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951.
M. M. Ballesteros Martín B. Esteban García E. Ortega-Gómez J. A. Sánchez Pérez 《Environmental science and pollution research international》2014,21(16):9522-9528
A new bioassay proposed in the patent P201300029 was applied to a pre-treated wastewater containing a mixture of commercial pesticides to simulate a recalcitrant industrial wastewater in order to determine its biodegradability. The test uses a mixture of standardized inoculum of the lyophilized bacteria Pseudomonas putida with the proper proportion of salts and minerals. The results highlight that biodegradation efficiency can be calculated using a gross parameter (chemical oxygen demand (COD)) which facilitates the biodegradability determination for routine water biodegradability analysis. The same trend was observed throughout the assay with the dehydrated and fresh inoculums, and only a difference of 5 % in biodegradation efficiency (E f) was observed. The obtained results showed that the P. putida biodegradability assay can be used as a commercial test with a lyophilized inoculum in order to monitor the ready biodegradability of an organic pollutant or a WWTP influent. Moreover, a combination of the BOD5/COD ratio and the P. putida biodegradability test is an attractive alternative in order to evaluate the biodegradability enhancement in water pre-treated with advanced oxidation processes (AOPs). 相似文献
952.
F. Sarasini D. Puglia E. Fortunati J. M. Kenny C. Santulli 《Journal of Polymers and the Environment》2013,21(3):881-891
In the present study, Phormium Tenax fiber reinforced PLA composites were processed by injection molding and twin screw compounding with a fiber content ranging from 10 to 30 wt%. Three surface treatment methods have been used to improve the Phormium Tenax fiber-matrix interfacial bonding that are as follows: (1) aqueous alkaline solution, (2) silane coupling agent, and (3) a combination of alkaline and silane treatment. The mechanical, thermal and morphological properties of the resulting composites were investigated. The results have shown that the moduli of surface treated fiber reinforced composites are lower than the ones obtained for untreated composites (as a consequence of the decrease in fiber modulus caused by the chemical treatments) and no significant increase in strength was observed for any of the composites compared to neat PLA. SEM micrographs of composite fractured surfaces confirmed an improvement in the interfacial strength, which was insufficient nonetheless to significantly enhance the mechanical behavior of the resulting composites. Results from thermogravimetric analysis and differential scanning calorimetry suggest that surface treatment of Phormium affects the ability of PLA to cold crystallize, and the thermal stability of the composites at the different fiber contents was reduced with introduction of alkali and silane treated Phormium fibers. 相似文献
953.
James Burdon Michael H.B. Hayes Malcolm E. Pick 《Journal of environmental science and health. Part. B》2013,48(1):37-51
Abstract Charge distributions in 1, 1'‐ethylene‐2, 2'‐bipyridylium (diquat), 1,1'‐dimethyl‐4,4'‐bipyridylium (paraquat) and 1‐methylpyridinium organocations were calculated by a Complete Neglect of Differential Overlap semi‐empirical quantum mechanical procedure. The data show that the positive charges in the organocations are distributed around the molecules and are greatest in the positions ortho and para to the heterocyclic nitrogen atoms. Earlier interpretations of the mechanisms of adsorption of paraquat and diquat by soils and clays assumed that the charges were located in the heterocyclic nitrogen atoms. Here some consideration is given to the influence of the charge delocalizations on the processes of adsorption by montmorillonite and vermiculite clay preparations. 相似文献
954.
Heather J. Shipley Karen E. Engates Valerie A. Grover 《Environmental science and pollution research international》2013,20(3):1727-1736
Nanoparticles offer the potential to improve environmental treatment technologies due to their unique properties. Adsorption of metal ions (Pb(II), Cd(II), Cu(II), Zn(II)) to nanohematite was examined as a function of sorbent concentration, pH, temperature, and exhaustion. Adsorption experiments were conducted with 0.05, 0.1, and 0.5 g/L nanoparticles in a pH 8 solution and in spiked San Antonio tap water. The adsorption data showed the ability of nanohematite to remove Pb, Cd, Cu, and Zn species from solution with adsorption increasing as the nanoparticle concentration increased. At 0.5 g/L nanohematite, 100 % Pb species adsorbed, 94 % Cd species adsorbed, 89 % Cu species adsorbed and 100 % Zn species adsorbed. Adsorption kinetics for all metals tested was described by a pseudo second-order rate equation with lead having the fastest rate of adsorption. The effect of temperature on adsorption showed that Pb(II), Cu(II), and Cd(II) underwent an endothermic reaction, while Zn(II) underwent an exothermic reaction. The nanoparticles were able to simultaneously remove multiple metals species (Zn, Cd, Pb, and Cu) from both a pH 8 solution and spiked San Antonio tap water. Exhaustion experiments showed that at pH 8, exhaustion did not occur for the nanoparticles but adsorption does decrease for Cd, Cu, and Zn species but not Pb species. The strong adsorption coupled with the ability to simultaneously remove multiple metal ions offers a potential remediation method for the removal of metals from water. 相似文献
955.
H. Barndõk M. Peláez C. Han W. E. Platten III P. Campo D. Hermosilla A. Blanco D. D. Dionysiou 《Environmental science and pollution research international》2013,20(6):3582-3591
This study reports the synthesis and characterization of composite nitrogen and fluorine co-doped titanium dioxide (NF-TiO2) for the removal of contaminants of concern in wastewater under visible and solar light. Monodisperse anatase TiO2 nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-TiO2 by direct incorporation into the sol–gel or by the layer-by-layer technique. The composite films were characterized with X-ray diffraction, high-resolution transmission electron microscopy, environmental scanning electron microscopy, and porosimetry analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was evaluated in a synthetic water solution and in an effluent from a hybrid biological concentrator reactor (BCR). Minor aggregation and improved distribution of monodisperse titania particles was obtained with NF-TiO2-monodisperse (10 and 50 nm) from the layer-by-layer technique than with NF-TiO2?+?monodisperse TiO2 (300 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-layer method achieved significantly higher degradation rates in contrast with NF-TiO2-monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO2-P25. Using NF-TiO2 layer-by-layer with monodisperse TiO2 (50 nm) under solar light irradiation, the respective degradation rates in synthetic water and BCR effluent were 14.6 and 9.5?×?10?3?min?1 for caffeine, 12.5 and 9.0?×?10?3?min?1 for carbamazepine, and 10.9 and 5.8?×?10?3?min?1 for atrazine. These results suggest that the layer-by-layer technique is a promising method for the synthesis of composite TiO2-based films compared to the direct addition of nanoparticles into the sol. 相似文献
956.
Edge TA El-Shaarawi A Gannon V Jokinen C Kent R Khan IU Koning W Lapen D Miller J Neumann N Phillips R Robertson W Schreier H Scott A Shtepani I Topp E Wilkes G van Bochove E 《Journal of environmental quality》2012,41(1):21-30
Canada's National Agri-Environmental Standards Initiative sought to develop an environmental benchmark for low-level waterborne pathogen occurrence in agricultural watersheds. A field study collected 902 water samples from 27 sites in four intensive agricultural watersheds across Canada from 2005 to 2007. Four of the sites were selected as reference sites away from livestock and human fecal pollution sources in each watershed. Water samples were analyzed for Campylobacter spp., Salmonella spp., Escherichia coli O157:H7, Cryptosporidium spp., Giardia spp., and the water quality indicator E. coli. The annual mean number of pathogen species was higher at agricultural sites (1.54 ± 0.07 species per water sample) than at reference sites (0.75 ± 0.14 species per water sample). The annual mean concentration of E. coli was also higher at agricultural sites (491 ± 96 colony-forming units [cfu] 100 mL(-1)) than at reference sites (53 ± 18 cfu 100 mL(-1)). The feasibility of adopting existing E. coli water quality guideline values as an environmental benchmark was assessed, but waterborne pathogens were detected at agricultural sites in 80% of water samples with low E. coli concentrations (<100 cfu 100 mL(-1)). Instead, an approach was developed based on using the natural background occurrence of pathogens at reference sites in agricultural watersheds to derive provisional environmental benchmarks for pathogens at agricultural sites. The environmental benchmarks that were derived were found to represent E. coli values lower than geometric mean values typically found in recreational water quality guidelines. Additional research is needed to investigate environmental benchmarks for waterborne pathogens within the context of the "One World, One Health" perspective for protecting human, domestic animal, and wildlife health. 相似文献
957.
Community-based collaborative groups involved in public natural resource management are assuming greater roles in planning,
project implementation, and monitoring. This entails the capacity of collaborative groups to develop and sustain new organizational
structures, processes, and strategies, yet there is a lack of understanding what constitutes collaborative capacity. In this
paper, we present a framework for assessing collaborative capacities associated with community-based public forest management
in the US. The framework is inductively derived from case study research and observations of 30 federal forest-related collaborative
efforts. Categories were cross-referenced with literature on collaboration across a variety of contexts. The framework focuses
on six arenas of collaborative action: (1) organizing, (2) learning, (3) deciding, (4) acting, (5) evaluating, and (6) legitimizing.
Within each arena are capacities expressed through three levels of social agency: individuals, the collaborative group itself,
and participating or external organizations. The framework provides a language and set of organizing principles for understanding
and assessing collaborative capacity in the context of community-based public forest management. The framework allows groups
to assess what capacities they already have and what more is needed. It also provides a way for organizations supporting collaboratives
to target investments in building and sustaining their collaborative capacities. The framework can be used by researchers
as a set of independent variables against which to measure collaborative outcomes across a large population of collaborative
efforts. 相似文献
958.
Secondary pest outbreak is a counterintuitive ecological backlash of pesticide use in agriculture that takes place with the increase in abundance of a non-targeted pest species after pesticide application against a targeted pest species. Although the phenomenon was well recognized, its alternative causes are seldom considered. Outbreaks of the southern red mite Oligonychus ilicis are frequently reported in Brazilian coffee farms after the application of pyrethroid insecticides against the coffee leaf miner Leucoptera coffeella. Selectivity favoring the red mite against its main predatory mites is generally assumed as the outbreak cause, but this theory has never been tested. Here, we assessed the toxicity (and thus the selectivity) of deltamethrin against both mite species: the southern red mite and its phytoseid predator Amblyseius herbicolus. Additionally, behavioral avoidance and deltamethrin-induced hormesis were also tested as potential causes of red mite outbreak using free-choice behavioral walking bioassays with the predatory mite and life-table experiments with both mite species, respectively. Lethal toxicity bioassays indicated that the predatory mite was slightly more susceptible than its prey (1.5×), but in more robust demographic bioassays, the predator was three times more tolerant to deltamethrin than its prey, indicating that predator susceptibility to deltamethrin is not a cause of the reported outbreaks. The predator did not exhibit behavioral avoidance to deltamethrin; however insecticide-induced hormesis in the red mite led to its high population increase under low doses, which was not observed for the predatory mite. Therefore, deltamethrin-induced hormesis is a likely cause of the reported red mite outbreaks. 相似文献
959.
Susan Taylor David B. Ringelberg Katerina Dontsova Charles P. Daghlian Marianne E. Walsh Michael R. Walsh 《Chemosphere》2013
Two compounds, 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO) are the main ingredients in a suite of explosive formulations that are being, or soon will be, fielded at military training ranges. We aim to understand the dissolution characteristics of DNAN and NTO and three insensitive muntions (IM) formulations that contain them. This information is needed to accurately predict the environmental fate of IM constituents, some of which may be toxic to people and the environment. We used Raman spectroscopy to identify the different constituents in the IM formulations and micro computed tomography to image their three-dimensional structure. These are the first three-dimensional images of detonated explosive particles. 相似文献
960.
Borage, white mustard and phacelia, green manure plants currently used in agriculture to improve soil properties were cultivated for 10 wk on various polluted soils with metal(loid) concentrations representative of urban brownfields or polluted kitchen gardens. Metal(loid) bioavailability and ecotoxicity were measured in relation to soil characteristics before and after treatment. All the plants efficiently grow on the various polluted soils. But borage and mustard only are able to modify the soil characteristics and metal(loid) impact: soil respiration increased while ecotoxicity, bioaccessible lead and total metal(loid) quantities in soils can be decreased respectively by phytostabilization and phytoextraction mechanisms. These two plants could therefore be used for urban polluted soil refunctionalization. However, plant efficiency to improve soil quality strongly depends on soil characteristics. 相似文献