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201.
Stanislaw Frackowiak Joanna Ludwiczak Karol Leluk 《Journal of Polymers and the Environment》2018,26(12):4360-4368
Biodegradable and ecologically friendly polymer materials attract great attention of many scientific groups in the world as they fit well in the sustainable development policy and are considered to be “a right thing to do” by the general public. Such polymers can be modified by the addition of different fillers, favorably of natural origin. In the paper we provide a comparison between composites based on two biodegradable polymers: poly(lactic acid)—biodegradable, natural stock polymer and poly(butylene succinate)—biodegradable polymer produced from fossil based materials. For each polymer we have prepared a series of composites with different fibres (natural: hemp and flax, and manmade: Cordenka) and different filler loadings. To fully characterize obtained materials thermal, mechanical and surface free energy measurements were performed, completed with morphology observations and an attempt to compare the experimental data for tensile measurements with values obtained using the modified rule of mixtures. The tensile results calculated using the modified rule of mixture for below 30% fibre loading are found to be fitting the experimental data. Composites mechanical properties and morphology were strongly affected by the type of fibre used and its loading, however thermal properties remained almost unchanged. In specific, Cordenka fibres tend to form bunches which presence greatly influences the mechanical properties but still our studies have shown clear advantage of manmade Cordenka fibres over the hemp and flax fibres when considering distribution and fibre–polymer interaction. 相似文献
202.
A national Baumol–Oates tax on waste in Denmark helped achieve a reduction of 26% in net solid waste from 1987 to 1998. The
tax, which is levied per ton of waste, was particularly effective as regards the heavier waste streams such as construction
waste and garden waste. When it comes to industrial and commercial waste, there are indications that the waste tax is not
sufficiently significant to induce changes in behavior, and that except for very waste-intensive enterprises, companies do
not seem to be very price sensitive. For household waste, the impact of the tax can be improved where tariffs for garbage
collection are weight based, rather than per unit. However, the waste sector is an area in which the price signals are modified
and filtered by institutionalized practices in municipal administration, and in which true-cost pricing is not easy to achieve.
Hence, the rational choice assumption of environmental economics needs to be supplemented by an institutional dimension to
interpret responses to environmental taxes correctly.
Received: July 13, 2001 / Accepted: October 2, 2001 相似文献
203.
Sławomir Stelmach Ryszard Wasielewski 《Journal of Material Cycles and Waste Management》2008,10(2):110-115
More than 1.1 million tons of municipal and industrial sewage sludge is produced annually in Poland. Most of this sewage sludge
is landfilled or used for recultivation and fertilization of soil. After accession of Poland to the EU, large investments
are planned for wastewater treatment, so it is expected that the amount of sewage sludge produced in Poland will grow in the
near future. It is well known that the combustion of sewage sludge is becoming a more and more popular utilization method
of such waste. Unfortunately, the current situation in Poland makes it impossible to incinerate the sewage sludge because
of a lack of incinerators. One possible solution for Poland is the co-firing of dried sewage sludge in existing coal-fired
utility boilers. This article presents results of initial Polish industrial trials of dried municipal sewage sludge and hard
coal co-combustion in an OP-230 pulverized coal boiler. Such a solution was shown to be technically viable and not to require
changes to the existing technological system. Cocombustion of sewage sludge with coal in power plants seems to be the best
solution for sludge utilization in the near future in Poland. 相似文献
204.
Aaron I. Packman Andrea Marion Mattia Zaramella Cheng Chen Jean-François Gaillard Denis T. Keane 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):433-442
Hyporheic exchange is known to provide an important control on nutrient and contaminant fluxes across the stream-subsurface
interface. Similar processes also mediate interfacial transport in other permeable sediments. Recent research has focused
on understanding the mechanics of these exchange processes and improving estimation of exchange rates in natural systems.
While the structure of sediment beds obviously influences pore water flow rates and patterns, little is known about the interplay
of typical sedimentary structures, hyporheic exchange, and other transport processes in fluvial/alluvial sediments. Here we
discuss several processes that contribute to local-scale sediment heterogeneity and present results that illustrate the interaction
of overlying flow conditions, the development of sediment structure, pore water transport, and stream-subsurface exchange.
Layered structures are shown to develop at several scales within sediment beds. Surface sampling is used to analyze the development
of an armor layer in a sand-and-gravel bed, while innovative synchrotron-based X-ray microtomography is used to observe patterns
of grain sorting within sand bedforms. We show that layered bed structures involving coarsening of the bed surface increase
interfacial solute flux but produce an effective anisotropy that favors horizontal pore water transport while limiting vertical
penetration. 相似文献
205.
Waste incineration is becoming increasingly necessary to tackle the rapidly rising amounts of municipal solid waste (MSW);
in China many large cities are already surrounded by a girdle of landfills. Still, the not-in-my-backyard (nimby) syndrome
holds strong. This attitude stems from fear of dioxins. These have been associated with incineration (‘dioxin factories’)
and at times also with polyvinylchloride. In this paper this issue is analysed. China should build additional trust in MSW
incineration, following promulgation of stricter emission standards, enforced by stringent controls. 相似文献
206.
K. Abdel Tawab M. M. Magida Sayeda M. Ibrahim 《Journal of Polymers and the Environment》2011,19(2):440-446
Blends of water—soluble polymers based on Poly vinyl alcohol (PVA) and Polyethylene glycol (PEG) have been prepared by the
solution casting technique. The effect of various doses of γ-radiation on the structural properties of PVA/PEG polymer blends
with all its compositions has been investigated. From the visual observation of all the blend compositions, it was found that,
the best compatibility of the blend is up to 40% PVA/60%PEG. The structure–Property behavior of all the prepared blends before
and after γ-irradiation was investigated by IR Spectroscopy, thermogravimetric analysis (TGA), mechanical properties and Scanning
electron microscope (SEM). The gel content and the swelling behavior of the PVA/PEG blends were investigated. It was found
that the gel content increases with increasing irradiation dose and PVA concentration in the blend. Swelling percent increased
as the composition of PEG increased in the blend. The results obtained by FTIR analysis and SEM confirm the existence of possible
interaction between PVA and PEG homopolymers. TGA of PVA/PEG blend, before and after γ-irradiation, showed that the unirradiated
and irradiated PVA/PEG blends are more stable against thermal decomposition than pure PVA. Improvement in tensile mechanical
properties of PVA/PEG blends was occurred. 相似文献
207.
Poly-β-hydroxybuyrate (PHB) is a carbon—energy storage material which is accumulated as intracellular granule in variety of
microorganism under nutrient starved conditions. Solid PHB is a biodegradable thermoplastic polymer and is utilizable in various
ways similar to many conventional plastics. Ralstonia eutropha (Alcaligenes sp.), a gram negative bacteria accumulates PHB as insoluble granules inside the cells when nutrients other than carbon are
limited. In this report effort has been made to analyze PHB granule synthesis inside Alcaligenes sp. NCIM 5085 by transmission electron microscopy and qualitative estimation of PHB was carried out by fourier transform
infrared spectroscopy which provide better precision compared to other conventional techniques previously applied for PHB
determination. Maximum PHB concentration of 2.20 ± 0.40 g/L and cell biomass of 3.42 ± 0.20 g/L was obtained after 48.0 h
of fermentation. Leudking-Piret equation deduced mixed growth associated product formation which varies from earlier reports. 相似文献
208.
Process,Characterization and Biodegradability of Aliphatic Aromatic Polyester/Sisal Fiber Composites
Chin-San Wu 《Journal of Polymers and the Environment》2011,19(3):706-713
The biodegradability, morphology, and mechanical properties of composite materials made of Poly(butylene adipate-co-terephthalate) (PBAT) and sisal fiber (SF) were evaluated. Composites containing acrylic acid-grafted PBAT (PBAT-g-AA/SF)
exhibited noticeably superior mechanical properties due to greater compatibility between the two components. The dispersion
of SF in the PBAT-g-AA matrix was highly homogeneous as a result of ester formation between the carboxyl groups of PBAT-g-AA
and hydroxyl groups in SF and the consequent creation of branched and cross-linked macromolecules. Each composite was subjected
to biodegradation tests in Rhizopus oryzae compost. Morphological observations indicated severe disruption of film structure after 60 days of incubation, and both the
PBAT and the PBAT-g-AA/SF composite films were eventually completely degraded. Water resistance of PBAT-g-AA/SF was higher
than that of PBAT/SF, although weight loss of composites buried in Rhizopus oryzae compost indicated that both were biodegradable, even at high levels of SF substitution. The PBAT-g-AA/SF films were more
biodegradable than those made of PBAT, implying a strong connection between these characteristics and biodegradability. 相似文献
209.
Hisanori Watanabe Hidekichi Yoshino 《Journal of Material Cycles and Waste Management》2011,13(2):113-117
Since hydrogen is a renewable energy source, biohydrogen has been researched in recent years. However, data on hydrogen fermentation
by a leachate from a waste landfill as inoculum are scarce. We investigated hydrogen production using a leachate from an industrial
waste landfill in Kanagawa Prefecture. The results showed no methane gas production, and the leachate was a suitable inoculum
for hydrogen fermentation. The maximum H2 yield was 2.67 mol of H2 per mol of carbohydrate added, obtained at 30°C and an initial pH of 7. The acetate and butyrate production was significant
when the H2 yield was higher. Oxidation–reduction potential analysis of the culture suggested that hydrogen-producing bacteria in the
leachate were facultative anaerobic. Scanning electron microscope observations revealed that the hydrogen-producing bacteria
comprised bacilli about 2 μm in length. 相似文献
210.