans. We have determined the nucleotide sequence of nearly all of the approximately 120-megabase euchromatic portion of the Drosophila genome using a whole-genome shotgun sequencing strategy supported by extensive clone-based sequence and a high-quality bacterial artificial chromosome physical map. Efforts are under way to close the remaining gaps; however, the sequence is of sufficient accuracy and contiguity to be declared substantially complete and to support an initial analysis of genome structure and preliminary gene annotation and interpretation. The genome encodes approximately 13,600 genes, somewhat fewer than the smaller Caenorhabditis elegans genome, but with comparable functional diversity. 相似文献
143.
A study was conducted to examine the effect of avian influenza virus (AIV) on chicken lymphocyte activation. Unprimed or Brucella abortus antigen (Ag)-primed lymphocytes were incubated with various doses of the T-cell mitogen concanavalin A (Con A) or Ag, respectively, plus serial dilutions of inactivated AIV for 72 hr, and cell proliferation was measured via uptake of tritiated thymidine. AIV enhanced the proliferative response to Con A or Ag by 150% or better, and the enhancement decreased in a viral dose-dependent manner. The effects were more readily observed in cells that had not been maximally activated by the Con A or Ag. The enhanced response was observed in lymphocytes from both white rock and white leghorn breeds of chicken and in mature peripheral blood lymphocytes or immature thymocytes. The viral activity could be abrogated by pre-treatment of the viral preparation with AIV-specific antisera or prior adsorption of the AIV with chicken erythrocytes. These results indicate that AIV can interact with and modify the in vitro activity of chicken lymphocytes and may exert modulatory effects on the avian immune system. 相似文献
144.
Detecting infected laying flocks is a vital part of many efforts to control egg-associated transmission of Salmonella enteritidis to humans. The relationship between the development of a specific antibody response in infected hens and the deposition of S. enteritidis in eggs is important for establishing the epidemiologic relevance of serologic testing methods. In two trials, laying hens were infected with large oral doses of phage types 13a and 14b isolates of S. enteritidis. Approximately 38% of all infected hens produced at least one contaminated egg, at an overall incidence of 5.2%, between 3 and 23 days postinoculation. As determined by enzyme-linked immunosorbent assay with an S. enteritidis flagellar antigen, 91.7% of inoculated hens produced specific serum antibodies. Although hens with very high antibody titers were associated with a significantly elevated frequency of egg contamination, a consistently direct relationship was not evident between the magnitude of the antibody responses of individual hens and the frequency at which they laid contaminated eggs. Accordingly, although serologic tests can be valuable screening tools for preliminary detection of S. enteritidis infections in poultry, the magnitude of the antibody responses detected in individual hens may not predict the overall risk of egg contamination associated with particular laying flocks. 相似文献
145.
The management of quality in the distribution of produce which exhibits significant and inevitable deterioration with time and event is a neglected but essential component of physical distribution management. This paper concentrates on horticultural produce and, in particular, on apples.Horticultural distribution is described as a system and systems thinking is employed to develop a ‘hard systems’ methodology for the management of quality. A management system is defined in terms of quality-price, quality-cost and quality-happening relations. An example from apple distribution demonstrates the methodology and is used to emphasize the central importance of quantitative models of price, cost, quality and of their interactions with time and happening. 相似文献
146.
147.
P E Holt 《The Veterinary record》1978,102(14):311-312
A survey was carried out at Kano abattoir in order to estimate the incidence of hydatidosis and cysticercosis in slaughtered livestock. Of the animal species examined, hydatid disease was found in sheep (11.4 per cent), goats (26.5 per cent), cattle (14.7 per cent) and camels (55.5 per cent). Cysticercus tenuicollis was found to be most prevalent in goats (34.2 per cent), followed by sheep (21.4 per cent) and cattle (0.1 per cent). Out of 4844 cattle examined, less than 2 per cent haboured Cysticercus bovis cysts; while Cysticercus ovis cysts were found in sheep (1 per cent) and goats (0.8 per cent). 相似文献
148.
Peter E. Holt 《The Journal of small animal practice》1977,18(6):415-422
Although relatively uncommon in small animal orthopaedics, tarsal collateral ligament injuries may present problems to the veterinary surgeon dealing with trauma cases. The author's method of approach to the condition and the management of thirteen cases are described and discussed. 相似文献
149.
150.