全文获取类型
收费全文 | 50643篇 |
免费 | 587篇 |
国内免费 | 639篇 |
专业分类
安全科学 | 1726篇 |
废物处理 | 2358篇 |
环保管理 | 6656篇 |
综合类 | 8146篇 |
基础理论 | 13315篇 |
环境理论 | 25篇 |
污染及防治 | 12760篇 |
评价与监测 | 3451篇 |
社会与环境 | 3105篇 |
灾害及防治 | 327篇 |
出版年
2023年 | 226篇 |
2022年 | 480篇 |
2021年 | 530篇 |
2020年 | 360篇 |
2019年 | 443篇 |
2018年 | 772篇 |
2017年 | 796篇 |
2016年 | 1188篇 |
2015年 | 924篇 |
2014年 | 1404篇 |
2013年 | 4092篇 |
2012年 | 1727篇 |
2011年 | 2344篇 |
2010年 | 1907篇 |
2009年 | 1938篇 |
2008年 | 2330篇 |
2007年 | 2327篇 |
2006年 | 2068篇 |
2005年 | 1777篇 |
2004年 | 1679篇 |
2003年 | 1733篇 |
2002年 | 1569篇 |
2001年 | 1928篇 |
2000年 | 1369篇 |
1999年 | 832篇 |
1998年 | 608篇 |
1997年 | 618篇 |
1996年 | 632篇 |
1995年 | 749篇 |
1994年 | 706篇 |
1993年 | 594篇 |
1992年 | 633篇 |
1991年 | 619篇 |
1990年 | 608篇 |
1989年 | 570篇 |
1988年 | 504篇 |
1987年 | 449篇 |
1986年 | 414篇 |
1985年 | 425篇 |
1984年 | 467篇 |
1983年 | 441篇 |
1982年 | 463篇 |
1981年 | 386篇 |
1980年 | 310篇 |
1979年 | 340篇 |
1978年 | 299篇 |
1977年 | 228篇 |
1975年 | 245篇 |
1973年 | 232篇 |
1972年 | 243篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Reynolds B Stevens PA Adamson JK Hughes S Roberts JD 《Environmental pollution (Barking, Essex : 1987)》1992,77(2-3):157-165
Data are presented demonstrating how clearfelling has changed soil and stream water aluminium chemistry. For soil waters, a strong empirical relationship was observed between inorganic aluminium (Al(inorg)) and total inorganic anion (TIA) concentrations. Before felling, chloride and sulphate accounted for the largest proportion of the TIA concentration. After felling, in soils where nitrification was active, nitrate became increasingly important. Where this led to an increase in TIA, Al(inorg) concentrations increased. Over five years, nitrate concentrations have fallen, along with TIA, resulting in a sympathetic decline in Al(inorg). Streams draining clearfelled areas initially became more acid, although chloride and sulphate concentrations decreased. Stream water nitrate concentrations increased soon after felling and remained higher than controls for up to four years. While nitrate concentrations were high, Al(inorg) remained unchanged. Subsequently, as nitrate and TIA decreased, Al(inorg) also declined to concentrations below those in the control stream. Clearfelling upland forests will not necessarily result in immediate improvements in water quality, although long-term benefits may be seen before canopy-closure of the next crop. 相似文献
72.
Skowroński T Szubińska S Jakubowski M Pawlik B 《Environmental pollution (Barking, Essex : 1987)》1992,76(2):163-167
Availability of cadmium to Synechocystis aquatilis (estimated by 109Cd sorption and cadmium toxicity-14C method) in solutions containing cadmium and complexing (KCl) or non-complexing (KNO3) salts, in the range of 0-0.5 m was investigated. Both cadmium surface adsorption and transport into the cells were lower in solutions containing cadmium chloride complexes (CdCl+, CdCl2, CdCl3-) than in those containing cadmium in the form of Cd2+. Also, cadmium toxicity in solutions of higher KCl concentrations, in which CdCl+ and CdCl2 forms predominated, was significantly limited. 相似文献
73.
Edmunds WM Kinniburgh DG Moss PD 《Environmental pollution (Barking, Essex : 1987)》1992,77(2-3):129-141
There is some evidence from southern Britain that shallow groundwaters in non-carbonate lithologies may be affected by acidic deposition. To investigate this, interstitial water profiles down to 12 m have been obtained from unsaturated sands or semi-consolidated sandstones from the Folkestone Beds (Lower Greensand) of Surrey and the Sherwood Sandstone of the West Midlands. The pH of the interstitial waters generally increased with depth and reflected an increase in the base saturation of the exchange complex. Beneath the highly acidic surface soil horizons (pH 3.0-3.5), interstitial waters with a pH of 4.0-4.5 were found down to depths of several metres. The pH progressively increased to around pH 5.5 because of base cation desorption and the weathering of silicate minerals. High concentrations of aluminium (10-20 mg litre(-1)) and other metals (Fe, Mn, Cu, Ni, Co, Zn, Be) were found in the interstitial water in the upper unsaturated zone. Most metal concentrations were strongly pH-dependent but also reflected the geochemical characteristics of the parent sands or sandstones. H+ and trace element concentrations were slightly higher beneath areas of afforestation than beneath heathland. The downward fluxes of solutes have been estimated using rainfall-derived chloride as a non-reactive solute. The profiles retain a record of 10-20 years input allowing the past inputs from SO4 and other species to be estimated using solute/chloride ratios. Cation exchange sites are probably depleted over a period of decades and there can be a significant decrease in the unsaturated zone pH as a result of increased or sustained acidic deposition. The shallow groundwater environment (0-15 m) in non-carbonate terrains is therefore a sensitive environment where high metal concentrations may be generated and may ultimately lead to water quality problems in shallow water supplies. 相似文献
74.
Igliski B. Skrzatek M. Kujawski W. Cichosz M. Buczkowski R. 《Environment, Development and Sustainability》2022,24(1):77-111
Environment, Development and Sustainability - Renewable energy (RE) plays an increasingly important role in the economy of almost every country in the world. In order to examine the state of... 相似文献
75.
Rate-temperature responses in scyphozoan medusae and polyps 总被引:1,自引:0,他引:1
The effects of temperature on oxygen consumption and spontaneous rhythmic activity have been investigated in various stages of the life histories of 3 species of jellyfish from the Chesapeake Bay, USA. All 3 species clearly show the ability to acclimate positively to temperature change. Thermal sensitivity of metabolism in the winter medusa Cyanea capillata fulva is fairly low at temperature intervals which are experienced in nature. Polyps of the two summer medusae, Chrysaora quinquecirrha and Aurelia aurita, show reduced metabolic sensitivity at temperatures normally accompanying high developmental activity and the onset of strobilation. 相似文献
76.
77.
78.
79.
80.