全文获取类型
收费全文 | 565篇 |
免费 | 41篇 |
国内免费 | 21篇 |
专业分类
林业 | 28篇 |
农学 | 24篇 |
基础科学 | 28篇 |
50篇 | |
综合类 | 208篇 |
农作物 | 22篇 |
水产渔业 | 14篇 |
畜牧兽医 | 205篇 |
园艺 | 7篇 |
植物保护 | 41篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 6篇 |
2021年 | 23篇 |
2020年 | 16篇 |
2019年 | 30篇 |
2018年 | 7篇 |
2017年 | 15篇 |
2016年 | 23篇 |
2015年 | 25篇 |
2014年 | 38篇 |
2013年 | 45篇 |
2012年 | 55篇 |
2011年 | 40篇 |
2010年 | 32篇 |
2009年 | 39篇 |
2008年 | 27篇 |
2007年 | 32篇 |
2006年 | 21篇 |
2005年 | 17篇 |
2004年 | 19篇 |
2003年 | 22篇 |
2002年 | 6篇 |
2001年 | 14篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 6篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有627条查询结果,搜索用时 234 毫秒
1.
Vunjia TIONG Shih-Keng LOONG Haryanti Azura MOHAMAD WALI Kim-Kee TAN Pui-Fong JEE Fang-Shiang LIM Jing-Jing KHOO Pooi-Fong WONG Li-Yen CHANG Sazaly ABUBAKAR 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(2):280
Corneal lesions appearing as white mass beneath intact epithelium, with ocular discharge in one mouse, was observed in a batch of laboratory-raised BALB/c mice (n=9 of 56). The affected mice remained active, well-groomed and had normal appetite. Isolates recovered from swab cultures of the external and internal contents of the eye had partial 16S rRNA gene sequence of 99.1% similarity to Streptococcus cuniculi. No previous report of S. cuniculi infection in laboratory rodents has been presented. The isolate was susceptible to all antibiotics tested. We suggest S. cuniculi is an opportunistic bacteria in laboratory mice but are uncertain of its source. Our findings revealed that S. cuniculi is able to colonize laboratory mice and should be considered when mice present with eye lesion or ocular discharge. 相似文献
2.
Gene Stevens David Dunn Matthew Rhine 《Communications in Soil Science and Plant Analysis》2018,49(8):958-966
Portable instruments have reduced on-site testing costs for soil pH and potassium in isolated locations. Acids could not be shipped to a remote Africa field laboratory. Bray-1 phosphorus (P) testing is difficult because hydrochloric (HCl) is required in the extraction solution and sulfuric acid (H2SO4) is used in color development stock solutions. Muriatic HCl acid and battery H2SO4 were available in a local stores. The objectives of this study were to evaluate the accuracy of P soil testing using diluted, non-reagent HCl for making modified Bray1-P extractant and non-reagent H2SO4 for color development. Experiment 1 was conducted with soil samples from fields using Sunnyside? and Klean Strip? HCl muriatic acids. Soil samples extracted with diluted reagent HCl were closely related to P results using diluted Klean Strip (R2 = 0.96) and Sunnyside (R2 = 0.84) HCl. In Experiment 2, two commercial brands of H2SO4 acid used to refill car battery cells were evaluated. Test results suggested that the battery H2SO4 acids are not suitable for making color development solution. In Experiment 3, a small battery powered spectrometer for P testing aquarium water was calibrated for soils. Samples from the Soil Science Society of America –North American Proficiency Testing program (NAPT) were tested with the meter and non-reagent HCl. Fiske-Subbarrow reducing agent and HCl were used in a variation procedure which does not require H2SO4 for color development. Eight of 10 samples tested proficient based on NAPT limits (2.5 x Median Absolute Deviation). 相似文献
3.
张喆 《北京农业职业学院学报》2019,33(6):81-86
实验室仪器设备是高校开展教学和科研工作的物质基础,随着高校教育教学改革的不断深入,实验教学的比重不断加大,实验室设备的维护和管理成为重要的日常教学管理工作,也成为近年来各高校面临的普遍问题和重要课题。当前实验室设备管理工作出现了一系列问题,需要改进实验室设备的日常维护与管理的方法,如统一管理和调配实验室、推动实验室信息管理系统建设、完善实验室设备管理制度等,从而为高校实验室的有效管理提供专业意见。 相似文献
4.
5.
联合国粮食及农业组织2018年向全球发布草地贪夜蛾Spodoptera frugiperda是重要的预警害虫。据报道,2019年我国已有26个省(区、市)的作物受到草地贪夜蛾为害。目前已经发现草地贪夜蛾幼虫对某些化学农药产生抗性的现象,为缓解其抗药性产生,具有主动寻找寄主害虫的昆虫病原线虫为草地贪夜蛾的生物防治提供了应用潜能。该文从昆虫病原线虫高效侵染种(品系)及其浓度、共生菌、草地贪夜蛾幼虫易感龄期、田间致死力及影响防控效果的因素等方面进行综述,以期为田间有效利用昆虫病原线虫防治草地贪夜蛾提供参考。 相似文献
6.
7.
8.
林木组培工厂化育苗技术的研究 总被引:9,自引:1,他引:9
叙述了建立一间年产100万株林木组培苗育苗工厂的情况。对实施林木工厂化育苗的技术路线,关键技术和几个生产工艺流程进行了论述,并对工厂的组成部分及设施,瓶苗大量移栽技术及组培苗苗圃管理等进行了较系统的研究。 相似文献
9.
10.
Experimental evaluation of rainbow trout Oncorhynchus mykiss predation on longnose dace Rhinichthys cataractae 下载免费PDF全文
Laboratory and in‐stream enclosure experiments were used to determine whether rainbow trout Oncorhynchus mykiss influence survival of longnose dace Rhinichthys cataractae. In the laboratory, adult rainbow trout preyed on longnose dace in 42% of trials and juvenile rainbow trout did not prey on longnose dace during the first 6 h after rainbow trout introduction. Survival of longnose dace did not differ in the presence of adult rainbow trout previously exposed to active prey and those not previously exposed to active prey ( = 0.28, P = 0.60). In field enclosures, the number of longnose dace decreased at a faster rate in the presence of rainbow trout relative to controls within the first 72 h, but did not differ between moderate and high densities of rainbow trout (F2,258.9 = 3.73, P = 0.03). Additionally, longnose dace were found in 7% of rainbow trout stomachs after 72 h in enclosures. Rainbow trout acclimated to the stream for longer periods had a greater initial influence on the number of longnose dace remaining in enclosures relative to those acclimated for shorter periods regardless of rainbow trout density treatment (F4,148.5 = 2.50, P = 0.04). More research is needed to determine how predation rates will change in natural environments, under differing amounts of habitat and food resources and in the context of whole assemblages. However, if rainbow trout are introduced into the habitat of longnose dace, some predation on longnose dace is expected, even when rainbow trout have no previous experience with active prey. 相似文献