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341.
There is a close relationship between agricultural production and environmental meteorological conditions. In the study of the correlation between them, the simulation models are paid more attention to the crop growth. In this paper the development of the studies on the crop growth dynamic simulation model in China is briefly reviewed. The relationships between meteorological conditions and each process of crop growth (such as photosynthesis, respiration, accumulation and distribution of assimilation products and growth of leaf area) are studied and simulated basing on the results from field experiments. Preliminary models for rice, wheat, maize and soybean have been developed, and some investigations about modelling methods, procedures and parameters in simulation models are made. 相似文献
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一火成形是中小型模锻的发展方向,它既能提高锻件质量、模具寿命,又能提高生产效率、降低成本、便于管理。此文以船用集装箱紧固钩锻件为例,就其一火成形的工艺及模具设计进行分析、讨论,重点介绍其工艺步骤、模具设计方案及要求。 相似文献
345.
WU Gang CHEN Fa-jun SUN Yu-cheng GE Feng .National Key Laboratory of Integrated Management of Pest Insects Rodents Institute of Zoology Chinese Academy of Sciences Beijing China. .Department of Biology Wuhan University of Technology Wuhan China 《环境科学学报(英文版)》2007,(11)
The growth,development and consumption of successive three generations of cotton bollworm,Helicoverpa armigera(Hübner),fed on cotton bolls grown under elevated CO_2(double-ambient vs.ambient)in open-top chambers were examined.Significant decreases in protein,total amino acid,water and nitrogen content and increases in free fatty acid were observed in cotton bolls.Changes in quality of cotton bolls affected the growth,development and food utilization of H.armigera.Significantly longer larval development duration in three successive generations and lower pupal weight of the second and third generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO_2.Significantly lower fecundity was also found in successive three generations of H.armigera fed on cotton bolls grown under elevated CO_2.The consumption per larva occurred significant increase in successive three generations and frass per larva were also significantly increased during the second and third generations under elevated CO_2.Significantly lower relative growth rate,efficiency of conversion of ingested food and significant higher relative consumption rate in successive three generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO_2.Significantly lower potential female fecundity,larval numbers and population consumption were found in the second and third generations of cotton bollworm fed on cotton bolls grown under elevated CO_2.The integrative effect of higher larval mortality rate and lower adult fecundity resulted in significant decreases in potential population consumption in the latter two generations.The results show that elevated CO_2 adversely affects cotton bolls quality,which indicates the potential population dynamics and potential population consumption of cotton bollworm will alleviate the harm to the plants in the future rising CO_2 atmosphere. 相似文献
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异相催化是催化反应的重要组成部分,其应用十分广泛。固一液异相催化作为环境科学领域中的一项比较新颖的技术,在研究污染物在多介质环境中的迁移转化行为、开发受污染环境修复及污废水处理新技术等诸多方面都具有很大的发展潜力。因此,对不同类型固一液异相催化剂在环境科学领域的应用研究逐渐成为国内外环境科学领域的研究热点之一。其中,金属和金属氧化物因对某些氧化一还原反应具有较好的催化作用,在饮用水脱氮、污废水脱卤及深度氧化处理等水处理领域的应用较为广泛;固态酸催化剂能催化聚合、裂化、水解反应,因此与某些有机污染物的降解密切相关;将同相催化剂固定化为异相催化剂,同样成为新技术开发的方向之一;天然催化剂对污染物在多介质环境中行为影响的研究近年来也屡有发表。此外,载体因对催化剂的活性及应用具有重要影响,也日益受到关注。文章对环境科学领域中固一液异相催化剂的应用研究进行了综述。 相似文献
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磷胁迫对水稻基因型根系形态及吸收铁锰铜锌的影响 总被引:5,自引:2,他引:5
采用营养液培养方法研究了缺磷胁迫下4种水稻基因型(90-90—1、金23A、90-68-1、CDR22)的根系形态变化情况及其吸收微量元素铁、锰、铜、锌的影响。结果表明,(1)磷胁迫下,每个基因型在磷胁迫下其根系形态发生了明显变化、如根长、根冠比均呈增加趋势,并且根表有红棕色铁氧化物膜包被。(2)磷胁迫下根系形态的变化影响了水稻对生长介质中铁、锰、铜、锌的吸收:正常水稻植株中铁、锰、锌的含量高于磷胁迫植株,其中磷营养状况对水稻吸收铁、锰影响最明显;而磷营养状况对水稻植株铜含量的影响与铁、锰、锌正好相反,且影响程度较小。 相似文献
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采用开放式悬浮型光催化反应器,以太阳能中紫外光替代紫外灯,激发染料污水悬浮液中TiO2产生OH自由基将染料催化氧化脱色,探讨了催化剂用量,催化剂活性,曝气,污水流速,反应器受辐射面积,Fe3+离子等对染料污水脱色率的影响,实验结果表明:在一般晴天的条件下,经过2小时太阳能辐射后,阳离子蓝X-GRRL染料脱色率在80%-93%之间,说明太阳能是非均相光催化氧化染料污水脱色处理的有效紫外光源,太阳能非均相光催化氧化染料污水脱色处理是经济实用,效率高,很有发展前景的污水脱色处理技术 相似文献