全文获取类型
收费全文 | 430篇 |
免费 | 26篇 |
国内免费 | 84篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 8篇 |
环保管理 | 60篇 |
综合类 | 278篇 |
基础理论 | 51篇 |
污染及防治 | 94篇 |
评价与监测 | 35篇 |
社会与环境 | 6篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 21篇 |
2014年 | 17篇 |
2013年 | 45篇 |
2012年 | 22篇 |
2011年 | 36篇 |
2010年 | 15篇 |
2009年 | 27篇 |
2008年 | 33篇 |
2007年 | 31篇 |
2006年 | 20篇 |
2005年 | 13篇 |
2004年 | 15篇 |
2003年 | 21篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 19篇 |
1999年 | 6篇 |
1998年 | 18篇 |
1997年 | 17篇 |
1996年 | 16篇 |
1995年 | 8篇 |
1994年 | 11篇 |
1993年 | 11篇 |
1992年 | 18篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有540条查询结果,搜索用时 17 毫秒
71.
重金属污染下龟壳攀鲈组织中ACP和AKP的活力比较 总被引:1,自引:0,他引:1
龟壳攀鲈是一种在极端污染水域中具备生存优势的鱼类,收集重污染区和轻污染区的龟壳攀鲈,并通过比较其体内各组织中的酸性磷酸酶(ACP)及碱性磷酸酶(AKP)活性来揭示其耐污能力。贵屿作为重污染区有4个采样点:大陇村、市上村、联堤村和北林村;潮州作为轻污染区有2个采样点:卧石村和洗马桥。水质结果表明,贵屿采样地水中的Pb、Cd、Cr、As、Hg含量分别是潮州采样点的27.6倍、3.9倍、5.8倍、3.9倍和3.5倍,说明贵屿采样地的污染远高于潮州的。酶活结果表明,在龟壳攀鲈所有组织中,内脏组织(胃肠、性腺、肝脏、脾脏、肾脏)中的ACP和AKP活力均高于外周组织(肌肉、鳞片、鳃);重金属污染均能提高攀鲈体内所有组织的ACP和AKP活力;AKP活性更容易受到重金属的影响,各组织的AKP活力增幅普遍超过ACP活力增幅;其中,受重金属影响最大的组织是脾脏,ACP和AKP活力可增长到2.37倍和6.21倍。这些结果说明了龟壳攀鲈可以通过显著升高内脏组织(如肠胃、肝脏、肾脏等)中ACP和AKP活性,以便更好地应对高污染环境;其中AKP更容易受到重金属的影响,适合用于作为评估污染的指标。 相似文献
72.
Adsorptive removal of Acid Blue 127 and Acid Yellow 17 from their single and binary solutions has been studied using powdered activated carbon (PAC). The dyes used extensively for dying of nylon fiber in textile industry are known as Nylomine Blue P-B (NB) and Nylomine Yellow P-4G (NY), respectively. Time-dependent results obtained from single-component system have been better predicted by two resistance diffusion model rather than homogeneous surface diffusion. The magnitudes of film- and intraparticle diffusion coefficients calculated from McKay equation are ~10?9 and ~10?15 m2 s?1, whereas surface diffusion coefficients have been estimated as ~10?13 m2 s?1 using Vermeulen approximation. Experimental equilibrium isotherms have been evaluated by changing initial dye concentrations in the range of 0.02–1.00 of mmol L?1. Freundlich isotherm parameters for individual solutions of the dyes have been used to predict their equilibrium behaviors in binary solutions by applying extended Freundlich model. Langmuir isotherm model and its extended form have also been fitted to the data for single- and binary-dye solutions, respectively. Thermodynamic functions derived from the temperature dependence of adsorption equilibrium constants in 298–318 K range show that adsorption processes are endothermic but spontaneous. 相似文献
73.
In the period following liming and before the introduction of brown trout to Loch Fleet, there was a reduction in the numbers of invertebrates, including the Chironomidae, Oligochaeta and Hydracarina in the loch, but an overall increase in invertebrates in the inlet and outlet streams. This was followed in the loch by a recovery in the numbers of certain groups (particularly the Trichoptera and Ephemeroptera) to pre-liming levels in spite of the introduction of the trout. The diets of the trout comprised a wide variety of aquatic and terrestrial organisms ranging in size from Fprotozoans to newts and are dominated by chironomids. Opportunistic type of feeding as found in the present study appears to be typical of the brown trout and is reported for many water bodies by other workers. Significant differences (P < 0.05 and P < 0.001) were found in the numbers and weights of certain food organisms in the stomachs of brown trout caught by different fishing methods in the summers of 1992 and 1993. Fish caught by gill net contained fewer planktonic crustaceans and chironomids, but greater numbers of trichopterans and terrestrial organisms, than in those caught by fly and spinner. the differences are probably related to differences in the depth at which the fish, caught by the various methods, were feeding. 相似文献
74.
从云南滇池水样中分离出具有解磷能力的有机磷细菌P-2,并利用现代分子生物学技术进行了初步鉴定.用0.01、5mg·L-1微囊藻毒素(MC-RR)处理有机磷细菌P-2,研究了MC-RR对其生长、细胞内酸碱磷酸酶活性(ACP和AKP)以及培养液中可溶性磷酸盐含量的影响.结果表明,高浓度MC-RR能显著抑制有机磷细菌的生长,延缓其细胞增殖,抑制细胞内酸碱磷酸酶活性以及培养液中可溶性磷酸盐含量的升高,因而可能改变或减缓生态系统中磷循环的进程,这表明微囊藻毒素在一定程度上可能调节水体细菌功能群落. 相似文献
75.
采用具有不同阴极材料的三相三维电极反应器,对300 mg/L酸性橙7(AO7)模拟废水进行处理研究,重点考察阴极材料对脱色率和反应体系矿化能力的影响,同时利用HPLC、UV-Vis、GC-MS等分析方法对·OH、H2O2以及降解产物进行测定,探讨了3种电极对AO7的降解行为.结果表明,在电压20 V条件下电解60 min后,活性炭纤维(ACF)、石墨和不锈钢等3种阴极体系对于AO7的脱色率均高于96%,三者之间没有明显差别.但是ACF体系对TOC的去除率可达到57.4%,高于其它两者.3种阴极体系中均有高活性的·OH和H2O2生成,但是ACF阴极体系中产生的浓度较高,从而决定了其具有较高的矿化能力.几种不同电极体系电解AO7过程中都遵循了相同的产生酮类和萘酚类物质的过程. 相似文献
76.
77.
Phosphorus is a vital nutrient for algal growth, thus, a better understanding of phosphorus availability is essential to mitigate harmful algal blooms in lakes. Wind waves are a ubiquitous characteristic of lake ecosystems. However, its effects on the cycling of organic phosphorus and its usage by phytoplankton remain poorly elucidated in shallow eutrophic lakes. A mesocosm experiment was carried out to investigate the responses of alkaline phosphatase activity fractions to wind waves in large, shallow, eutrophic Lake Taihu. Results showed that wind-driven waves induced the release of alkaline phosphatase and phosphorus from the sediment, and dramatically enhanced phytoplanktonic alkaline phosphatase activity. However, compared to the calm conditions, bacterial and dissolved alkaline phosphatase activity decreased in wind-wave conditions. Consistently, the gene copies of Microcystis phoX increased but bacterial phoX decreased under wind-wave conditions. The ecological effects of these waves on phosphorus and phytoplankton likely accelerated the biogeochemical cycling of phosphorus and promoted phytoplankton production in Lake Taihu. This study provides an improved current understanding of phosphorus availability and the phosphorus strategies of plankton in shallow, eutrophic lakes. 相似文献
78.
79.
80.
不同环境条件下偶氮染料酸性大红GR的生物降解性能 总被引:1,自引:0,他引:1
为了考察不同环境条件下偶氮染料酸性大红GR生物降解性能,采用已驯化的混合菌群作为接种液进行偶氮染料酸性大红GR脱色试验。结果表明,微氧条件下(静置敞口培养),偶氮染料酸性大红GR脱色效果最佳,染料脱色主要发生在菌体的对数生长期。混合菌群对pH、温度适应范围较广,pH为3.32~9.18,温度在20℃~37℃范围内均可以获得较好脱色效果,脱色率均在80%以上。微氧条件下酸性大红GR降解历程表明,偶氮基整个共轭系统被破坏,生成了一种新的结构,使原有的某些精细结构在二阶导数光谱中得以表现,由此探讨其生物降解机理。 相似文献