全文获取类型
收费全文 | 3402篇 |
免费 | 34篇 |
国内免费 | 175篇 |
专业分类
安全科学 | 97篇 |
废物处理 | 195篇 |
环保管理 | 315篇 |
综合类 | 621篇 |
基础理论 | 780篇 |
环境理论 | 2篇 |
污染及防治 | 1131篇 |
评价与监测 | 269篇 |
社会与环境 | 186篇 |
灾害及防治 | 15篇 |
出版年
2023年 | 18篇 |
2022年 | 76篇 |
2021年 | 44篇 |
2020年 | 29篇 |
2019年 | 38篇 |
2018年 | 117篇 |
2017年 | 50篇 |
2016年 | 76篇 |
2015年 | 89篇 |
2014年 | 92篇 |
2013年 | 272篇 |
2012年 | 94篇 |
2011年 | 162篇 |
2010年 | 145篇 |
2009年 | 162篇 |
2008年 | 168篇 |
2007年 | 196篇 |
2006年 | 148篇 |
2005年 | 122篇 |
2004年 | 144篇 |
2003年 | 142篇 |
2002年 | 114篇 |
2001年 | 240篇 |
2000年 | 147篇 |
1999年 | 71篇 |
1998年 | 40篇 |
1997年 | 47篇 |
1996年 | 33篇 |
1995年 | 40篇 |
1994年 | 42篇 |
1993年 | 41篇 |
1992年 | 30篇 |
1991年 | 35篇 |
1990年 | 27篇 |
1989年 | 32篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 15篇 |
1984年 | 18篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1975年 | 12篇 |
1973年 | 9篇 |
1972年 | 10篇 |
排序方式: 共有3611条查询结果,搜索用时 250 毫秒
601.
Liu Y.Xu Y.Zhang H.Yang H. 《应用与环境生物学报》2018,(3):602-608
To study heavy metal pollution and assess the health risk of river water in Huayuan County, Xiangxi, Hunan Province, 11 water samples were collected from the Huayuan River and Brother Rivers in August and December 2016. Heavy metal (Pb, Zn, Cr, Cu, Fe, and Ni) concentrations were determined from the samples. The health risk assessment model recommended by the U.S. Environmental Protection Agency (USEPA) was applied to assess the health risk of heavy metals in the main surface waters of Huayuan County. The results indicated that the concentrations of heavy metals (Pb, Zn, Cr, Cu, Fe, and Ni) of surface water in the research area were 2.57 × 10-3, 4.66 × 10-4, 1.65 × 10-3, 6.27 × 10-4, 0.19, and 8.50 × 10-4 mg/L, respectively. The health risk of surface waters with heavy metals was high. Therefore, the chemical carcinogenic substance (Cr) health risk index was five or six times higher than that of chemical non-carcinogens (Pb, Zn, Cu, and Ni). The average health risk indices of non-carcinogenic substances were in the order Pb > Cu > Zn > Ni. The correlation and principal component analysis of surface water showed that the six heavy metal elements were composed of three main components in the main surface waters of the county. The first principal component was comprised of Fe and Ni (33.28%), which was mainly from internal pollution. The second component was comprised of Cu and Cr (26.98%), which was primarily due to industrial waste water, rainwater leaching mineral waste produced by heavy metal mining, and smelting enterprises. The third component, resulting from geochemical pollution, was Zn (17.10%). The health risk indices triggered by heavy metal in surface waters was high. Heavy metal pollutants in the research area need to be controlled in the order Cr, Pb, Cu, Zn and Ni. © 2018 Science Press. All rights reserved. 相似文献
602.
Liu P.Wang Y.Su K. 《应用与环境生物学报》2018,(3):557-562
In order to solve the problem of poor treatment of phosphorus in membrane bioreactor (MBR) with long sludge retention time (SRT), a ferric salt was added to enhance phosphorus removal; FeCl36H2O (Fe/P = 2.0) was added to the reactor. The removal efficiency of nitrogen, organic matters, and phosphorus in the MBR was investigated systematically. Moreover, this study focused on the membrane performance, the change of active sludge flora, and the effect of adding a ferric salt on membrane fouling before and after the addition. It was seen that adding the ferric salt could not affect the removal of COD and NH4 +-N and the removal rate of COD and NH4 +-N reached over 90%. However, the average removal rate of phosphorus was 52%, while the removal rate increased by nearly 40% after adding the ferric salt. The effects of adding ferric salts on the dominant bacteria and biological phosphorus removal of activated sludge were further studied. The results showed that the addition of ferric salt (Fe/P = 2.0) decreased the diversity of active sludge flora and relative abundance of some phosphorusaccumulating organisms and had a negative effect on biological phosphorus removal. The analysis of transmembrane pressure difference (TMP) recording revealed that the concentration of iron salts did not exacerbate membrane fouling. The results showed that the concentration of iron salts entering the membrane bioreactor would reduce the relative abundance and phosphorus removal efficiency of the activated sludge in the system to a certain extent, but it had no obvious effect on membrane fouling. It allowed the effluent to attain acceptable standards, especially with respect to phosphorus removal efficiency. © 2018 Science Press. All rights reserved. 相似文献
603.
604.
为探讨丙烯腈(Acrylonitrile,AN)对雄性小鼠的生殖毒性作用机制,将250只SPF级昆明种雄性小鼠按体重随机分为5组:3个AN染毒组(1.25、2.50、5.00mg·kg-1)、1个阴性对照组(生理盐水0.01mL·g-1)和1个阳性对照组(环磷酰胺40mg·kg-1),腹腔注射染毒5d,每天1次.于初次染毒后第7、14、21、28、35d分五批处死小鼠,检测分析小鼠精子运动参数的变化.结果表明,5个观察终点各剂量组精液参数(精子密度、活动度、运动速度、运动方式参数、空间位移程度)变化与阴性对照均无显著差异(p>0.05).提示,在试验浓度范围内,AN对小鼠精子运动参数无影响. 相似文献
605.
Journal of Polymers and the Environment - In this study, a novel bead form IPN type resin comprising poly (2-Dimethylaminoethyl) methacrylate and carboxymethyl chitosan networks with a high dye... 相似文献
606.
Y.F. Khalil 《Journal of Loss Prevention in the Process Industries》2013,26(1):96-103
This paper discusses the results of an experimental program carried out to determine dust cloud deflagration parameters of selected solid-state hydrogen storage materials, including complex metal hydrides (sodium alanate and lithium borohydride/magnesium hydride mixture), chemical hydrides (alane and ammonia borane) and activated carbon (Maxsorb, AX-21). The measured parameters include maximum deflagration pressure rise, maximum rate of pressure rise, minimum ignition temperature, minimum ignition energy and minimum explosible concentration. The calculated explosion indexes include volume-normalized maximum rate of pressure rise (KSt), explosion severity (ES) and ignition sensitivity (IS). The deflagration parameters of Pittsburgh seam coal dust and Lycopodium spores (reference materials) are also measured. The results show that activated carbon is the safest hydrogen storage media among the examined materials. Ammonia borane is unsafe to use because of the high explosibility of its dust. The core insights of this contribution are useful for quantifying the risks associated with use of these materials for on-board systems in light-duty fuel cell-powered vehicles and for supporting the development of hydrogen safety codes and standards. These insights are also critical for designing adequate safety features such as explosion relief venting and isolation devices and for supplementing missing data in materials safety data sheets. 相似文献
607.
Experimental and theoretical studies were conducted to investigate the pyrophoricity and water-reactivity risks associated with employing sodium alanate (NaAlH4) complex metal hydride in on-board vehicular hydrogen (H2) storage systems. The ignition and explosivity of NaAlH4 upon exposure to oxidizers in air or water were attributed to the spontaneous formation of stable hydroperoxyl intermediates on the NaAlH4 surface and/or H2 production, as well as the large driving force for NaAlH4 conversion to favorable hydroxide products predicted by atomic and thermodynamic modeling. The major products from NaAlH4 exposure to air: NaAl(OH)4, gibbsite and bayerite Al(OH)3, and Na2CO3 observed by XRD, were identified to be formed by surface-controlled reactions. The reactivity risks were significantly minimized, without compromising de-/re-hydrogenation cyclability, by compacting NaAlH4 powder into wafers to reduce the available surface area. These core findings are of significance to risk mitigation and H2 safety code and standard development for the safe use of NaAlH4 for on-board H2 storage in light-duty vehicles. 相似文献
608.
609.
Tan K Yang MX Radloff SE Hepburn HR Zhang ZY Luo LJ Li H 《Die Naturwissenschaften》2008,95(12):1165-1168
Although the structure of the dance language is very similar among species of honeybees, communication of the distance component
of the message varies both intraspecifically and interspecifically. However, it is not known whether different honeybee species
would attend interspecific waggle dances and, if so, whether they can decipher such dances. Using mixed-species colonies of
Apis cerana and Apis mellifera, we show that, despite internal differences in the structure of the waggle dances of foragers, both species attend, and act
on the information encoded in each other’s waggle dances but with limited accuracy. These observations indicate that direction
and distance communication pre-date speciation in honeybees. 相似文献
610.
Arsenic speciation for the phytoremediation by the Chinese brake fern, Pteris vittata 总被引:1,自引:0,他引:1
Arsenic (As) speciation for the phytoremediation by the Chinese brake fern was studied. In particular, the mechanism of how plants induce compounds containing thiol (SH) and proteins by As exposure in terms of the relationship between As and phosphate uptaken into plant cells was examined. Pteris vittata callus could efficiently reduce As(V) to As(III) by the rapid introduction of reductase and synthesize thiols leading to phytochelatins production. Furthermore, Pteris vittata could control phosphate concentration in the cells corresponding to the concentration of arsenite and arsenate. To our best knowledge, this is the first report to show the mechanisms of such high As tolerance of Pteris vittata using their callus in terms of in vitro approach for the analysis of As speciation and metabolism route. 相似文献