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181.

Pakistan is an agricultural country and due to the shortage of clean water, most of the irrigated area (32,500 ha) of Pakistan was supplied with wastewater (0.876?×?109 m3/year). Concentrations of heavy metals in radish (Raphanus sativus) and turnip (Brassica rapa) taken from vegetable fields in Sargodha, Pakistan, were measured. Untreated wastewater was used persistently for a long time to irrigate these vegetable fields. A control site was selected that had a history of fresh groundwater irrigation. Mean metal concentrations were found for irrigation water, soil, and vegetables. In irrigation water, concentrations of Mo and Pb at three sites and Se at sites II and III were higher than the recommended limits. In vegetables, concentrations of Mo and Pb were above the maximum permissible limits. High bioconcentration factor was observed for Zn (12.61 in R. sativus and 11.72 in B. rapa) at site I and high pollution load index was found for Pb (3.89 in R. sativus and 3.87 in B. rapa) at site II. The differences in metal concentrations found in samples depended upon different soil nature and assimilation capacities of vegetables at different sites which in turn depended upon different environmental cues. The entrance of metal and metalloids to human body may happen through different pathways; however, the food chain is the chief route through which metals are transferred from vegetables to individuals. Health risk index observed for metals, (Mo, As, Ni, Cu, and Pb) higher than 1 indicated high risk through consumption of these vegetables at three sites.

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182.
The present research focuses on estimating forest area change with respect to the ongoing forest land conversion. The study tests the hypothesis that forest land is being converted to the selected land use categories with high growth tendency and controlling deforestation rate to its half of the present level would significantly improve the land cover under forest. The rate of forest land conversion to other land use categories is analyzed and then compared with the total area expanded under three land use classes. We used Systems dynamic modeling approach to estimate forest area by simulating forest land conversion in Pakistan, projecting to 2030. The results show that rangeland, built-up area and cultivated land have increased over time; growth rate of built-up area (9%) is highest followed by rangeland area (1.7%) and cultivated area (0.3%), respectively; rangeland is the dominant category in terms of area expanded (0.74 m. ha). Sensitivity analysis showed that reducing deforestation rate to half of the past level of 1% could not significantly improve forest area; therefore, it is suggested that controlling deforestation alone is not an effective strategy unless drastic measures, e.g., demarcation of forest boundaries, land use control policy and afforestation campaign would be started in the country.  相似文献   
183.
The aim of the present study was to appraise the levels of heavy metal contamination (Zn and Pb) in sediment of the Langat River (Selangor, Malaysia). Samples were collected randomly from 15 sampling stations located along the Langat River. The parameters measured were pH, redox potential, salinity, electrical conductivity, loss of ignition, cation exchanges capacity (Na, Mg, Ca, K), and metal ions (Zn and Pb). The geo-accumulation index (I geo) and contamination factor (C f) were applied to determine and classify the magnitude of heavy metal pollution in this urban river sediment. Results revealed that the I geo of Pb indicated unpolluted to moderately polluted sediment at most of the sampling stations, whereas Zn was considered to be within background concentration. The I geo results were refined by the C f values, which showed Pb with very high C f at 12 stations. Zinc, on the other hand, had low to moderate C f values. These findings indicated that the sediment of the Langat River is severely polluted with Pb. The Zn concentration at most sampling points was well below most sediment quality guidelines. However, 40% of the sampling points were found to have a Pb concentration higher than the consensus-based probable effect concentration of 128 mg/kg (concentrations above this value are likely to cause harmful effects). This result not only highlights the severity of Pb pollution in the sediment of the Langat River, but also the potential risk it poses to the environment.  相似文献   
184.
Rare earths (RE), chemically uniform group of elements due to similar physicochemical behavior, are termed as lanthanides. Natural occurrence depends on the geological circumstances and has been of long interest for geologist as tools for further scientific research into the region of ores, rocks, and oceanic water. The review paper mainly focuses to provide scientific literature about rare earth elements (REEs) with potential environmental and health effects in understanding the research. This is the initial review of RE speciation and bioavailability with current initiative toward development needs and research perceptive. In this paper, we have also discussed mineralogy, extraction, geochemistry, analytical methods of rare earth elements. In this study, REEs with their transformation and vertical distribution in different environments such as fresh and seawater, sediments, soil, weathering, transport, and solubility have been reported with most recent literature along key methods of findings. Speciation and bioavailability have been discussed in detail with special emphasis on soil, plant, and aquatic ecosystems and their impacts on the environment. This review shows that REE gained more importance in last few years due to their detrimental effects on living organisms, so their speciation, bioavailability, and composition are much more important to evaluate their health risks and are discussed thoroughly as well.  相似文献   
185.

Information on the detection of pesticides in fresh water Lakes of Kashmir (Dal and Mansbal) through GC–MS technique is scarce, and also the recovery in biochemical parameters (AST, ALT and ALP) of fish after transferring them to clean media has not been reported yet. The water samples were collected from three sites and analyzed for their pesticide profile by dispersive liquid–liquid micro extraction (DLLME) followed by GC–MS. Influence of pesticides on liver marker enzymes of Cyprinus carpio and Carassius carassius was also investigated. The results obtained showed the presence of three main pesticides viz. chlorpyrifros, dimethoate and dichlorvos in waters of Dal Lake whereas no pesticide was detected in waters of Mansbal. The higher values for AST, ALT and ALP activities and decrease in protein content were obtained in the samples from the Dal Lake compared with those from Mansbal Lake (p < 0.05). These data when compared with the values found in C. carpio and C. carassius from both the Dal Lake and Mansbal Lake kept under laboratory conditions after 15, 30, 45 and 60 days of maintenance in clean media found that during depuration, all the enzyme activities came down significantly (p < 0.05) indicating the compensatory response by the fish against the pesticide stress. Therefore, these parameters could be used as indicators of pesticide pollution in aquatic organisms and were recommended for environmental monitoring for investigating the mechanism involved in the recovery pattern.

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186.
In the present work covalently crosslinked smart polymeric system of hydrogel based on poly vinyl alcohol (PVA) and methacrylic acid (MA) was designed by free radical polymerization with different compositions using glyoxal (40 % water solution) as crosslinker. It was observed that swelling of hydrogel had a pronounced enhancing effect on increasing the concentration of MA due to availability of more ionized carboxylic groups of MA but produced an opposite effect on increasing the concentration of glyoxal owing to less porous structure. As far as PVA is concerned, swelling did not show significant effect on increasing the concentration of PVA. Hydrophilic polymer PVA rich in hydroxyl group pertained to be highly interactive with water. It was examined that the release of metoprolol tartrate decreased with increased concentration of glyoxal, but increased with increase in concentration of MA. PVA/MA hydrogel was characterized by Fourier transform infrared spectroscopy and X-ray diffraction to study the structure and crystallinity of hydrogel respectively. Morphology was studied through scanning electron microscopy. Furthermore differential scanning calorimetry and thermogravimetric analysis were also performed to characterize thermal stability. It may be concluded that the mechanism of drug release was mainly non-Fickian diffusion.  相似文献   
187.
Environment, Development and Sustainability - The study utilized the tree covers per cent, agroforestry suitability, present and future (2050) climate, agriculture vulnerability (2050), percentage...  相似文献   
188.
Although investigation of microplastics (MPs) present in air environment has been intensively carried out, quantification, characteristics, and distribution of MPs released from the waste burning furnace (WBF) has been missing in literature. The aim of this study was to characterize the presence of MPs released from WBFs and analyze their associated health impacts. The examined locations were at two WBFs (nominated as TPS1 and TPS2) in Sidoarjo, Indonesia. MPs were collected using a 9 cm diameter glass beaker for a period of 8 h at two different sampling points, which are 3 and 15 m from each WBF. Several characteristics of MPs in terms of the number of particles, size, shape, color, and polymer type were comprehensively characterized. This study found that the obtained MPs were of fiber type and in the range of 46–77 and 41–59 particles at TPS1 and TPS2, respectively. In general, the polymer types of MPs were, respectively, cellophane and polytetrafluoroethylene at TPS1 and TPS2. Moreover, it was estimated that about 1.9–2.3 MPs can enter the human body via inhalation. This study offers a pilot examination of MPs released from WBF and findings from this study are crucial to provide new knowledge as a basis to carefully regulate the use of WBF particularly that are located closely to local community.  相似文献   
189.
The City of Amman, Jordan, has been subjected to persistent increase in road traffic due to overall increase in prosperity, fast development and expansion of economy, travel and tourism. This study investigates traffic noise pollution in Amman. Road traffic noise index L 10(1 h) was measured at 28 locations that cover most of the City of Amman. Noise measurements were carried out at these 28 locations two times a day for a period of one hour during the early morning and early evening rush hours, in the presence and absence of a barrier. The Calculation of Road Traffic Noise (CRTN) prediction model was employed to predict noise levels at the locations chosen for the study. Data required for the model include traffic volume, speed, percentage of heavy vehicles, road surface, gradient, obstructions, distance, noise path, intervening ground, effect of shielding, and angle of view. The results of the investigation showed that the minimum and the maximum noise levels are 46 dB(A) and 81 dB(A) during day-time and 58 dB(A) and 71 dB(A) during night-time. The measured noise level exceeded the 62 dB(A) acceptable limit at most of the locations. The CTRN prediction model was successful in predicting noise levels at most of the locations chosen for this investigation, with more accurate predictions for night-time measurements.  相似文献   
190.
Indoor air quality has become one of the most seriousenvironmental concerns as an average person spends about 22 hrindoors on a daily basis. The study reported in this article, wasconducted to determine the effectiveness of three commercialHVAC (Heating Ventilation Air Conditioning) duct cleaning processes in reducing the level of airborne particulate matterand viable bioaerosols. The three HVAC sanitation processeswere: (1) Contact method (use of conventional vacuum cleaning ofinterior duct surfaces); (2) Air sweep method (use of compressedair to dislodging dirt and debris); (3) Rotary brush method(insertion of a rotary brush into the ductwork to agitate anddislodge the debris). Effectiveness of these sanitationprocesses was evaluated in terms of airborne particulate andviable bioaerosol concentrations in residential homes. Eightidentical homes were selected in the same neighborhood. Twohomes were cleaned using each procedure and two were used ascontrols. It was found that both particle count readings andbioaerosol concentrations were higher when cleaning was beingperformed than before or after cleaning, which suggests thatdirt, debris and other pollutants may become airborne as aresult of disturbances caused by the cleaning processes.Particle count readings at 0.3 micron size were found to haveincreased due to cigarette smoking. Particle counts at 1.0micron size were reduced due to HVAC duct cleaning. Post-levelbioaerosol concentrations, taken two days after cleaning, werefound to be lower than the pre-level concentrations suggestingthat the cleaning procedures were effective to some extent.Homes cleaned with the Air Sweep procedure showed the highestdegree of reduction in bioaerosol concentration among the threeprocedures investigated.  相似文献   
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