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   60篇
  免费   0篇
安全科学   7篇
废物处理   1篇
环保管理   7篇
综合类   12篇
基础理论   6篇
污染及防治   7篇
评价与监测   4篇
社会与环境   2篇
灾害及防治   14篇
  2022年   1篇
  2021年   1篇
  2019年   3篇
  2018年   1篇
  2016年   1篇
  2013年   3篇
  2012年   2篇
  2011年   3篇
  2009年   3篇
  2008年   6篇
  2007年   2篇
  2006年   2篇
  2005年   5篇
  2004年   1篇
  2003年   2篇
  2002年   2篇
  2001年   1篇
  2000年   2篇
  1999年   3篇
  1998年   2篇
  1997年   2篇
  1996年   4篇
  1995年   3篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1980年   1篇
排序方式: 共有60条查询结果,搜索用时 15 毫秒
41.
棉浆粕综合废水的生物处理研究   总被引:1,自引:0,他引:1  
浆粕厂在生产粘胶纤维原料时产生的有机废水,其组分较为复杂,废水治理具有一定的技术难度。采用水解酸化-好氧法与传统活性污泥法两种方案对棉浆粕生产综合废水进行生物处理的平行对照表明,驯化活性污泥可有效地去除废水中易生物降解的有机物。娄浆粕废水进水CODcr浓度在(1200~1800)mg/L范围内,CODcr负荷(1.8~2.8)kg/(m^3.d)时,CODcr去除率可达58%~64%,BOD5去除  相似文献   
42.
气候变化对水稻虫害的影响   总被引:8,自引:0,他引:8  
李淑华 《灾害学》1995,10(2):43-47
气候变化对水稻虫害的影响李淑华(中国农科院农业气象研究所,北京100081)摘要温室效应引起的气候变化,将会对水稻害虫的繁殖代数、越冬界限、迁飞规律等生态学特征产生一定的影响。从而造成害虫在田间的危害时间延长,发生程度加重的趋势,应引起广泛的重视。主...  相似文献   
43.
RS在森林病虫害监测研究中的应用   总被引:13,自引:0,他引:13  
森林病虫害是影响森林健康的主要因素之一。森林病虫害的快速准确监测、检测及其损害评估无论对森林经营者还是生态学家都具有重要意义。在大的空间尺度上,遥感数据早已被广泛有效地用于检测森林病虫害所引起的失叶现象。目前,在森林病虫害的遥感监测方面所利用的遥感数据主要有Landsat TM,MSS和SPOT HRV等卫星遥感数据和多种航空遥感数据;此外,各种地面辅助地理散据和野外调查数据可以提高对森林病虫害的监测精度。不同类型的森林往往感染不同的森林病虫害,而不同的森林病虫害所引起的森林受损症状不同,有的病虫害导致森林反射光谱的显著变化,有的则导致森林大量失叶。因此,对不同病虫害的遥感监测方法不同。随着技术的进步,传统的图像增强、图像分类和影像差等病虫害监测技术已显粗糙。近年来,更多、更复杂的图像处理方法被广泛用于检测病虫害引起的森林变化,各种数学方法和GIS技术也为病虫害的遥感监测提供了新的活力。虽然森林病虫害的遥感监测面临挑战,但随着计算机软硬件技术和遥感技术的进步,森林病虫害的遥感检测依然具有广阔的发展空间。  相似文献   
44.
在新疆北疆低肥力地区,以膜下滴灌棉花为对象,设置了水肥双因子的大田试验,研究了水肥配合对作物产量、养分吸收、养分及水分利用效率以及对土壤有效氮、磷的影响。研究表明,在旱薄地上,水肥皆有增产效果,在2种肥料中,氮肥效果更显著,作物产量随氮肥增加而显著增加,而FA效果大小则和氮肥配合、灌水量有密切关系。灌水、施肥之间有明显...  相似文献   
45.
陕西省农作物病虫害与气候变化的关系分析   总被引:6,自引:0,他引:6  
张俊香  延军平 《灾害学》2001,16(2):27-30
分析了陕西省降水、气温变化以及厄尔尼诺事件、拉尼娜事件、太阳黑子活动与农作物病虫害的关系,认为:陕西省农作物病虫害与气温变化存在显著的正相关关系;气候条件是病虫害发生或流行的主要控制因子;厄尔尼诺事件、拉尼娜事件以及太阳黑子活动与农作物病虫害的发生或流行存在密切的关系。  相似文献   
46.
Natural fibres offer an interesting alternative to petrochemical products. Reclaimed cotton is mainly used as a low cost fibre to “fill” composites used as interior parts in the automotive industry. Mechanical requirements of such composites are low and the potential of the cotton-fibre to reinforce plastics is not used adequately. This paper gives background information and discusses the use of the cotton fibres in composites compared to ramie fibres. In this study the fibre strength was tested with a Dia-Stron device, fineness was tested with Fibreshape. A roller card is well suited to process fibres to a multi layer web. Cotton and ramie fibres were embedded in epoxy resin and a bio-based resin PTP®. The composites were tested for impact and tensile properties. The results show that mechanical properties of the composites are strongly influenced by fibre properties. The data and results demonstrate the important role force-elongation characteristics of fibre play in optimising the properties of natural fibre composites. Cotton with its morphological and mechanical properties can play a more crucial role to optimise products with a view to improve the impact properties.  相似文献   
47.
棉铃虫暴发的特点,成因及治理对策   总被引:12,自引:0,他引:12  
戴小枫  郭予元 《灾害学》1994,9(1):22-30
本文就1992年我国棉铃虫暴发成灾的特点与成因进行了详细的分析,并讨论了治理这一灾害性农业害虫的策略与方法。  相似文献   
48.
Fumigation is required to protect cottonseed in storage and pre-shipment from insect pests and/or microorganisms. Fumigation of cottonseed with carbon disulphide (CS2), carbonyl sulphide (COS), ethanedinitrile (C2N2), ethyl formate (EF), methyl bromide (MB) and phosphine (PH3) showed that >85% of the fumigants disappeared within 5?h of exposure. COS maintained >20?mg L–1 for 24?h. After 1?day of aeration, 75%–85% of the absorbed COS and MB and 20%–40% of the absorbed CS2, EF and PH3 were released from treated cottonseed. The fumigant residues were reduced by 80% for COS, 50% for EF or MB and 25% for CS2 after 1?day of aeration. After 13?days of aeration, fumigant residues were reduced by 95% for MB, 65% for EF, 55% for CS2 and to natural levels in the COS residue. Carbon disulphide, COS, PH3, EF and C2N2 had no effect on the germination of cottonseed, but germination was reduced to 50% by MB. COS has potential as a fumigant for control of insect pests in cottonseed because it dissipates quickly and does not negatively impact germination. On the other hand, MB appears to strongly absorb and requires an extended period for residues to dissipate, and it negatively impacts germination.  相似文献   
49.
This study aimed to assess the glyphosate application effects on the Cerotoma arcuata Oliver (Coleoptera: Chrysomelidae) population in glyphosate-resistant soybean crops. Field studies were conducted with glyphosate and the insecticide endosulfan to observe the effects of these pesticides on C. arcuata, on its damages in the crop and on the populations of natural enemies in glyphosate-resistant soybean crops. Moreover, the lethal and behavioral sublethal response of C. arcuata to glyphosate and endosulfan was conducted in the laboratory. The results of the field and laboratory experiments showed that glyphosate caused moderate toxicity and high irritability in C. arcuata and that endosulfan caused high toxicity and irritability. Therefore, the direct effect of glyphosate on C. arcuata was negative and does not explain the population increases of this pest in glyphosate-resistant soybean. However, the glyphosate also decreased the density of predators. Thus, the negative effect of glyphosate on the predators may be related to population increases of C. arcuata in glyphosate-resistant soybean crops, however, more studies are needed to better evidence this relationship. This study suggests that glyphosate can impact other non-target organisms, such as herbivorous insects and natural enemies and that the use of this herbicide will need to be carefully stewarded to prevent potential disturbances in beneficial insect communities in agricultural systems.  相似文献   
50.
试论开展中国农作物病虫害危害流行的长期气象预测研究   总被引:26,自引:6,他引:20  
从开展中国宵作物病虫害危害浒的长期气象预测研究的必要性出发,结合国内外的研究现状,提出提高宵作物病虫害长期预测的准确性、时效性是宵作物病虫病综合防治的首要措施,并建议围绕中国宵作物病虫害宏观气候可预测性的机理、浒的前兆性气候指标、浒气候区划、影响的关键气象因子、预报模式的气象信息技术改造等方面开展中国宵作物病虫害危害流行的长期气象预测研究。  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