全文获取类型
收费全文 | 1542篇 |
免费 | 98篇 |
国内免费 | 398篇 |
专业分类
安全科学 | 134篇 |
废物处理 | 72篇 |
环保管理 | 129篇 |
综合类 | 742篇 |
基础理论 | 214篇 |
污染及防治 | 441篇 |
评价与监测 | 162篇 |
社会与环境 | 102篇 |
灾害及防治 | 42篇 |
出版年
2024年 | 6篇 |
2023年 | 25篇 |
2022年 | 89篇 |
2021年 | 53篇 |
2020年 | 68篇 |
2019年 | 40篇 |
2018年 | 41篇 |
2017年 | 61篇 |
2016年 | 62篇 |
2015年 | 68篇 |
2014年 | 106篇 |
2013年 | 143篇 |
2012年 | 134篇 |
2011年 | 144篇 |
2010年 | 88篇 |
2009年 | 112篇 |
2008年 | 106篇 |
2007年 | 105篇 |
2006年 | 88篇 |
2005年 | 67篇 |
2004年 | 37篇 |
2003年 | 81篇 |
2002年 | 57篇 |
2001年 | 52篇 |
2000年 | 42篇 |
1999年 | 27篇 |
1998年 | 12篇 |
1997年 | 26篇 |
1996年 | 16篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有2038条查询结果,搜索用时 234 毫秒
551.
Shouhai Li Chunpeng Wang Xiaowei Zhuang Yong Hu Fuxiang Chu 《Journal of Polymers and the Environment》2011,19(1):301-311
Renewable resource-based composites were prepared with acorn powder and Thermoplastic resin poly(lactic acid) (PLA) by twin-screw
extrusion followed by injection molding processing or hot-compression molding processing. The study of the composites microstructure
showed poor adhesion between acorn powder and PLA matrix. The hygroscopicity, mechanical properties and melt flow property
of composites were promising even though the composites had a 70 wt% content of acorn powder. Silane coupling agent, 4,4′-Methylenebis
(phenyl isocyanate) and PLA grafted with maleic anhydride did not show obvious effect on mechanical properties of composites.
The impact resistance strength of reinforced composites with steel fiber webs were improved greatly in comparison with those
having no steel fiber webs. Thermal properties results of DSC and DMA showed that the presence of acorn powder significantly
affected the crystallinity, crystallization temperature (Tc), glass transition temperature (Tg) and melting temperature (Tm) of PLA matrix. The study results proved that composites had superior mechanical properties, enough to partially replace
the conventional thermoplastic plastics. 相似文献
552.
水资源短缺和水污染是我国面临的重要环境问题.受流域自然整体性和流动性的影响,某一行政区的污染通常可以通过水体向另一个或多个行政区转移.传统理论上,人们认为造成跨行政区流域水污染治理困境的主要原因是经济增长方式、产业结构、环境执法效率和管理体制的障碍.实际上,以上因素难以从根本上解释跨行政区流域水污染的治理困境.文章运用博弈理论对流域污染治理中中央政府和地方政府之间的信号传递博弈,以及流域上下游地方政府之间的污染治理博弈进行了分析,结果表明:在区域利益、信息不对称和缺乏激励机制的影响下,地方政府很难真正履行中央政府的治理政策,而污染外部性和利益冲突则使各行政区之间难以达成合作治理,府际博弈的非理性均衡成为跨行政区流域水污染治理困境的深层次原因.鉴于此,跨行政区流域水污染治理必须理解政府的角色和行为,才能找到有效的治理对策.中央政府有必要增强政策威胁的置信度,提高监督和惩治水平,克服地方政府和污染企业达成利益同盟,并通过重复博弈建立行政区之间的流域合作治理机制. 相似文献
553.
Unusual Salinity Conditions in the Yangtze Estuary in 2006: Impacts of an Extreme Drought or of the Three Gorges Dam? 总被引:1,自引:0,他引:1
During the extreme dry year of 2006, abnormal salinity conditions in the Changjiang Estuary of the Yangtze River occurred
in partial coincidence with the second impoundment phase of the TGD (Three Gorges Dam). Analysis of discharge observations
in the upper reaches of the estuary and of salinity observations in the estuary as a whole reveals that in 2006 salinity was
over 100 mg/l during 275 days, over 250 mg/l during 75 days and over 400 mg/l during 48 days. It is well known that this is
due to extreme low discharges from the upper catchment area into the estuary. Moreover, large amounts of water consumed along
the lower reaches of the Yangtze River can also aggravate the low discharges that lead to stronger saltwater intrusion in
the estuary. Of the 75 days that salinity was over 250 mg/l, the low discharge was decreased further by 10 to 20% due to water
consumption. The additional impact of the impoundment phase of the TGD (lasting 37 days in autumn) was noticeable only during
7 days in 2006. During that period, the relative contributions of the TGD and the water consumption in the lower reaches of
the Yangtze River amounted to 70 and 30%, respectively. It may be concluded that the impact of the second impoundment phase
of the TGD on salinity intrusion in the estuary was modest, while the extreme drought of 2006 was the dominant cause. 相似文献
554.
555.
In the present study, groups of juvenile Atlantic salmon (Salmo salar) were fed gelatine capsules containing fish-food spiked with PFOA or PFOS (0.2 mg kg−1 fish) and solvent (methanol). The capsules were given at days 0, 3 and 6. Blood, liver and whole kidney samples were collected prior to exposure (no solvent control), and at days 2, 5, 8 and 14 after exposure (Note: that day 14 after exposure is equal to 7 d recovery period). We report on the differences in the tissue bioaccumulation patterns of PFOS and PFOA, in addition to tissue and compound differences in modulation pattern of biotransformation enzyme genes. We observed that the level of PFOS and PFOA increased in the blood, liver and kidney during the exposure period. Different PFOS and PFOA bioaccumulation patterns were observed in the kidney and liver during exposure- and after the recovery periods. Particularly, after the recovery period, PFOA levels in the kidney and liver tissues were almost at the control level. On the contrary, PFOS maintained an increase with tissue-specific differences, showing a higher bioaccumulation potential (also in the blood), compared with PFOA. While PFOS and PFOA produced an apparent time-dependent increase in kidney CYP3A, CYP1A1 and GST expression, similar effects were only temporary in the liver, significantly increasing at sampling day 2. PFOA and PFOS exposure resulted in significant decreases in plasma estrone, testosterone and cortisol levels at sampling day 2, and their effects differed with 17α-methyltestostrerone showing significant decrease by PFOA (also for cholesterol) and increase by PFOS. PFOA significantly increased estrone and testosterone, and no effects were observed for cortisol, 17α-methyltestosterone and cholesterol at sampling day 5. Overall, the changes in plasma steroid hormone levels parallel changes in CYP3A mRNA levels. Given that there are no known studies that have demonstrated such tissue differences in bioaccumulation patterns with associated differences in toxicological responses in any fish species or lower vertebrate, the present findings provide some potential insights and basis for a better understanding of the possible mechanisms of PFCs toxicity that need to be studied in more detail. 相似文献
556.
Wang Q Wang L Chen X Rao KM Lu SY Ma ST Jiang P Zheng D Xu SQ Zheng HY Wang JS Yu ZQ Zhang R Tao Y Yuan J 《Environmental science and pollution research international》2011,18(6):987-996
Background
Di-(2-ethylhexyl) phthalate (DEHP) is a common plasticizer used in industrial and diverse consumer products. Animal studies indicate DEHP caused developmental, reproductive, and hepatic toxicities. However, human studies of the potential effects of DEHP are limited.Methods
The exposed site with a history of over 20 years of waste plastic recycling was located in Hunan Province, China. The reference site without known DEHP pollution source was about 50 km far away from the exposed site. In this study, 181 workers working in plastic waste recycling and 160 gender?Cage matched farmers were recruited. DEHP concentrations in water and cultivated soil samples, serum thyroid-stimulating hormone, malondialdehyde (MDA), superoxide dismutase (SOD), urinary 8-hydroxy-2??-deoxyguanosine (8-OHdG), and micronuclei frequency in human capillary blood lymphocytes were analyzed.Results
Mean levels of DEHP were greater in environment at the recycling site than at reference site (industry wastewater for the exposed: 42.43 ??g/l; well water: 14.20 vs. 0.79 ??g/l, pond water: 135.68 vs. 0.37 ??g/l, cultivated soil: 13.07 vs. 0.81 mg/kg, p?0.05 for all). The workers had higher median levels of MDA (3.80 vs. 3.14 nmol/ml) and urinary 8-OHdG (340.37 vs. 268.18 ??mol/mol creatinine) and decreased SOD activities (112.15 vs. 123.82 U/ml) than the reference group (p?0.01 for all). Multivariate analysis revealed that the history of working in waste plastic recycling was an independent risk factor for the increased urinary 8-OHdG levels in the male workers (p?0.01).Conclusions
The occupational DEHP exposure might contribute to oxidative deoxyribonucleic acid damage in the male workers. 相似文献557.
Jian-Guang Wu Xiang-Yu Meng Xiao-Meng Liu Xian-Wei Liu Zhi-Xia Zheng De-Qian Xu Guo-Ping Sheng Han-Qing Yu 《Environmental management》2010,46(4):610-617
Life cycle assessment (LCA) was applied to analyze a food-processing wastewater treatment plant and investigate the economic
and environmental effects of the plant. With the long-term operational data of this plant, an inventory of relative inputs,
e.g., flow rate, chemical oxygen demand (COD), and suspended solids, etc., and outputs of the plant, e.g., effluent COD and
suspended solids, methane production, etc., was compiled. The potential environmental effects associated with those inputs
and outputs were evaluated, and the results of the inventory analysis and impact assessment phases of the plant were interpreted.
One feature of this study was the assessment of the treatment plant based on both energy and material flows. Another feature
was the establishment of an assessment model with an integration of plant operating parameters, system recognition and grey
relation. The analytical results are helpful for the design and operation of wastewater treatment plants. 相似文献
558.
In this study, we present a general protocol for the making of surface-imprinted core-shell magnetic beads via reversible addition-fragmentation chain transfer (RAFT) polymerization using RAFT agent functionalized iron oxide nanoparticles as the chain transfer agent. The resulting composites were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) analysis, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface-imprinted magnetic beads were demonstrated with a homogeneous polymer films (thickness of about 22 nm), spherical shape, and exhibited magnetic property (Ms = 0.41 mA m2 g−1) and thermal stability. Rebinding experiments were carried out to determine the specific binding capacity and selective recognition. The as-synthesized surface-imprinted core-shell magnetic beads showed outstanding affinity and selectivity towards bisphenol A over structurally related compounds, and easily reach the magnetic separation under an external magnetic field. In addition, the resulting composites reusability without obviously deterioration in performance was demonstrated at least five repeated cycles. 相似文献
559.
浙东沿海城市大气颗粒物污染特征及来源解析研究 总被引:5,自引:0,他引:5
对2009年夏季浙东沿海地区环境空气质量进行监测,监测大气颗粒物(TSP、PM10、PM2.5、PM1.0)浓度,分析颗粒物污染特征、水溶性离子及无机元素组成,运用化学质量平衡受体模型(CMB模型)对浙东沿海地区大气TSP来源进行解析.结果表明,浙东沿海地区的大气颗粒物主要以细颗粒物为主,颗粒物中主要的水溶性离子为SO2-4、NH+4、Ca2+,土壤尘是该地区大气TSP的主要来源,北仑、乐清和奉化TSP中土壤尘的分担率分别达到55.49%、42.52%、40.70%,各监测点TSP来源具有一定的地域特征. 相似文献
560.