全文获取类型
收费全文 | 35985篇 |
免费 | 1040篇 |
国内免费 | 6052篇 |
专业分类
安全科学 | 1778篇 |
废物处理 | 1973篇 |
环保管理 | 3711篇 |
综合类 | 11973篇 |
基础理论 | 7676篇 |
环境理论 | 4篇 |
污染及防治 | 10748篇 |
评价与监测 | 2380篇 |
社会与环境 | 2037篇 |
灾害及防治 | 797篇 |
出版年
2023年 | 362篇 |
2022年 | 993篇 |
2021年 | 948篇 |
2020年 | 715篇 |
2019年 | 672篇 |
2018年 | 952篇 |
2017年 | 1063篇 |
2016年 | 1364篇 |
2015年 | 1394篇 |
2014年 | 1852篇 |
2013年 | 3338篇 |
2012年 | 2042篇 |
2011年 | 2246篇 |
2010年 | 1952篇 |
2009年 | 1918篇 |
2008年 | 2092篇 |
2007年 | 1973篇 |
2006年 | 1867篇 |
2005年 | 1355篇 |
2004年 | 1187篇 |
2003年 | 1233篇 |
2002年 | 1153篇 |
2001年 | 1259篇 |
2000年 | 1065篇 |
1999年 | 774篇 |
1998年 | 576篇 |
1997年 | 575篇 |
1996年 | 576篇 |
1995年 | 492篇 |
1994年 | 421篇 |
1993年 | 373篇 |
1992年 | 369篇 |
1991年 | 277篇 |
1990年 | 282篇 |
1989年 | 245篇 |
1988年 | 225篇 |
1987年 | 179篇 |
1986年 | 140篇 |
1985年 | 147篇 |
1984年 | 176篇 |
1983年 | 161篇 |
1982年 | 206篇 |
1981年 | 142篇 |
1980年 | 119篇 |
1979年 | 153篇 |
1978年 | 118篇 |
1977年 | 107篇 |
1976年 | 101篇 |
1975年 | 83篇 |
1974年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Hashmi Muhammad Zaffar Chen Kezhen Khalid Foqia Yu Chunna Tang Xianjin Li Aili Shen Chaofeng 《Environmental science and pollution research international》2022,29(4):4991-5005
Environmental Science and Pollution Research - E-waste generation has become a serious environmental challenge worldwide. Taizhou of Zhejiang Province, situated on the southeast coastline of China,... 相似文献
952.
Li Shan Xu Quanli Yi Junhua Liu Jing 《Environmental science and pollution research international》2022,29(48):72655-72669
Environmental Science and Pollution Research - Droughts in winter and spring are one of the most prominent natural disasters in the Yunnan Province in China. They occur frequently, with long... 相似文献
953.
The Ukrainian Carpathians are characterized by high air pollution caused by emissions from numerous industries. We have been monitoring the state of forests in this region since 1989. The highest levels of tree defoliation (>30%) are found close to industrial emission sources and in the upper mountain forests of the Ivano-Frankivsk and Chernivtsi regions. This is caused by a combination of strong anthropogenic influences (pollution, illegal uses, recreation) as well as poor site and climatic conditions. In the Ivano-Frankivsk region, Cd and Mo accumulate in forest soils; Cr, Mo and Zn soil concentrations are higher than their limit levels; and Pb concentrations exceed toxic levels close to industrial areas (10% of the region territory). Local background levels of heavy metals are greatly exceeded in snow close to industrial regions. Analysis of correlation matrices shows that the chemical elements Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn occur at pollution levels in natural ecosystems in the Ukrainian Carpathians. Maximum concentrations of toxic elements occur in the oak forest zone; the most industrially developed area of the region. Toxic heavy metals in the Ukrainian Carpathians forests enter with precipitation and dustfall, then become fixed in soil and accumulate in leaves, needles of vascular plants and mosses. Concentrations of these metals decrease with altitude: highest in the oak forests, less in beech, and lowest in the spruce forest zones. However, some chemical elements have the highest concentrations in spruce forests; V in needles, As in snow, and Ba and Al in soils. 相似文献
954.
With the help of a large number of monitoring sites, the behaviour of F in forested ecosystems of a formerly polluted area (M?hlin and Rheinfelden, Switzerland) could be studied over 30 years. An aluminium smelting plant originated the pollution of this area in the past: however, after the installation of a filtration plant in 1958 the F emissions were reduced and since 1991 almost absent the primary production of aluminium was stopped. The present-day area with elevated F contents (water-soluble F with >20 mg/kg) is restricted to a radius of about 1000 m from the plant. In 1969 this area had a radius of about 3 and 5 km. Between 1969 and 2000 a significant decrease in the soluble F content in the soil was observed together with a substantial decrease of F in the vegetation. The net losses of water-soluble F in the soil were in the range of 35 up to more than 70% of the original concentration and the F losses in the vegetation between 60 up to more than 80%. After the reduction of high F deposition rates the accumulated SOM was decomposed within the observation period 1969-1993. The combined decrease in F and humus led to chain reactions with losses of major elements and a dealumination of clay minerals, i.e. removal of interlayered Al of 2:1 minerals and consequent formation of smectites. 相似文献
955.
Zinati GM Li Y Bryan HH Mylavarapu RS Codallo M 《Journal of environmental science and health. Part. B》2004,39(1):209-223
Composts improve organic carbon content and nutrients of calcareous soils but the accumulation and distribution of phosphorus and heavy metals among various fractions in soil may vary under the south Florida conditions. The accumulation of P, Cd, Ni, and Pb with depth and the distribution of water soluble, exchangeable, carbonate, Fe-Mn oxides, organic and residual forms of each element were investigated in soils amended with municipal solid waste (MSW) compost, co-compost and biosolids compost and inorganic fertilizer (as control). Total concentrations of P, Cd, Ni, and Pb were higher in the 0-22 cm soil layers and decreased considerably in the rock layers. These elements were in the decreasing order of P > Pb > Ni > Cd. Amounts of water soluble and exchangeable forms of P, Cd, Ni and Pb were negligible at 0-22 cm soil depths except for Cd in the 10-22 cm depth. Amending calcareous soil with either organic or inorganic amendments rendered phosphorus, nickle and lead in the residual form followed by Fe-Mn oxides form in the 0-10 and 10-22 cm soil layers. Cadmium was predominantly in the Fe-Mn oxides fraction followed by the residual and carbonate forms in both soil layers. A significant positive correlation was found between various organic carbon fractions and organic forms of P, Cd and Pb in the surface soil layer. Soil amended with MSW compost had higher concentration of Cd in the organic fraction whereas, co-compost and MSW compost amended soil had higher concentrations of organic Ni fraction in the 0-10 cm soil layer. 相似文献
956.
The environment of East China Sea (ECS) has been faced by huge stresses from anthropogenic activities and population growth in the Yangtze River drainage basin and the areas along the coasts. Improper use of natural resources and short-term economic objectives have resulted in severe environmental degradation in a fairly short time frame and the degradation has now reached a level where the health and well being of the coastal populations are threatened. The main pollutants are inorganic nitrogen, phosphate, oil hydrocarbons, organic matters and heavy metals. Nutrients cause eutrophication of the coastal waters and the estuarine area and very often stimulate the occurrence of red tides. The environmental pollution of Yangtze River basin directly impact on the state of the marine environment in the ECS. The ecosystem stability is maintained by a steady water discharge from the river, that mixes with the marine salty water in the estuary, and the sediment loads from the river that balance ocean erosion in the delta and its adjacent coastal area. The large-scale water transfer and dam constructions in the Yangtze River basin will change this basis. For the ECS the challenge is to reverse the negative processes taking place and to restore ecosystem balance. The main challenge is to integrate socioeconomic and environmental decision making in order to promote sustainable development. A better understanding of the driving forces in society that cause these environmental pressures is required in order to overcome these obstacles. International cooperation may be an important contributor to the progress and in particular provide access to financial, technological, scientific and human resource assistance. 相似文献
957.
el-Demerdash FM Yousef MI Kedwany FS Baghdadi HH 《Journal of environmental science and health. Part. B》2004,39(3):443-459
Role of alpha-tocopherol (vitamin E), beta-carotene and/or their combination as antioxidants against the toxicity of fenvalerate on blood hematology, free radicals, biochemical parameters, and semen quality were studied in male rats. Fenvalerate (20 mg/kg BW), vitamin E (100 mg/kg BW), beta-carotene (10 mg/kg BW), and vitamin E plus beta-carotene (100 + 10 mg/kg BW, respectively) were given alone or in combination with fenvalerate. The tested doses were given to rats every other day for 30 days. Results obtained showed that fenvalerate significantly (P < 0.05) induced free radicals in plasma and brain and insignificantly in liver and testes. While, vitamin E, beta-carotene alone and/or in combination decreased the levels of free radicals in plasma, liver, testes, and brain. The activities of glutathione S-transferase (liver), alkaline phosphatase (plasma and liver), aspartate aminotransferase (plasma, liver, and testes) and alanine aminotransferase (plasma and liver) were significantly (P < 0.05) increased due to fenvalerate administration. The activity of acetylcholinesterase was significantly (P < 0.05) decreased in brain and plasma, while plasma glucose, urea, creatinine, and bilirubin concentrations were significantly (P < 0.05) increased in rats treated with fenvalerate. Also, results showed a significant (P < 0.05) alterations in plasma proteins, hematological parameters, body weight, and relative weights of organs. Sperm concentration and motility (%) were significantly (P < 0.05) decreased, while dead and abnormal sperm increased in rats exposed to fenvalerate. Vitamin E, beta-carotene alone and/or in combination did not cause any changes in the investigated parameters, but improved semen quality and minimized the toxic effect of fenvalerate. The obtained results demonstrated the beneficial influences of vitamin E, beta-carotene alone and/or in combination in reducing the harmful effects of fenvalerate. 相似文献
958.
Leaching and uptake of heavy metals by ten different species of plants during an EDTA-assisted phytoextraction process 总被引:10,自引:0,他引:10
In a pot experiment, the potential use of 10 plant species, including six dicotyledon species and four monocotyledon species, was investigated for the EDTA-enhanced phytoextraction of Pb from contaminated soil. Mung bean and buckwheat had a higher sensitivity to the EDTA treatment in soils. In the 2.5 and 5.0 mmol kg(-1) EDTA treatments, the Pb concentrations in the shoots of the six dicotyledon species ranged from 1,000 to 3,000 mg kg(-1) of dry matter, which were higher than those of the monocotyledon species. The highest amount of phytoextracted Pb (2.9 mg Pb pot(-1)) was achieved in sunflowers, due to the high concentration of Pb in their shoots and large biomass, followed by corns (1.8 mg Pb pot(-1)) and peas (1.1 mg Pb pot(-1)). The leaching behavior of heavy metals as a result of applying EDTA to the surface of the soil was also investigated using short soil-leaching columns (9.0-cm diameter, 20-cm height) by the percolation of artificial rainfall. About 3.5%, 15.8%, 13.7% and 20.6% of soil Pb, Cu, Zn and Cd, respectively, were leached from the soil columns after the application of 5.0 mmol kg(-1) of EDTA. The growth of sunflowers in the soil columns had little effect on the amount of metals that were leached out. This was probably due to the shallowness of the layer of soil, the short time-span of the uptake of metals by the plant and the plant's simple root systems. 相似文献
959.
Effects of four chlorobenzenes on serum sex steroids and hepatic microsome enzyme activities in crucian carp, Carassius auratus 总被引:1,自引:0,他引:1
Four chlorobenzenes (chlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, p-chloro-methylbenzene) were administrated to the crucian carps (Carassius auratus) by peritoneal injections in the laboratory for 30 days. Serum testosterone and 17 beta-estradiol concentrations were detected using radioimmunology assay (RIA), and the activities of two hepatic microsome enzymes, glutathione s-transferase (GST) and UDP-glucuronosyltransferase (UDPGT), were measured using the modified methods as described by Habig and Owens. Results showed that the four chlorobenzenes caused significant increases in serum testosterone concentration in the crucian carps (P < 0.05) compared to the controls, but they caused no significant effect on 17 beta-estradiol level. All test chemicals caused a change in hepatic GST activity in crucian carps, with significant increases in enzyme activity (P < 0.05). Chlorobenzene, 1,3-dichlorobenzene and p-chloro-methylbenzene resulted in a marked inhibition to UDPGT activity in crucian carp (P < 0.05) except 1,4-dichlorobenzene. The changes in hepatic microsome enzyme activities may have resulted in the alterations of serum sex steroids levels in the crucian carps. The results indicated that these four chlorobenzenes may result in the changes of endocrine functions and may affect the reproductive success of this and other species. 相似文献
960.
Gimeno BS Bermejo V Sanz J de la Torre D Elvira S 《Environmental pollution (Barking, Essex : 1987)》2004,132(2):297-306
Ozone (O3) phytotoxicity has been reported on a wide range of plant species. However, scarce information has been provided regarding the sensitivity of semi-natural grassland species, especially those from dehesa Mediterranean grasslands, in spite of their great biological diversity and the high O3 levels recorded in the region. A screening study was carried out in open-top chambers (OTCs) to assess the O3-sensitivity of representative therophytes of these ecosystems based on the response of selected growth-related parameters. Three O3 treatments and 3 OTCs per treatment were used. Legume species were very sensitive to O3, because 78% of the tested species showed detrimental effects on their total biomass relative growth rate (RGR) following their exposure to O3. The Trifolium genus was particularly sensitive showing O3-induced adverse effects on most of the assessed parameters. Gramineae plants were less sensitive than Leguminosae species because detrimental effects on total biomass RGR were only observed in 14% of the assessed species. No relationship was found between relative growth rates when growing in clean air and O3 susceptibility. The implications of these effects on the performance of dehesa acidic grasslands and on the definition of ozone critical levels for the protection of semi-natural vegetation are discussed. 相似文献