全文获取类型
收费全文 | 1116篇 |
免费 | 189篇 |
国内免费 | 334篇 |
专业分类
安全科学 | 36篇 |
废物处理 | 10篇 |
环保管理 | 153篇 |
综合类 | 873篇 |
基础理论 | 352篇 |
环境理论 | 2篇 |
污染及防治 | 92篇 |
评价与监测 | 62篇 |
社会与环境 | 50篇 |
灾害及防治 | 9篇 |
出版年
2024年 | 12篇 |
2023年 | 38篇 |
2022年 | 38篇 |
2021年 | 44篇 |
2020年 | 44篇 |
2019年 | 59篇 |
2018年 | 32篇 |
2017年 | 54篇 |
2016年 | 46篇 |
2015年 | 66篇 |
2014年 | 60篇 |
2013年 | 100篇 |
2012年 | 116篇 |
2011年 | 86篇 |
2010年 | 88篇 |
2009年 | 89篇 |
2008年 | 58篇 |
2007年 | 76篇 |
2006年 | 81篇 |
2005年 | 56篇 |
2004年 | 54篇 |
2003年 | 41篇 |
2002年 | 32篇 |
2001年 | 42篇 |
2000年 | 37篇 |
1999年 | 22篇 |
1998年 | 44篇 |
1997年 | 32篇 |
1996年 | 16篇 |
1995年 | 16篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1973年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有1639条查询结果,搜索用时 15 毫秒
911.
912.
Rathinam Aravindhan Jonnalagadda Raghava RaoBalachandran Unni Nair 《Journal of environmental management》2009
Phenol and substituted phenols are toxic organic pollutants present in tannery waste streams. Environmental legislation defines the maximum discharge limit to be 5–50 ppm of total phenols in sewers. Thus the efforts to develop new efficient methods to remove phenolic compounds from wastewater are of primary concern. The present work aims at the use of a modified green macro alga (Caulerpa scalpelliformis) as a biosorbent for the removal of phenolic compounds from the post-tanning sectional stream. The effects of initial phenol concentration, contact time, temperature and initial pH of the solution on the biosorption potential of macro algal biomass have been investigated. Biosorption of phenol by modified green macro algae is best described by the Langmuir adsorption isotherm model. Biosorption kinetics of phenol onto modified green macro algal biomass were best described by a pseudo second order model. The maximum uptake capacity was found to be 20 mg of phenol per gram of green macro algae. A Boyd plot confirmed the external mass transfer as the slowest step involved in the biosorption process. The average effective diffusion coefficient was found to be 1.44 × 10−9 cm2/s. Thermodynamic studies confirmed the biosorption process to be exothermic. 相似文献
913.
海洋油气开发工程环评中公众参与探讨 总被引:2,自引:2,他引:0
根据我国环境影响评价公众参与现状和海洋油气开发工程公众参与实践,对海洋油气开发工程环评中公众参与进行初步探讨。目前海洋油气开发工程公众参与存在的问题主要有:相关公众界定较难、公众主要是在环评机构主导下的被动参与、信息不对称使公众难以正确表达意见、相关公众中个人的环境素养和法制意识不高。根据存在的问题,建议通过以下方法提高海洋油气开发工程环评公众参与水平:研究制定海洋工程公众参与技术方法规范;掌握好公众参与时机,尽早启动,调动公众主动参与;科学确定公众范围,选择好公众参与对象;结合实际选择公众参与方式。 相似文献
914.
不同遮光方式的抑藻效果比较研究 总被引:3,自引:1,他引:2
藻类的生长繁殖与其自身通过光照进行光合作用有着密不可分的关系。研究了遮光面积、遮光周期、遮光率与水体叶绿素a含量和藻类密度之间的关系,探讨不同遮光方式对藻类生长的抑制作用;以及不同遮光方式下水体中氮磷浓度的变化情况。实验结果显示:遮光50%以上的实验桶内的叶绿素a含量和藻类密度相对于不遮光减少50%以上;从上午9:00至下午3:00遮光,12 d可以使绿素a浓度和藻类数量相对于不遮光减少70%以上;遮光率达到67%以上时,抑藻效果才较为明显,第12 d时,叶绿素a含量和藻类密度相对于不遮光减少50%以上。遮光是抑制藻类暴发的有效措施之一,不同水体可以根据具体情况选择不同的遮光方式。 相似文献
915.
Alya Limayem Francisco Gonzalez Andrew Micciche Edward Haller Bina Nayak Shyam Mohapatra 《Journal of environmental science and health. Part. B》2016,51(12):868-872
Wastewater-algal biomass is a promising option to biofuel production. However, microbial contaminants constitute a substantial barrier to algal biofuel yield. A series of algal strains, Nannochloris oculata and Chlorella vulgaris samples (n = 30), were purchased from the University of Texas, and were used for both stock flask cultures and flat-panel vertical bioreactors. A number of media were used for isolation and differentiation of potential contaminants according to laboratory standards (CLSI). Conventional PCR amplification was performed followed by 16S rDNA sequencing to identify isolates at the species level. Nanotherapeutics involving a nanomicellar combination of natural chitosan and zinc oxide (CZNPs) were tested against the microbial lytic groups through Minimum Inhibitory Concentration (MIC) tests and Transmission Electronic Microscopy (TEM). Results indicated the presence of Pseudomonas spp., Bacillus pumilus/ safensis, Cellulosimicrobium cellulans, Micrococcus luteus and Staphylococcus epidermidis strains at a substantial level in the wastewater-fed algal reactors. TEM confirmed the effectiveness of CZNPs on the lytic group while the average MICs (mg/mL) detected for the strains, Pseudomonas spp, Micrococcus luteus, and Bacillus pumilus were 0.417, 3.33, and 1.458, respectively. Conclusively, CZNP antimicrobials proved to be effective as inhibitory agents against currently identified lytic microbial group, did not impact algae cells, and shows promise for in situ interventions. 相似文献
916.
Persistent organic pollutants in plastic marine debris found on beaches in San Diego, California 总被引:1,自引:0,他引:1
Plastic debris were collected from eight beaches around San Diego County, California. Debris collected include: pre-production pellets and post-consumer plastics including fragments, polystyrene (PS) foam, and rubber. A total of n = 2453 pieces were collected ranging from <5 mm to 50 mm in size. The plastic pieces were separated by type, location, and appearance and analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its breakdown products, and chlordanes. PAH concentrations ranged from 30 ng g−1 to 1900 ng g−1, PCBs from non-detect to 47 ng g−1, chlordanes from 1.8 ng g−1 to 60 ng g−1, and DDTs from non-detect to 76 ng g−1. Consistently higher PAH concentrations found in PS foam samples (300-1900 ng g−1) led us to examine unexposed PS foam packaging materials and PS virgin pellets. Unexposed PS foam contained higher concentrations of PAHs (240-1700 ng g−1) than PS virgin pellets (12-15 ng g−1), suggesting that PAHs may be produced during manufacturing. Temporal trends of debris were investigated at one site, Ocean Beach, where storm events and beach maintenance were found to be important variables influencing debris present at a given time. 相似文献
917.
Bährs H Menzel R Kubsch G Stösser R Putschew A Heinze T Steinberg CE 《Chemosphere》2012,87(11):1193-1200
Dissolved organic matter (DOM) has been shown to affect phytoplankton species directly. These interactions largely depend on the origin and molecular size of DOM and are different in prokaryotes and eukaryotes. In a preceding study, however, two humic substance preparations did not adversely affect coccal green algae or cyanobacterial growth even at high concentrations of dissolved organic carbon (DOC). These results contradicted previous findings, showing a clear, negative response of different phototrophs to much lower DOC concentrations. To test whether or not at least defined building blocks of humic substances (HSs) are effective algicidal structures, we enriched two humic preparations with hydroquinone and p-benzoquinone, respectively, and exposed two different green algae, Pseudokirchneriella subcapitata and Monoraphidium braunii, and two cyanobacterial species, Synechocystis sp. and Microcystis aeruginosa, to the unmodified and enriched HSs. As response variables, growth rates in terms of biomass increase, chlorophyll-a content, and photosynthetic yield were measured. The highest concentration (4.17 mM DOC) of the modified HSs clearly inhibited growth; the cyanobacterial species were much more sensitive than the green algal species. However, realistic ecological concentrations did not adversely affect growth. Aerating the exposure solution for 24 h strongly reduced the inhibitory effect of the modified HSs. The algicidal effect was obviously caused by monomers and not by polymerised high molecular weight HSs themselves. Furthermore, the maximum quantum yield (Φ PSII max) was stimulated in the green algal species by low and medium DOC concentrations, but reduced in the cyanobacterial species upon exposure to higher HS concentrations. The quinone- and phenol-enriched HSs only showed algicidal activity at high concentrations of 4.17 mM DOC and lost their effects over time, presumably by oxidation and subsequent polymerisation. This study confirms that the applied humic substances themselves are not effective algicides even if enriched in effective structures. 相似文献
918.
《中华人民共和国防治海岸工程建设项目污染损害海洋环境管理条例》颁布实施以来,对各评估单位进行环境评审的工作起了指导性作用,但在实施过程中,评估单位对《海洋环境影响报告》编制格式的理解偏差而造成某些章节所论述的内容与标题意图不符,或论述分析不够全面等问题。本文通过对《海洋环境影响报告》编制格式的剖析,提出了一些建议与看法以供各相关单位参考。 相似文献
919.
920.
利用啤酒废水培养极大螺旋藻(Spirulina maxima)。研究了初始COD、DO、氮磷元素等培养条件对藻生物量(每mL培养液中极大螺旋藻的质量,以干重计)及废水水质的影响。实验结果表明:将废水稀释至COD=700 mg/L,控制DO=2.5 mg/L,并添加氮磷元素使废水的碳氮磷质量比为225∶15∶1,培养3 d,极大螺旋藻的藻生物量可达175.55 mg/L,即每吨啤酒废水可生产极大螺旋藻175.55 g;废水中COD,TN,NH3-N,NO3-,TP的去除率分别达到85.43%,94.54%,74.66%,94.53%,61.54%。利用啤酒废水培养螺旋藻在收获极大螺旋藻生物质的同时,还能对废水起到一定程度的净化作用。 相似文献