全文获取类型
收费全文 | 12730篇 |
免费 | 674篇 |
国内免费 | 4840篇 |
专业分类
安全科学 | 1083篇 |
废物处理 | 732篇 |
环保管理 | 1108篇 |
综合类 | 7199篇 |
基础理论 | 2114篇 |
环境理论 | 2篇 |
污染及防治 | 4394篇 |
评价与监测 | 608篇 |
社会与环境 | 518篇 |
灾害及防治 | 486篇 |
出版年
2024年 | 39篇 |
2023年 | 223篇 |
2022年 | 670篇 |
2021年 | 579篇 |
2020年 | 512篇 |
2019年 | 396篇 |
2018年 | 515篇 |
2017年 | 624篇 |
2016年 | 670篇 |
2015年 | 857篇 |
2014年 | 1007篇 |
2013年 | 1332篇 |
2012年 | 1185篇 |
2011年 | 1195篇 |
2010年 | 929篇 |
2009年 | 887篇 |
2008年 | 931篇 |
2007年 | 799篇 |
2006年 | 652篇 |
2005年 | 488篇 |
2004年 | 387篇 |
2003年 | 442篇 |
2002年 | 391篇 |
2001年 | 329篇 |
2000年 | 327篇 |
1999年 | 270篇 |
1998年 | 266篇 |
1997年 | 265篇 |
1996年 | 241篇 |
1995年 | 182篇 |
1994年 | 133篇 |
1993年 | 130篇 |
1992年 | 112篇 |
1991年 | 80篇 |
1990年 | 58篇 |
1989年 | 28篇 |
1988年 | 27篇 |
1987年 | 11篇 |
1986年 | 17篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
891.
892.
893.
David Sinclair Richard J. Countess Benjamin Y. H. Liu David Y. H. Pui 《Journal of the Air & Waste Management Association (1995)》2013,63(7):661-663
The diffusion battery, an assembly of circular tubes or rectangular channels, is one of the best devices available for measuring the size and size distribution of submicron aerosols in the diameter range 0.002 to 0.2 µ m. The performance of these batteries is known from molecular diffusion theory, but until now has not been checked experimentally in this size range because of the lack of the necessary monodisperse aerosols. Experimental measurements on singly charged monodisperse aerosols from 0.01 µm to 0.1 µ m are described using a General Electric and a Pollak condensation nucleus counter to measure the aerosol penetration through the stages of a set of portable diffusion batteries in series. Particle sizes in the range tested could be selected at will by adjusting the voltage of an electric mobility classifier. The fraction of aerosol of a given size passing through each battery stage was found to agree closely with the penetration calculated from molecular diffusion theory for that size. This shows that the theory is correct and confirms that the aerosol produced by the electric mobility classifier was monodisperse. In addition, it was found that the difference in penetration between a charged versus a neutralized aerosol was insignificant except for the smallest aerosols used. 相似文献
894.
895.
Zhong-Yi Li Jiu-Yu Li Yuan Liu Ren-Kou Xu 《Environmental science and pollution research international》2014,21(17):10461-10469
The streaming potential has been wildly used in charged parallel plates, capillaries, and porous media. However, there have been few studies involving the ζ potential of clay soils based on streaming potential measurements. A laboratory apparatus was developed in this study to measure the streaming potential (ΔE) of bulk clay soils’ coupling coefficient (C) and cell resistance (R) of saturated granular soil samples. Excellent linearity of ΔE versus liquid pressure (ΔP) ensured the validity of measurements. The obtained parameters of C and R can be used to calculate the ζ potential of bulk soils. The results indicated that the ζ potentials measured by streaming potential method were significantly correlated with the ζ potentials of soil colloids determined by electrophoresis (r 2?=?0.960**). Therefore, the streaming potential method can be used to study the ζ potentials of bulk clay soils. The absolute values of the ζ potentials of four soils followed the order: Ultisol from Jiangxi?>?Ultisol from Anhui?>?Oxisol from Guangdong?>?Oxisol from Hainan, and this was consistent with the cation exchange capacities of these soils. The type and concentration of electrolytes affected soil ζ potentials. The ζ potential became less negative with increased electrolyte concentration. The ζ potentials were more negative in monovalent than in divalent cationic electrolyte solutions because more divalent cations were distributed in the shear plane of the diffuse layer as counter-cations on the soil surfaces than monovalent cations at the same electrolyte concentration. 相似文献
896.
Yuan Sui Samir Droby Danfeng Zhang Wenjie Wang Yongsheng Liu 《Environmental science and pollution research international》2014,21(24):13956-13963
Significant losses in harvested fruit can be directly attributable to decay fungi and quality deterioration. Hot water treatment (HWT) has been demonstrated to be an effective and economic environment-friendly approach for managing postharvest decay and maintaining fruit quality. In this study, the effects of HWT (45 °C for 10, 15, 20, and 25 min) on in vitro growth of Fusarium oxysporum, in vivo Fusarium rot, and natural decay of melon were investigated. HWT inhibited spore germination and germ tube elongation of F. oxysporum. Protein impairment and ATP consumption triggered by HWT contributed to the inhibitory effect. Results of in vivo studies showed that HWT effectively controlled Fusarium rot and natural decay of melon. Correspondingly, HWT induced a significant increase in content of total phenolic compounds and lignin of melon. These findings indicate that the effects of HWT on Fusarium rot may be associated with the direct fungal inhibition and the elicitation of defense responses in fruit. Importantly, HWT used in this study had beneficial effects on fruit quality as well. HWT may represent an effective non-chemical approach for management of postharvest Fusarium rot. 相似文献
897.
Xiao-Zhang Yu Xue-Hong Zhang Wei Liu 《Environmental science and pollution research international》2014,21(2):1411-1417
Responses of free amino acids to botanical assimilation of free cyanide were investigated. Young rice seedlings (Oryza sativa L. cv. XZX 45) were grown in nutrient solution amended with free cyanide (KCN). Cyanide was analyzed in solution as well as in plant materials to estimate the phyto-assimilation potential. Free amino acids in different parts of plants were also measured to determine metabolic responses to KCN exposure. Phyto-assimilation of KCN was obvious, and the rates were positively correlated to the concentration supplied. Although changes in total amino acid content in plant materials were negligible during KCN metabolism (p?>?0.05), responses of different amino acids to KCN treatments were quite different. All treatments with KCN increased the content of proline (Pro) and isoleucine (Ile) in roots significantly compared with control (p?<?0.05), while changes of aspartic acid, lysine, and histidine in roots were more evident at higher KCN treatments (p?<?0.05). Results indicate that the content of Pro, Ile, and tyrosine showed pronounced increase in shoots of rice seedlings exposed to KCN at 1.44 mg CN/L or higher (p?<?0.05). Other amino acids slightly changed in all plant materials exposed to KCN (p?>?0.05). Results indicate that specific amino acids in rice seedlings showed positive response to non-toxic concentrations of exogenous KCN. These findings could provide additional insights into the inducible mechanisms underlying the involvement of amino acids in KCN metabolism. 相似文献
898.
The increasing volume of CO2 embodiment in international trade adds a layer of complexity to environmental policies and has raised arguments on the traditional production based responsibility for CO2 emissions. In order to help understand the quantity of CO2 embodiment in trade and its policy implications, this paper gives observations to recently emerging literatures that quantitatively discuss CO2 embodiment in trade. The analytical approaches share the principle of using input and output modeling but vary dramatically in study boundary and estimation accuracy. The calculations can be roughly categorized into three types: direct quantification of CO2 embodiments in multiregional trade, direct quantification of CO2 embodiment in bilateral trade, and indirect analysis by comparing the scenarios with or without trade. The practical estimations strongly rely on trade partner selection and data availability. An obvious imbalance of net CO2 embodiment in the commodity trade between major developed countries and developing economies as a whole was confirmed by these literatures. Carbon taxes and other possible limitations on CO2 emissions have been addressed. The consistency across the calculations could be enhanced by systematic analyses in more detail to convince the international community to take binding commitments for the reduction of global CO2 emissions. 相似文献
899.
本文提出安全科学技术也是第一生产力的观点。文中简析了科学、技术和科学技术的内涵及其相互关系;研究了科学技术与生产力的关系;阐述安全科学技术也是第一生产力:探讨了发展高科技与安全科学技术的关系;安全科学技术发展中应注意的问题。 相似文献
900.
四川省自贡市蛋鸡场鸡粪处理工艺 总被引:2,自引:0,他引:2
本文主要阐述自贡市蛋鸡场在养鸡生产实践中面临着鸡粪处理这一难题,选用四川省农机所设计,并由四川省资中通风机械厂试剂的GZS-0.5型鸡粪干燥成套设备进行鸡粪加工的工作,本场对GZS-0.5型鸡粪干燥成套设备废气的净化处理有所改进创新。 相似文献