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561.
乐安江沉积物对重金属的吸附模式研究──表面络合模式在天然沉积物研究中的应用 总被引:6,自引:0,他引:6
应用表面络合理论及其研究方法对乐安江沉积物的表面特征及对重金属的吸附特性进行了研究.进行了乐安江沉积物样品的表面电位滴定实验及样品对重金属Cu、Cd的吸附实验.应用图解法及FITEQL优化程序确定了表面络合模式中的相应参数,并对模式的预测能力进行了检验.研究了3种表面络合模式即恒定容量模式,扩散层模式和三层模式的拟合应用情况.结果表明,3种表面络合模式均能较好地描述天然沉积物的吸附过程,但哪种模式从化学原理上看更正确尚不能证明.从模式计算的难易程度分析,扩散层模式有一定优势.模式应用中应特别强调的是模式参数间的相关性和一致性. 相似文献
562.
Energy budgets are proposed for four teleost and two elasmobranch species as well as for the main icthyofauna groups for a surf-zone ecosystem. The ecology of surf-zone fishes of eastern Cape beaches, Algoa Bay South Africa, is reviewed. Using the equationC=F+U+R
d
+R
R
+B, the following general energy budgets were derived for fishes: teleosts – 100=10+4+21+23+42; elasmobranchs – 100=11+2+16+24+48; whereC: food consumption;F: faeces;U: nonfaecal excretion;R
d
: apparent specific dynamic action;R
R
: routine metabolism;B: growth. These show that most of the energy consumed is used in metabolism (R
d
+R
R
) and growth (B) whereas excretion (U) only accounts for a small portion. The energy budgets developed are within ranges recorded for other species. The main feeding groups of surf-zone icthyofauna are the southern mulletLiza richardsonii, the sandsharkRhinobatos annulatus, benthic feeders, zooplankton feeders, omnivorous and piscivorous fish with biomass values of 1000, 1000, 3000, 2400, 400 and 400 kJ m–1, respectively; and annual consumption budgets of 22107, 13725, 65710, 65476, 9758 and 8517 kJ m–1 yr–1, respectively.L. richardsonii feeds mainly on surf diatoms, consuming 0.5% of total diatom production. Zooplankton production supplies 91%, and macrobenthic production 9%, of the energy needs of other non-piscivorous carnivorous fishes. Piscivorous fishes consume 30% of the available fish production. Nonfaecal-energy production (8229 kJ m–1 yr–1) is utilised by surf diatoms, and faecal-energy production (30 341 kJ m–1 yr–1), is returned to the detritus pool to be utilised by the microbial loop in surf-waters. Our current knowledge of surf-zone energetics indicates that fishes are important predators. This study confirms the concept that the ecosystem generates adequate food for the fish assemblage. Fishes recycle energy, as excretory products, via the detritus pool and surf-diatoms, while fishes moving across the outer boundary of the surf-zone export energy from the system. Data presented, therefore, also support the general concept of a self-sustaining beach/surf-zone ecosystem.Please address all correspondence and requests for reprints to Dr Du Preez at his present address: Research Unit for Fish Biology, Rand Afrikaans University, P.O. Box 524, Johannesburg 2000, Republic of South Africa 相似文献
563.
564.
565.
Jinxin He Jianjun Hu Diraviyam Thirumalai Ruediger Schade Enqi Du 《Journal of environmental science and health. Part. B》2016,51(1):8-13
Gentamicin (Gent) is an aminoglycoside antibiotic being used in livestock sector. Gent residues could cause some genetic disorders by nonsense mutations. This study aimed to develop IgY-based ELISA for the detection of Gent in animal products. Gent was conjugated with Bovine serum albumin (BSA) by carbodiimide method for further immunization in the laying chickens. PEG-6000 extraction method was employed to extract IgY from the egg yolk. The titer of anti-Gent-IgY attained the peak of 1:256,000 after the 5th booster immunization. Checkerboard titration confirmed that, anti-Gent IgY in 1:2,000 dilution could give an Optical Density (OD) 1.0 at 2 µg mL?1 of Gent-OVA coating concentration. IgY-based indirect competitive ELISA (Ic-ELISA) showed that, the IC50 value of anti-Gent IgY was 2.69 ng mL?1 and regression curve equation was y = ?16.27x + 56.97 (R2 = 0.95, n = 3), confirming that, the detection limit (LOD, IC10 value) was 0.01 ng mL?1. Recoveries from fresh milk, pork and chicken samples were ranged from 69.82% to 94.32%, with relative standard deviation lower than 10.88%. Our results suggested that generated anti-Gent IgY antibodies can be used in routine screening analysis of Gent residues in food samples. 相似文献
566.
Magnesium (Mg) has a great potential to reduce vehicle weight, fuel consumption, and greenhouse gas emissions. The Chinese Mg industry has developed rapidly since the 1990s. The output of Mg reached 700,000 tons in 2006, accounting for more than 70% of global Mg production. Most of Mg is produced in China through the Pidgeon process that has an intensive energy usage and generates a large amount of greenhouse gas (GHG) emissions, which may offset the potential advantage of using Mg parts in automobiles. It is critical to quantify the energy usage and GHG emissions through entire life cycle when the Mg are applied to automobiles. It is also essential to evaluate cost implications of the Mg parts application in automobiles and ensure it to be cost competitive. The objectives of this study are (1) Build a life cycle inventory (LCI) of Mg produced by Pidgeon process; (2) Establish an LCA model that can evaluate GHG emissions and energy usage for the Mg automotive application; (3) Estimate the cost implications of the Mg parts application in automobiles.An Mg LCI was built based on interviews and surveys and the GREET model was adapt for this study. The results indicated that, for each kilogram of Mg produced by Pidgeon process, GHG emissions and energy usage would be 27 kg CO2eq and 280 MJ, which are five times higher than steel production. Replacing steel with 82 kg Mg on a base automobile would lower curb weight by 5.7%, but only reduce life cycle GHG emissions and energy usage by 0.8% and 1.3%. Scenario analyses indicated that potential reduction of life cycle GHG emissions and energy usage could reach to 15%, if secondary weight saving and a smaller engine were included. Cost analyses also show 18% reduction when the additional weight saving and a smaller displacement engine were included, under a 100,000 km driving distance and gasoline price at $1.0/l. 相似文献
567.
Yang Wang Wenjie Du Lianliang Chen Haoran Wang Ziyang Shan Zhengyang Zhou Wenwei Li 《环境科学学报(英文版)》2023,35(2):745-757
Air pollution is a major obstacle to future sustainability, and traffic pollution has become a large drag on the sustainable developments of future metropolises. Here, combined with the large volume of real-time monitoring data, we propose a deep learning model, iDeepAir, to predict surface-level PM2.5 concentration in Shanghai megacity and link with MEIC emission inventory creatively to decipher urban traffic impacts on air quality. Our model exhibits high-fidelity in reproducing pollutant concentrations and reduces the MAE from 25.355 µg/m3 to 12.283 µg/m3 compared with other models. And identifies the ranking of major factors, local meteorological conditions have become a nonnegligible factor. Layer-wise relevance propagation (LRP) is used here to enhance the interpretability of the model and we visualize and analyze the reasons for the different correlation between traffic density and PM2.5 concentration in various regions of Shanghai. Meanwhile, As the strict and effective industrial emission reduction measurements implementing in China, the contribution of urban traffic to PM2.5 formation calculated by combining MEIC emission inventory and LRP is gradually increasing from 18.03% in 2011 to 24.37% in 2017 in Shanghai, and the impact of traffic emissions would be ever-prominent in 2030 according to our prediction. We also infer that the promotion of vehicular electrification would achieve further alleviation of PM2.5 about 8.45% by 2030 gradually. These insights are of great significance to provide the decision-making basis for accurate and high-efficient traffic management and urban pollution control, and eventually benefit people's lives and high-quality sustainable developments of cities. 相似文献
568.
569.
The different toxicity characteristics of arsenic species result in discrepant ecological risk.The predicted no-effect concentrations(PNECs) 43.65, 250.18, and 2.00 × 103μg/L were calculated for As(III), As(V), and dimethylarsinic acid in aqueous phase, respectively. With these PNECs, the ecological risk from arsenic species in Pearl River Delta in China and Kwabrafo stream in Ghana was evaluated. It was found that the risk from As(III) and As(V)in the samples from Pearl River Delta was low, while much high in Kwabrafo stream. This study implies that ecological risk of arsenic should be evaluated basing on its species. 相似文献
570.
灾后承接非政府组织援助系统工程的综合集成模式——以汶川8.0级地震为例 总被引:2,自引:2,他引:0
分析了承接非政府组织(NGO)援助复杂巨系统的框架结构、时空结构、运行结构及整体特性;提出了地震灾后承接援助系统工程的综合集成模式;分别就承接援建集成工程的运作模式和具体实施框架进行了讨论;就援建系统工程、迎建系统工程、应急组织系统工程和保障系统工程等具体实施工程做了细致的阐述。 相似文献