全文获取类型
收费全文 | 1155篇 |
免费 | 210篇 |
国内免费 | 324篇 |
专业分类
安全科学 | 168篇 |
废物处理 | 27篇 |
环保管理 | 156篇 |
综合类 | 634篇 |
基础理论 | 298篇 |
污染及防治 | 95篇 |
评价与监测 | 33篇 |
社会与环境 | 28篇 |
灾害及防治 | 250篇 |
出版年
2024年 | 11篇 |
2023年 | 26篇 |
2022年 | 32篇 |
2021年 | 52篇 |
2020年 | 44篇 |
2019年 | 54篇 |
2018年 | 49篇 |
2017年 | 60篇 |
2016年 | 70篇 |
2015年 | 70篇 |
2014年 | 54篇 |
2013年 | 98篇 |
2012年 | 112篇 |
2011年 | 108篇 |
2010年 | 100篇 |
2009年 | 76篇 |
2008年 | 53篇 |
2007年 | 90篇 |
2006年 | 82篇 |
2005年 | 54篇 |
2004年 | 56篇 |
2003年 | 55篇 |
2002年 | 35篇 |
2001年 | 39篇 |
2000年 | 24篇 |
1999年 | 23篇 |
1998年 | 27篇 |
1997年 | 16篇 |
1996年 | 16篇 |
1995年 | 16篇 |
1994年 | 22篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有1689条查询结果,搜索用时 531 毫秒
901.
金属材料在盐湖卤水中的耐蚀性 总被引:4,自引:0,他引:4
通过现场暴露试验获得了12种典型金属材料在盐湖卤水中暴露181d、415d和810d的腐蚀结果,讨论了它们在卤水中的耐蚀性。TH200、QT500-5、Q235和16Mn在盐湖卤水中的耐蚀性较好。QT500-5的耐蚀性好于TH200。304、316L和430不锈钢在盐湖卤水中发生较轻的点蚀和缝隙腐蚀,耐蚀性较好;其耐蚀顺序为316L>304>430。T2、QSi3-1在盐湖卤水中有好的耐蚀性。L6、6066和LC4(BL)在盐湖卤水中发生严重的点蚀和缝隙腐蚀,耐蚀性差。 相似文献
902.
Castor canadensis ) management in Wyoming, USA, was sent to 5265 private-land managers and 124 public-land managers during 1993. The survey
was developed in response to increasing interest in beaver management and beaver reintroduction possibilities. Private-land
managers responding to the survey supplied information on 62,859 km2 of land area and 20,037 km of streams. Primary concerns about beaver damage centered on (in decreasing order of importance)
blocked irrigation ditches, girdled timber, blocked culverts, and flooded pastures, roads, crops, and timber. Primary benefits
that landowners perceive that beaver give them were, in order of importance, elevated water tables, increased riparian vegetation,
and increased stock-watering opportunities. Public-land managers also listed these benefits and detriments among their top
concerns for beaver. Over 45% of landowners with beaver on their property and all of the public-land managers displayed an
interest in a beaver reintroduction program and in more proactive beaver management. 相似文献
903.
904.
雨生红球藻3个株系的生长及对光盐反应初探 总被引:5,自引:0,他引:5
对雨生红球藻3个株系(No.3、No.712和No.797)的生长、对诱导虾青素形成的光盐因子的反应进行了比较,结果表明:No.3、No.712和No.797的生长速率分别为0.128d^-1,0.137d^-1和0.144d^-1;外加盐的量较大(4gL^-1)时导致雨生红球藻细胞数的减少,而外加盐浓度较低(2gL^-1)时,细胞数的反应因株系和光照的不同而有所差异;盐和强光照均导致静细胞比例显著增加;盐的加入仅在弱光照下诱导雨生红球藻3个株系的虾青素累积,在强光照下却导致件株系虾青素含量的下降,强光照下不外加盐时No.3、NO.712和No.797藻液的虾青素含量无显著差异,分别为2.15、2.77和2.45mg L^-1。图1表2参12 相似文献
905.
906.
907.
福建省沿海地区海盐和大气污染物反应的致酸作用 总被引:4,自引:0,他引:4
本文着重研究福建省沿海地区盐和大气污染物反应的致酸作用,从源排放估算、致酸前体物观测、大气气溶胶组成分析、降水离子特征分析四个层次进行讨论,结果表明HCl人为排放源仅占SO2,NOs的4%;大气中活性氯;HCl最大浓度为4.23μg/m^-3,Cl2最大浓度为3.97μg.m^-3,气溶胶中Cl^-/Na^+比和降水中Cl/Na^+比背离,降水中过量氯与H浓度呈现正相关,过量氯对H浓度最大贡献达3 相似文献
908.
Ahmed MK Habibullah-Al-Mamun M Hossain MA Arif M Parvin E Akter MS Khan MS Islam MM 《Chemosphere》2011,84(1):143-149
This experiment was conducted to study the genotoxic potentials of sodium arsenite (NaAsO2) in freshwater fish Oreochromis mossambicus by using alkaline comet assay and micronucleus (MN) test. Fish were exposed to three different concentrations (3 ppm, 28 ppm and 56 ppm) of arsenic and gill, liver and blood tissue samples were collected after 48 h, 96 h and 192 h of exposure. Arsenic exposure induced DNA damage in all tissues examined in a concentration dependent manner. A significant (p < 0.05) increase in the comet tail DNA (%) of the exposed fish liver, gill, and blood was observed after 48 h and 96 h of exposure, but a decline in DNA damage was recorded in all the tissues at all the three concentrations studied after 192 h of exposure. Liver tissue exhibited significantly (p < 0.05) higher DNA damage at all the concentrations examined, followed by gill and blood. Higher liver tail DNA (51.38 ± 0.21%) refers that it is more prone to injury to arsenic toxicity than the gill and blood. In blood samples arsenic induced micronucleus formation in a concentration dependent manner and highest (5.8 ± 0.46%) value was recorded in 56 ppm after 96 h of exposure, whereas, it was decreased after 192 h of exposure at all the three concentrations of NaAsO2 examined which refers to the DNA repairing ability of fish to arsenic toxicity. The results of this study depict the genotoxic potentials of arsenic to fish which in turns provide insight on advanced study in aquatic toxicology. 相似文献
909.
Salting our landscape: an integrated catchment model using readily accessible data to assess emerging road salt contamination to streams 总被引:1,自引:0,他引:1
Jin L Whitehead P Siegel DI Findlay S 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1257-1265
A new integrated catchment model for salinity has been developed to assess the transport of road salt from upland areas in watersheds to streams using readily accessible landscape, hydrologic, and meteorological data together with reported salt applications. We used Fishkill Creek (NY) as a representative watershed to test the model. Results showed good agreement between modeled and measured stream water chloride concentrations. These results suggest that a dominant mode of catchment simulation that does not entail complex deterministic modeling is an appropriate method to model salinization and to assess effects of future applications of road salt to streams. We heuristically increased and decreased salt applications by 100% and results showed that stream chloride concentrations increased by 13% and decreased by 7%, respectively. The model suggests that future management of salt application can reduce environmental concentrations, albeit over some time. 相似文献
910.