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281.
断裂研究是区域和场地稳定性评价以及工程抗震设计中的一项重要的基础性工作。对于有断裂通过的工程场地,从断裂、场地土层和工程三者相互作用的角度出发,开展有针对性的场地断裂活动效应及地震稳定性研究,对保证工程的安全建设和可靠运行有着极为重要的现实意义。本文试以宿迁三线船闸的建设为例,对场地断裂活动效应的风险进行分析与评价。 相似文献
282.
大坝减震气幕实验研究 总被引:1,自引:1,他引:1
针对平面模型 ,从流固耦合理论出发 ,以有限元分析为主要研究手段 ,应用基于理想气体状态方程的气幕隔震的压力有限元模型 ,计算坝体动力响应。结果表明气幕对大坝有良好的隔震性能 ,可降低水压力75 %以上。针对平面模型 ,用初位移激震分几种工况进行实验。用位移传感器测得坝面的位移时程 ,动水压力用脉动传感器进行测量。模型实验得到气幕减震后 ,动水压力降低 70 % ,与计算结果基本相符。证明了理论的正确性。 相似文献
283.
S. Trlat I. Sochet B. Autrusson K. Cheval O. Loiseau 《Journal of Loss Prevention in the Process Industries》2007,20(4-6):509-516
The number of explosive attacks on civilian buildings has recently increased and the pattern of damage inflicted on structures when an explosion takes place at altitude remains quite difficult to predict. The primary aim of the work reported here was to enhance the understanding of how blast waves from an explosion at altitude interact with the ground and with a structure. Small-scale experiments were conducted using a propane–oxygen stoichiometric mixture as explosive. This approach is original because it models high-explosive detonation in terms of gaseous charge explosion using TNT equivalents. Several non-dimensional laws are expressed and validated by experiments. These relationships allow determination of the propagation of a blast wave and its interaction with a structure as a function of the position of the explosive charge when the explosion occurs at altitude. Then, from knowledge of the blast loading, using Hopkinson's scaling law and TNT equivalents, we can predict the interaction of blast waves with the ground and a structure on a real scale. Simulations were performed using the Autodyn code, and good correlation with the experimental results was obtained. 相似文献
284.
W. Keller N. D. Yan J. M. Gunn J. Heneberry 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):317-322
Over 7,000 lakes around Sudbury, Ontario, Canada were acidified by S deposition associated with emissions from the Sudbury
metal smelters and more distant S sources. Air pollution controls have led to widespread changes in damaged Sudbury lakes,
including increased pH and decreased concentrations of SO4, metals and base cations. While chemical improvements have often been substantial, many lakes are still acidified, although
water quality recovery is continuing. Biological recovery has been observed in some lakes among various groups of organisms
including fish, zooplankton, phytoplankton and zoobenthos. Generally, however, biological recovery is still at an early stage.
Lakes around Sudbury are also showing that the recovery of acid-damaged lakes is closely linked to the effects of other major
environmental stressors such as climate change, base cation depletion and UV-B irradiance. Future studies of the recovery
of acid-damaged lakes around Sudbury, and in other regions, will need to consider the interactions of these and other stressors. 相似文献
285.
286.
刘华 《中国环境管理干部学院学报》2007,17(4):90-93
在教学中,经济学理论抽象难以理解,经济学家在20世纪中叶将实验方法引入经济学研究。我院在《西方经济学》的教学中,模拟完全竞争市场、货币创造实践等课堂实验,通过学生参与和教师引导的方法,调动学生的学习热情和兴趣,摆脱僵化的、单向的、平面化的模式,探索互动、双向、探索式的教学模式。 相似文献
287.
采用荧光光谱法和紫外可见分光光度法研究了胃蛋白酶与对磺酸基杯芳烃和对磺酸基杯芳烃相互作用时光谱性质的变化,发现两种对磺酸基杯芳烃对胃蛋白酶的荧光均有猝灭作用,并根据Stern—Volmer方程及紫外-可见吸收光谱得出猝灭机理均为静态猝灭。根据反应的热力学参数得出对磺酸基杯芳烃对胃蛋白酶的作用力均属于静电作用力,并依据Forster无辐射能量转移理论得出荧光给体(胃蛋白酶)-受体(对磺酸基杯芳烃)间的距离r。用同步荧光光谱技术考察了两种对磺酸基杯芳烃对胃蛋白酶构象的影响。 相似文献
288.
“水蚯蚓-微生物共生系统”细观机理模型(T-FCASM)建立及校验 总被引:2,自引:2,他引:0
基于浙江省诸暨市菲达宏宇污水处理厂新型氧化沟工艺的现场长期观察和试验研究,提出“水蚯蚓-微生物共生系统”的新技术原理,获得了“水蚯蚓-微生物共生系统”中污染物输入量与输出量随时间的动态变化规律,并建立了水蚯蚓作用的传递函数,从而实现水蚯蚓在污水处理和污泥降解过程中对污染物去除作用的模拟.以全耦合活性污泥模型(FCASM3)为基础平台,结合水蚯蚓作用的传递函数,最终建立了污水厂“水蚯蚓-微生物共生系统”细观机理模型(T-FCASM).利用对该污水处理厂常规水质指标测定和进水模型组分分析等试验结果,完成了对“水蚯蚓-微生物共生系统”细观机理模型(T-FCASM)的校验工作.动态模拟结果表明:T-FCASM实现了对回流污泥浓度的准确模拟;同时该模型能够对污水处理厂生物去除有机物及脱氮过程进行较准确的模拟,而对生物除磷过程的模拟,由于该污水处理厂低磷进水的原因,与实测值存在一定的偏差. 相似文献
289.
290.
Objective: A new method is suggested for coordination of vehicle motion actuators; where driver feedback and capabilities become natural elements in the prioritization.Methods: The method is using a weighted least squares control allocation formulation, where driver characteristics can be added as virtual force constraints. The approach is in particular suitable for heavy commercial vehicles that in general are over actuated. The method is applied, in a specific use case, by running a simulation of a truck applying automatic braking on a split friction surface. Here the required driver steering angle, to maintain the intended direction, is limited by a constant threshold. This constant is automatically accounted for when balancing actuator usage in the method.Results: Simulation results show that the actual required driver steering angle can be expected to match the set constant well. Furthermore, the stopping distance is very much affected by this set capability of the driver to handle the lateral disturbance, as expected.Conclusion: In general the capability of the driver to handle disturbances should be estimated in real-time, considering driver mental state. By using the method it will then be possible to estimate e.g. stopping distance implied from this. The setup has the potential of even shortening the stopping distance, when the driver is estimated as active, this compared to currently available systems. The approach is feasible for real-time applications and requires only measurable vehicle quantities for parameterization. Examples of other suitable applications in scope of the method would be electronic stability control, lateral stability control at launch and optimal cornering arbitration. 相似文献