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我国蔬菜生产系统由于长期过量施肥导致氮肥利用率低和环境问题严重,氮肥配施硝化抑制剂是降低活性氮损失、增加蔬菜产量和提高氮肥利用率的有效策略,然而缺乏系统研究.基于数据整合分析的方法,系统分析了氮肥配施硝化抑制剂[双氰胺(DCD)、3,4-二甲基吡唑磷酸盐(DMPP)和2-氯-6-三氯甲基吡啶(NP)]对我国蔬菜生产的产量、植株氮吸收、氮肥利用率和氧化亚氮减排效应的影响,进一步揭示不同田间管理措施对其效果的影响.结果表明,氮肥配施硝化抑制剂能够显著提高蔬菜产量(9.2%)、植株氮吸收(10.4%)和氮肥利用效率(11.2%),同时减少氧化亚氮排放(28.4%).不同硝化抑制剂类型中,NP对增产效应和氧化亚氮减排效应的影响幅度最高,分别为16.1%和32.0%,其次是DMPP和DCD.硝化抑制剂在不同氮肥用量中能提高蔬菜产量(6.7%~14.7%)和减少氧化亚氮排放(14.6%~36.8%).在中性和碱性菜地土壤中,硝化抑制剂的增产效应和氧化亚氮减排效应的影响幅度较酸性土大.硝化抑制剂在露地栽培、根菜类和叶菜类的条件下对产量的增加和氧化亚氮的减排效果较好.主成分分析表明,土壤总氮含量和土壤pH是影响硝化抑制剂对蔬菜产量形成和驱动氧化亚氮排放的主要因素.综上,硝化抑制剂是实现蔬菜系统提质增效、节肥减排的重要举措.同时,农户应根据土壤和田间管理措施选择适宜硝化抑制剂类型,以最大限度提高其有效性. 相似文献
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E. Bitoun C. Bodemer J. Amiel Y. de Prost C. Stoll P. Calvas A. Hovnanian 《黑龙江环境通报》2002,22(2):121-126
Netherton syndrome (NS) is a severe autosomal recessive ichthyosis with no specific treatment or prenatal diagnosis available at present. The recent identification of SPINK5, which encodes a serine protease inhibitor, as the defective gene enables DNA-based prenatal diagnosis to be carried out. Here we report the first direct molecular prenatal diagnosis of a lethal form due to a recurrent SPINK5 mutation in three consanguineous Turkish families. XmnI restriction enzyme digestion and DNA sequencing demonstrated that each deceased affected child was homozygous for mutation 153delT inherited from each parent. Analysis of fetal DNA from amniotic fluid cells in Family 1 and from a chorionic villus sampling in Family 3 showed that the fetus was heterozygous for 153delT in both cases. The pregnancies were carried to term and the newborns were unaffected. In Family 2, fetal DNA analysis from chorionic villus biopsy showed in a first pregnancy that the fetus was homozygous for 153delT. The pregnancy was terminated at 13 weeks and DNA analysis of fetal keratinocytes confirmed the prenatal prediction. In a second pregnancy in Family 2, fetal DNA analysis showed heterozygosity for 153delT, and the pregnancy was continued. Direct SPINK5 mutation analysis in families at risk for NS represents the first early, rapid and reliable method for prenatal diagnosis of this life-threatening form of ichthyosis. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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大豆皂甙复合物抑制猴免疫缺陷病毒活性的观察 总被引:9,自引:0,他引:9
以猴免疫缺陷病毒(SIV)为靶病毒和相应的CEMx174细胞系统为模型,以AZT为阳性对照药物,观察了从大豆提取的皂甙复合物及大豆胰蛋白酶抑制剂对细胞病变的影响.结果表明,大豆皂甙复合物具有明显的抗SIV作用,而大豆胰蛋白酶抑制剂则无抗SIV作用. 相似文献
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Zhao-xia Song Hong-wu He Yao-ting Fan Hong-wei Hou 《International Journal of Green Energy》2017,14(3):330-335
The redox state of carbon sources directly affected the ratio of NADH/NAD+ which was coupled to the hydrogen production by Bacillus sp. FS2011. The addition of the inhibitor of pyruvate dehydrogenase multi-enzyme complex (PDHc)E1 could regulate hydrogen production by FS2011 or pretreated compost in batch cultivation. With the addition of appropriate amount of inhibitor, hydrogen production via the NADH pathway was increased, leading to the higher overall hydrogen production. The maximum hydrogen yields of 307.6 ± 13.21 mL/g by FS2011 with the inhibitor of 80 ppm and 362.1 ± 10.1 mL/g by pretreated compost with the inhibitor of 60 ppm were observed, which were increased by 8.7% and 17.8% compared with the controls, respectively. Meanwhile the production of soluble metabolic byproducts such as butyrate, acetate and so on were decreased, resulting in reducing the difficulty of wastewater treatment. 相似文献
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