全文获取类型
收费全文 | 4071篇 |
免费 | 441篇 |
国内免费 | 1858篇 |
专业分类
安全科学 | 412篇 |
废物处理 | 181篇 |
环保管理 | 352篇 |
综合类 | 3181篇 |
基础理论 | 686篇 |
污染及防治 | 950篇 |
评价与监测 | 238篇 |
社会与环境 | 249篇 |
灾害及防治 | 121篇 |
出版年
2024年 | 16篇 |
2023年 | 115篇 |
2022年 | 254篇 |
2021年 | 275篇 |
2020年 | 271篇 |
2019年 | 194篇 |
2018年 | 205篇 |
2017年 | 256篇 |
2016年 | 217篇 |
2015年 | 290篇 |
2014年 | 315篇 |
2013年 | 448篇 |
2012年 | 391篇 |
2011年 | 425篇 |
2010年 | 321篇 |
2009年 | 309篇 |
2008年 | 302篇 |
2007年 | 320篇 |
2006年 | 278篇 |
2005年 | 175篇 |
2004年 | 149篇 |
2003年 | 130篇 |
2002年 | 125篇 |
2001年 | 96篇 |
2000年 | 98篇 |
1999年 | 73篇 |
1998年 | 59篇 |
1997年 | 52篇 |
1996年 | 52篇 |
1995年 | 42篇 |
1994年 | 30篇 |
1993年 | 23篇 |
1992年 | 20篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1974年 | 1篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有6370条查询结果,搜索用时 859 毫秒
241.
242.
Ma Hongxue Hu Guangchao Zhang Le Huo Xiangtao Guo Min Zhang Mei 《Journal of Material Cycles and Waste Management》2023,25(4):2222-2231
Journal of Material Cycles and Waste Management - This paper utilizes desulfurization ash (DA), fly ash (FA) and ordinary Portland cement (OPC) to prepare unfired high-strength road-base stones by... 相似文献
243.
244.
The dissipation of chlorpyrifos in pakchoi-vegetated soil was investigated in the summer and autumn in a greenhouse and field, respectively. The dissipation of chlorpyrifos in pakchoi-grown soil was comparatively described by fitting the residue data to seven models (lst-order, 1.5th-order, 2nd-order, RF lst-order, RF 1.5th-order, RF 2nd-order, and bi-exponential or two-compartment models). Statistical analysis was performed using the SPSS 11.5 statistical package. The bi-exponential model was selected as the optimal model according to the coefficient of determination r^2. The dissipation half-lives (DT50) of chlorpyrifos in pakchoi-vegetated soil at the recommended dose in the summer and autumn, calculated by the bi-exponential model, were 0.6 and 1.2 d in a greenhouse, 0.4 and 1.0 d in a field, respectively; the corresponding values at double dose were 1.2 and 2.1 d in a greenhouse, 0.5 and 1.3 d in a field, respectively. The kinetic data indicate the dissipation of chlorpyrifos in pakchoi-grown soil in a greenhouse is slower than that in a field, and dissipates slower in the autumn than in the summer. 相似文献
245.
QIN Min XIE Pin-hu LIU Wen-qing LI Ang DOU Ke FANG Wu LIU Jian-guo ZHANG Wei-jun 《环境科学学报(英文版)》2006,18(1):69-75
Measurements of nitrous acid (HONO) and nitrogen dioxide (NO2) in Beijing City have been performed by means of a developed differential optical absorption spectroscopy (DOAS) system based on photodiode array (PDA), during the autumn of 2004. HONO and NO2 were simultaneously identified by their characteristic absorption bands in the spectral region between 337 nm and 372 nm with high sensibility and time resolution. The concentrations of HONO exhibit obviously diurnal variation with a nocturnal maximum and a daytime minimum. The highest HONO value up to 11.8 μg/m^3 was observed during the night of 2/3 September. Possible sources of the observed HONO were discussed. Good correlation to NO2 indicates that NO2 is a main source component. The measurement also shows direct emission of HONO is an imnortant source in strongly polluted urban area. 相似文献
246.
Cyclodextrins (CDs), with hydrophobic interior cavity and hydrophilic external surface, are capable of accelerating or inhibiting chemical degradation of organophosphorus pesticides through forming inclusion complexes between CDs and pesticides. This work evaluated the effects of CDs on hydrolysis of malathion in an attempt to assess their potential application in environmental approach. β-CD and its two derivatives, randomly methylated β-CD (RAMEB) and hydroxypropyl β-CD (HP-β-CD), were tested. It was found that RAMEB could inhibit the hydrolysis of malathion, and this was the function of pH and temperature, the inhibitory effects increase with increasing concentration of RAMEB and elevating temperature between 15 and 35℃. On the other hand, β-CD and HP-β-CD have little or no stabilizing effects on malathion at all pH and temperature studied, except that the large concentration of β-CD and HP- β-CD can mildly reduce hydrolysis of malathion. Both 2 mol/L and 5 mol/L urea increase the inhibitory effects of RAMEB on hydrolysis of malathion at 25℃, oH 9.0. 相似文献
247.
248.
数字产业化与产业数字化是数字经济的"双重向度",其耦合协调程度对于优化数字经济发展结构具有重要意义.揭示与阐述数字产业化与产业数字化的耦合机理,建立评价两者耦合协调度的理论模型,设计评价两者耦合协调状况及趋势的指标体系,运用长江经济带11省市2013~2018年的面板数据,实证分析长江经济带数字产业化与产业数字化的耦合协调度.结果表明:长江经济带数字产业化水平和产业数字化水平稳步提升,总体耦合协调度区域差异明显,存在数字产业化滞后产业数字化的趋势.从加快推进新型数字产业发展、以"新基建"助力传统产业数字化转型、为区域间数字经济协调发展和区域内数字化转型构建更好制度体系、加强数字人才培养和激励等方面,提出促进我国数字产业化与产业数字化融合发展的政策建议. 相似文献
249.
250.
为探究大型地铁站多线路火灾场景中的综合危险性,采用火灾动力学软件FDS构建“T”型换乘站全尺寸模型,对不同火源位置、不同火源功率以及是否开启地铁排烟风机等12组工况进行数值模拟;采用性能化方法确定可用疏散时间,并通过综合火灾风险评估方法计算各工况总安全指数。结果表明:1号线站厅层和2号线站台层双点火灾为最不利火灾场景;1号线站台层和2号线站厅层双点火灾为相对安全火灾场景;火源功率的增大会增加地铁火灾危险性,但不同火源位置工况中的安全指数变化趋势相似;排烟模式开启前,1号线站厅层火灾会导致较大的火灾危险性;排烟模式开启后,地铁总安全指数显著上升且安全指数变化趋势改变,此时2号线站台层火灾会导致较大的火灾危险性。 相似文献