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761.
762.
牡蛎壳粉末投加UASB反应器的运行特性 总被引:1,自引:0,他引:1
采用牡蛎壳粉末作为UASB反应器的辅助介质,探讨了牡蛎壳钙盐的溶出特性,系统考察了运行期中牡蛎壳粉末添加方式、进水有机负荷、水力停留时间等因素对反应器出水COD、碱度与pH的影响,分析了污泥比产甲烷活性变化。结果表明,当初始pH从5到9变化时,牡蛎壳粉末溶出Ca2+浓度为40~65 mg/L,平衡pH稳定在7.7~8.0;当进水COD负荷从3.4 kg/(m3·d)逐渐增至7.0 kg/(m3·d)、牡蛎壳粉末投加量从1.5 g/d逐渐增至3.2 g/d时,与未投加的反应器相比,投加牡蛎壳粉末反应器的启动周期缩短了10%左右,COD去除率与比产甲烷活性分别提高了13.3%和22%。投加牡蛎壳粉末可有效提供碱度,加快污泥的颗粒化进程。 相似文献
763.
764.
765.
Changes in plankton abundance, biomass, and chemical composition under the influence of the cooling system of the Beloyarsk Nuclear Power Plant 总被引:1,自引:0,他引:1
The abundance and biomass of phytoplankton and zooplankton proved to noticeably decrease after the water passed through the
cooling system of the Beloyarsk Nuclear Power Plant: the phytoplankton perished by 38% (65 metric tons per day), and the zooplankton,
by 55% (6 t/day). In the period between 1985 and 1991, the concentration of60Co in the plankton of water intake and discharge canals varied from 120 to 1400 Bq/kg dry weight, and that of137Cs, from 150 to 1040 Bq/kg dry weight, which is commensurable with the content of radionuclides in the plants and grounds
of the Beloyarsk reservoir. In 1985, it was noted that the plankton passing through the cooling system of the nuclear power
plant became enriched with Ca, Fe, Mg, Mn, Co, Cs, Cu, Mo, Ni, Pb, Si, Sn, Ti, V, and W. 相似文献
766.
A. V. Trapeznikov V. N. Pozolotina I. V. Molchanova P. I. Yushkov V. N. Trapeznikova E. N. Karavaeva M. Ya. Chebotina A. Aarkrog H. Dahlgaard S. P. Nielsen Q. Chen 《Russian Journal of Ecology》2000,31(4):224-232
Data on the current radioecological situation in the Techa-Iset' river system, which was contaminated by radioactive wastes
from the Mayak Production Association in the 1940s and 1950s, are discussed. Mathematical models are presented that describe
the decrease in the contamination of water, bottom sediments, hydrobionts, and floodplain soils with an increase in the distance
from the discharge site. The amounts of90Sr,99Tc,137Cs, and transuranium elements in the main components of the ecosystem are estimated. 相似文献
767.
移动床生物膜反应器在污水处理中的应用研究 总被引:24,自引:0,他引:24
应用好氧移动床生物膜反应器处理生活污水,厌氧复合生物反应器处理高浓度有机废水,厌氧-好氧移动床生物膜工艺处理食品废水的试验均取得良好的效果。试验结果表明,该工艺具有处理效率高,出水水质稳定,耐冲击负荷能力强,占地少,结构紧凑,维护管理简单的特点。 相似文献
768.
Huifeng Liu Guohua Liu Ya Li Xing Wu Dan Liu Xiaoqin Dai Ming Xu Fengting Yang 《Environmental science and pollution research international》2016,23(20):20269-20280
Land use conversion and fertilization have been widely reported to be important managements affecting the exchanges of greenhouse gases between soil and atmosphere. For comprehensive assessment of methane (CH4) and nitrous oxide (N2O) fluxes from hilly red soil induced by land use conversion and fertilization, a 14-month continuous field measurement was conducted on the newly converted citrus orchard plots with fertilization (OF) and without fertilization (ONF) and the conventional paddy plots with fertilization (PF) and without fertilization (PNF). Our results showed that land use conversion from paddy to orchard reduced the CH4 fluxes at the expense of increasing the N2O fluxes. Furthermore, fertilization significantly decreased the CH4 fluxes from paddy soils in the second stage after conversion, but it failed to affect the CH4 fluxes from orchard soils, whereas fertilizer applied to orchard and paddy increased soil N2O emissions by 68 and 113.9 %, respectively. Thus, cumulative CH4 emissions from the OF were 100 % lower, and N2O emissions were 421 % higher than those from the PF. Although cumulative N2O emissions were stimulated in the newly converted orchard, the strong reduction of CH4 led to lower global warming potentials (GWPs) as compared to the paddy. Besides, fertilization in orchard increased GWPs but decreased GWPs of paddy soils. In addition, measurement of soil moisture, temperature, dissolved carbon contents (DOCs), and ammonia (NH4 +-N) and nitrate (NO3 ?-N) contents indicated a significant variation in soil properties and contributed to variations in soil CH4 and N2O fluxes. Results of this study suggest that land use conversion from paddy to orchard would benefit for reconciling greenhouse gas mitigation and citrus orchard cultivation would be a better agricultural system in the hilly red soils in terms of greenhouse gas emission. Moreover, selected fertilizer rate applied to paddy would lead to lower GWPs of CH4 and N2O. Nevertheless, more field measurements from newly converted orchard are highly needed to gain an insight into national and global accounting of CH4 and N2O emissions. 相似文献
769.
770.
The role of bacteria in the heavy metals removal and growth of Sedum alfredii Hance in an aqueous medium 总被引:1,自引:0,他引:1
This study was the first attempt to examine the possible role of the naturally occurring rhizospheric bacteria in heavy metal removal by Sedum alfredii Hance, a terrestrial Zn/Cd hyperaccumuluator, from Zn, Cd, Cu and Pb contaminated water using antibiotic ampicillin. Moreover, the toxicity symptom in plants under heavy metal stress expressed as total chlorophyll, chlorophyll a and b content, growth inhibition, root length, and N, P contents were studied, and the possible relationship among them were also discussed. These results indicate that rhizospheric bacteria may play an important role in the uptake of N and P by S. alfredii, and consequently result in the increase of Chlorophyll content in the leaves and plant biomass due to improved photosynthesis. At the same time, root length significantly decreased under the treatment with ampicillin, which suggested that rhizospheric bacteria appeared to protect the roots against heavy metal toxicity. The Pb, Zn, Cu and Cd concentrations in the roots, stems and leaves of S. alfredii were much higher than those exposed to ampicillin. Accordingly, metal concentrations in the contaminated water without ampicillin treatment were lower than those treated with ampicillin. These results suggest that the rhizospheric bacteria may be useful in plant tolerance to heavy metal toxicity, and also accelerate the metal removal from contaminated water. 相似文献