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181.
Susanne Heiska Olli-Pekka Tikkanen Matti Rousi Riitta Julkunen-Tiitto 《Chemoecology》2007,17(4):245-253
Summary. Vole feeding amongst herbal willows that have a high concentration of salicylates in their bark and leaves, and may therefore
be cultivated for use as raw material for herbal medicine was tested in the field and in laboratory conditions. Eight clones
of dark-leaved willow (Salix myrsinifolia Salisb.) were cultivated for two years with six different methods combining three fertilisation levels (none, low and high),
black plastic mulch applied for suppressing weed competition and unmulched control. Samples for the laboratory feeding trial
were taken from the unfertilised plants during willow winter dormancy and twigs were fed to 16 voles as a multi-choice experiment.
The bark area removed was calculated from image analysis of the material left by the voles. The diameter and the bark thickness
of the twigs were measured. Concentrations of salicin, salicortin, HCH-salicortin, picein, triandrin, triandrin derivative,
gallocatechin, (+)-catechin, luteolin-7-glucoside, hyperin, total condensed tannins and total nitrogen were measured from
the twigs fed to voles in the laboratory. Browsing by a natural population of voles amongst winter-dormant willows was measured
in the field. In the laboratory, voles browsed on 80% of the twigs and in the field voles browsed on 33% of the twigs. Vole
feeding followed similar patterns in the field and in the laboratory experiment; feeding was clearly higher amongst the plants
grown in unmulched control compared to those in plastic mulch. The same clones, 1, 2 and 6 were preferred in both experiments.
Voles preferred thin twigs to thick ones. Feeding correlated negatively with concentrations of salicylates and tannins. As
vole feeding seems to be highly affected by willow cultivation method and plant genotype, careful selection of cultivated
clones and cultivation methods can enhance the reliability of herbal willow cultivation. 相似文献
182.
姜小文 《湖南环境生物职业技术学院学报》2002,8(2):98-104
综述了微繁、胚培养、胚乳培养、花药培养、原生质体培养与融合、转基因和基因克隆、分子标记等生物技术近年来在柑桔等南方果树上的应用. 相似文献
183.
184.
活性污泥法快速培菌的探索与实践 总被引:2,自引:0,他引:2
本文介绍了一种快速培养,驯化活性微生物的方法,大大缩短了微物生长的停滞期,使活性污泥在培菌、驯化方面有很大的改进,做到节约时间、降低成本、减轻培菌期间的环境污染。使活性污泥法更加快速、高效。 相似文献
185.
张文丽 《防灾科技学院学报》2004,6(1):38-41
在制图教学中,利用CAD绘制二维工程图,建立三维立体虚拟模型,培养学生思维能力,使学生达到读图并绘制完整、正确、清晰的二维工程图的目的。 相似文献
186.
报道了西双版纳纳板河流域自然保护区3个拉祜族村寨对土地和野生植物资源的利用现状,认为转变单纯采集为栽培种植价值大的野生植物是发展的根本出路。 相似文献
187.
188.
From 1935 to 2000, the net open water area of Inle Lake in Central Shan State, Myanmar decreased from 69.10 to 46.69 km2, a loss of 32.4% during this 65-year period. Local beliefs are that losses in lake area have been even greater within the
last 100–200 years. Various activities, including timber removal, shifting agriculture in the uplands by various ethnic groups,
and unsustainable cultivation practices on the low- and mid-level hillslopes around the lake, have been blamed for both historical
and ongoing sedimentation. We take issue with attributing loss of lake area to these activities, and propose instead that
ongoing “in-lake” and “near-lake” agricultural practices are the main sources of contemporary sediment and loss of open water
area. About 93% (i.e., 20.84 km2) of the recent loss in open water area of the lake is due to the development of floating garden agriculture, largely along
the west side of the lake. Direct environmental impacts associated with this practice and with other agriculture activities
within the wetlands and margins of the lake include sedimentation, eutrophication, and pollution. Whilst the sustainability
of hillslope agriculture and past forestry practices can indeed be questioned, a more urgent need is to address these "in-lake"
and "near-lake" practices. 相似文献
189.
190.
以米脂县高西沟村为例,通过构建耕地集约利用评价指标体系,利用主成分分析方法进行分析,探讨高西沟在实施有效的水土治理措施后,耕地集约利用情况,得出结论:1997—2006年米脂县高西沟村耕地集约利用情况呈波动上升趋势,1999~2001年出现下降趋势,这与当年的自然灾害有关;高西沟村非农指数、单位化肥投入、复种指数和人均纯收入,极大地影响到耕地的集约利用水平,说明农户的经济情况影响高西沟耕地集约利用程度。 相似文献