全文获取类型
收费全文 | 1062篇 |
免费 | 45篇 |
国内免费 | 334篇 |
专业分类
安全科学 | 61篇 |
废物处理 | 64篇 |
环保管理 | 88篇 |
综合类 | 536篇 |
基础理论 | 190篇 |
污染及防治 | 360篇 |
评价与监测 | 48篇 |
社会与环境 | 32篇 |
灾害及防治 | 62篇 |
出版年
2023年 | 17篇 |
2022年 | 59篇 |
2021年 | 43篇 |
2020年 | 27篇 |
2019年 | 30篇 |
2018年 | 40篇 |
2017年 | 42篇 |
2016年 | 41篇 |
2015年 | 59篇 |
2014年 | 80篇 |
2013年 | 101篇 |
2012年 | 96篇 |
2011年 | 93篇 |
2010年 | 77篇 |
2009年 | 65篇 |
2008年 | 79篇 |
2007年 | 69篇 |
2006年 | 75篇 |
2005年 | 47篇 |
2004年 | 31篇 |
2003年 | 32篇 |
2002年 | 32篇 |
2001年 | 29篇 |
2000年 | 21篇 |
1999年 | 20篇 |
1998年 | 22篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有1441条查询结果,搜索用时 31 毫秒
741.
代谢表面活性剂菌处理含油污泥的研究 总被引:6,自引:0,他引:6
试验采用异位生物修复技术堆肥法,对某炼厂油泥进行生物修复处理研究.用微生物代谢的表面活性剂对油泥进行预处理,洗脱油泥中部分油分后进行堆肥试验,投加从油田含油土壤中获得的以石油为唯一碳源、代谢高效生物表面活性剂的微生物C-2菌、F-2菌以及无机营养物和疏松剂(锯末),降解油泥中的石油污染物.经过外源微生物和内源微生物共同作用120 d,油泥中的石油烃总量由22 910 mg/kg下降到3 000 mg/kg以下.试验利用色谱-质谱联用方法分析了降解前后石油组分的变化.菌株经传统方法鉴定为蜡状芽孢杆菌、枯草芽孢杆菌. 相似文献
742.
德兴铜矿周边地区土壤酶活性研究 总被引:1,自引:1,他引:0
采用逐步多元回归和主成分分析的方法研究了德兴铜矿周边土壤中重金属和土壤酶活性的关系.结果表明:德兴铜矿周边各功能区均受到不同程度的Cu、Cd污染,Pb、Zn未超过《土壤环境质量标准》(GB 15618--1995)二级标准;各功能区土壤酶活性有显著差别,逐步回归分析表明土壤酶活性与Cu、Zn全量、生物可利用态Cu含量有显著线性关系,而与Cd、Pb无明显相关;土壤酶活性和生物可利用态Cu呈负线性关系,而与残渣态Cu有正线性关系.主成分分析显示,土壤酶信息系统的第1、第2主成分可反映酶活性总变异的96.27%,根据第1主成分对功能区酶活性的分类结果与土壤生物可利用态Cu含量的分类结果基本一致,提示土壤酶活性指标可以反映土壤生物可利用态Cu含量. 相似文献
743.
744.
For marine organisms, decoupling between the planktonic larval stage and the benthic-associated juvenile stage can lead to
variable patterns of population replenishment, which have the potential to influence the effectiveness of marine reserves.
We measured spatial and temporal variability in larval supply and recruitment of fishes to coral reefs of different protection
levels and tested whether protection level influenced the relationship between supply and recruitment. We sampled pre-settlement
larvae and newly settled recruits from four reefs (two reserves and two non-reserves) in the Florida Keys National Marine
Sanctuary, USA. Replicate point measures of larval supply over 14 months and 17 monthly measurements of recruitment varied
significantly among months and sites. Sites with the same protection level had significantly different patterns of larval
supply as well as larval and recruit diversity, but recruitment magnitude differed only by protection level, where densities
were greater at reserves. Differences in larval supply among sites included two particularly large peaks in larval abundance
at one site, possibly associated with the observed passage of small-scale oceanographic features. To examine whether relationships
between larval supply and recruitment varied by protection level, we selected one species that was present in both the light
trap samples and the monthly recruitment surveys. Recruitment of the bicolor damselfish Stegastes partitus was significantly and positively related to larval supply at three of the four sites thus, protection level did not influence
this linkage. Since local variability among sites can lead to spatial differences in population replenishment, characterization
of larval supply and recruitment to potential marine reserve sites may help to identify optimal locations in a region and
contribute to more effective reserve design. 相似文献
745.
Habitat loss is considered as one of the primary causes of species extinction, especially for a species that also suffers from an epidemic disease. Little attention has been paid to the combined effect of habitat loss and epidemic transmission on the species spatiotemporal dynamics. Here, a spatial model of the parasite–host/prey–predator eco-epidemiological system with habitat loss was studied. Habitat patches in the model, instead of undergoing a random loss, were spatially clustered by different degrees. Not only the quantity of habitat loss but also its clustering degree was shown to affect the equilibrium of the system. The infection rate and the probability of successful predation were keys to determine the spatial patterns of species. The epidemic disease is more likely to break out if only a small amount of suitable patches were lost. Counter-intuitively, infected preys are more sensitive to habitat loss than predators if the lost patches are highly clustered. This result is new to eco-epidemiology and implies a possibility of using spatial arrangement of suitable (or unsuitable) patches to control the spread of epidemics in the ecological system. 相似文献
746.
Developing low-carbon economy and enhancing carbon productivity are basic approaches to coordinating economic development and protecting global environment, which are also the major ways to address climate change under the framework of sustainable development. In this paper, the authors analyze the annual rate of carbon productivity growth, the differences of carbon productivity of different countries, and the factors for enhancing carbon productivity. Consequently, the authors clarify their viewpoint that the annual rate of carbon productivity growth can be used to weigh the efforts that a country takes to address climate change, and propose policies and suggestions on promoting carbon production. 相似文献
747.
748.
基于过渡金属离子掺杂技术,制备了在室内光辐照条件下具有良好光催化抗菌性能的可见光响应型铁掺杂TiO2光催化涂料.研究结果表明,在可见光活性光催化涂料中添加1%的纳米TiO2时,抗菌效果最好,光照24 h后对大肠杆菌、白色念珠球菌、黑曲霉的杀菌率分别达到99.9%、97.2%、82%.采用致孔剂聚乙二醇6 000对光催化... 相似文献
749.
Spatial and seasonal distribution of selected antibiotics in surface waters of the Pearl Rivers, China 总被引:1,自引:0,他引:1
Yang JF Ying GG Zhao JL Tao R Su HC Liu YS 《Journal of environmental science and health. Part. B》2011,46(3):272-280
The distribution and occurrence of 15 antibiotics in surface water of the Pearl River System (Liuxi River, Shijing River and Zhujiang River) and effluents of four wastewater treatment plants (WWTPs) were investigated in two sampling events representing wet season and dry season by using rapid resolution liquid chromatography-electrospray tandem mass spectrometry (RRLC-MS/MS) in positive ionization mode. Only eight antibiotics (sulfadiazine, sulfapyridine, sulfamethazine, sulfamethoxazole, trimethoprim, roxithromycin, erythromycin-H?O and norfloxacin) were detected in the water samples of the three rivers and the effluents. The detection frequencies and levels of antibiotics in the dry season were higher than those in the wet season. This could be attributed to the dilution effects in the wet season and relatively lower temperature in the dry season under which antibiotics could persist for a longer period. The levels of the detected antibiotics in different sites are generally in a decreasing order as follows: Shijing River ≥WWTP effluent ≥Zhujiang River ≥ Liuxi River. Risk assessment based on the calculated risk quotients showed that only erythromycin-H?O and roxithromycin detected in the Pearl Rivers might have adverse effects on aquatic organisms. 相似文献
750.
Li Y Su B Liu J Du X Huang G 《Journal of the Air & Waste Management Association (1995)》2011,61(7):771-777
To assess the effects of three types of Mg and P salt mixtures (potassium phosphate [K3PO4]/magnesium sulfate [MgSO4], potassium dihydrogen phosphate [K2HPO4]/MgSO4, KH2PO4/MgSO4) on the conservation of N and the biodegradation of organic materials in an aerobic food waste composting process, batch experiments were undertaken in four reactors (each with an effective volume of 30 L). The synthetic food waste was composted of potatoes, rice, carrots, leaves, meat, soybeans, and seed soil, and the ratio of C and N was 17:1. Runs R1-R3 were conducted with the addition of K3PO4/ MgSO4, K2HPO4/MgSO4, and KH2PO4/MgSO4 mixtures, respectively; run R0 was a blank performed without the addition of Mg and P salts. After composting for 25 days, the degrees of degradation of the organic materials in runs R0-R3 were 53.87, 62.58, 59.14, and 49.13%, respectively. X-ray diffraction indicated that struvite crystals were formed in runs R1-R3 but not in run R0; the gaseous ammonia nitrogen (NH3-N) losses in runs R0-R3 were 21.2, 32.8, 12.6, and 3.5% of the initial total N, respectively. Of the tested Mg/P salt mixtures, the K2HPO4/ MgSO4 system provided the best combination of conservation of N and biodegradation of organic materials in this food waste composting process. 相似文献