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971.
We report for the first time the use of beetroot fibers to eliminate heavy metals from polluted water. This biomass is used to remove lead, copper and zinc ions. The kinetics and beetroot fibers fixation capacities of lead, zinc and copper according to various physico‐chemical parameters such as pH, and the concentration of metal solutions were studied. The experiments were carried out in a laboratory column with fixed bed. For kinetic studies, samples of metal solutions were taken at regular intervals and measured by atomic absorption spectrometry. pH at 6.6 shows a maximum retention of the above cited metals by beetroot fibers (98%, 92%, 90% respectively). Quantity of cations retained by this biomass in simple and mixture solution is respectively estimated to be 23.6, 14.02 and 14.64 mg/g. Results indicate the usefulness of this biomass in the remediation of water contaminated by heavy metals by a rapid, practical and efficient method.  相似文献   
972.
Intake of many persistent organic pollutants (POPs) including dioxins, dibenzofurans and PCBs is almost exclusively from gastrointestinal ingestion of animal fats in the diet. With polybrominated diphenyl ether (PBDE) brominated flame retardants (BFRs), no consensus exists at present as to the extent of intake from food, from indoor dust or other routes of intake. Vegans, or pure vegetarians, were previously found to have low body burden of dioxins and dibenzofurans in blood. Data reported here for the first time show a trend towards lower PBDE levels with longer time periods without ingestion of food of animal origin in 8 adult residents of the United States. A stronger relationship between lower PBDE levels and time without meat, specifically, is consistent with substantial PBDE intake from meat relative to fish or dairy products in Americans. These vegans had somewhat lower PBDE levels with a range 12.4–127 and a median 23.9?ppb than published reports of US general population samples which had a range of 4–366 and median of 26?ppb. Our findings suggest that food of animal origin may be a major but not the sole contributor to human body burden of PBDEs.  相似文献   
973.
Fresh and healthy specimens of Oreochromis niloticus (mean weight 70.5± 1.23 g and mean length, 12.3± 1.5cm) and Clarias gariepinus (mean weight, 41.8±2.3 g and mean length 13.78 ± 1.2 cm) were exposed to heavy metal lead, ranging in concentration from 10 to 18 mg L‐1 for O. niloticus and 20 to 28 mg L‐1 for C. gariepinus respectively. The 96 h LC50 for both the species was computed as 12.45 mg L‐1 (O. niloticus) and 22.65 mg L‐1 (C. gariepinus). The cichlid fish was exposed to sublethal concentration of lead (2, 4 and 6 mgL‐1) and catfish (4, 8 and 12 mgL‐1). The erythrocytes count, haemoglobin concentration, haematocrit and the value of serum glucose increased significantly (P < 0.01), whereas leucocytes count, serum protein and serum triglyceride after intoxication declined in both the species with the same pattern but in different quantity. After 96 h of time a significant depletion of muscle and liver glycogen was noted, being greater in muscle (16.7% in O. niloticus) and in liver (15.9% in C. gariepinus). The response of fish to lead was dose dependent.  相似文献   
974.
The biodegradation of two popular nitramine energetics were investigated. The HMX (octa‐hydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine) was mineralized by anaerobic mixed denitrifiers in digested sewage sludge culture. An initial HMX concentration of 120 mg/L decreased to a non‐detectable level (> 99% removal efficiency) in 8 days of incubation under strict anaerobic conditions. It was, however, not effectively metabolized by single denitrifying species, P. aeruginosa, B. subtilis in a nitrogen limiting condition under their optimum growth conditions. The other nitramine energetic, ADN (ammonium dinitramide), was mineralized well in the anaerobic mixed culture. The initial ADN concentration of 250 mg/L was reduced to non‐detectable levels (> 99% removal efficiency) in 5 days of incubation under anaerobic conditions. These results show that the anaerobic mixed culture, compared to the pure monoculture, is superior in the degradation of nitramine energetics.  相似文献   
975.
The optimal parameters for the degradation of pure terephthalic acid (PTA) wastewater by the white rot fungus Phanerochaete chrysosporium were investigated. The relative mathematical model, objective function equation, constraint equations, constraint conditions and computer program were established in the optimal method. The results showed that the optimal value of the reactor volume needed was 9798 m3. It could save 83.82% of the reactor volume, which was needed for the native bacterium YZ1. This optimal method is simple, useful and economical for average treatment plants. Using the optimal parameters and P. chrysosporium to design and operate the treatment process of PTA wastewater would increase the treatment efficiency and decrease the cost.  相似文献   
976.

Using two analytical techniques (ICP‐AES and ASV) the heavy metal pollution of Arge? River was studied. These techniques are characterized by similar analytical performances.

The samples were collected from 13 sites starting from Capra Lake (altitude 2241 m) and finishing at Oltenita city (altitude 10 m).

Arge? River is the fifth longest river in Romania after Siret, Mure?, Olt and Some?, its length is 340 km and the river flows through four cities, Curtea de Arge?, Pite?ti, Gae?ti and Oltenita.

The results of the determinations of Cu, Cd, Zn and Pb, indicate that the Arge? River shows relatively low pollution.  相似文献   
977.
This is the first report showing reduction of particle matter and PAHs from incense burning by addition of oyster shell. Worshiping ancestors and gods by burning incense sticks and joss paper is a very important tradition in many Asian regions. More than 45 % of families in Taiwan burn incense twice a day. Unlike joss paper burning, most of the incense burning occurs indoors, thus creating a risk for human health. Previous reports have indeed evidenced toxicity of incense, notably due to particulate matter and polycyclic aromatic hydrocarbons (PAHs). However, there are few methods to reduce particle matter and PAHs from incense burning. We hypothesize that oyster shell may be used to reduce incense fumes toxicity. Indeed a large amount of unused oyster shell is discarded due to increasing seafood consumption. Here, two types of incense were made in the laboratory, and then 5–30 % of oyster shells were added to the incense to study the reduction of particle matter and PAHs. Results show that reduction of particle matter and PAH emission increased with oyster shell addition. The reduction of emission factors is ?35 % for mean particle matter, ?21 % for particle-phase PAHs, and ?37 % for benzo[a]pyrene equivalent concentration (BaPeq), using 30 % oyster shell additive. The addition of 10 % oyster shell reduces the burning time by 8.3 min, increases the burning rate by 3.4 mg/min, and reduces particle matter by 6.4 mg/g incense, particle-phase PAHs by 0.67 μg/g incense, and BaPeq by 0.23 μg/g incense. The reductions of particle matter, particle-phase PAHs, and BaPeq correspond to about 640 metric tons, 67, and 23 kg, respectively, per year. Our findings will help to produce safer and cleaner incense.  相似文献   
978.
本文以抚顺矸石山立地条件下树龄为10年的刺槐Robinia pseudoacacia L.、火炬Rhus typhina Nutt、白榆Ulmus pumila L.、沙棘Hippophae rhamnoides L.林以及植被自然恢复裸地(CK)5种植被恢复模式为研究对象,按土壤发生学层次进行采样,对土壤有机质、碱解氮、有效磷、速效钾、pH、过氧化氢酶、蔗糖酶和脲酶等指标进行研究,结果表明:与CK相比,4种造林模式显著提高了Ah层的土壤有机质和养分含量,其中,有机质、有效磷改良效果最好的是白榆模式,分别增加了194.8%、442.9%;速效钾改良效果最好的是刺槐模式,增加了262.0%;碱解氮则是火炬模式改良效果最好,增加了509.2%。不同造林模式与CK相比增加了各层次的过氧化氢酶、脲酶、蔗糖酶活性,其中,蔗糖酶和过氧化氢酶活性Ah层最大的是火炬模式,增加了134.5%和880.9%;脲酶酶活性最大的是白榆模式,增加了119.1%。从垂直角度看,有机质、碱解氮、过氧化氢酶、脲酶随土层加深含量降低,在C层达到最小值,而速效钾、有效磷、蔗糖酶的最小值则出现在AC层;不同模式对土壤pH影响不一,垂直规律不明显。  相似文献   
979.
Deliberation over and relative preference for general or specific (broad or narrow) constructs has long been an important issue in organizational behavior research. In this article, we provide a review of this general issue and some specific recommendations for researchers. We begin by discussing whether the general versus specific issue is an important debate and by discussing other underlying issues (the role of researcher preferences, distinction between reflective and formative indicators, and distinction between constructs and measures of constructs). Building on Chen's (this issue) analysis of core self‐evaluations, we first discuss how the general–specific debate has progressed in core self‐evaluations research. We then discuss three other important areas in which this debate has played out: intelligence, five‐factor model of personality, and job attitudes. Finally, we offer a framework to help guide decisions about whether to utilize general measures, specific measures, or both and conclude by providing recommendations for the use of general and specific measures in organizational behavior research. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
980.
In order to avoid existing shortcomings of chlorine leakage treatment, we developed a new chlorine scavenger. The main composition of the chlorine scavenger was calcium hydroxide. The chlorine scavenger was prepared by wet process with water as solvent through adding surface active agent and silicone oil, etc. The influence of surfactant on modified powder was investigated, which included the sodium dodecyl benzene sulfonate, the sodium stearate, the water-soluble silicone oil, the emulsifying silicon oil and the amino silicone oil, and the effect of modification of judgment were illustrated, which mainly involved the sifting rate, the bulk density, the contact angle, on this basis, also the author analyzed the powder of modification by using SEM analysis and size distribution, The modified powder had the following characteristics: high absorptivity, anti-caking, good air permeability and so on. The results showed that overall performance of modified powder was better than the performance of unmodified powder. The adding amount of sodium stearate was preferably 2% while the optimum amount of emulsifying silicon oil and amino silicone oil was 3%. The comprehensive performance of powder modified with compound modifiers was better than the performance of the powder modified with a single modifier. The property of powder modified with sodium stearate and amino silicone oil had a good performance analyzed from the uniformity of particle size distribution of the powder and anti-caking. The powder modified with sodium stearate and emulsifying silicon oil had a good absorption rate of chlorine.  相似文献   
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