全文获取类型
收费全文 | 243篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 5篇 |
废物处理 | 16篇 |
环保管理 | 20篇 |
综合类 | 25篇 |
基础理论 | 48篇 |
污染及防治 | 58篇 |
评价与监测 | 60篇 |
社会与环境 | 10篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 10篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 5篇 |
2014年 | 13篇 |
2013年 | 21篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 14篇 |
2009年 | 16篇 |
2008年 | 17篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 15篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1970年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1959年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有247条查询结果,搜索用时 234 毫秒
161.
In this study, a comparative thermodynamic performance analysis of cascade system (CCS) for cooling and heating applications is presented and compared for different refrigerant couples. The CCS consists of the low-temperature cycle (LTC) and high-temperature cycle (HTC). The CO2 was used as working fluid in LTC, whereas the HFE 7000, R134a, R152a, R32, R1234yf, and R365mfc refrigerants were used in HTC. The heating and cooling coefficients of performance (COPht, COPcl) and exergy efficiency of CCS are investigated parametrically according to various factors such as the evaporator, condenser, and reference temperatures. After thermodynamic analyses are completed, the COPcl of CCS is obtained as 1.802, 1.806, 1.826, 1.769, 1.777, and 1.835 for CO2-HFE7000, CO2-R134a, CO2-R152a, CO2-R32, CO2-R1234yf, and CO2-365mfc refrigerant couples, respectively. Furthermore, the heat exchanger has the highest exergy destruction rate, whereas the expansion valves have the lowest of exergy destruction rate. 相似文献
162.
梅树经氟化氢熏气后,离区纤维素酶活力升高,这可能是某些植物受大气氟污染后产生非正常落叶的原因。熏气前喷洒生长调节物质,可以相对降低纤维素酶活力,有效地抑制大气氟污染产生的落叶效应。 相似文献
163.
Ayşe N. Kiraççakali 《Chemistry and Ecology》2020,36(7):651-662
ABSTRACT Deltamethrin is a widely used pyrethroits worldwide. Although the chemical is used to combat insects, it has effects on other non-target organisms. Deltamethrin is extensively used in agriculture, animal husbandry, and domestic areas in the Lake Van basin. The aim of this study was to determine the cytotoxic, genotoxic, and oxidative damage from deltamethrin on the primary hepatocyte culture of Lake Van fish (Alburnus tarichi). In this study, the toxic effects of different concentrations (0.01, 0.1, 1, and 10?µM) of deltamethrin in the primary hepatocyte culture of Lake Van fish were investigated via liver enzymes aspartase aminotransferase (AST) and alanine aminotransferase (ALT), and the total antioxidant status (TAS), total oxidant status (TOS), lipid peroxidation (MDA), and DNA damage (8-OHdG). Deltamethrin caused an increase in the AST and ALT levels dependent on the dosage and time. The TAS and TOS levels increased at the end of 24?h and there was no difference at the end of 48?h. Deltamethrin did not affect the MDA level, but increased the 8-OHdG (P?<?0.05). In conclusion, it can be said that high doses of deltamethrin (1 and 10?µM) have a toxic effect on the primary hepatocyte culture of Lake Van fish. 相似文献
164.
Investigation of organic nitrogen and carbon removal in the aerobic digestion of various sludges 总被引:2,自引:0,他引:2
Nitrification and carbon removal are investigated in aerobicbatch digestion of various sludges. The experiments arecarried out with activated sludge (Test 1) and with amixture of activated and primary settling sludge (Test2). The nitrification rate was monitored, measuring theNO2
- concentration. At the 3rd day of thedigestion 40.7 mgNO2-N/l and 3.89 mgNO2-N/l werefound in Tests 1 and 2 respectively. In a digestion process,the degradation of biomass indicates the beginning of theendogenous phase. Our measure for biomass content of thesludge was protein analysis. In Test 1, the first day valuesof 50.93 mgTOC/ gdry matter/day and 138.53mgprotein-C/gdry matter/day for specific TOC andprotein-C removal rates showed, that the digestion processbegan in the endogenous phase. For Test 2, since theendogenous phase began after removal of raw organic matter inprimary settling sludge, specific TOC and protein-C removalrates were observed to be 60.12 mgTOC/gdry matter/dayand 26.72 mgprotein-C/gdry matter/day,respectively. 相似文献
165.
In a recent study of aqueous phase methyl tertiary butyl ether (MTBE) adsorption onto hydrophobic molecular sieves, the solid phase micro-extraction gas chromatography analytical technique was used to measure MTBE concentrations in water. The method was especially beneficial in measuring MTBE concentrations in the microg/l range, but anomalies were observed that investigators should be aware of before employing this technique. Specifically, it was observed that the calibration of the extraction fiber with known MTBE concentrations was non-linear over all concentration ranges. The technique was not suited to higher concentrations, and dilutions were necessary to increase the working range of the technique. Lastly, the fiber was observed to extract increasingly less MTBE from known standard solutions over time, requiring repeated calibrations to obtain reliable concentrations of unknown samples. 相似文献
166.
167.
168.
Permethrin, a synthetic pyrethroid pesticide and potential toxic pollutant contaminating aquatic ecosystems, was investigated in the present study for acute toxicity. Guppy fish (Poecilia reticulata) were selected for the bioassay experiments. The experiments were repeated 3 times and the 48-h LC(50) was determined for the guppies. The static test method of acute toxicity test was used. Water temperature was regulated at 20+/-1 degrees C. In addition, behavioral changes at each permethrin concentration were observed for the individual fish. Data obtained from the permethrin acute toxicity tests were evaluated using the probit analysis statistical method. The 48-h LC(50) value for guppy was estimated as 245.7 microg/l. Values in the range of 0.05-97.0 microg/l have been reported for various other fish species. 相似文献
169.
Dr. S. Artan N. Başaran H. Hassa S. Özalp T. Şener B. S. Şayli C. Cengiz M. Özdemi̊ T. Durak I. Dölen T. Özgünen M. Tuna 《黑龙江环境通报》1995,15(12):1135-1142
In order to determine the incidence of confined placental mosaicism (CPM) in term placentae and to show the presence of specific sites and the effect on fetal development, 125 placentae from uneventful pregnancies were analysed by cytogenetic methods. The incidence was at least 4.8 per cent and there were no specific sites on the placenta. Although the number of cases is still too small, we found CPM to be associated with intrauterine growth retardation in six cases. 相似文献
170.
Snejana Moncheva Jacek Namiesnik Resat Apak Patricia Arancibia-Avila Fernando Toledo Seong-Gook Kang 《Chemistry and Ecology》2013,29(1):31-41
The aim of this investigation was to examine biochemical differences in the gastropod Rapana venosa (R. venosa) from polluted (RvP) and nonpolluted (RvN) sites of the Black Sea's Bulgarian coast that may serve as bioindicators of environmental quality. Mussels Mytilus galloprovincialis (MMg) were collected from polluted (MMgP) and nonpolluted (MMgN) sites at the same time for comparison. Bioactive compounds and the antioxidant activity of dry matter (DM) methanol extracts from RvP and RvN were determined. Three-dimensional fluorometry (3D-FL) and Fourier transform infrared (FTIR) analyses were used to evaluate polyphenols and proteins. DM methanol extracts from RvP, and to lesser extent RvN, showed high amounts of total phenolics (23.22±2.9 and 15.60±1.8 mg GAE · g?1 DW) and exhibited high levels of antioxidant activity in some radical scavenging assays (μ MTE · g?1 DW): 56.38±5.2 and 33.79±3.3 by 2,2azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) diamonium salt (ABTS·+); 54.79±5.6 and 33.7±2.6 by cupric reducing antioxidant capacity (CUPRAC); 62.34±6.8 and 30.31±3.9 by the 1diphenyl-2-picrylhydrazyl method (DPPH). A correlation in the above indices was found between R. venosa and M. galloprovincialis, but all results were relatively higher for M. galloprovincialis than for R. venosa. The obtained indices of R. venosa may serve as a bioindicator of environmental ecological quality. 相似文献