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991.
不同密度沉水植物腐解过程中水体DOM变化特征 总被引:1,自引:0,他引:1
选取白洋淀淀区的泥、水以及晒干的优势沉水植物金鱼藻、轮藻为研究对象,设置6个密度梯度模拟实验,分别于实验进行的50 d和100 d采集水样,运用紫外和荧光光谱技术研究沉水植物腐解阶段水体中溶解性有机质(DOM)的变化。结果显示,同步荧光光谱中,类蛋白峰荧光强度的变化不具规律性,类腐殖质峰荧光强度随密度的增加呈上升趋势,I2/I1的值随着密度的增加或时间的推移均逐渐增大;三维荧光光谱中,随着密度的增加,类富里酸荧光峰A和C的强度逐渐增加,而类色氨酸荧光峰T1的强度变化不大,腐解植物的密度大于3 kg/m3时各组均产生了类海洋腐殖质荧光峰B且强度随密度的增加逐渐增强,C峰的强度与水样中的COD和TP呈显著正相关;紫外光谱测定中,A253/A203的值随着密度的增加或时间的推移而逐渐增大,水体中的芳香族化合物也增多。 相似文献
992.
基于物质流分析的江苏省区域生态效率评价 总被引:2,自引:0,他引:2
物质流分析被认为是适用于生态效率评价的重要工具和方法之一,但应用于区域生态效率评价的研究尚较少。根据生态效率理论、物质流分析理论与方法,建立了基于物质流账户的3个层面的区域生态效率评价指标:区域直接生态效率、区域总生态效率、整体生态效率。以江苏省为例,全面评价了 1995~2005年江苏省不同层面的生态效率,结果表明:(1)江苏省区域直接生态效率远高于我国同期水平。区域总生态效率和整体生态效率相对较低,分别仅为区域直接生态效率 15%~22%和 7%~8%左右;(2)1995~2005年,区域直接生态效率呈先上升后下降趋势,原因在于物质生产率未有显著提高以及近年来重工业在产业结构中比重的增加;(3)整体生态效率的变化趋势与区域直接生态效率类似,原因主要是近年江苏省对区外物质和资源的进口量显著增加;(4)区域总生态效率则表现为先快速上升后缓慢上升的趋势。在对研究结果及成因进行分析和讨论的基础上,提出了提高区域生态效率的建议. 相似文献
993.
994.
Dong ethnic people have rich indigenous knowledge in terms of their daily life and production, which plays an important role in the sustainable development of their village. This paper aims to understand traditional knowledge of Dong ethnic people in resource management and population control, including traditional resource management, traditional medicinal knowledge and village regulations in Zhanli Village in Southeast Guizhou Province. The research methods include key informant interview, group discussio... 相似文献
995.
996.
Tao Huang Xiangyang Li Chongguo Tian Xianming Yang Li Wang Yuan Zhao Jianmin Ma Hong Gao 《Environmental science and pollution research international》2013,20(10):7167-7174
HCHs and DDTs were banned in 1983 in China; however, they are still remaining in various environmental media. Since endosulfan was introduced in China in 1994, it is widely used in agriculture. In this study, temporal and spatial uses of endosulfan, HCHs, and DDTs in Gansu province of China have been presented. It is estimated that the total usage is 701 tons for endosulfan between 1994 and 2007, 1,712 tons for HCHs between 1952 and 1983, and 462 tons for DDTs between 1951 and 1983, respectively. Endosulfan usage increased dramatically in 1998 due to its application on other crops except on cotton. The HCH and DDT usage displayed a rapid increase after 1972, reaching the peak in 1976 and in 1975, respectively; since then, they declined until being banned in 1983. The gridded usage inventories of these three kinds of organochlorine pesticides in Gansu province, with a 1/4° longitude by 1/6° latitude resolution, have been created by using different crops for endosulfan and the area of dry farmland for HCHs and DDTs as surrogate data. The most intensive use was in northwestern regions for endosulfan and southeastern regions for HCHs and DDTs in Gansu province. 相似文献
997.
998.
Huan-Yan Xu Shu-Yan Qi Yan Li Yuan Zhao Ji-Wei Li 《Environmental science and pollution research international》2013,20(8):5764-5772
A cationic dye, Rhodamine B (RhB), could be efficiently discolored by heterogeneous Fenton-like reaction catalyzed by natural schorl. In this work, with the main goal of the optimization for RhB discoloration, central composite design under the response surface methodology (RSM) was employed for the experiment design and process optimization. The significance of a second-order polynomial model for predicting the optimal values of RhB discoloration was evaluated by the analysis of variance and 3D response surface and counter plots for the interactions between two variables were constructed. The Pareto graphic analysis of the discoloration process indicated that, among all the variables, solution pH (X 3, 47.95 %) and H2O2 concentration (X 1, 24.39 %) had the largest influences on the heterogeneous Fenton-like discoloration of RhB. Based on the model prediction, the optimum conditions for RhB discoloration were determined to be 45 mM H2O2 concentration, 2.5 g/L schorl dosage, solution pH 2, and 110 min reaction time, with the maximum RhB discoloration ratio of 98.86 %. The corresponding experimental value of RhB discoloration ratio under the optimum conditions was determined as 99.31 %, which is very close to the optimized one, implying that RSM is a powerful and satisfactory strategy for the process optimization. 相似文献
999.
Shao D Liang P Kang Y Wang H Cheng Z Wu S Shi J Lo SC Wang W Wong MH 《Chemosphere》2011,83(4):443-448
This study investigated total mercury (THg) and methylmercury (MeHg) concentrations in five species of freshwater fish and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The concentrations of THg and MeHg in fish pond surface sediments were 33.1-386 ng g(-1) dry wt and 0.18-1.25 ng g(-1) dry wt, respectively. The age of ponds affected the surface sediment MeHg concentration. The vertical distribution of MeHg in sediment cores showed that MeHg concentrations decreased with increasing depth in the top 10 cm. In addition, a significant correlation was observed between %MeHg and DNA from Desulfovibrionacaea or Desulfobulbus (p<0.05) in sediment cores. Concentrations of THg and MeHg in fish muscles ranged from 7.43-76.7 to 5.93-76.1 ng g(-1) wet wt, respectively, with significant linear relationships (r=0.97, p<0.01, n=122) observed between THg and MeHg levels in fish. A significant correlation between THg concentrations in fish (herbivorous: r=0.71, p<0.05, n=7; carnivorous: r=0.77, p<0.05, n=11) and corresponding sediments was also obtained. Risk assessment indicated that the consumption of largemouth bass and mandarin fish would result in higher estimated daily intakes (EDIs) of MeHg than reference dose (RfD) for both adults and children. 相似文献
1000.
采用管式炉高温热解-NaOH-Na2CO3混合液碱浸-CuSO4·5H2O沉淀的方法回收生态修复植物蜈蚣草中的砷,最终得到产品砷酸铜。该方法的最佳工艺条件为:热解温度600 ℃,热解时间30 min,CaO加入量(CaO与蜈蚣草的质量比)8%; m(NaOH)∶m(Na2CO3)=1∶3,碱浸温度70 ℃, 碱浸时间2 h, 固液比1∶10; 沉淀反应pH 5, 沉淀反应温度70 ℃。采用该方法处理生态修复植物蜈蚣草,得到产品砷酸铜的纯度为93%,砷回收率达88%。 相似文献