全文获取类型
收费全文 | 2060篇 |
免费 | 117篇 |
国内免费 | 715篇 |
专业分类
安全科学 | 214篇 |
废物处理 | 98篇 |
环保管理 | 159篇 |
综合类 | 1187篇 |
基础理论 | 300篇 |
污染及防治 | 595篇 |
评价与监测 | 96篇 |
社会与环境 | 141篇 |
灾害及防治 | 102篇 |
出版年
2024年 | 5篇 |
2023年 | 38篇 |
2022年 | 121篇 |
2021年 | 98篇 |
2020年 | 88篇 |
2019年 | 91篇 |
2018年 | 91篇 |
2017年 | 88篇 |
2016年 | 109篇 |
2015年 | 125篇 |
2014年 | 129篇 |
2013年 | 183篇 |
2012年 | 154篇 |
2011年 | 201篇 |
2010年 | 160篇 |
2009年 | 141篇 |
2008年 | 139篇 |
2007年 | 133篇 |
2006年 | 113篇 |
2005年 | 74篇 |
2004年 | 57篇 |
2003年 | 64篇 |
2002年 | 76篇 |
2001年 | 62篇 |
2000年 | 58篇 |
1999年 | 48篇 |
1998年 | 36篇 |
1997年 | 42篇 |
1996年 | 33篇 |
1995年 | 30篇 |
1994年 | 33篇 |
1993年 | 22篇 |
1992年 | 17篇 |
1991年 | 11篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有2892条查询结果,搜索用时 15 毫秒
101.
为了解白鹤滩蓄水运行前黑水河下游鱼类资源的现状、受到的主要威胁及其保护措施,于2014年1~12月在黑水河下游干支流江段采用电捕法进行了渔获物调查。结果显示:12个月共调查发现鱼类28种,隶属于3目8科23属,其中喜流水生境、产粘沉性卵、以着生藻类或/和底栖动物为食物的鱼类种类较多;调查区域鱼类个体规格普遍较小,其中齐口裂腹鱼Schizothorax prenanti、短体副鳅Paracobitis potanini、红尾副鳅Paracobitis varigatus、短须裂腹鱼Schizothorax wangchiachii、前鳍高原鳅Triplophysa anterodorsalis、中华纹胸鮡Glyptothorax sinense和凹尾拟鲿Pseudobagrus emarginatus为调查区域的主要经济鱼类;上半年和下半年的渔获物结构在统计学上差异显著(R=0.81,p=0.1%0.05),鱼类在金沙江干流和黑水河下游之间的相互迁徙比较明显;CPUE呈现先波动下降然后逐月上升的趋势,其中10月份的CPUE最低;丰度生物量比较曲线显示2014年各月的渔获物结构均处于严重干扰状态。黑水河下游河道采砂以及过度捕捞是白鹤滩蓄水前影响黑水河下游鱼类资源的主要因素,建议通过控制采砂的江段、采砂的时间以及全面禁捕保护该区域的鱼类资源。 相似文献
102.
Y. Chen H. R. Jia S. Niu X. Zhang H. L. Wang Y. Z. Ye Q. S. Chen Z. L. Yuan 《Russian Journal of Ecology》2018,49(1):40-46
Species turnover patterns can be inconsistent due to differences in the dispersal ability of different growth forms. Here, species of trees, shrubs, herbs, and bryophytes in the Xiaoqinling National Nature Reserve in China were analyzed to determine patterns of species turnover along an elevation and spatial gradient. Variance partitioning was used to assess the relative contribution of topographic heterogeneity and dispersal limitation to species turnover. Our results suggest that the effect of dispersal limitation is more important than topographic heterogeneity on species turnover in temperate mountane ecosystems in the study area. Dispersal limitation has a greater effect on trees species turnover than on shrubs, herbs or bryophytes species turnover. 相似文献
103.
Ye Suping Li Yanshun Department of Law Suzhou University Suzhou Jiangsu China 《中国人口.资源与环境(英文版)》2006,4(4)
Economic development has made a negative impact on the environment.However,our proceedings on public interest action are almost blank,causing many of the cases related to the environmental protection to be rejected by the court for the reason that the prosecutors fail to provide enough evidence.Therefore,we can take the U.S.system of civil action for reference to improve our public interest action while employing proxy litigation.The measures can be included as follows:relax the plaintiff qualifications;establish the necessary lead procedures;invert the responsibility of providing evidence. 相似文献
104.
Peng Liu Xiaoliang Liang Yanliu Dang Junkai He Alireza Shirazi-Amin Laura A. Achol Shanka Dissanayake Hanlin Chen Mingli Fu Daiqi Ye Steven L. Suib 《环境科学学报(英文版)》2021,33(3):293-303
Ceria is widely used as a catalyst for soot combustion, but effects of Zr substitution on the reaction mechanism is ambiguous. The present work elucidates effects of Zr substitution on soot combustion over cubic fluorite-structured nanoceria. The nanostructured CeO2, Ce0.92Zr0.08O2, and Ce0.84Zr0.16O2 composed of 5–6 nm crystallites display Tm-CO2 (the temperature at maximum CO2 yield) at 383, 355, and 375°C under 10 vol.% O2/N2, respectively. The size of agglomerate decreases from 165.5 to 51.9–57.3 nm, which is beneficial for the soot-ceria contact. Moreover, Zr increases the amount of surface oxygen vacancies, generating more active oxygen (O2? and O?) for soot oxidation. Thus, the activities of Ce0.92Zr0.08O2 and Ce0.84Zr0.16O2 in soot combustion are better than that of CeO2. Although oxygen vacancies promote the migration of lattice O2?, the enriched surface Zr also inhibits the mobility of lattice O2?. Therefore, the Tm-CO2 of Ce0.84Zr0.16O2 is higher than that of Ce0.92Zr0.08O2. Based on reaction kinetic study, soot in direct contact with ceria preferentially decomposes with low activation energy, while the oxidation of isolated soot occurs through diffusion with high activation energy. The obtained findings provide new understanding on the soot combustion over nanoceria. 相似文献
105.
Chlorine dioxide (ClO2) disinfection usually does not produce halogenated disinfection by-products, but the formation of the inorganic by-product chlorite (ClO2–) is a serious consideration. In this study, the ClO2– formation rule in the ClO2 disinfection of drinking water was investigated in the presence of three representative reductive inorganics and four natural organic matters (NOMs), respectively. Fe2+ and S2– mainly reduced ClO2 to ClO2– at low concentrations. When ClO2 was consumed, the ClO2– would be further reduced by Fe2+ and S2–, leading to the decrease of ClO2–. The reaction efficiency of Mn2+ with ClO2 was lower than that of Fe2+ and S2–. It might be the case that MnO2 generated by the reaction between Mn2+ and ClO2 had adsorption and catalytic oxidation on Mn2+. However, Mn2+ would not reduce ClO2–. Among the four NOMs, humic acid and fulvic acid reacted with ClO2 actively, followed by bovine serum albumin, while sodium alginate had almost no reaction with ClO2. The maximum ClO2– yields of reductive inorganics (70%) was higher than that of NOM (around 60%). The lower the concentration of reductive substances, the more ClO2– could be produced by per unit concentration of reductive substances. The results of the actual water samples showed that both reductive inorganics and NOM played an important role in the formation of ClO2– in disinfection. 相似文献
106.
自行设计、加工一套阀门内漏模拟试验装置,通过对不同尺寸阀门的模拟检测和数据分析,找出阀门发生内漏时的最佳检测位置,并发现阀门内漏时的声发射信号与系统压力、阀门尺寸之间的关系,保证了石化企业阀门内漏检测工作的顺利开展. 相似文献
107.
利用WRF(天气研究与预报模式)输出的高分辨率气象数据驱动HYSPLIT_4.9(混合单粒子拉格朗日轨迹模式),结合PSCF(潜在源贡献因子)和CWT(权重浓度轨迹分析)模拟研究复杂地形下兰州城市尺度大气污染物局地输送特征、潜在源区及其对空气质量的影响. 结果表明:2002—2008年影响兰州城区冬季12月空气质量的轨迹可分为5类,输送类型可分为城区内输送和城区外输送. 第1、3类轨迹出现频率均大于20%且污染轨迹出现频率均大于38%,是污染物的主要输送路径,对应潜在源区为兰州城关区东北部和榆中县东部,这2个源区对ρ(PM10)的影响最大,对ρ(SO2)的影响最小,对ρ(PM10)、ρ(SO2)和ρ(NO2)的贡献分别超过200、80和60 μg/m3. 来自榆中县的第4类轨迹和兰州西固区的第5类轨迹易造成大气重污染,而来自皋兰县的第2类轨迹属于清洁轨迹. 兰州冬季污染既受局地输送的影响,也与地面天气形势密切相关. 相似文献
108.
109.
文章回顾了瑞典的环境税费,特别是与能源相关的环境税的发展沿革,从环境效益、财政效益、能源结构调整效应三个方面分析了瑞典能源-环境税的效果,并展望瑞典环境税的发展前景.最后指出了瑞典环境税制度对中国的借鉴意义. 相似文献
110.