全文获取类型
收费全文 | 44109篇 |
免费 | 460篇 |
国内免费 | 409篇 |
专业分类
安全科学 | 1403篇 |
废物处理 | 2116篇 |
环保管理 | 5760篇 |
综合类 | 6408篇 |
基础理论 | 11542篇 |
环境理论 | 12篇 |
污染及防治 | 11283篇 |
评价与监测 | 3254篇 |
社会与环境 | 2919篇 |
灾害及防治 | 281篇 |
出版年
2023年 | 210篇 |
2022年 | 411篇 |
2021年 | 461篇 |
2020年 | 287篇 |
2019年 | 370篇 |
2018年 | 663篇 |
2017年 | 687篇 |
2016年 | 1094篇 |
2015年 | 779篇 |
2014年 | 1202篇 |
2013年 | 3691篇 |
2012年 | 1477篇 |
2011年 | 1941篇 |
2010年 | 1639篇 |
2009年 | 1686篇 |
2008年 | 1993篇 |
2007年 | 2026篇 |
2006年 | 1796篇 |
2005年 | 1574篇 |
2004年 | 1538篇 |
2003年 | 1478篇 |
2002年 | 1385篇 |
2001年 | 1730篇 |
2000年 | 1213篇 |
1999年 | 779篇 |
1998年 | 569篇 |
1997年 | 567篇 |
1996年 | 621篇 |
1995年 | 653篇 |
1994年 | 574篇 |
1993年 | 516篇 |
1992年 | 536篇 |
1991年 | 501篇 |
1990年 | 475篇 |
1989年 | 487篇 |
1988年 | 445篇 |
1987年 | 360篇 |
1986年 | 331篇 |
1985年 | 342篇 |
1984年 | 390篇 |
1983年 | 372篇 |
1982年 | 415篇 |
1981年 | 331篇 |
1980年 | 259篇 |
1979年 | 298篇 |
1978年 | 257篇 |
1977年 | 213篇 |
1976年 | 200篇 |
1975年 | 203篇 |
1973年 | 233篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
681.
The ability of bentonite to remove malachite green from aqueous solutions has been studied for different adsorbate concentrations by varying the amount of adsorbent, temperature, pH and shaking time. Maximum adsorption of the dye, i.e. >90% has been achieved in aqueous solutions using 0.05 g of bentonite at a pH of 9. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° were calculated from the slope and intercept of the linear plots of ln KD against 1/T. Analysis of adsorption results obtained at 298, 308, 318 and 328 K showed that the adsorption pattern on bentonite seems to follow the Langmuir, Freundlih and D–R isotherms. The temperature increase reduces adsorption capacity by bentonite, due to the enhancement of the desorption step in the mechanism. The numerical values of sorption free energy (Ea) of 1.00–1.12 kJ mol−1 indicated physical adsorption. The kinetic data indicated an intraparticle diffusion process with sorption being first order. The rate constant k was 0.526 min−1. The concentration of malachite green oxalate was measured before and after adsorption by using UV–Vis spectrophotometer. 相似文献
682.
Study of metabolites from the degradation of polycyclic aromatic hydrocarbons (PAHs) by bacterial consortium enriched from mangrove sediments 总被引:3,自引:0,他引:3
The PAH metabolites produced during degradation of fluorene, phenanthrene and pyrene by a bacterial consortium enriched from mangrove sediments were analyzed using the on-fiber silylation solid-phase microextraction (SPME) combining with gas chromatography–mass spectrometry (GC–MS) method. Seventeen metabolites at trace levels were identified in different PAH degradation cultures based on the full scan mass spectra. In fluorene degradation cultures, 1-, 2-, 3- and 9-hydroxyfluorene, fluorenone, and phthalic acid were detected. In phenanthrene and pyrene degradation cultures, various common metabolites such as phenanthrene and pyrene dihydrodiols, mono-hydroxy phenanthrene, dihydroxy pyrene, lactone and 4-hydroxyphenanthrene, methyl ester, and phthalic acid were found. The detection of various common and novel metabolites demonstrates that SPME combining with GC–MS is a quick and convenient method for identification as well as monitoring the real time changes of metabolite concentrations throughout the degradation processes. The knowledge of PAH metabolic pathways and kinetics within indigenous bacterial consortium enriched from mangrove sediments contributes to enhance the bioremediation efficiency of PAH in real environment. 相似文献
683.
The recognition of pharmaceuticals as significant environmental contaminants has only been a recent phenomenon. Therefore there is a paucity of data relating to the fate and effects of pharmaceuticals once they enter an aquatic receiving system. The amount of work that needs to be done in terms of risk assessment for pharmaceuticals required by regulatory agencies is substantial. This paper has determined the environmental partitioning coefficient (Kd) of 13 diverse human pharmaceuticals in three model systems of differing combinations of solid phases and solutions. The Kd values were then compared with distribution values of the pharmaceuticals in the human body determined from pharmacological studies. This was done to assess the functional relationship between Kd and distribution values in the human body (VD). Kd values ranged from 3 to 2450 L kg−1. Regression coefficients ranged from r2 = 0.62–0.72, indicating that VD values are a useful indicator for the Kd values of the tested pharmaceuticals within the batch sorption systems. The relationship between Kd and VD should therefore be further explored to determine whether this relationship can be applied to a broader range of pharmaceuticals in more diverse environmental systems. Exploiting available human pharmacological data in such a way would be of great benefit in prioritising human pharmaceuticals as environmental contaminants in the risk assessment process. 相似文献
684.
Broad range analysis of endocrine disruptors and pharmaceuticals using gas chromatography and liquid chromatography tandem mass spectrometry 总被引:3,自引:0,他引:3
Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) have been globally detected in impacted natural waters. The detection of trace quantities of EDCs and PPCPs in the environment is of great concern since some of these compounds have known physiological responses at low concentrations. EDCs can have a wide range of polarities, acidic and basic moieties, and exist in trace quantities, which often requires numerous complex extractions, large sample collection volumes, and multiple instrumental analyses. A comprehensive method has been developed allowing for the analysis of 58 potential EDCs in various water matrices using a single solid-phase extraction (SPE) of a 1 L sample with subsequent analyses using both gas chromatography and liquid chromatography, each coupled with tandem mass spectrometry (GC–MS/MS and LC–MS/MS). Instrument detection limits ranged between 0.12–7.5 pg with corresponding method reporting limits of 1–10 ng l−1 in water. Recoveries for most compounds were between 50% and 112% with good reproducibility (RSD 6–22%). 相似文献
685.
Cripe GM McKenney CL Hoglund MD Harris PS 《Environmental pollution (Barking, Essex : 1987)》2003,125(2):295-299
Pest control agents, such as juvenile hormone analogues (JHA), have been developed to limit effects on non-target organisms that co-inhabit insect pest habitats. Rhithropanopeus harrisii, an estuarine xanthid crab, was used to observe the impacts of the JHA, fenoxycarb, on the pattern of complete larval development as well as survival of larvae and successful metamorphosis to first crab stage. Significant mortality occurred in the first of four zoeal stages (after 2-3 days of exposure) at the highest treatment of 240 microg fenoxycarb/l and in megalopae exposed to 48 microg fenoxycarb/l. The time required to metamorphose to the first crab stage was significantly increased for megalopae in all treatments 48 microg/l. This delay in development was sufficient to significantly prolong the entire developmental period from zoea to crabs. Unexposed larvae developed to crabs in an average of 16 days; larvae exposed to >/=48 microg/l required 19-20 days. Reduced survival and extended duration of developing larval stages in the life history of a benthic invertebrate may alter the population dynamics of these organisms in the estuary. 相似文献
686.
Lilian D. Steckert William E. Furtado Gabriela T. Jerônimo Scheila A. Pereira Gabriel F. A. Jesus José Luiz P. Mouriño 《Journal of environmental science and health. Part. B》2019,54(4):237-246
Fish may bioaccumulate contaminants from the aquatic environment and extend them to the food chain provoking risks to human health. This study evaluated the microbiological parameters of the pond´s water and trace elements concentrations in samples of water, sediment, feed and muscle of farmed Nile tilapia used for human consumption in southern Brazil. A total of 240 fish were collected from 12 tilapia farms. Sediment, tank water and dry ration used in the animals' diet were collected for analysis. Analysis were performed by Energy Dispersion X-ray Fluorescence (EDXRF), Inductively Coupled Plasma Mass Spectrometer (ICP-MS), Induced Coupled Plasma Optical Emission Spectrometer (ICP-OES), and Atomic Absorption Spectrometer (AAS-VGA). In addition, the microbiological analysis of the water was carried out. The concentrations of Se, I, Fe, Cu and Zn in fish muscle were higher than the recommended by the Brazilian legislation, considering the advised daily intake for adults. The arsenic element had concentrations above the limit stipulated by the present Brazilian legislation, observed in all samples of muscle, sediment and tank water highlighting a possible environmental and fish contamination by the toxic element. Moreover, the arsenic concentration in the water presented a positive correlation (ρ?=?0.33) with arsenic in the muscle, suggesting that tilapia is a good environmental bioindicator, once they properly reflect the levels of arsenic in the water. It is suggested to perform an arsenic speciation for quantification of the inorganic form and accurate assessment of the degree of toxicity in the muscle samples and risks it can bring to human health. Regarding the other potentially toxic elements (Hg, Pb and Cd), and microbiological analysis of water it was verified that the consumption of the fish in question does not raise risks, since the values are within a quality benchmark established by law. The concentration of total and fecal coliforms in pond´s water in the facilities was in agreement with the microbiological indexes required by the legislation of CONAMA class II. Western region presented the lowest concentrations of fecal coliforms when compared to the other regions. There was no significant difference in the microbiological counts of total heterotrophic bacteria, Vibrio spp. and Pseudomonas spp. among the regions. 相似文献
687.
Srichandan Suchismita Baliarsingh Sanjiba Kumar Prakash Satya Lotliker Aneesh A. Parida Chandanlal Sahu Kali Charan 《Environmental science and pollution research international》2019,26(12):12025-12041
Environmental Science and Pollution Research - Seasonal distribution of phytoplankton community and size structure was assessed in three different tropical ecosystems of the western Bay of Bengal... 相似文献
688.
El-Din Eman Ahmed Alaa Mostafa Heba El-Sayed Samak Mai A. Mohamed Eman M. El-Shafei Dalia Abdallah 《Environmental science and pollution research international》2019,26(21):21556-21564
Environmental Science and Pollution Research - The evaluation of the toxicological effects of titanium dioxide nanoparticles (TiO2NPs) is increasingly important due to their growing occupational... 相似文献
689.
Macchi Marianela Festa Sabrina Vega-Vela Nelson E. Morelli Irma S. Coppotelli Bibiana M. 《Environmental science and pollution research international》2019,26(25):25932-25944
Environmental Science and Pollution Research - A natural phenanthrene-degrading consortium CON was inoculated with an exogenous strain Sphingobium sp. (ex Sp. paucimobilis) 20006FA yielding the... 相似文献
690.
The effect of bromide on the mutagenicity of artificially recharged groundwater and purified artificially recharged groundwater after chlorine, ozone, hydrogen peroxide, permanganate, and UV treatments alone and in various combinations was studied. The highest mutagenicity was observed after chlorination, while hydrogen peroxide-ozone-chlorine treatment produced the lowest value for both waters. Chlorinated waters, which were spiked with bromide, had up to 3.7 times more mutagenic activity than waters without bromide after every preoxidation method. 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) was found to correspond as much as 76% of the overall mutagenicity in the waters not spiked with bromide. MX formation was found to be lower when the treated water contained bromide, implicating the formation of brominated MX analogues. Trihalomethane formation increased when the treated water contained bromide. 相似文献