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741.
我国秦至清末的疫病灾害研究   总被引:4,自引:0,他引:4  
杨俭  潘凤英 《灾害学》1994,9(3):76-81
本文根据《中国历代天灾人祸表》中疫病的文字记载,统计出各个历史时期疫病发生时间(季节)、频数及其与旱、涝(水)、地震、战争等灾难事件的关系,进而推测历史时期疫病所包含的急性传染病。统计发生周期,证实疫病周期与太阳、太阳系活动规律有明显的相关性。  相似文献   
742.
城市地震灾害预测的基本内容和减灾决策过程   总被引:12,自引:1,他引:12  
本文研究了下列四个问题:(1)对我国现有建筑进行了易损性分类,并定义了一个区分易损性类别的定量指标;(2)按目前现有建筑建立了各类易损性结构的震害矩阵和它们与未来若干年后的震害矩阵的关系;(3)分析并了种类易损性结构的地震损失率;(4)提出了一个人员死亡的估计方法和确定减灾方案的决策方法。  相似文献   
743.
ABSTRACT: water resources supply and demand time series consist of several or all of the four basic characteristics: tendency, intermittency, periodicity and stochasticity. Their importance changes from one type of variables to another. Historic developments of analysis of time series in hydrology have varied significantly over the past, from the stress on search for periodicities and persistence in annual series to the emphasis on the series stochastic properties. Supply and demand series are often highly interrelated, which fact is most often neglected in planning water resources systems in general, and water storage capacities in particular. The future of series analysis in water resources will likely be by a joint use of physically-based structural analysis and the use of advanced methods of treating data by stochastic processes, statistical estimation and inference techniques. The most intriguing challenge of the future of this analysis may be the treatment of nonnormal, nonlinear and in general nonstationary hydrologic and water use time series. The proper treatment of complex multivariate processes will also challenge the specialists, especially for the purposes of transfer of information between data on variables at given points, or between data at several points of a given variable, or both.  相似文献   
744.
ABSTRACT: A key parameter in modeling two-phase flow phenomena is relative permeability. It is important to understand which variables influence relative permeability, especially since so few measurements of relative permeability have been made for typical contaminants at hazardous waste sites. This paper focuses on the effect of five variables on relative permeability: intrinsic permeability, pore-size distribution, viscosity ratio, interfacial tension, and wettability, by critically reviewing previously published relative permeability experiments. The wide variability in the functional relationship between relative permeability and saturation should be considered in attempts to model two-phase flow.  相似文献   
745.
本文介绍了用甲醛-硼氢化钠系统衍生水小二乙烯三肢的衍生化气相色谱测定方法。测定条件:TSD检测器,260℃;色谱柱:PT28%AT223+4%KOH涂在GasChromR80~100目。1.4m×3mm。线性范围:2.5~20mg/L。回收率:92~107%。相对标准偏差;9%。  相似文献   
746.
干燥箱内密封消解光度法测定化学需氧量   总被引:1,自引:0,他引:1  
本文详细探讨了用干燥箱代替回流装置消解COD样品,然后用光度法准确测定COD值的实验方法;COD校准曲线采用苯二甲酸氢钾标准溶液制作。在实验确定的条件下作葡萄糖溶液的回收和实样对比试验,结果比较满意,证明该方法是可行的。  相似文献   
747.
原子荧光光度法测定水中汞的不确定度分析   总被引:2,自引:0,他引:2  
用原子荧光光度法对测定水中汞的不确定度进行分析,找出影响不确定的因素,对测量不确定度进行计算和评定,结果表明影响其测量不确定度主要因素是原子荧光光强度值带来的不确定度,其它因素是次要的.  相似文献   
748.
菏泽市气象因子与空气质量相关性研究与应用   总被引:2,自引:2,他引:2  
利用气象因子与空气中污染物之间的相互关系,建立了旨在反映两者内在关系的多元回归方程模型。利用气象参数预报值和当日污染物监测结果,对次日空气中污染浓度进行预测。  相似文献   
749.
The purpose of this paper is to present and compare two independent sets of environmental gamma spectrometry measurements of137 Cs collected nearly 14 years apart. One set of data was collected in 1978 by a contractor of the U.S. Department of Energy during an aerial radiological survey of the northern atolls of the Marshall Islands. That program used helicopter mounted sodium-iodide scintillation detectors; measurements were made from an altitude of 38 m. The second measurement program was conducted from early 1990 through late 1994 by the Republic of the Marshall Islands Government in a survey of the entire nation. This latter program used ground level in situ gamma spectrometry with high-purity germanium detectors. In this comparison, we highlight differences between the findings of the two studies and probable reasons for those differences, though we also discuss the effectiveness of the two techniques for monitoring the ionizing radiation environment. In the comparison of exposure rates from 137Cs, fair agreement was noted after accounting for radioactive decay during the intervening years. Though the distributions were statistically different over their entire range, they were nearly identical above 1 R h-1. There was considerable difference in the estimates of137 Cs inventory; the difference was greater at low activity levels with the NaI measurements consistently larger than the in situ measurements. Reasons for this difference is attributed to three factors which differed between the two studies: (1) the assumed penetration of the cesium into the soil column, (2) the assumption of soil density, and (3) differences in the ability of the two different detector systems to reject interfering spectral contributions. Precise measurement of the lowest levels has implications for determining those atolls that exceeded the deposition of 137Cs from global fallout. This issue is discussed in addition to a comparison of the findings from the two measurement programs.  相似文献   
750.
多拉纳萨依原生金矿床,属于非石英脉型。该矿床金的成矿元素组合主要为Au-Bi-W-Ag,其原生与次生晕指示元素组合分别为Au-Ag-Bi-Sb-Mo-W-As和Au-Ag-Bi-Sb-Mo-W-As-Hg,两者具相似性。Au,As,Sb,Cu,Pb的分布型式在原生晕和次生晕中基本相同。次生晕应由原生晕或原生矿化体等元素引起,因此可直接根据次生异常场找寻与确定原生矿化体。  相似文献   
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