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181.
Mohan Feroz Khan Samuel Godwin Wesley 《Environmental monitoring and assessment》2011,175(1-4):623-632
Activities of 210Po and 210Pb in various tissues of four species of decapod crabs and two species of cephalopod mollusks (cuttlefishes) of Kudankulam coast were studied. A non-uniform distribution of these radionuclides was observed between the organs. Of all the tissues, 210Po and 210Pb were found accumulated more in the hepatopancreas and intestine of crabs and in the digestive gland, shell gland, and intestine of cephalopods. Among crabs, Charybdis lucifera registered a little higher 210Po and 210Pb activities. The cephalopod species Loligo duvauceli displayed higher 210Po and 210Pb in some organs when compared to Sepia pharaonis. The muscle of all the species registered lower activity. In cephalopods, the activity ratio of 210Po/210Pb fell within the range of 1?C2 for most of the organs, and in crab tissues, it varied from 1.7 to 31.4. The biological concentration factor for organs of cephalopods ranged from 1.2 ×103 to 4.3 ×105 for 210Po and 4.8 ×102 to 8.4 ×104 for 210Pb and for organs of crabs it varied between 2.0 ×104 and 1.9 ×106 for 210Po and 9.2 ×102 and 2.4 ×104 for 210Pb. The study revealed that the organs associated with digestion and metabolism displayed a higher activity concentration than the other tissues. A significant variation in the accumulation of 210Po and 210Pb was noted between species (P?<?0.05). The activity levels recorded are in agreement with values recorded in related organisms in other parts of the world. The data generated will act as a reference database for these organisms of this coast in which a nuclear power station is under construction. 相似文献
182.
Alam JB Hossain A Khan SK Banik BK Islam MR Muyen Z Rahman MH 《Environmental monitoring and assessment》2007,134(1-3):233-242
Surma River is polluted day by day by human activities, poor structured sewerage and drainage system, discharging industrial
and household wastes. The charas (natural channels) are responsible for surface runoff conveyance from its urban catchments
to the receiving Surma River. Water samples have been collected from a part of Surma River along different points and analyzed
for various water quality parameters during dry and monsoon periods. Effects of industrial wastes, municipal sewage, and agricultural
runoff on river water quality have been investigated. The study was conducted within the Chattak to Sunamganj portion of Surma
River, which is significant due to the presence of two major industries – a paper mill and a cement factory. The other significant
feature is the conveyors that travel from India to Chattak. The river was found to be highly turbid in the monsoon season.
But BOD and fecal coliform concentration was found higher in the dry season. The water was found slightly acidic. The mean
values of parameters were Conductivity 84–805 μs; DO: dry-5.52 mg/l, monsoon-5.72 mg/l; BOD: dry-1mg/l, monsoon-0.878 mg/l;
Total Solid: dry-149.4 mg/l, monsoon-145.7 mg/l. In this study, an effort has been taken to investigate the status of concentration
of phosphate (PO−4) and ammonia–nitrogen (NH4–N) at four entrance points of Malnichara to the city, Guali chara, Gaviar khal and Bolramer khal. Data has been collected
from March–April and September–October of 2004. Concentrations have been measured using UV Spectrophotometer. Although the
phosphate concentration has been found within the limit set by DOE for fishing, irrigation and recreational purposes, however
ammonia–nitrogen has been found to exceed the limit. 相似文献
183.
Farhat Nabeela Azizullah Azizullah Roqaia Bibi Syeda Uzma Waheed Murad Shakirullah Khan Shakir Waheed Ullah Muhammad Qasim Donat-Peter Häder 《Environmental science and pollution research international》2014,21(24):13929-13942
Water pollution with pathogenic microorganisms is one of the serious threats to human health, particularly in developing countries. The main objective of this article is to highlight microbial contamination of drinking water, the major factors responsible for microbial contamination, and the resulting health problems in Pakistan. Furthermore, this study will be helpful for researchers and administrative agencies to initiate relevant studies and develop new policies to protect further deterioration of water supply with pathogenic microbes and ensure clean and safe drinking water to the public in Pakistan. In Pakistan, water at the source, in the distribution network, and at the consumer tap is heavily polluted with coliforms and fecal coliforms all over the country. An overview of more than 7,000 water samples reviewed here reveals that an average of over 71 and 58 % samples in the country was contaminated with total coliforms and fecal coliforms, respectively. Drinking water contamination accounts for 20 to 40 % of all diseases in the country, which causes national income losses of Rs 25–58 billion annually (US$0.25–0.58 billion, approximately 0.6–1.44 % of the country’s GDP). Improper disposal of industrial and municipal wastes is the most important factor responsible for water pollution in the country followed by cross-contamination due to old and leaking pipes and lack of water filtration and disinfection facilities. There is an urgent need for emergency steps to stop further deterioration of water quality and improve the existing water quality so as to protect the public from widespread waterborne diseases. 相似文献
184.
Ravi K. Srivastava Robert E. Hall Sikander Khan Kevin Culligan Bruce W. Lani 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1367-1388
Abstract Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done to use them more effectively. Furthermore, the paper discusses recent developments in NOx controls. The popular primary control technologies in use in the United States are low-NOx burners and overfire air. Data reflect that average NOx reductions for specific primary controls have ranged from 35% to 63% from 1995 emissions levels. The secondary NOx control technologies applied on U.S. coal-fired utility boilers include reburning, selective noncatalytic reduction (SNCR), and selective catalytic reduction (SCR). Thirty-six U.S. coal-fired utility boilers have installed SNCR, and reported NOx reductions achieved at these applications ranged from 15% to 66%. Recently, SCR has been installed at >150 U.S. coal-fired utility boilers. Data on the performance of 20 SCR systems operating in the United States with low-NOx emissions reflect that in 2003, these units achieved NOx emission rates between 0.04 and 0.07 lb/106 Btu. 相似文献
185.
Driving Forces for the Marsh Wetland Degradation in the Honghe National Nature Reserve in Sanjiang Plain, Northeast China 总被引:7,自引:0,他引:7
Demin Zhou Huili Gong Yiyong Wang Shahbaz Khan Kuiyi Zhao 《Environmental Modeling and Assessment》2009,14(1):101-111
In the study, we analyze and assess quantitatively the spatial pattern of vegetation and its ecological degradation information
in the Honghe National Nature Reserve (HNNR), a Ramsar-designated site in Northeast China. Statistics from historical survey
data are used to measure the degradation of marshes over time and changes in the hydrological regime. Long-term statistical
data are also employed to analyze both natural and human impacts on these changes. Both the wetland degradation model and
its mechanisms are discussed in this paper. The research finds that the loss of water and other types of degradation in the
vegetation habitat caused by the rapid deterioration of the hydrological regime has threatened the status of HNNR as a “storage
area of natural genes.” Scientifically constructed strategies are urgently required to ensure sustainable economic benefits
that do not adversely affect this nature reserve. 相似文献
186.
Biju A. George Hector M. Malano Ahmad Raza Khan Anju Gaur Brian Davidson 《Environmental Modeling and Assessment》2009,14(6):691-704
To keep pace with population and economic growth, the city of Hyderabad, India, will need to identify and develop new supply
sources almost continually. Increasing population growth rate, declining surface water resources, overexploitation of groundwater,
deterioration of ground water quality and poor sewage treatment are the major water-related issues in Hyderabad. This paper
reviews the current situation facing policy makers who need to come to terms with the problem of restricted water supply and
increasing demand in an urban centre such as Hyderabad, India. The City Water Balance model developed in this study can be
used to analyse different scenarios that include water conservation, urban wastewater reuse and improvement of distribution
and conveyance efficiency. Water conservation programs, which include a 5% conveyance efficiency improvement, reusing 90 million
cubic metres (MCM) of urban runoff and adoption of water harvesting by 0.5 million households together with recycling 120
MCM of wastewater recycling wastewater would be sufficient to meet the water demand by 2031, if the population grows at a
rate of 2.5%. 相似文献
187.
To reduce SO2 emissions, ammonia gas was injected into a coal-fired fluidized-bed combustor under staged commbustion condition. The combustor was 2 m high with a 30 cm static bed height and a freeboard height of 170 cm. The ammonia gas was injected at 52 cm and 65 cm above the distributor, which had a temperature of ca. 700 °C, by an uncooled stainless-steel tube injector. The experiments investigated the effects of ammonia gas injection on sulphur dioxide emissions at staged conditions, varying the: (i) excess air level, (ii) secondary air ratio, (iii) fluidizing velocity, (iv) ammonia injection position, and (v) the ammonia : sulphur dioxide molar ratio.A maximum reduction of 66% in SO2 emissions was found at 40% excess air, 65 : 35 staging, 1.5 m/s fluidizing velocity, 65 cm injection height, and an NH3 : SO2 molar ratio of 1.2. The onset of SO2 reduction occurred at an NH3 : SO2 ratio of 0.5. The fluidizing velocity, excess air, level of staging, and ammonia injection height all have a significant influence on SO2 reduction.It is difficult to determine how the SO2 reduction varies with the operating conditions when ammonia is injected in the high temperature zone of the combustor. As sulphur oxides-ammonia reactions are low temperature reactions, the findings confirm the occurrence of reactions above the freeboard or near the exit to the cyclone. 相似文献
188.
Ghulam Akhmat Khalid Zaman Tan Shukui Danish Irfan Muhammad Mushtaq Khan 《Environmental science and pollution research international》2014,21(9):5940-5951
The objective of the study is to examine the causal relationship between energy consumption and environmental pollutants in selected South Asian Association for Regional Cooperation (SAARC) countries, namely, Bangladesh, India, Nepal, Pakistan, and Srilanka, over the period of 1975–2011. The results indicate that energy consumption acts as an important driver to increase environmental pollutants in SAARC countries. Granger causality runs from energy consumption to environmental pollutants, but not vice versa, except carbon dioxide (CO2) emissions in Nepal where there exists a bidirectional causality between CO2 and energy consumption. Methane emissions in Bangladesh, Pakistan, and Srilanka and extreme temperature in India and Srilanka do not Granger cause energy consumption via both routes, which holds neutrality hypothesis. Variance decomposition analysis shows that among all the environmental indicators, CO2 in Bangladesh and Nepal exerts the largest contribution to changes in electric power consumption. Average precipitation in India, methane emissions in Pakistan, and extreme temperature in Srilanka exert the largest contribution. 相似文献
189.
Sireesh Babu Maddinedi Badal Kumar Mandal Nawaz Khan Fazlur-Rahman 《Environmental Chemistry Letters》2017,15(3):467-474
There is a demand for the development of environmental friendly methods for the synthesis of graphene composites. Reduced graphene oxide/silver (RGO/Ag) nanocomposites are very good catalysts. Here, we propose a simple, green method for the synthesis of RGO/Ag nanocomposite using the amino acid tyrosine as bioreductant and stabilizing agent. RGO/Ag nanocomposite was characterized by using various analytical techniques and studied for its catalytic degradation of 4-nitrophenol. Results of attenuated total reflectance Fourier transform infrared spectroscopy and Zeta potential at ?55 mV reveal the surface capping of tyrosine onto the reduced graphene oxide nanosheets. RGO/Ag nanocomposites show excellent catalytic reduction of 4-nitrophenol with NaBH4, when compared to actual individual silver nanoparticles. 相似文献
190.
Sardar Khan Abd El-Latif Hesham Min Qiao Shafiqur Rehman Ji-Zheng He 《Environmental science and pollution research international》2010,17(2):288-296