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111.
112.
连续 2a实地调查了太湖鼋头渚地区鹭鸟的觅食生境 ,并搜集其雏鸟的反吐物 ,初步掌握了该地区不同鹭鸟对觅食生境的选择与食物组成情况。结果表明 ,无锡鼋头渚地区白鹭与夜鹭主要在鱼塘、湖泊觅食 ,白鹭在湖滨觅食 ,而夜鹭还会到湖中央水面觅食 ;池鹭觅食区域较广 ,主要在鱼塘。鹭群主要的食物类型是鱼类 ,白鹭食物几乎全为鱼类 ,夜鹭 95 %的食物为鱼类 ,兼有少量的蛙类、甲壳类和小型哺乳类动物。 相似文献
113.
Stephen B. Malcolm 《Chemoecology》1990,1(1):12-21
Summary Cardenolide sequestration by a hemimetabolous aphid and a holometabolous butterfly from the neotropical milkweed,Asclepias curassavica L., is compared. The oleander aphid,Aphis nerii B. de F., sequestered a similarly narrow range of cardenolide concentrations to the monarch butterfly,Danaus plexippus (L.), from the wide range of concentrations available in leaves of A.curassavica. However, A.nerii sequestered significantly less cardenolide (269 µg/0.1 g) thanD. plexippus (528 µg/0.1 g). The honeydew excreted by A.nerii was comprised of 46% cardenolide. The complete polarity range of 25 cardenolides detected by thin layer chromatography in A.curassavica was represented in the 17 whole aphid cardenolides and the 20 aphid honeydew cardenolides detected. D.plexippus sequestered a narrower polarity range of 11 cardenolides, having eliminated low polarity cardenolide genins and glycosides. It is suggested that these chemical differences may be related to interactions among the broad feeding tactics of sucking or chewing milkweed leaves, life history constraints of holometabolyversus hemimetaboly, the distribution of milkweed food resources in space and time, and the dynamics of natural enemies. 相似文献
114.
研究了褶皱臂尾轮虫(Brachionus plicatilis)在不同温度、盐度、饵料种类、pH值和光照条件下滤水率(F)和摄食率(G)的变化情况。结果表明:(1)温度对褶皱臂尾轮虫的摄食有显著影响(P0.05)。褶皱臂尾轮虫摄食的适宜温度范围为25~30℃,最适摄食温度为25℃;(2)盐度对褶皱臂尾轮虫的摄食也有显著影响(P0.05)。褶皱臂尾轮虫适宜的摄食盐度范围为20~30,最适摄食盐度为30;(3)褶皱臂尾轮虫对5种不同藻类食物滤水率F的顺序为:牟氏角毛藻(Chaetocerosmuelleri Lermumerman)小新月菱形藻(Nitzschia clostertum)金藻8701(Isochrysis galbanaPark 8701)小球藻(Chlorellasp.)扁藻(Tetraselmis chuii);摄食率G的顺序为:小球藻金藻8701牟氏角毛藻小新月菱形藻扁藻;(4)褶皱臂尾轮虫适宜的摄食pH值范围为8.0~9.0,最适摄食pH值为9.0;(5)在条件允许的情况下,适宜的光照有利于褶皱臂尾轮虫的摄食。 相似文献
115.
Quan Yuan Hui Gong Hao Xi Kaijun Wang 《Frontiers of Environmental Science & Engineering》2020,14(3):49
116.
利用SBR,控制曝气量为60 L/h,利用在线pH曲线控制曝气时间,成功实现了短程生物脱氮过程,并考察了不同进水方式下SBR运行性能及N2O产量。结果表明,分段进水能够有效降低短程生物脱氮过程中外加碳源投加量。在原水进水碳氮比较低时,采用递增进水量的进水方式,能够有效降低生物脱氮过程中NO-2积累量,从而降低系统N2O产量。1次进水、2次等量进水和2次递增进水方式下,生物脱氮过程中N2O产量分别为11.1、8.86和5.04 mg/L。硝化过程中NO-2-N的积累是导致系统N2O产生的主要原因。部分氨氧化菌(AOB)在限氧条件下以NH+4-N作为电子供体,NO-2-N作为电子受体进行反硝化,最终产物是N2O。 相似文献
117.
Farm‐level Economic and Water Quality Impacts of Comprehensive Nutrient Management Plan Implementation in the Ohio River Basin
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Edward Osei Bing Du Larry Hauck Huijun Li Alexander Tanter 《Journal of the American Water Resources Association》2017,53(3):641-654
In this article, we provide an assessment of comprehensive nutrient management plans (CNMPs) as a tool for addressing nonpoint nutrient and sediment losses from the animal feeding operations (AFOs) in the Ohio River Basin. We employ a macro modeling system to determine the aggregate economic and water quality impacts of CNMP implementation on AFOs in the entire basin. Results of the study indicate that implementing CNMPs on AFOs will help reduce sediment and organic nutrient losses from their current levels at moderate cost. The flexibility inherent in CNMP designs means farmers may be able to achieve water quality and other conservation goals at less cost with CNMPs than with other less flexible policy options. 相似文献
118.
Anne-Sophie Fournier Frances Mason Barnaby Peacocke & Claudine Prudhon 《Disasters》2000,23(4):343-349
The NGO, Action contre la Faim (ACF), has been operating in Burundi since 1994, where the situation has dramatically hampered humanitarian programmes. These include poor security resulting in an inability to maintain 24-hour care for the severely malnourished and poor access to the beneficiaries, all within a politically and economically unstable context. However, ACF has been able to capitalise on lessons learnt and reflect on ways to move forward, which have included the improvement of their capacities in the treatment of severe malnutrition and the integration within broader disciplines and national structures.
The protocols for the treatment of severe malnutrition currently used in Burundi have been developed as a result of the research of ACF over the past five years. Other aspects of the nutrition programme remain to be further developed. These include, for example, an improved capacity to care for severely malnourished adolescents and adults; and also a better knowledge of the beneficiaries to allow for stronger links between the provision of treatment and support for their longer-term food security. 相似文献
The protocols for the treatment of severe malnutrition currently used in Burundi have been developed as a result of the research of ACF over the past five years. Other aspects of the nutrition programme remain to be further developed. These include, for example, an improved capacity to care for severely malnourished adolescents and adults; and also a better knowledge of the beneficiaries to allow for stronger links between the provision of treatment and support for their longer-term food security. 相似文献
119.
A. F. Safonkin 《Russian Journal of Ecology》2000,31(3):203-206
The influence of food change on the development of the mothArchips podana was studied. Larvae of a natural population were collected from an apple tree. Nevertheless, the minimal duration of development
and the maximal weight of pupae in the next generation were observed in insects that developed on plum, pear, and currant,
rather than on apple trees. Transfer has effect on larvae of late instars: transfer from the plum to other trees results in
the deterioration of developmental parameters, while that from apple to plum and currant leads to their improvement. This
procedure has an effect on the proportion of pupating larvae. The timing of egg laying influences the development and mortality
of the larvae. The development of adults from older clutches on apple is comparable to that on plum. 相似文献
120.
Marc Slattery 《Chemoecology》1999,9(3):97-104
Summary. Fungal pathogenesis of the sea fan Gorgonia ventalina has developed on the Belize barrier reef during 1997 and 1998. The disease incidence (= percent of infected sea fans) remained
unchanged at two sites along the barrier reef crest between years. However, the incidence increased significantly at an offshore
atoll during that time, as did the virulence (= percent tissue loss). Grazing by the gorgonian specialist mollusc Cyphoma gibbosum increased on infected sea fans. Sea fan responses to fungal infection included significant decreases in a furano-germacrene
compound with antifeedant activity and significant increases in the concentration of sclerites at the site of infection. Feeding
assays utilizing C. gibbosum and a natural assemblage of reef fishes indicated sclerites are an effective deterrent, to both consumers, at both pre- and
post-infected concentrations. In contrast, the compound was only deterrent to the fish, and only at concentrations found in
pre-infected sea fans. These data indicate that sea fan pathogenesis can directly and indirectly affect population health
via virulent tissue necrosis and pathogen-mediated reductions in grazer resistance, respectively.
Received 4 November 1998; accepted 5 April 1999. 相似文献