全文获取类型
收费全文 | 4404篇 |
免费 | 236篇 |
国内免费 | 204篇 |
专业分类
安全科学 | 206篇 |
废物处理 | 51篇 |
环保管理 | 1324篇 |
综合类 | 1717篇 |
基础理论 | 674篇 |
环境理论 | 10篇 |
污染及防治 | 111篇 |
评价与监测 | 87篇 |
社会与环境 | 598篇 |
灾害及防治 | 66篇 |
出版年
2024年 | 14篇 |
2023年 | 62篇 |
2022年 | 73篇 |
2021年 | 106篇 |
2020年 | 102篇 |
2019年 | 104篇 |
2018年 | 83篇 |
2017年 | 152篇 |
2016年 | 151篇 |
2015年 | 135篇 |
2014年 | 147篇 |
2013年 | 276篇 |
2012年 | 201篇 |
2011年 | 230篇 |
2010年 | 157篇 |
2009年 | 160篇 |
2008年 | 180篇 |
2007年 | 229篇 |
2006年 | 181篇 |
2005年 | 205篇 |
2004年 | 213篇 |
2003年 | 188篇 |
2002年 | 157篇 |
2001年 | 137篇 |
2000年 | 165篇 |
1999年 | 160篇 |
1998年 | 124篇 |
1997年 | 101篇 |
1996年 | 80篇 |
1995年 | 93篇 |
1994年 | 63篇 |
1993年 | 60篇 |
1992年 | 60篇 |
1991年 | 43篇 |
1990年 | 34篇 |
1989年 | 13篇 |
1988年 | 20篇 |
1987年 | 13篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 10篇 |
1977年 | 15篇 |
1973年 | 11篇 |
1972年 | 9篇 |
1971年 | 15篇 |
排序方式: 共有4844条查询结果,搜索用时 248 毫秒
701.
702.
张菲菲 《再生资源与循环经济》2012,5(1):24-26
在再生资源产业快速发展过程中,集散市场、分拣中心与加工园区等新兴产业形态令人瞩目。这些新兴产业形态的出现是再生资源产业经济效率提高的要求,是产业地位提升的需要,是先进理念注入的结果,是技术进步的必然趋势。其代表着再生资源产业更先进的生产力,标志着再生资源产业的庞大产业链条正在形成。应从新兴产业形态中,发掘再生资源产业发展的内生动力,推动再生资源产业又好又快发展。 相似文献
703.
The effect of interaction of alcohol and kola nut on sodium pump activity was studied in Wistar rats. Thirty Wistar rats were divided into six groups of five rats per group. Control received a placebo (4 mL of distilled water). Groups 2–6 were treated for a period of 21 days with 10% (v/v) alcohol, 50 mg caffeine/kg, 50 mg kola nut/kg, or a combination of 10% (v/v) alcohol + 50 mg kola nut/kg, or 10% (v/v) alcohol + 50 mg caffeine/kg, respectively. One day after the final exposure, brains were harvested and several biochemical parameters examined including activities of total ATPase, ouabain-insensitive ATPase, ouabain sensitive ATPase (Na+–K+-ATPase) and levels of nonenzymatic breakdown of ATP and inorganic phosphate (Pi) released. Results showed that the essential enzyme of the brain responsible for neuronal function, Na+–K+-ATPase, was inhibited by alcohol–kola nut co-administration relative to control, resulting in a decreased ATP production, ion transport and action potential, leading to loss of neuronal activities. 相似文献
704.
通过对南黄海中部49个表层沉积物样品进行总有机碳,粒度,多环芳烃和甲基菲等GS-MS定量分析,探讨了研究区沉积物中多环芳烃分布特征,分子组成,评估南黄海中部多环芳烃污染水平并识别其来源.研究表明,南黄海中部14种多环芳烃总量(ΣPAHs)在81.63~6567.31 ng/g之间,其中优控多环芳烃(ΣEPA PAHs)11种,含量为29.2~1029.1 ng/g,平均含量255.1 ng/g,与国内外其他地区相比有机污染水平为中-低;苝为研究区内主要多环芳烃,分布较为广泛,其含量占所有PAHs的6.40%~88.85%,低含量苝与人为活动有关,而高含量苝代表了陆源有机质输入;多环芳烃组成,异构体分析和甲基菲特征表明,研究区优控多环芳烃主要为煤和高等植物燃烧或不完全燃烧产物以气溶胶形式输入,但部分样品表现出明显的石油源特性也证实了石油燃料,原油泄露产生的多环芳烃客观存在. 相似文献
705.
Kebede Nigussie Mekonnen Bhagwan Singh Chandravanshi Mesfin Redi-Abshiro Robert Ian McCrindle 《毒物与环境化学》2013,95(10):1501-1515
For the determination of 15 potentially toxic elements (V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sn, Hg, and Pb) in plant and sediment samples of the Akaki River, Ethiopia, inductively coupled plasma–mass spectrometry, inductively coupled plasma–optical emission spectrometry, and a RA-915+ mercury analyzer were applied. Sediment and plant samples were mineralized using a closed-vessel microwave-assisted digestion system. The elemental concentrations varied considerably in plant and sediment samples. The minimum concentration was observed for known toxic elements (As, Hg, and Cd) while the highest concentration was observed for the elements of relatively low toxicity Zn, Mn, and Fe. The concentration of Cr, Fe, Pb, Zn, and As in Swiss chard surpassed the maximum permissible levels at specific sites. At some of the sites, the sediment quality guidelines are surpassed for Cu, Zn, and Pb. 相似文献
706.
In the present investigation, hepatotoxic effect of a commercially available insecticide formulation of dicofol (Colonel–S® 18.5% emulsified concentrate) was studied in the developing chick embryo. Fertilized eggs of Gallus domesticus were immersed in three different dose concentrations, i.e. 250, 500, and 1000 mg L?1 of Colonel–S on “0” and fourth days of incubation for 60 min at 37 °C and incubated till embryonic day 16. Severe histopathological cellular lesions, such as extensive cell degeneration and necrosis with enlarged blood sinusoids, cytoplasmic vacuolization, and leucocyte infiltrations with congestion or dilation of central vein, appeared in dose-depended manner. Dicofol treatment also caused significant decrease in the levels of total protein, glycogen, and glutathione content and an increase in alkaline phosphatase activity of embryonic liver, whereas glutamic pyruvic transaminase activity showed mixed response. 相似文献
707.
AbstractA rapid and selective technique for extraction, preconcentration and determination of trace amounts of cobalt in water and pharmaceutical samples by air-assisted liquid–liquid microextraction combined with flame atomic absorption spectrometry is proposed. 1-Nitroso-2-naphthol is used as a complexing agent and 1-octanol as an extraction solvent. Parameters relevant for analytical effectivity, i.e. pH of sample solution, concentration of complexing agent, volume of extraction solvent, and number of extraction cycles are optimized using a Box–Behnken design. At optimum conditions, a dynamic linear range of 5–600?µg L?1 is obtained, with a limit of detection of 1.2?µg L?1. The method is used for determination of Co(II) in environmental water and pharmaceutical samples. 相似文献
708.
Alfred J. Vella Bernardette Mintoff Victor Axiak Dorita Agius Roberto Cassone 《毒物与环境化学》2013,95(3-4):491-510
The speciation of organotins in seawater, surface microlayer and sediments in the marine environment of Malta is described. Concentrations of tributyltin (TBT) in bulk seawater inside the harbours were as high as 0.3 μg Sn L‐1 but were below detection limits (5 ng Sn L‐1) in open sea, 1.6 km offshore. In sediments, TBT levels were highest for the yacht marinas and ranged between 0.03 and 1.5 ug Sn g‐1. Dibutyltin is more common in the surface microlayer than TBT. Diphenyl and monophenyltin were found infrequently in bulk seawater and in sediments. Tetrasubstituted organotins, namely, MenBu(4_n)Sn, where n = 1, 2, and 3, were found frequently in TBT‐contaminated sediments (0.1–9μg Sng‐1), in seawater and in the microlayer where concentrations as high as 140 μg Sn L‐1 (Me3BuSn) were measured. Direct environmental methylation of TBT and that of its debutylated analogues may play a significant role in the geochemical cycling of tin under certain environmental conditions. 相似文献
709.
710.
The Gulf of Aqaba exhibits a strong seasonality due to convective mixing during winter and stratification during summer. The present study provides a detailed appraisal of summer and winter sea-water characteristics at the northern coast of the Gulf of Aqaba, that is witnessing rapid development and increasing changes in its geomorphological characteristics. Sea-water temperature, salinity, nutrients, and chlorophyll a concentrations were measured biweekly at five coastal and four cross-sectional stations during the periods February to April and July to September 2004. Meteorological conditions were continuously recorded at the Marine Science Station. The coastal study sites included four open coastal stations and a marina with one-way exchange with the open water. The effect of convective mixing was clearly apparent on the sea-water characteristics. Natural seasonal characteristics of higher nutrients and chlorophyll a concentrations were recorded during winter at most of the open coastal stations. In the cross-sectional stations, the concentrations of nutrients and chlorophyll a were not different between the surface and the bottom during winter, but the bottom waters had generally higher concentrations during summer. Some deviations from the natural seasonal cycle were recorded at the marina and other coastal stations. Here, higher nutrient and chlorophyll a concentrations were recorded in summer than in winter. These deviations that are most likely due to anthropogenic effects are discussed. 相似文献