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331.
本文从综合利用资源的角度出发,介绍了利用部份低品位矿产生产水泥工业原料、水泥产品具有显著的经济效益和社会效益。 相似文献
332.
In this study, black rice husk ash (BRHA) from a rice mill in Thailand was ground and used as a partial cement replacement. The durability of conventional concretes with high water–binder ratios was investigated including drying shrinkage, autogenous shrinkage, depth of carbonation, and weight loss of concretes exposed to hydrochloric (HCl) and sulfuric (H2SO4) acid attacks. Two different replacement percentages of cement by BRHA, 20% and 40%, and three different water–binder ratios (0.6, 0.7 and 0.8) were used. The ratios of paste volume to void content of the compacted aggregate (γ) were 1.2, 1.4, and 1.6. As a result, when increasing the percentage replacement of BRHA, the drying shrinkage and depth of carbonation reaction of concretes increased. However, the BRHA provides a positive effect on the autogenous shrinkage and weight loss of concretes exposed to hydrochloric and sulfuric acid attacks. In addition, the resistance to acid attack was directly varied with the (SiO2 + Al2O3 + Fe2O3)/CaO ratio. Results show that ground BRHA can be applied as a pozzolanic material and also improve the durability of concrete. 相似文献
333.
334.
《Journal of Manufacturing Processes》2014,16(4):511-517
In this paper, laser additive manufacturing (LAM) of Fe–TiC composite coating on AISI 1030 carbon steel is investigated using a numerical and experimental method. In order to have a desired result using LAM, it is crucial to understand the effects of the process parameters’ values on the TiC morphology and microstructure. For this purpose, the LAM process is numerically simulated in order to calculate cooling rate and peak temperature. Experimental data and numerical results are in good agreement in terms of the phase development. Results show that cooling rate plays a crucial role in phase transformation in the clad, however, final microstructure strongly depends on the cooling rate and powder's chemical composition. Two main carbide morphologies (i.e. dendritic and particulate) are studied and relevant cooling rates are detected. Based on this paper and developed map, it is possible to control the cooling rate in order to achieve specific carbide morphologies in the clad. In this study, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are used to characterize clads’ microstructure. 相似文献
335.
陈本峰 《安全.健康和环境》2014,14(4):29-31
结合中海福建天然气有限责任公司在安全文化建设方面的成功实践,对企业安全文化建设的途径和方法提出建议。 相似文献
336.
337.
总结了绿色建材的基本概念与评价方法,介绍了绿色混凝土、绿色墙体材料、绿色涂料、相变储能建筑材料,认为绿色建材和绿色建筑技术将成为未来建筑行业的主要研究方向之一,今后我国绿色建材发展的主要前提首先是提高政府、设计人员的环保意识,其次要健全评价体系。 相似文献
338.
Seidel B Alm M Peters R Kördel W Schäffer A 《Environmental science and pollution research international》2006,13(2):125-130
Background Due to the bovine spongiform encephalopathy (BSE), specified risk material (SRM) as well as animal meat and bone meal (MBM)
are banned from the food and feed chain because of a possible infection with pathogenic prions (PrPSc). Nowadays, prions are
widely accepted to be responsible for TSE(transmissible spongiform encephalopathies)-caused illnesses like BSE and scrapie,
and especially for the occurrence of the new variant of CJD in humans. Presently, SRM and MBM are burnt under high temperatures
to avoid any hazards for humans, animals or the environment. The aim of this study was to evaluate a method using animal fat
separated from Category I material which includes SRM and the carcasses of TSE-infected animals, or animals suspected of being
infected with TSE, as a source for producing biodiesel by transesterification, analogous to the biodiesel process using vegetable
oil.
Methods For this purpose, animal fat was spiked with scrapie-infected hamster brain equivalents – as representative for a TSE-infected
animal – and the biodiesel manufacturing process was downscaled and performed under lab-scale conditions.
Results and Discussion The results analysed by Western blotting showed clearly that almost each single step of the process leads to a significant
reduction of the concentration of the pathogenic prion protein (PrPSc) in the main and side-products.
Conclusion The data revealed that the biodiesel production, even from material with a high concentration of pathogenic prions, can be
considered as safe.
Recommendations and Outlook The obtained results indicated that biodiesel produced from prion-contaminated fat was safe under the tested process conditions.
However, it has to be pointed out that the results cannot be generalized because a different process control using other conditions
may lead to different results and then has to be analysed independently. It is clear that the production of biodiesel from
high risk material represents a more economic usage than the combustion of such material. 相似文献
339.
从理论和实践两方面提出用后浇带的方法,可以达到控制混凝土水池裂缝,取消或扩大永久伸缩缝间距的目的,同时介绍了后浇带的设计原则和施工方法,以及注意事项 相似文献
340.
Burchard H. Heede 《Journal of the American Water Resources Association》1972,8(3):523-530
ABSTRACT The influence of a forest on the formation of steps in two small streams of the Colorado Rocky Mountains was studied. Steps provided by logs fallen across the channel added to flow energy reduction. The streams required additional gravel bars to adjust to slope. Average step length between logs and gravel bars was strongly related to channel gradient and median bed material size. Based on the average number of log steps per 50 feet of channel, an average of 116 percent of gravel bars were added at Fool Creek and 60 percent at Deadhorse Creek. The latter had 52 percent more logs in the channel and therefore required less bed material movement than the former. Although these are “rushing mountain streams,” most flow velocities ranged between 0.5 and 2.5 f.p.s. Exponents of a function relating rate of change of depth or velocity to discharge indicated that dynamic stream equilibrium was attained. Implications for forest management are that sanitation cuts (removal of dead and dying trees) would not be permissible where a stream is in dynamic equilibrium and bed material movement should be minimized. 相似文献