首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   337篇
  免费   15篇
  国内免费   1篇
林业   36篇
农学   29篇
基础科学   2篇
  49篇
综合类   26篇
农作物   21篇
水产渔业   24篇
畜牧兽医   118篇
园艺   17篇
植物保护   31篇
  2023年   2篇
  2022年   12篇
  2021年   9篇
  2020年   7篇
  2019年   14篇
  2018年   15篇
  2017年   18篇
  2016年   10篇
  2015年   8篇
  2014年   7篇
  2013年   27篇
  2012年   14篇
  2011年   19篇
  2010年   14篇
  2009年   13篇
  2008年   17篇
  2007年   8篇
  2006年   10篇
  2005年   10篇
  2004年   11篇
  2003年   3篇
  2002年   5篇
  2001年   2篇
  2000年   5篇
  1999年   7篇
  1997年   2篇
  1995年   4篇
  1994年   3篇
  1992年   5篇
  1991年   2篇
  1990年   4篇
  1989年   3篇
  1988年   7篇
  1987年   4篇
  1986年   3篇
  1981年   4篇
  1980年   6篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1976年   3篇
  1975年   2篇
  1974年   2篇
  1973年   1篇
  1972年   4篇
  1971年   5篇
  1970年   5篇
  1969年   1篇
  1967年   3篇
  1946年   1篇
排序方式: 共有353条查询结果,搜索用时 15 毫秒
1.
Effects of amikacin, gentamicin, kanamycin, and streptomycin on renal tissue superoxide dismutase, glutathione peroxidase, glutathione and malondialdehyde, serum creatinine, potassium, sodium, total protein, glucose, uric acid, and total bilirubin levels were investigated. All aminoglycoside antibiotics decreased renal tissue glutathione levels.  相似文献   
2.
3.
Marine bio-sourced chitosan nanoparticles (CSNP) are antimicrobial and immunomodulatory agents beneficial for fish medicine. Herein, dietary CSNP was investigated for the amelioration of the systemic inflammatory responses of an induced fish model. One hundred and forty-four rainbow trout were assigned to one pathogen-free and non-supplemented group (negative control), and three challenged groups: non-supplemented (positive control), CSNP-preventive, and CSNP-therapeutic. After a feeding experiment extended for 21 days, the organosomatic indices (OSI) and molecular aspects were assessed. After a challenge experiment extended for further 28 days, CSNP-therapeutic intervention was assessed on fish survival and systemic inflammatory responses on pathology, histo-morphology, and molecular aspects. With CSNP administration, OSI nonsignificantly decreased and the relative expression of targeted inflammatory-mediator genes was significantly increased. The CSNP-therapeutic fish showed an RPS of 80% as compared to the positive control group, and CSNP-therapeutic administration retained the highest gene expression augmentation up to 28 days after the challenge. Notably, the splenic reticulin fibers framework of the CSNP-therapeutic group retained the highest integrity among the groups during the infection. After recovery, reticulin fibers density in the CSNP-therapeutic samples was significantly higher than in the negative control group, which indicates high innate immunity. Thus, CSNP showed promising biotherapeutic features enhancing fish resistance against infections.  相似文献   
4.
5.
This research aims to make an analysis of energy use efficiency of apple (‘Starkrimson Delicious’ and ‘Golden Delicious’) production in E?irdir region of Turkey, during the production season of 2012. Production data this research was collected in 2013. In order to determine the energy use efficiency of apple, various surveys have been conducted in 71 apple farms, selected through Simple Random Sampling method, located in E?irdir region of Turkey. The data have been collected through face to face questionnaires and first hand observations. The energy input and output values in apple production have been calculated as 34,703.63 MJ ha?1 and 95,034 MJ ha?1, respectively. Energy inputs consist of diesel fuel energy by 29.04?%, chemical fertilizers energy by 24.28?%, machinery energy by 15.70?%, chemical energy by 9.84?%, human labor energy by 8.54?%, electricity energy by 5.63?%, irrigation energy by 3.97?%, farmyard manure energy by 2.88?% and lime energy by 0.12?%. Energy use efficiency, energy productivity, specific energy and net energy in apple production have been calculated as 2.74, 1.16 kg MJ?1, 0.86 MJ kg?1 and 60,330.36 MJ ha?1, respectively. The total energy input consumed has been classified as direct, by 47.17?%, indirect, by 52.83?%, renewable, by 15.38?% and non-renewable, by 74.62?%.  相似文献   
6.
The aim of this research is to compose the energy input-output analysis of plum in Nevsehir province in Turkey. This research was conducted at the plum cultivating facilities during the 2015–2016 production seasons in Nevsehir province of Central Anatolian Region in Turkey. The agricultural input energies and output energies used in plum cultivation were calculated to determine the energy input-output analysis. According to the research findings, the energy inputs in plum cultivation were calculated respectively 3920?MJ ha?1 (44.99%) chemical fertilizers energy, 1618.91?MJ ha?1 (18.58%) diesel fuel energy, 1125.85?MJ ha?1 (12.92%) chemicals energy, 1069.20?MJ ha?1 (12.27%) machinery energy, 723.24?MJ ha?1 (8.30%) human labour energy and 255?MJ ha?1 (2.93%) irrigation water energy. Production output plum yield were calculated as 12,112.50?MJ ha?1. The energy output/input ratio, specific energy, energy usage efficiency and net energy calculations were calculated respectively as 1.39, 1.37?MJ kg?1, 0.73?kg MJ?1 and 3400.30?MJ ha?1.  相似文献   
7.
BackgroundDiarrheagenic E. coli (DEC) strains are a major cause of diarrheal diseases in both developed and developing countries. Healthy asymptomatic animals may be reservoirs of zoonotic DEC, which may enter the food chain via the weak points in hygiene practices.AimWe investigated the prevalence of DEC along the pig production continuum from farm-to-fork.MethodsA total of 417 samples were collected from specific points along the pig production system, that is, farm, transport, abattoir and food. E. coli was isolated and enumerated using Colilert. Ten isolates from each Quanti-tray were selected randomly and phenotypically identified using eosin methylene blue agar selective media. Real-time polymerase chain reaction (PCR) was used to confirm the species and to classify them into the various diarrheagenic pathotypes. Antimicrobial susceptibility was determined against a panel of 20 antibiotics using the Kirby-Bauer disk diffusion method and EUCAST guideline.ResultsThe final sample size consisted of 1044 isolates, of which 45.40% (474/1044) were DEC and 73% (762/1044) were multidrug-resistant. Enteroinvasive E. coli (EIEC) was the most predominant DEC at all the sampling sites.ConclusionThe presence of DEC in food animal production environments and food of animal origin could serve as reservoirs for transmitting these bacteria to humans, especially in occupationally exposed workers and via food. Adherence to good hygienic practices along the pig production continuum is essential for mitigating the risk of transmission and infection, and ensuring food safety.  相似文献   
8.
A pot experiment was conducted to evaluate the efficiency of farm yard manure (FYM) and lime (calcium carbonate) on reducing the uptake of Cd by rice in two Cd contaminated soils of Chittagong. The effects of farm yard manure, lime and farm yard manure mixed with lime (FYM + Lime) on rice (Oryza sativa L.) growth, Cd uptake by rice and 0.1 N HC1 extractable Cd in soil were investigated. Results showed that addition of lime and farm yard manure mixed with lime significantly decreased 0.1 N HCl extractable Cd in the city sewage soil. Application of farm yard manure significantly decreased Cd concentration in rice in the city sewage soil. Lime and farm yard manure mixed with lime significantly reduced Cd concentration in rice m both the contaminated soils. Lime was more efficient than farm yard manure in reducing the uptake of Cd by rice.  相似文献   
9.
Journal of Crop Science and Biotechnology - Priming is a safe, easy, and effective way to increase plant tolerance against stress. This research aims to study the metabolic status of the...  相似文献   
10.
This study was carried out to determine the effect of water stress on five different generative stages of soybeans and to evaluate the CROPGRO-soybean model under semi-arid climatic conditions. The study was conducted at the Faculty of Agricultural Engineering, Harran University research field in 2003 and 2004 growing seasons. Plants received full irrigation during vegetative stages, after which it was cut off at different reproductive stages (treatments): R1-2, beginning of flowering and full bloom; R3, beginning of pod; R4, full pod; R5, beginning of seed; and R6, full seed. The control treatment was full irrigation throughout. Observed yields ranged from 1955 (R6) to 3684 kg ha−1 (control) in 2003, and from 1867 (R6) to 3952 kg ha−1 (control) in 2004, respectively. Generally, in both of the years any water stress imposed on soybeans in three different generative stages (R3, R5, and R6) resulted in substantial yield reduction compared with full irrigation; yield reduction was greatest at the R6 stage. Biomass and 1000 seed weight also showed significant difference. Overall, CROPGRO-soybean simulated parameters from all treatments were higher compared with observed ones. Although simulated yield results were close to measured ones, they could not track observed yield patterns. Generally, the CROPGRO-soybean simulation model failed to satisfactorily mimic observed soybean yield, biomass, and 1000 seed weight and therefore it is suggested not to be used for similar scenarios and climatic conditions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号