全文获取类型
收费全文 | 134篇 |
免费 | 20篇 |
国内免费 | 86篇 |
专业分类
安全科学 | 9篇 |
废物处理 | 5篇 |
环保管理 | 17篇 |
综合类 | 132篇 |
基础理论 | 38篇 |
污染及防治 | 36篇 |
社会与环境 | 3篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 9篇 |
2019年 | 6篇 |
2018年 | 15篇 |
2017年 | 11篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 29篇 |
2012年 | 13篇 |
2011年 | 18篇 |
2010年 | 11篇 |
2009年 | 5篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
排序方式: 共有240条查询结果,搜索用时 625 毫秒
161.
对姜堰市种猪场的污染现状进行了分析,提出猪粪综合利用取得的良好效果。具有操作简单、能耗低、实用性强等特点。 相似文献
162.
超高温预处理对猪粪堆肥过程碳氮素转化与损失的影响 总被引:5,自引:0,他引:5
以猪粪、砻糠为原料,利用自行设计的超高温预处理装置,开展了为期56d的模拟堆肥试验,比较了超高温预处理好氧堆肥(HPC)和常规高温好氧堆肥(CK)过程中碳、氮素转化及损失.结果表明,CK有机质最大降解度(42.58%)比HPC堆体(49.29%)小,但降解速率常数(0.1d-1)高于HPC(0.07d-1),两种堆肥工艺碳素降解率差异不显著.HPC堆体NH4+-N、TN质量分数平均比CK高143.9%、11.2%,而NO3--N质量分数则比CK低58.8%.HPC堆肥后期胡敏酸含量及腐殖质聚合程度分别比CK高45.2%~56.8%、59.1%~65.3%.在预处理阶段以及后续堆肥阶段,HPC、CK有机碳损失率分别为48%、51%,氮损失率分别为18%、27%.说明超高温预处理不仅有利于堆肥过程的保氮,而且促进富里酸向胡敏酸的转化,提高了堆肥产品腐殖化水平. 相似文献
163.
164.
我国主要粮食品种供给与消费平衡分析 总被引:12,自引:1,他引:11
论文基于城市和农村人口及其人均食物消费、粮食工业产品产量、肉蛋奶水产品产量、单位面积种子用量等估算了2013年我国主要粮食品种实际消费量和合理膳食结构下的理想消费量。研究结果显示:我国稻谷、玉米、小麦和薯类以国内生产为主,大豆主要依赖进口;我国稻谷和小麦以口粮消费为主,玉米和豆类以饲料用粮消费为主,薯类以工业用粮和饲料用粮消费为主;稻谷、小麦、玉米和薯类结余量较大,豆类结余量少;按照现有的饮食结构,只需要71%的稻谷生产量和52%的小麦生产量就能完全满足口粮需求。未来应关注稻谷和小麦口粮生产,实施全过程监管以及资金和技术支持,其他用途或品种的粮食生产应由市场主导。 相似文献
165.
采用脉冲式SBR法,对城市污水进行了深度脱氮试验研究.从理论上分析了进水次数和进水量对脉冲式SBR工艺运行特性的影响,得出了脱氮效率公式,并通过试验研究了这些因素对工艺运行的实际影响.理论分析表明,在不投加外碳源的情况下,随着进水次数的增加,脱氮效率依次增加.根据进水C/N的高低,进水方式可分为不等量递增进水、等量进水和不等量递减进水.试验表明,当原水中有机碳源充足时,不等量递减的进水方式相对于等量的进水方式投加较少的外碳源就能实现深度脱氮;随着进水次数的增加,外碳源的投量依次减少,但操作变得复杂,对于普通的城市污水建议采用3次等量的进水方式.采用脉冲式SBR只需投加少量外碳源就可以使处理后的城市污水出水TN低于2mg/L,TN平均去除率达到97.3%. 相似文献
166.
Large males dominate: ecology,social organization,and mating system of wild cavies,the ancestors of the guinea pig 总被引:1,自引:0,他引:1
Matthias Asher Tanja Lippmann Jörg T. Epplen Cornelia Kraus Fritz Trillmich Norbert Sachser 《Behavioral ecology and sociobiology》2008,62(9):1509-1521
Ecological factors differently affect male and female animals and thereby importantly influence their life history and reproductive
strategies. Caviomorph rodents are found in a wide range of habitats in South America and different social and mating systems
have evolved in closely related species. This permits to study the impact of ecological factors on social evolution. In this
study, we investigated the social organization and the mating system of the wild cavy (Cavia aperea), the ancestor of the domestic guinea pig, in its natural habitat in Uruguay. Based on our laboratory investigations, we
expected a polygynous system with large males controlling access to females. Results from radiotelemetry and direct observations
showed that females occupied small stable home ranges which were largely overlapped by that of one large male, resulting in
a social organization of small harems. In some cases, small satellite males were associated with harems and intermediate-sized
roaming males were occasionally observed on the study site. However, microsatellite analyses revealed that offspring were
exclusively sired by large males of the same or neighboring harems, with a moderate degree of multiple paternity (13–27%).
Thus, the mating system of C. aperea can be described as polygynous and contrasts with the promiscuous organization described for other species of cavies (Cavia magna, Galea musteloides and Microcavia australis) living under different ecological conditions. Our findings stress the strong impact of environmental factors on social evolution
in Caviomorphs as resource distribution determines female space use and, thereby, the ability of males to monopolize females.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
167.
Umapron Sadubthummarak Preeda Parkpian Mathuros Ruchirawat Manoch Kongchum R. D. Delaune 《Journal of environmental science and health. Part. B》2013,48(11):974-982
Jatropha seed cake contains high amounts of protein and other nutrients, however it has a drawback due to toxic compounds. The aim of this study was to investigate the methods applied to detoxify the main toxin, phorbol esters in jatropha seed cake, to a safe and acceptable level by maintaining the nutritional values. Phorbol esters are tetracyclic diterpenoids-polycyclic compounds that are known as tumor promoters and hence exhibited the toxicity within a broad range of species. Mismanagement of the jatropha waste from jatropha oil industries would lead to contamination of the environment, affecting living organisms and human health through the food chain, so several methods were tested for reducing the toxicity of the seed cake. The results from this investigation showed that heat treatments at either 120°C or 220°C for 1 hour and then mixing with adsorbing bentonite (10%), nanoparticles of zinc oxide (100 μg/g) plus NaHCO3 at 4%, followed by a 4-week incubation period yielded the best final product. The remaining phorbol esters concentration (0.05–0.04 mg/g) from this treatment was less than that reported for the nontoxic jatropha varieties (0.11–0.27 mg/g). Nutritional values of the seed cake after treatment remained at the same levels found in the control group and these values were crude protein (20.47–21.40 + 0.17–0.25%), crude lipid (14.27–14.68 + 0.13–0.14%) and crude fiber (27.33–29.67 + 0.58%). A cytotoxicity test conducted using L929 and normal human dermal fibroblast cell lines confirmed that most of the toxic compounds, especially phorbol esters, were shown as completely eliminated. The results suggested that the detoxification of phorbol esters residues in the jatropha seed cake was possible while it also retained nutritional values. Therefore, the methods to detoxify phorbol esters are necessary to minimize the toxicity of jatropha seed cake. Further, it is essential to reduce the possible environmental impacts that may be generated throughout the jatropha waste-handling process. However additional tests such as digestibility as well as acceptability of the treated jatropha seed cake should be conducted using both in vivo and in vitro studies before recommending the jatropha seed cake as a source of renewable animal feed and other value-added products. 相似文献
168.
Sayuri Shimazu Yukiko Kawabata Akito Inayoshi Hideyuki Inui Hitoshi Ashida Hideo Ohkawa 《Journal of environmental science and health. Part. B》2013,48(8):741-749
Four expression plasmids for recombinant human aryl hydrocarbon receptor (hAhR) consisting of a ligand binding domain of hAhR, a DNA-binding domain of LexA and a transactivation domain of VP16 as well as β-glucuronidase (GUS) reporter genes were constructed. All the expression plasmids were transformed into tobacco plants. The selected transgenic tobacco plants were used to assay. PCB congeners showed GUS activity in a TEF-dependent manner. The selected transgenic tobacco plant XhD4V17 was compared with the transgenic tobacco plants XmD4V26 and XgD2V23 containing recombinant mouse (m) AhR-mediated GUS reporter gene expression cassette and recombinant guinea pig (g) AhR-mediated GUS reporter gene expression cassette for PCB congener-inducible GUS activity. The data revealed that the tobacco plant XgD2V23 was the most active in PCB congener-inducible GUS activity. In a 1:1 mixture of PCB126 and PCB80 a reduced PCB126-induced GUS activity was observed in plant XgD2V23, which could possibly be due to interaction between PCB126 and PCB80. 相似文献
169.
170.
Yu HY Shen RL Liang Y Cheng H Zeng EY 《Environmental pollution (Barking, Essex : 1987)》2011,159(12):3700-3705
Existing evidence indicated that dichlorodiphenyltrichloroethane (DDT)-containing antifouling paints were an important source of DDT residues to mariculture zones. However, the magnitude of the impact on aquafarming environment has remained largely unknown. In the present study, the concentrations of DDT and its metabolites (designated as DDXs) were determined in harbor sediment and antifouling paint samples collected from a typical mariculture zone in South China. Compositional and concentration correlation analyses implicated the DDT-containing antifouling paints for fishing boat maintenance as an important source of DDT in the mariculture zone. The annual emission of DDXs to the study region was estimated at 0.58 tons/yr. Furthermore, a comparison of the expected DDT loadings in pelagic fish and field measurements indicated that fish feed especially trash fish was a major source of DDTs in the fish body. Nevertheless, the use of DDT-containing antifouling paints should be limited to prevent further deterioration in aquafarming environment. 相似文献