全文获取类型
收费全文 | 1340篇 |
免费 | 38篇 |
国内免费 | 61篇 |
专业分类
林业 | 179篇 |
农学 | 288篇 |
基础科学 | 82篇 |
119篇 | |
综合类 | 391篇 |
农作物 | 50篇 |
水产渔业 | 76篇 |
畜牧兽医 | 203篇 |
园艺 | 23篇 |
植物保护 | 28篇 |
出版年
2024年 | 18篇 |
2023年 | 68篇 |
2022年 | 69篇 |
2021年 | 43篇 |
2020年 | 27篇 |
2019年 | 44篇 |
2018年 | 33篇 |
2017年 | 28篇 |
2016年 | 31篇 |
2015年 | 45篇 |
2014年 | 69篇 |
2013年 | 77篇 |
2012年 | 74篇 |
2011年 | 66篇 |
2010年 | 97篇 |
2009年 | 99篇 |
2008年 | 90篇 |
2007年 | 66篇 |
2006年 | 70篇 |
2005年 | 62篇 |
2004年 | 36篇 |
2003年 | 38篇 |
2002年 | 34篇 |
2001年 | 33篇 |
2000年 | 25篇 |
1999年 | 12篇 |
1998年 | 11篇 |
1997年 | 4篇 |
1996年 | 9篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 10篇 |
1982年 | 3篇 |
排序方式: 共有1439条查询结果,搜索用时 15 毫秒
61.
62.
GENG Yue MA Jing JIA Ran XUE Li-qin TAO Chuan-jiang LI Chong-jiu MA Xiao-dong LIN Yan 《中国农业科学(英文版)》2013,(2):305-313
The long-lasting application of representative herbicide atrazine (ATR) has given rise to the accumulation of its residues in the groundwater. To investigate the impact of long-term ATR use on groundwater safety, the residues of ATR and its metabolites, desethylatrazine (DEA), deisopropylatrazine (DIA) and hydroxyatrazine (HA) were monitored in groundwater and top soil at the major corn growing region of Qian’an and Gongzhuling in Jilin Province, China. The residues of the target compounds were analyzed by UPLC-MS/MS. The limits of detection (LODs) of ATR, DEA, DIA, and HA were 0.5, 0.5, 5, and 0.5 ng L-1 in groundwater and 0.33, 0.33, 3.3, and 0.33 μg kg-1 in soil. The target compounds were found in 94% of groundwater samples and 100% of soil samples. The compounds detected most frequently in groundwater were ATR (89%), DEA (64%) and HA (17%), whereas in soil were ATR (97%), DEA (36%) and HA (97%). DIA was not detected in any determined groundwater and soil sample. Average residues were 106.8 ng L-1 for ATR, 0.9 ng L-1 for DEA and 0.3 ng L-1 for HA in groundwater, whereas 11.1 μg kg-1 for ATR, 0.4 μg kg-1 for DEA and 7.8 μg kg-1 for HA in soil. ATR residues detected in groundwater samples were below standards for drinking water quality (GB5749-2006, 2 μg L-1), while the total residues of ATR and its chloro-s-triazine metabolites (DEA and DIA) were below current WHO (World Health Organization) guideline value (GV, 0.1 mg L-1). In addition, concentrations of HA in groundwater were determined below current WHO GV (0.2 mg L-1). The results indicated that ATR is safe to be used in Jilin Province under the current application scheme. However, total residues of ATR and DEA were detected in nearly all wells, thus, it is necessary to pay attention on groundwater monitoring for ATR and its metabolites. 相似文献
63.
64.
65.
66.
几个沙棘品种抗逆性试验研究 总被引:1,自引:0,他引:1
根据寒温带半干旱地区的自然条件,选择耐盐碱性、耐寒性、耐水湿三项指标在温室盆钵内对HF-14、HF-4两个沙棘优良无性系及对照品种(楚伊)进行人工模拟抗逆性测定。其结果为:3个无性系对盐碱的耐受性均较强并无明显差别,可在中度以下盐碱地上栽培;3个无性系具有一定的耐旱能力,但在长期持续干旱条件下,生长量明显下降,生长势衰弱,增加感病机会,应给予灌溉,3个无性系的耐旱次序为HF-4>HF-14>楚伊;3个无性系对水湿条件的耐受力基本相同,在长期积水的条件下,根系不发育,生长受到抑制,栽植沙棘不应选择低洼内涝,排水不良的地块。 相似文献
67.
Reclaimed soils in mining area usually display low fertility and present Cd stress. The amendment of modified biochar effectively fixes Cd in soils,enhances soil fertility, and reduces Cd stress in soil microorganisms. However, the effect of thiourea-modified biochar(TBC) on microbial adaptability to Cd stress in mining reclamation soils is still unclear. The present work studied the Cd immobilization and microbial community changes in a mining reclamation soil displaying extreme Cd contaminatio... 相似文献
68.
69.
王春选 《农村.农业.农民》2009,(3)
建设生态文明重要思想的提出,是我国继物质文明、精神文明、政治文明之后的又一现代化建设重大战略部署,构成中国特色社会主义理论的重要内容。贯彻落实科学发展观,加强生态文明建设研究具有重要的现实意义。 相似文献
70.