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971.
高速铁路的安全及其系统的构成 总被引:2,自引:3,他引:2
分析了高速铁路相对于常规铁路在安全技术方面的新要求和主要的技术难点;论述了除基础设施外,涉及人一机一环各因素间的安全问题;在此基础上提出了高速铁路安全系统的构成以及在我国发展的意见。 相似文献
972.
当代大学生就业难的道德困境 总被引:1,自引:0,他引:1
在当前社会主义市场经济环境下,如何引导好大学毕业生树立正确的就业观,如何平衡功利主义与责任意识、享乐思想与奉献精神之间的关系,如何在企业需求与学校人才培养模式之间形成良性互动,是当前大学教育工作面临的重要课题。充分调动政府、社会、企业、学校各自资源的力量,是解决当代大学生就业困境的重要出路。 相似文献
973.
974.
桥墩的抗震性能试验是桥梁抗震分析的基础性研究工作。考虑到空心截面的优越性和地震时地面运动的多维性,通过拟静力试验研究双向水平地震作用下矩形空心钢筋混凝土桥墩的抗震性能具有十分重要的意义。文章从单向水平地震作用下桥墩的抗震性能、双向水平地震作用下桥墩的抗震性能、单双向水平地震作用下桥墩抗震性能的比较这三个方面进行了综述。 相似文献
975.
Changyong Wu Yongzhen Peng Xiaoling Li Zhiqiang Chen 《Frontiers of Environmental Science & Engineering in China》2010,4(2):150-156
In this study, an anaerobic/anoxic/oxic (A2O) wastewater treatment process was implemented to treat domestic wastewater with short-term atrazine addition. The results
provided an evaluation on the effects of an accidental pollution on the operation of a wastewater treatment plant (WWTP) in
relation to Chemical Oxygen Demand (COD) and biological nutrient removal. Domestic wastewater with atrazine addition in 3
continuous days was treated when steady biological nutrient removal was achieved in the A2O process. The concentrations of atrazine were 15, 10, and 5 mg·L−1 on days 1, 2 and 3, respectively. The results showed that atrazine addition did not affect the removal of COD. The specific
NH4
+ oxidation rate and NO3
− reduction rate decreased slightly due to the short-term atrazine addition. However, it did not affect the nitrogen removal
due to the high nitrification and denitrification capacity of the system. Total nitrogen (TN) removal was steady, and more
than 70% was removed during the period studied. The phosphorus removal rate was not affected by the short-term addition of
atrazine under the applied experimental conditions. However, more poly-hydroxy-alkanoate (PHA) was generated and utilized
during atrazine addition. The results of the oxygen uptake rate (OUR) showed that the respiration of nitrifiers decreased
significantly, while the activity of carbon utilizers had no obvious change with the atrazine addition. Atrazine was not removed
with the A2O process, even via absorption by the activated sludge in the process of the short-term addition of atrazine. 相似文献
976.
Edward D. Ramsey Qiubai Sun Zhiqiang Zhang Wei Guo Jing Y. Liu Xiu H. Wu 《环境科学学报(英文版)》2010,22(9):1462-1468
A direct aqueous supercritical fluid extraction (SFE) system using carbon dioxide provides a sustainable means by which a vast
range of industries may continue to depend on well established infrared (IR) techniques to determine oil-in-water. The SFE-IR method
provides an environmentally friendly substitute for current national standard IR reference methods for measuring oil-in-water that rely
on using increasingly restricted ozone depleting solvents whose manufacture is being phased out in accordance with international law.
The SFE-IR analysis of a 500 mL water sample can be accomplished in 15 min. A rapid on-line SFE-IR calibration method has been
implemented. With this calibration method, SFE-IR accuracy for determining diesel oil in 500 mL spiked water samples using single
wave number measurement was 86.0%–98.8% with precision (RSD) ranging from 2.5%–7.0%. Using a general purpose calculation
which involves measuring infrared absorbance values at three di erent wave numbers, SFE-IR method accuracy for determining
diesel oil in 500 mL spiked water samples was 83.7%–92.2% with RSD 1.0%–9.3%. Data is presented that indicates current long
established national standard IR reference methods involving three wave number calculations should be reviewed since, without careful
consideration, the inclusion of calculated aromatic hydrocarbon species contributions to final oil-in-water concentration values may
provide less accurate results. 相似文献
977.
Characterization of mechanochemical treated fly ash from
a medical waste incinerator 总被引:1,自引:0,他引:1
Zheng Peng Qiong Ding Yangzhao Sun Chen Jiang Xinhua Gao Jianhua Yan 《环境科学学报(英文版)》2010,22(10):1643-1648
The mechanochemical treatment of fly ash generated from a medical waste incinerator was subjected to grinding for 2 hr at 400
r/min in a planetary ball mill. The treated fly ash was characterized by a suite of analytical methods including High Resolution Gas
Chromatograph/High Resolution Mass Spectrometer, Mastersizer 2000 Particle Size Analyzer, QUADRASORBTM SI Surface Area
Analyzer, Scanning Electron Microscopy and X-ray di raction. Results showed that abatement e ciency of polychlorinated dibenzop-
dioxins and polychlorinated dibenzofurans (PCDDs/Fs) in terms of total concentration averagely amount to 76% which was relatively
higher than that of I-TEQ concentration averagely amount to 56%; the most concentration of toxic congeners as well as isomers of
PCDDs/Fs decreased after mechanochemical treatment. The treated fly ash was characterized by a more homogeneous distribution of
concaves as well as the significant decreasing in overall particle size and great enlargement in surface area. The major crystallization
phases or intensities were considerably changed by mechanochemical treatment, of which a new phase containing chlorine formed may
be a possible factor suggesting chlorination reaction occurring on the crystalline surface. 相似文献
978.
979.
本文在分析地震危机事件特征以及管理人才在汶川地震的抗震救灾过程中的作用的基础上,总结出危机管理人才的素质及能力要求,并试探着提出培养和提高管理人才危机管理能力的途径. 相似文献
980.
城市内涝实时监测系统初探 总被引:1,自引:0,他引:1
目前城市内涝已成为困扰城市健康发展的难题,本文对内涝的成因和现状进行了总结,提出建立城市内涝实时监测系统的必要性和紧迫性.系统利用布置在道路雨水管道检查井内的终端监测器,获得各监测点在暴雨发生时的实际水深值,并结合当地GIS系统,使各路段的淹没情况实现在计算机上的动态可视.文章重点介绍了该系统在具体建设过程中监测区域的划分和监测点的布置原则,增强了可操作性.系统一方面实时监测城市各点水情,是暴雨时合理调度可用资源,采取有效防内涝措施的重要依据;另外收集各雨水管道负荷现状,为管线改造、损失评估提供参考资料.本系统经济和社会效益显著,应用前景广阔. 相似文献