全文获取类型
收费全文 | 2138篇 |
免费 | 188篇 |
国内免费 | 980篇 |
专业分类
安全科学 | 146篇 |
废物处理 | 181篇 |
环保管理 | 242篇 |
综合类 | 1430篇 |
基础理论 | 528篇 |
污染及防治 | 495篇 |
评价与监测 | 55篇 |
社会与环境 | 83篇 |
灾害及防治 | 146篇 |
出版年
2024年 | 8篇 |
2023年 | 44篇 |
2022年 | 82篇 |
2021年 | 104篇 |
2020年 | 92篇 |
2019年 | 97篇 |
2018年 | 111篇 |
2017年 | 122篇 |
2016年 | 124篇 |
2015年 | 132篇 |
2014年 | 187篇 |
2013年 | 268篇 |
2012年 | 184篇 |
2011年 | 215篇 |
2010年 | 142篇 |
2009年 | 156篇 |
2008年 | 103篇 |
2007年 | 173篇 |
2006年 | 163篇 |
2005年 | 118篇 |
2004年 | 97篇 |
2003年 | 88篇 |
2002年 | 75篇 |
2001年 | 66篇 |
2000年 | 58篇 |
1999年 | 52篇 |
1998年 | 37篇 |
1997年 | 36篇 |
1996年 | 41篇 |
1995年 | 32篇 |
1994年 | 24篇 |
1993年 | 13篇 |
1992年 | 16篇 |
1991年 | 15篇 |
1990年 | 7篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有3306条查询结果,搜索用时 15 毫秒
71.
采用批次小试实验对不同腐熟程度的蓝藻进行厌氧发酵产沼气实验研究。结果表明,新鲜蓝藻在30-35℃时腐熟7 d后,可在35℃的厌氧温度下获得最高的产气速率和246 mL/g COD的产气量,产气潜力为354 mL/g(VS)。厌氧反应15 d后,累计产气量、COD和VFA浓度趋于稳定。淀粉酶和脱氢酶的活性在厌氧反应初期受到抑制,蛋白酶活性和辅酶F420浓度在厌氧系统中逐渐增加,分别在第6天达到27.66μmol/(g VS·min)和第15天达到0.62μmol/g(VS)。15-18d是腐熟蓝藻适宜的中温厌氧发酵时间,少于以新鲜蓝藻为基质的厌氧消化时间。蓝藻腐熟过程促进了厌氧反应,腐熟7 d的蓝藻厌氧系统具有更高的微生物活性和产甲烷能力。 相似文献
72.
73.
介绍了氧化铁黄生产中的废水治理情况,同时其产生的废渣可回收利用。经过治理产生的环境、经济和社会效益显著。 相似文献
74.
Pencycuron application to soils: degradation and effect on microbiological parameters 总被引:2,自引:0,他引:2
Clay loam soil from agricultural fields of alluvial (AL) soil (typic udifluvent) and coastal saline (CS) soil (typic endoaquept) were investigated for the degradation and effect of pencycuron application at field rate (FR), 2-times FR (2FR) and 10-times FR (10FR) with and without decomposed cow manure (DCM) on soil microbial variables under laboratory conditions. Pencycuron degraded faster in CS soil and in soil amended with DCM. Pencycuron spiking at FR and 2FR resulted in a short-lived (in case of 10FR slightly longer) and transitory toxic effect on soil microbial biomass-C (MBC), ergosterol content and fluorescein diacetate hydrolyzing activity (FDHA). Amendment of DCM did not seem to have any counteractive effect of the toxicity of pencycuron on the microbial variables. The ecophysiological status of the soil microbial communities as expressed by microbial metabolic quotient (qCO2) and microbial respiration quotient (Q(R)) changed, but for a short period, indicating pencycuron induced disturbance. The duration of this disturbance was slightly longer at 10FR. Pencycuron was more toxic to the metabolically activated soil microbial populations, specifically the fungi. It is concluded that side effects of pencycuron at 10FR on the microbial variables studied were only short-lived and probably of little ecological significance. 相似文献
75.
Organic residue decomposition: The minicontainer-system a multifunctional tool in decomposition studies 总被引:1,自引:0,他引:1
Gerhard Eisenbeis Ralf Lenz Thomas Heiber 《Environmental science and pollution research international》1999,6(4):220-224
The Minicontainer-test, first described by Eisenbeis (1993), was designed to study the kinetics of organic residue decomposition
at a microsite level. It is derived from the litterbag technique and consists of polyethylene minicontainers (volume about
1.5 cm3) filled with a test substrate (litter, straw, cellulose, etc.). The minicontainers (MCs) are closed at either end with plastic
gauze discs of variable mesh size (e.g. 20 μm, 250 μm, 500 μm or 2 mm). A definite number of such units are inserted into
PVC-bars, which can be implanted into the soil horizontally or vertically, or be exposed on the soil surface horizontally.
The bars are very stable and can be exposed in different environments for months to years. If required, the bars can be removed
temporarily and stored, e.g. during soil cultivation. Should fresh litter be used, two phases of decomposition can be distinguished:
a fast initial phase, which can be mainly related to the effect of leaching, and a second slow phase depending mainly on the
activity of soil organisms and litter quality. Several questions can be addressed to investigations using MCs, e.g. 1) parts
of the soil fauna which are involved in decomposition (nematodes, microarthropods, and smaller specimens of the macrofauna,
e.g. enchytraeidae, diplopods and dipteran larvae) can be extracted from the litter substrate using a miniscale high gradient
extractor, 2) the organic mass loss of litter can be determined, 3) microbial biomass (Cmic, Nmic) can be assessed by fumigation extraction and 4) microbial activity (respiration) in the test substrate can also be assessed
by use of standardised methods. Compared to litterbag studies, the larger number of small replicate units improves the statistical
evaluation. Until today the Minicontainer-test has been applied in forestry and agriculture, e.g. studying the effects of
liming, soil restoration and the application of insecticides, e.g. Diflubenzuron (Dimilin) and Btk (Bacillus thuringiensis var.kurstaki). 相似文献
76.
Yoshitaka Yonezawa Manabu Fukui Shigeki Masunaga Yoshikuni Urushigawa 《Chemosphere》1994,28(12):2179-2184
The relation between dechlorination activities of 1,2,4-trichlorobenzene and anaerobic microbial activity were studied in the sediment collected at three sites in Ise Bay in Japan. The degradation rate of spiked 1,2,4-trichlorobenzene (3nmol ml−1) ranged from 15 to 35 pmol day−1 ml−1 wet sediment and about 1/3 to 1/2 of degraded the trichlorobenzene was recovered as dechlorinated products. Among the dichlorobenzenes, the 1,2-isomer had the highest and 1,3-isomer had the lowest production rate. Comparing the three sampling sites, the trichlorobenzene degradation and dichlorobenzenes production rates were related to the sulfate reducing activity for the unit number of sulfate reducing bacteria. Production rates of dichlorobenzenes were completely inhibited by adding molybdate (20 mM), nitrate (60 mM), and formaldehyde solution (4 %). These results indicated that dechlorination activity in the Ise Bay sediment was supported by sulfate reduction activity in the sediment, and not supported by any other anaerobic microbial activity. 相似文献
77.
78.
The influence of intact (FLT) and photomodified (phFLT) fluoranthene (0.05, 0.5 and 5 μmol l−1) and herbicide Basagran (5, 20, 35 and 50 nmol l−1) on the germination, growth of seedlings and photosynthetic processes in pea plants (Pisum sativum L., cv. Garde) was investigated. The germination was significantly inhibited already by the lowest concentration (0.05 μmol l−1) of FLT and phFLT, while Basagran caused inhibition only in higher concentrations (35 and 50 nmol l−1). The growth of roots was significantly inhibited by higher concentration 5 μmol l−1 of both FLT and phFLT and the shoot of seedlings was significantly influenced only by photomodified form. The length of root and shoot was inhibited already by concentration 5 nmol l−1 of Basagran. Organic compounds applied on chloroplasts suspension influenced primary photochemical processes of photosynthesis. In chlorophyll fluorescence parameters, the significant increase of F0 values and the decrease of FV/FM and ΦII values by application of FLT (0.5 and 5 μmol l−1) and phFLT (0.05, 0.5 and 5 μmol l−1) was recorded. The maximum capacity of PSII (FV/FM) was influenced by the highest (50 nmol l−1) and the effective quantum yield of PSII (ΦII) already by the lowest (5 nmol l−1) concentration of Basagran. Hill reaction activity decreased and was significantly inhibited by higher concentration (0.5 and 5 μmol l−1) of FLT and phFLT and already by the lowest concentration (5 nmol l−1) of Basagran. 相似文献
79.
Mal'kova M. G. Pal'chekh N. A. Yakimenko V. V. Kuz'min I. V. 《Russian Journal of Ecology》2004,35(1):27-34
The spatial structure of populations has been studied in two rodent species inhabiting the subzone of meadow steppes of the steppe zone of Omsk oblast: the narrow-sculled vole (Microtus gregalis Pall.) and steppe lemming (Lagurus lagurus Pall.). Their populations are represented by combinations of territorial family groups whose structure and spatial distribution vary by season depending on population density, the phase of the population cycle, and the status of their members in the population. In the areas cohabited by M. gregalis and L. lagurus, the pattern of territory use and the rhythm of animal activity during the day depend primarily on their total density: under conditions of low density, the population groups of both species are spatially separated; at increased density, they are distributed with respect to the pattern of daily activity. Both species jointly use part of the territory but at different times of day: M. gregalis, mainly at night and in the morning; L. lagurus, in the daytime. 相似文献
80.
Methodological Basis of Ecological Safety Standards for the Technogenic Impact of Mineral Resource Exploitation 总被引:1,自引:0,他引:1
A new methodological approach to the development of biological and technological safety standards for the impact of underground mining on the natural biota is proposed. 相似文献