首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   63篇
  免费   6篇
  国内免费   3篇
安全科学   6篇
废物处理   1篇
环保管理   3篇
综合类   25篇
基础理论   18篇
污染及防治   7篇
评价与监测   3篇
社会与环境   6篇
灾害及防治   3篇
  2021年   1篇
  2020年   2篇
  2019年   1篇
  2018年   2篇
  2017年   4篇
  2016年   3篇
  2015年   7篇
  2014年   1篇
  2013年   5篇
  2012年   3篇
  2011年   6篇
  2010年   2篇
  2009年   4篇
  2008年   1篇
  2007年   7篇
  2004年   2篇
  2003年   2篇
  2002年   4篇
  2001年   5篇
  2000年   3篇
  1999年   3篇
  1995年   1篇
  1992年   1篇
  1988年   1篇
  1949年   1篇
排序方式: 共有72条查询结果,搜索用时 78 毫秒
21.
Effective protection of the ~19 000 IUCN-listed threatened species has never been more pressing. Ensuring the survival of the most vulnerable and irreplaceable taxa and places, such as those identified by the Alliance for Zero Extinction (AZE) species and their associated sites (AZEs&s), is an excellent opportunity to achieve the Aichi 2020 Targets T11 (protected areas) and T12 (preventing species extinctions). AZE taxa have small, single-site populations that are especially vulnerable to human-induced extinctions, particularly for the many amphibians. We show that AZEs&s can be protected feasibly and cost-effectively, but action is urgent. We argue that the Alliance, whose initial main aim was to identify AZEs&s, must be followed up by a second-generation initiative that directs and co-ordinates AZE conservation activities on the ground. The prominent role of zoos, conservation NGOs, and governmental institutions provides a combination of all-encompassing knowhow that can, if properly steered, maximize the long-term survival of AZEs&s.  相似文献   
22.
23.
Economic development in Africa is expected to increase levels of bushmeat hunting through rising demand for meat and improved transport infrastructure. However, few studies have tracked long‐term changes in hunter behavior as a means of testing this prediction. We evaluated changes in hunter behavior in a rural community in Equatorial Guinea over a period of rapid national economic growth, during which time road access to the regional capital greatly improved. We conducted offtake surveys (Supporting Information) over 3 7‐week periods at the same time of year in 1998, 2003, and 2010 and conducted hunter and household interviews (Supporting Information) in 2003 and 2010. We tested whether relations existed among catch, hunting effort, hunting strategy, and income earned through hunting and other livelihoods in 2003 and 2010. Although village offtake increased from 1775 kg in 1998 to 4172 kg in 2003, it decreased in 2010 to 1361 kg. Aggregate catch per unit effort (i.e., number of carcasses caught per hunter and per trap) decreased from 2003 to 2010, and the majority of hunters reported a decrease in abundance of local fauna. Although these results are indicative of unsustainable hunting, cumulative changes in offtake and catch per unit effort were driven by a contraction in the total area hunted following an out‐migration of 29 of the village's hunters, most of whom left to gain employment in the construction industry, after 2003. Hunters operating in both 2003 and 2010 hunted closer to the village because an increased abundance of elephants posed a danger and because they desired to earn income through other activities. Our study provides an example of national economic development contributing to a reduction in the intensity and extent of hunting. Factores de Cambio en la Captura de Cazadores y Estrategias de Caza en Sendje, Guinea Ecuatorial  相似文献   
24.
为了解消落带土壤有机污染物邻苯二甲酸二丁酯(DBP)的环境行为,采用静态淹水法研究了三峡库区消落带土壤向上覆水迁移释放规律以及上覆水温度、光照、含氧量等外界环境条件对其影响.结果表明,消落带土壤中DBP在淹水前期由土壤向上覆水中迁移释放,该过程分为短暂但是释放速率较快的快速释放阶段和释放时间较长但释放速率较慢的慢速释放阶段,其中慢释放是主要控速步骤,此过程可以很好地用二室一级动力模型拟合.在淹水中期释放达到最大值,继续淹水后,释放到水体中的DBP转而由水体向土壤中迁移,最终在淹水后期上覆水DBP含量达到平衡状态.随着温度的升高,DBP向上覆水释放的强度增大,同时增加了DBP快速释放的速率,降低了慢速释放速率.不同光源照射下,DBP向水体释放浓度不同,采用自然光照的处理中上覆水DBP的浓度高于采用UVB、UVA光源处理;DBP在上覆水达到最大浓度后,UVB、UVA处理中上覆水DBP含量减少比较快速,而自然光处理相对要缓慢.上覆水中的含氧量对DBP的最大释放量与达到最大释放的时间有影响,总体上来看,上覆水中含氧量越高,上覆水DBP含量越高;上覆水高氧处理和低氧气处理,上覆水中DBP最大浓度提前至淹水第8d出现,自然状态下DBP在淹水第12 d达到最大值.土壤中共存的邻苯二甲酸双(2-乙基己基)酯(DEHP)对DBP的释放有明显影响:在淹水第4~12 d,添加DEHP组分试验的DBP释放量要明显大于单一组分的DBP释放量,而且快、慢释放速率均要比单一DBP组分处理的大.微生物活性对消落带土壤淹水过程中邻苯二甲酸二丁酯迁移释放存在一定的影响但效果并不明显,添加微生物活性抑制剂处理后DBP的迁移量要略小于对照组.  相似文献   
25.
Phosphogypsum (PG) is a by-product of the phosphorus–fertiliser industry and represents an environmental concern since it contains pollutants such as cadmium (Cd). We have recently shown that the overexpression of a proton pump gene (TaVP1) in transgenic tobacco (Nicotiana tabacum) led to an enhanced Cd tolerance and accumulation. The aim of this study was to evaluate the potential of transgenic Arabidopsis thaliana plants harbouring the TaVP1 gene to phytoremediate phosphogypsum. A pot experiment was carried out under greenhouse conditions. Transgenic A. thaliana plants harbouring the TaVP1 gene were grown on various substrates containing phosphogypsum (0, 25, 50 and 100 %) for 40 days. At the end of the growth period, we examined the growth (germination, root length, fresh weight) and physiological parameters (chlorophyll and protein contents, catalase activity and proteolysis) as well as the cadmium, Mg, Ca, and P contents of the A. thaliana plants. In order to evaluate Cd tolerance of the A. thaliana lines harbouring the TaVP1 gene, an in vitro experiment was also carried out. One week-old seedlings were transferred to Murashige and Skoog agar plates containing various concentrations of cadmium; the germination, total leaf area and root length were determined. The growth and physiological parameters of all A. thaliana plants were significantly altered by PG. The germination capacity, root growth and biomass production of wild-type (WT) plants were more severely inhibited by PG compared with the TaVP1 transgenic A. thaliana lines. In addition, TaVP1 transgenic A. thaliana plants maintained a higher antioxidant capacity than the WT. Interestingly, elemental analysis of leaf material derived from plants grown on PG revealed that the transgenic A. thaliana line accumulated up to ten times more Cd than WT. Despite its higher Cd content, the transgenic A. thaliana line performed better than the WT counterpart. In vitro evaluation of Cd tolerance showed that TaVP1 transgenic A. thaliana lines were more Cd-tolerant than the WT plants. These results suggested that ectopic expression of a vacuolar proton pump in A. thaliana plants can lead to various biotechnological applications including the phytoremediation of industrial wastes.  相似文献   
26.
旋流萃取分离技术处理石化电脱盐废水   总被引:1,自引:0,他引:1       下载免费PDF全文
陈永强  龚小芝  陈发 《化工环保》2015,35(3):297-299
采用旋流萃取分离技术处理某炼油厂常减压装置电脱盐废水(初始废水含油量约为5 000 mg/L),优化了废水除油的工艺条件。试验结果表明,废水除油的最佳工艺条件为:旋流萃取分离机中心转子的转速960 r/min、废水流量2 000 L/h、废水温度80℃。废水经旋流萃取分离后,废水的含油量小于200 mg/L,废水除油效果较好;分离后油相的含水量约为0.1%(w),盐质量浓度小于20 mg/L,可回注到常减压装置原料罐循环利用。对于2 Mt/a的常减压装置,采用旋流萃取分离技术后,每年可减少支出100.4万元。  相似文献   
27.
对江苏省数字地震台网观测系统与模拟台网观测系统在震级测定方面的一致性进行了探讨。定量分析了数字台网的“速度型震级”、“仿真位移型震级”与模拟台网位移震级的差异。初步结果表明 ,在测量误差允许范围内 ,数字网的“仿真位移型震级”可以替代模拟网的位移震级 ,震级测定的连续性要求基本可以保证。  相似文献   
28.
建立了同时测定水中54种挥发性有机物(VOCs)的吹扫捕集-气相色谱-质谱联用法,并对吹扫捕集条件进行了优化。优化后的方法,54种VOCs在0.50~40.00μg/L质量浓度范围内线性良好,相关系数R2均0.995 6,检出限为0.021~0.105μg/L,加标回收率为76.4%~110.8%,相对标准偏差为2.33%~15.8%。该法操作简单,消耗费用低,分析速度快,具有良好的灵敏度、回收率和重现性,能够满足生活饮用水中54种VOCs的同时测定。  相似文献   
29.
We used data on number of carcasses of wildlife species sold in 79 bushmeat markets in a region of Nigeria and Cameroon to assess whether species composition of a market could be explained by anthropogenic pressures and environmental variables around each market. More than 45 mammal species from 9 orders were traded across all markets; mostly ungulates and rodents. For each market, we determined median body mass, species diversity (game diversity), and taxa that were principal contributors to the total number of carcasses for sale (game dominance). Human population density in surrounding areas was significantly and negatively related to the percentage ungulates and primates sold in markets and significantly and positively related to the proportion of rodents. The proportion of carnivores sold was higher in markets with high human population densities. Proportion of small‐bodied mammals (<1 kg) sold in markets increased as human population density increased, but proportion of large‐bodied mammals (>10 kg) decreased as human population density increased. We calculated an index of game depletion (GDI) for each market from the sum of the total number of carcasses traded per annum and species, weighted by the intrinsic rate of natural increase (rmax) of each species, divided by individuals traded in a market. The GDI of a market increased as the proportion of fast‐reproducing species (highest rmax) increased and as the representation of species with lowest rmax (slow‐reproducing) decreased. The best explanatory factor for a market's GDI was anthropogenic pressure—road density, human settlements with >3000 inhabitants, and nonforest vegetation. High and low GDI were significantly differentiated by human density and human settlements with >3000 inhabitants. Our results provided empirical evidence that human activity is correlated with more depleted bushmeat faunas and can be used as a proxy to determine areas in need of conservation action.  相似文献   
30.
赤水河水环境态势研究   总被引:1,自引:0,他引:1  
分析了赤水河近5a水质变化情况,对超标因子进行了原因探讨,并提出了应对措施。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号