全文获取类型
收费全文 | 2569篇 |
免费 | 133篇 |
国内免费 | 1079篇 |
专业分类
安全科学 | 157篇 |
废物处理 | 138篇 |
环保管理 | 208篇 |
综合类 | 1551篇 |
基础理论 | 415篇 |
环境理论 | 1篇 |
污染及防治 | 971篇 |
评价与监测 | 115篇 |
社会与环境 | 105篇 |
灾害及防治 | 120篇 |
出版年
2024年 | 5篇 |
2023年 | 62篇 |
2022年 | 157篇 |
2021年 | 117篇 |
2020年 | 108篇 |
2019年 | 98篇 |
2018年 | 92篇 |
2017年 | 122篇 |
2016年 | 171篇 |
2015年 | 202篇 |
2014年 | 186篇 |
2013年 | 247篇 |
2012年 | 223篇 |
2011年 | 241篇 |
2010年 | 211篇 |
2009年 | 184篇 |
2008年 | 171篇 |
2007年 | 164篇 |
2006年 | 150篇 |
2005年 | 70篇 |
2004年 | 69篇 |
2003年 | 88篇 |
2002年 | 74篇 |
2001年 | 58篇 |
2000年 | 72篇 |
1999年 | 73篇 |
1998年 | 63篇 |
1997年 | 56篇 |
1996年 | 55篇 |
1995年 | 45篇 |
1994年 | 39篇 |
1993年 | 35篇 |
1992年 | 17篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1972年 | 2篇 |
1918年 | 1篇 |
1917年 | 1篇 |
1916年 | 1篇 |
排序方式: 共有3781条查询结果,搜索用时 62 毫秒
911.
Assessment of potential soybean cadmium excluder cultivars at different concentrations of Cd in soils 总被引:2,自引:0,他引:2
The selection of cadmium-excluding cultivars has been used to minimize the transfer of cadmium into the human food chain. In this experiment, five Chinese soybean plants were grown in three soils with different concentrations of Cd (0.15, 0.75 and 1.12 mg/kg). Variations in uptake, enrichment, and translocation of Cd among these soybean cultivars were studied. The results indicated that the concentration of Cd in seeds that grew at 1.12 mg/kg Cd in soils exceeded the permitted maximum levels in soybeans. Therefore, our results indicated that even some soybean cultivars grown on soils with permitted levels of Cd might accumulate higher concentrations of Cd in seeds that are hazardous to human health. The seeds of these five cultivars were further assessed for interactions between Cd and other mineral nutrient elements such as Ca, Cu, Fe, Mg, Mn and Zn. High Cd concentration in soil was found to inhibit the uptake of Mn. Furthermore, Fe and Zn accumulations were found to be enhanced in the seeds of all of the five soybean cultivars in response to high Cd concentration. Cultivar Tiefeng 31 was found to fit the criteria for a Cd-excluding cultivar under different concentrations of Cd in soils. 相似文献
912.
Amines have been considered as promising candidates for post-combustion CO2 capture. A mechanistic understanding for the chemical processes involved in the capture and release of CO2 is important for the rational design of amines. In this study, the structural effects of amines on the kinetic competition among three typical products (carbamates, carbamic acids and bicarbonate) from amines + CO2 were investigated, in contrast to previous thermodynamic studies to tune the reaction of amines with CO2 based on desirable reaction enthalpy and reaction stoichiometry. We used a quantum chemical method to calculate the activation energies (Ea) for the reactions of a range of substituted monoethanolamines with CO2 covering three pathways to the three products. The results indicate that the formation of carbamates is the most favorable, among the three considered products. In addition, we found that the Ea values for all pathways linearly correlate with pKa of amines, and more importantly, the kinetic competition between carbamate and bicarbonate absorption pathways varies with pKa of the amines, i.e. stronger basicity results in less difference in Ea. These results highlight the importance of the consideration of kinetic competition among different reaction pathways in amine design. 相似文献
913.
914.
研究了以美国为首的发达国家城镇化的发展历程,称为“A模式”,主要特征为城市低密度蔓延、全民机动化、资源大量消耗、一次性产品泛滥、过度消费等,总结经验教训,对比中国特色城镇化的发展历程,称为“ B模式”,主要特点是起步晚、水平较低、速度快,从资源与环境的角度分析了中国城镇化发展状况以及面临的形势,指出中国继续以“B模式”的城镇化发展将不可持续,不再适应中国建设“新型城镇化”的发展目标和日益提高的环保要求,探索实现中国“新型城镇化”的发展目标的“C模式”,即是坚持以节约优先、保护优先、自然恢复为原则,走以新型工业化和农业现代化推动下的新型城镇化道路。 相似文献
915.
916.
917.
918.
Jiao He Guoli Zi Zhiying Yan Yongli Li Jiao Xie Deliang Duan Yongjuan Chen Jiaqiang Wang 《环境科学学报(英文版)》2014,26(5):1195-1202
Cyanobacteria, which occurred in eutrophic water harvest solar light to carry out photosynthesis with high efficiency. In this work, cyanobacteria (Microcystis sp.) were used as biotemplate to synthesize titania structure. The synthesized titania sample had similar morphology to that of the original template in spite of the fragile unicellular structures and extremely high water content of cyanobacterial cells. Incorporation of biogenic C, as well as the morphology inherited from biotemplate improved visible- light absorbance of the titania structure. The sample exhibited higher visible-light photocatalytic activity than commercial titania photocatalyst Degussa P25 for Rhodamine B (RhB) degradation. Compared with those C-doped titania photocatalysts prepared by other methods, cyanobacteria templated titania photocatalyst offer some potential for competitive advantages. The reported strategy opened up a new use for the cyanobacteria. It could also be used for titania in applications such as treatment of polluted water, dye-sensitized solar cells, or other regions. 相似文献
919.
920.
通过对当前应急救援队伍的装备配置和维护保养情况进行调查,结合基层队伍的专项训练情况,分析现阶段应急救援队伍应急保障中存在的薄弱点,就如何提高应急救援队伍的救援能力提出建议。 相似文献