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151.
152.
Flatfish species, such as the turbot (Scophthalmus maximus), are common targets for toxic effects, since they are exposed through the food chain (ingestion of contaminated preys) and are in direct contact with the waterborne contaminant and sediments. Furthermore, these fish species live in close proximity to interstitial water that frequently dissolves high amounts of contaminants, including metals. Despite this significant set of characteristics, the present knowledge concerning flatfish contamination and toxicity by metals is still scarce. To attain the objective of assessing the effects of metals on a flatfish species, S. maximus specimens were chronically exposed to lead, copper and zinc, at ecologically relevant concentrations, and biochemical (oxidative stress: catalase and glutathione S-transferases activities, and lipid peroxidation; neurotoxicity: cholinesterase activity) parameters were assessed on selected tissues (gills and liver). Copper had no significant effects on all tested parameters; lead was causative of significant increases in liver GSTs activities and also in lipoperoxidation of gill tissue; exposure to zinc caused a significant increase in catalase activity of gill tissue. None of the tested metals elicited noteworthy effects in terms of neurotoxicity. The obtained results showed that only the metal lead is of some environmental importance, since it was able to cause deleterious modifications of oxidative nature at relevant concentrations.  相似文献   
153.
During 2008 and 2009, an epidemic affected sponges of the genus Ircinia in the Western Mediterranean. Investigations at a site on the European coast (6o43′08.80′′N; 3o43′52.20′′W) and another on the African coast (35o10′51.00′′N; 2o25′33.00′′W) revealed healthier African populations. The disease started with small pustules on the sponge surface, which subsequently coalesced forming larger, extensive lesions. An ultrastructural study suggested that a twisted rod is the etiological agent. It infected the sponges from the outside, initially killing the cells below the ectosome and then penetrating deeper into the body. The sponges responded to the bacterial progression by secreting concentric barriers of collagen and concentrating phagocytic cells at the diseased zones. This primitive immune system successfully resisted the disease in many instances, although mortality reached 27% in the studied populations. Epidemic outbreaks recur each year in September through November, arguably favored by abnormally high seawater temperatures in August.  相似文献   
154.
Fecal contamination of water bodies causes a public health problem and economic loss. To control such contamination management actions need to be guided by sound science. From 2007–2009 a study was undertaken to determine the sources of fecal bacteria contamination to the marine waters adjoining the Town of Wrightsville Beach, North Carolina, USA. The research effort included sampling for fecal coliform and Enterococcus bacteria, sampling for optical brighteners, dye studies, and use of molecular bacterial source tracking techniques including polymerase chain reaction (PCR) and terminal restriction fragment polymorphism (T-RFLP) fingerprinting of the Bacteroides–Prevotella group. Of the 96 samples collected from nine locations during the study, the water contact standard for Enterococcus was exceeded on 13 occasions. The T-RFLP fingerprint analyses demonstrated that the most widespread source of fecal contamination was human, occurring in 38% of the samples, with secondary ruminant and avian sources also detected. Optical brightener concentrations were low, reflecting a lack of sewage line leakage or spills. A lack of sewer leaks and lack of septic systems in the town pointed toward discharge from boat heads into the marine waters as the major cause of fecal contamination; this was supported by dye studies. Based on these data, the Town initiated action to have the U.S. Environmental Protection Agency declare the coastal waters (out to 3 nautical miles), the nearby Atlantic Intracoastal Waterway and its tributaries a no-discharge zone (NDZ) to alleviate the human fecal pollution. The Town garnered supporting resolutions from other local communities who jointly petitioned the North Carolina Department of Environmental and Natural Resources. This State regulatory agency supported the local government resolutions and sent an application for an NDZ to the EPA in April 2009. The EPA concurred, and in February 2010 the coastal waters of New Hanover County, NC, became the first marine area on the U.S. eastern seaboard between Delaware and the Florida Keys to be declared a no-discharge zone.  相似文献   
155.
Increasing levels of Heracleum persicum (golpar) in drinking water were studied in broilers. Two hundred and forty-one-day-old male chickens were allocated to one of six treatments: control, without added phytogenics nor probiotics in drinking water, and probiotics at recommended manufacturer’s level (P) or 1.0, 1.5, 2.0, and 2.5 ml/l of golpar extract solution (G1, G1.5, G2, and G2.5 treatments, respectively) in drinking water. As a result of this study, no linear or quadratic trends in the feed intake (FI) and feed conversion rate (FCR) due to golpar supplementation were found. Body weight gain, final body weight, and relative carcass weight showed a positive linear response with increasing levels of golpar supplementation. Neither golpar nor probiotics had effects on the percentages of edible parts of the carcass. Golpar supplementation levels caused a linear negative response of the albumin content in blood plasma, whereas both abdominal fat as percentage of carcass weight and uric acid levels in blood plasma linearly increased. The effects on Ig responses were only observed at 42 days of age and were similar in probiotics and the highest level of golpar supplementation. Based on our results, both probiotics and golpar supplementation could improve broiler performance and immune function.  相似文献   
156.
Abstract

Pesticides containing copper are used on wide range in vegetable production, especially in the open field. Copper has an excellent fungicidal effect against diseases of tomato, pepper, onion and in practical use it is essential as bactericide in the above mentioned crops.

The fungicides containing copper are freely available on the market, they are not expensive and widely used without any special knowledge. They are popular in simple home gardens as well as in hi‐tech vegetable production and are used even in all forms of “bio”; culture.

From the other side, copper can be toxic. The allowable level is 10 mg Cu/kg product. This concentration may be found after the first treatment and it increases after every further application.

In our experiments the copper absorbancy and accumulation has been investigated at different pesticide doses and under different experimental conditions.

The analytical measurements, the sample preparation, the instrument calibration have been made by the Inductively Coupled Plasma Spectrometer at the Department of Chemistry of the University of Horticulture and Food Industry.  相似文献   
157.
Territorial user rights for fisheries have been advocated as a way to achieve sustainable resource management. However, few researchers have empirically assessed their potential as ancillary marine conservation instruments by comparing them to no‐take marine protected areas. In kelp (Lessonia trabeculata) forests of central Chile, we compared species richness, density, and biomass of macroinvertebrates and reef fishes among territorial‐user‐right areas with low‐level and high‐level enforcement, no‐take marine protected areas, and open‐access areas in 42 100‐m subtidal transects. We also assessed structural complexity of the kelp forest and substratum composition. Multivariate randomized permutation tests indicated macroinvertebrate and reef fish communities associated with the different access regimes differed significantly. Substratum composition and structural complexity of kelp forest did not differ among access regimes. Univariate analyses showed species richness, biomass, and density of macroinvertebrates and reef fishes were greater in highly enforced territorial‐user‐right areas and no‐take marine protected areas than in open‐access areas. Densities of macroinvertebrates and reef fishes of economic importance were not significantly different between highly enforced territorial‐user‐right and no‐take marine protected areas. Densities of economically important macroinvertebrates in areas with low‐level enforcement were significantly lower than those in areas with high‐level enforcement and no‐take marine protected areas but were significantly higher than in areas with open access. Territorial‐user‐right areas could be important ancillary conservation instruments if they are well enforced. Derechos de Usuario Territoriales para Pesquerías como Instrumentos Accesorios para la Conservación Marina Costera en Chile  相似文献   
158.
159.
Gray, Stephen T., Jeffrey J. Lukas, and Connie A. Woodhouse, 2011. Millennial‐Length Records of Streamflow From Three Major Upper Colorado River Tributaries. Journal of the American Water Resources Association (JAWRA) 47(4):702‐712. DOI: 10.1111/j.1752‐1688.2011.00535.x Abstract: Drought, climate change, and shifting consumptive use are prompting a widespread reassessment of water availability in the Upper Colorado River basin. Here, we present millennial‐length records of water year (October‐September) streamflow for key Upper Colorado tributaries: the White, Yampa, and Little Snake Rivers. Based on tree rings, these records represent the first paleohydrological reconstructions from these subbasins to overlap with a series of Medieval droughts (∼ad 800 to 1300). The reconstructions show marked interannual variability imbedded in nonstationary behavior over decadal to multidecadal time scales. These reconstructions suggest that, even in a millennial context, gaged flows from a handful of years (e.g., 1977 and 2002) were extremely dry. However, droughts of much greater duration and magnitude than any in the instrumental record were regular features prior to 1900. Likewise these reconstructions point to the unusual wetness of the gage period, and the potential for recent observations to paint an overly optimistic picture of regional water supplies. The future of the Upper Colorado River will be determined by a combination of inherent hydroclimatic variability and a broad range of human‐induced changes. It is then essential that regional water managers, water users, and policy makers alike consider a broader range of hydroclimatic scenarios than is offered by the gage record alone.  相似文献   
160.
The environmental problem posed by construction and demolition waste (C&D waste) is derived not only from the high volume produced, but also from its treatment and disposal. Treatment plants receive C&D waste which is then transformed into a recycled mixed aggregate. The byproduct is mainly used for low-value-added applications such as land escape restoration, despite the high quality of the aggregate. In the present work, the chemical composition properties and grading curve properties of these aggregates are defined. Furthermore, the resulting recycled concrete with a high proportion of recycled composition, from 20% to 100% replacement of fine and coarse aggregate, is characterized physically and mechanically. An environmental study of the new construction material when all aggregates are substituted by C&D waste shows a low toxicity level, similar to that of other construction materials. The new material also has improved properties with respect to standard concrete such as high fire resistance, good heat insulation, and acoustic insulation.  相似文献   
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