全文获取类型
收费全文 | 17161篇 |
免费 | 162篇 |
国内免费 | 285篇 |
专业分类
安全科学 | 315篇 |
废物处理 | 856篇 |
环保管理 | 1640篇 |
综合类 | 2783篇 |
基础理论 | 3898篇 |
环境理论 | 6篇 |
污染及防治 | 4688篇 |
评价与监测 | 1402篇 |
社会与环境 | 1940篇 |
灾害及防治 | 80篇 |
出版年
2023年 | 122篇 |
2022年 | 297篇 |
2021年 | 290篇 |
2020年 | 145篇 |
2019年 | 186篇 |
2018年 | 367篇 |
2017年 | 359篇 |
2016年 | 532篇 |
2015年 | 349篇 |
2014年 | 638篇 |
2013年 | 1498篇 |
2012年 | 694篇 |
2011年 | 828篇 |
2010年 | 670篇 |
2009年 | 686篇 |
2008年 | 860篇 |
2007年 | 902篇 |
2006年 | 735篇 |
2005年 | 624篇 |
2004年 | 612篇 |
2003年 | 556篇 |
2002年 | 518篇 |
2001年 | 581篇 |
2000年 | 410篇 |
1999年 | 221篇 |
1998年 | 153篇 |
1997年 | 164篇 |
1996年 | 163篇 |
1995年 | 217篇 |
1994年 | 164篇 |
1993年 | 146篇 |
1992年 | 140篇 |
1991年 | 148篇 |
1990年 | 153篇 |
1989年 | 129篇 |
1988年 | 109篇 |
1987年 | 108篇 |
1986年 | 99篇 |
1985年 | 111篇 |
1984年 | 113篇 |
1983年 | 94篇 |
1982年 | 107篇 |
1981年 | 94篇 |
1980年 | 88篇 |
1979年 | 91篇 |
1977年 | 64篇 |
1974年 | 64篇 |
1973年 | 67篇 |
1972年 | 85篇 |
1964年 | 67篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
961.
Asogan N. Gounden Sreekanth B. Jonnalagadda 《Environmental monitoring and assessment》2013,185(10):8227-8237
The ozone-initiated oxidation of 2-chloroethanol was followed by monitoring the consumption of the halogenated organic substrate. Gas chromatographic analysis of the ozonated products showed an increase in conversion from about 1 % after 3 h of ozone treatment to about 22 % after 12 h. The yields of major ozonated products identified and quantified namely acetaldehyde, acetic acid, and chloride ion increased proportionately as a function of ozone treatment time. The percent conversion of 2-chloroethanol in the presence of acetic acid or ethyl acetate were found to be higher than those under solvent-free conditions with similar products obtained. The use of activated charcoal during the ozonolyis of 2-chloroethanol showed a significant increase in the percent conversion of the substrate compared to solvent free ozonation. Based on the experimental findings, the overall mechanism for the reaction between 2-chloroethanol and ozone is described. 相似文献
962.
963.
964.
V. Vijayasree Hebsy Bai S. Naseema Beevi Thomas Biju Mathew Thomas George George Xavier 《Environmental monitoring and assessment》2015,187(5):299
Dissipation and decontamination of chlorantraniliprole (Coragen 18.5 SC) in brinjal and okra fruits were studied following field application at single and double doses of 30 and 60 g ai ha?1, and the residues of the insecticide was estimated using LC-MS/MS. Initial residues of chlorantraniliprole at single and double doses on the fruits of brinjal were 0.72 and 1.48 mg kg?1, while on okra fruits, the residues were 0.48 and 0.91 mg kg?1, respectively. The residues reached below detectable level of 0.01 mg kg?1 on the 10th day. Half-life of chlorantraniliprole at 30 and 60 g ai ha?1 on brinjal was 1.58 and 1.80 days with the calculated waiting period of 0.69 and 2.38 days, whereas on okra, the values were 1.60 and 1.70 and 0 and 1.20 days, respectively. The extent of removal of chlorantraniliprole using simple decontaminating techniques at 2 h and 3 days after spraying was 40.99–91.37 % and 29.85–89.12 %, respectively, from brinjal fruits and 47.78–86.10 % and 41.77–86.48 %, respectively, from okra fruits. 相似文献
965.
966.
967.
968.
Montes AM González-Farias FA Botello AV 《Environmental monitoring and assessment》2012,184(3):1359-1369
The lagoon system of Navachiste-Macapule is located in northern Mexico, in the state of Sinaloa, with an area of 24,000 ha.
The main economic activity in the area is agriculture, and the lagoon lies next to the irrigation district ID-063 which covers
116,615 ha. The purpose of this study is to evaluate the levels of pollution generated by organochlorine pesticides (OC) in
the surface sediments of the lagoon and in the agricultural drains of the ID-063 that are supposedly transported into the
system as a result of agricultural activities and runoff from adjacent land. For this, between 2006 and 2007, 45 surface sediment
samples were collected (warm dry, rainy and cold dry) from 15 sampling sites, during the three climatic seasons. Of these,
eight were located inside the lagoon in marine conditions (salinity >31 PSU) and seven in the agricultural drains of the ID-063
in freshwater conditions (salinity <5 PSU). The average concentration of the OC in the sediments was 44.75 ng g − 1, among which the group of the alicyclic compounds presented the greatest concentrations. The average value of the total organic
carbon (TOC) in the sediments of the system was 0.90%. The sediments collected inside the lagoon had an average OC concentration
of 18.97 ng g − 1, and the predominant type of sediment was fine to very fine sand. The average OC concentration in the sediments collected
in the agricultural drains was 75.69 ng g − 1, where fine sediments (silt) were predominant. The presence of methoxychlor, endrin and heptachlor suggested that these compounds
were continuously used in the system, even though their use is forbidden in Mexico. 相似文献
969.
de Figueiredo DR Ferreira RV Cerqueira M de Melo TC Pereira MJ Castro BB Correia A 《Environmental monitoring and assessment》2012,184(1):471-485
The information on bacterial community composition (BCC) in Portuguese water bodies is very scarce. Cértima River (central
western Portugal) is known to have high levels of pollution, namely organic. In the present work, the BCC from a set of 16
water samples collected from Cértima River Basin and its main tributaries was characterized using 16S rDNA–denaturing gradient
gel electrophoresis, a culture-independent molecular approach. Molecular data were related to environmental parameters through
multivariate analysis to investigate potential impact of water pollution along the river. Principal component analysis using
environmental data showed a water quality gradient from more pristine waters (at the mountain tributaries) to waters with
increasingly eutrophic potential (such as Fermentelos Lake). This gradient was mainly defined by factors such as organic and
inorganic nutrient sources, electrical conductivity, hydrogen carbonate concentration, and pH. Molecular results showed variations
in BCC along Cértima River Basin but in the main river section, a Bacteroidetes phylotype (Flavobacterium sp.) proved to be dominant throughout the river course. Multivariate analysis suggests that spatial variation of BCC along
the Cértima River Basin depended mainly on parameters such as Chl a, total suspended solid (TSS), total organic carbon, electrical conductivity, and HCO
_boxclose^-_{3}^{-} levels. Bacteroidetes phylotypes were all related to higher electrical conductivity and HCO3-_{3}^{-} levels although some of these were also correlated with high SO42-_{4}^{2-} and others with high soluble reactive phosphorus, nitrate, TN, and Kjeld-N levels. The Gammaproteobacteria occurrence was correlated with high SO42-_{4}^{2-} levels. One of the Betaproteobacteria phylotypes showed to correlate with low redox potential (Eh) and high temperature, pH, TSS, and Chl a levels while another one showed a negative correlation with Chl a values. 相似文献
970.
Fernandes CE Das A Nath BN Faria DG Loka Bharathi PA 《Environmental monitoring and assessment》2012,184(5):2677-2689
We investigated the influence on bacterial community and biochemical variables through mechanical disturbance of sediment-akin
to small-scale mining in Kalbadevi beach, Ratnagiri, a placer-rich beach ecosystem which is a potential mining site. Changes
were investigated by comparing three periods, namely phase I before disturbance, phase II just after disturbance, and phase
III 24 h after disturbance as the bacterial generation time is ≤7 h. Cores from dune, berm, high-, mid-, and low-tide were
examined for changes in distribution of total bacterial abundance, total direct viability (counts under aerobic and anaerobic
conditions), culturability and biochemical parameters up to 40 cm depth. Results showed that bacterial abundance decreased
by an order from 106 cells g − 1 sediment, while, viability reduced marginally. Culturability on different-strength nutrient broth increased by 155% during
phase II. Changes in sedimentary proteins, carbohydrates, and lipids were marked at berm and dune and masked at other levels
by tidal influence. Sedimentary ATP reduced drastically. During phase III, Pearson’s correlation between these variables evolved
from non-significant to significant level. Thus, simulated disturbance had a mixed effect on bacterial and biochemical variables
of the sediments. It had a negative impact on bacterial abundance, viability and ATP but positive impact on culturability.
Viability, culturability, and ATP could act as important indicators reflecting the disturbance in the system at short time
intervals. Culturability, which improved by an order, could perhaps be a fraction that contributes to restoration of the system
at bacterial level. This baseline information about the potential mining site could help in developing rational approach towards
sustainable harnessing of resources with minimum damage to the ecosystem. 相似文献