全文获取类型
收费全文 | 584篇 |
免费 | 17篇 |
国内免费 | 194篇 |
专业分类
安全科学 | 26篇 |
废物处理 | 28篇 |
环保管理 | 54篇 |
综合类 | 255篇 |
基础理论 | 109篇 |
污染及防治 | 240篇 |
评价与监测 | 44篇 |
社会与环境 | 21篇 |
灾害及防治 | 18篇 |
出版年
2023年 | 9篇 |
2022年 | 24篇 |
2021年 | 20篇 |
2020年 | 14篇 |
2019年 | 15篇 |
2018年 | 22篇 |
2017年 | 25篇 |
2016年 | 28篇 |
2015年 | 37篇 |
2014年 | 41篇 |
2013年 | 65篇 |
2012年 | 44篇 |
2011年 | 60篇 |
2010年 | 38篇 |
2009年 | 26篇 |
2008年 | 51篇 |
2007年 | 47篇 |
2006年 | 32篇 |
2005年 | 21篇 |
2004年 | 17篇 |
2003年 | 17篇 |
2002年 | 24篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 14篇 |
1998年 | 12篇 |
1997年 | 19篇 |
1996年 | 19篇 |
1995年 | 8篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
排序方式: 共有795条查询结果,搜索用时 31 毫秒
771.
利用超声/H2O2协同作用生成氧化能力极强的羟基自由基(.OH)降解苯酚。确定高效液相色谱分析的适宜条件为室温,检测波长277 nm,流动相配比55/45(V甲醇/水),流速为0.5 mL/min,测得各物质的回收率在95.2%100.3%之间,证明高效液相色谱法是测定苯酚及其中间产物的一种有效的分析方法。HPLC法分析苯酚的降解过程首先是由羟基自由基攻击苯环,生成对苯二酚、邻苯二酚,然后继续羟基化,生成顺丁烯二酸,进一步氧化,最终生成二氧化碳和水。 相似文献
772.
五大连池水体中氮素分布及规律的初步研究 总被引:1,自引:0,他引:1
分析了2009年9月至2010年10月五大连池水体的总氮、氨氮、硝氮3项指标.得出水体氮素的年度变化规律及相关性,即总氮和氨氮、氨态氮与硝态氮两组指标的相关性很高,总氮与硝态氮之间相关性较弱.3种指标都是冬季明显高于其他季节,总氮在春季最低随后升高,氨态氮和硝态氮在春夏秋季均维持较低水平,且结合3者变化规律,夏季和秋季... 相似文献
773.
Farías Torbidoni EI 《Environmental management》2011,47(3):482-496
Planning and management for recreational activities in protected areas involves an understanding of many complex factors.
Segmentation of recreation demand and of the main physical or sporting activities can contribute to the design of more efficient
management strategies, which may help to maintain or significantly enhance satisfaction with the recreation experience, and
this in turn could improve the interest in and appreciation of the natural environment. The current study examined the motivations
of hikers in three small Natura 2000 protected areas. It establishes a typology or categorization as a contribution to better
management based on a survey conducted through on-site personal interviews with a representative sample of 569 hikers. Through
an analysis of the principal intervening components by means of cluster analysis, we identified three groups of hikers based
on three motivational dimensions: (1) nature-minded hikers, (2) sporting hikers and (3) general-purpose hikers. The most striking
results were the significant differences among group variables related to visit behaviour (frequency and duration of visits
and number of people per group), previous knowledge (protection status of the areas) and recreational frequentation (trail
categories and protected areas visited). A positive correlation between the degree of sympathy for nature and the degree of
satisfaction with the recreational experience (including positive evaluation of the public facilities, signposting and services
offered) was also observed. The results are discussed in terms of their applicability and implications in hiking management
in protected natural areas such as those of Natura 2000. 相似文献
774.
We present and discuss the results of a comprehensive study addressing the non-aerated region of the skimming flow in steep stepped spillways. Although flows in stepped spillways are usually characterized by high air
concentrations concomitant with high rates of energy dissipation, the non-aerated region becomes important in small dams and/or
spillways with high specific discharges. A relatively large physical model of such spillway was used to acquire data on flow
velocities and water levels and, then, well-resolved numerical simulations were performed with a commercial code to reproduce
those experimental conditions. The numerical runs benefited from the ability of using multi-block grids in a Cartesian coordinate
system, from capturing the free surface with the TruVOF method embedded in the code, and from the use of two turbulence models: the k-e{k{-}\varepsilon} and the RNGk-e{k{-}\varepsilon} models. Numerical results are in good agreement with the experimental data corresponding to three volumetric flow rates in
terms of the time-averaged velocities measured at diverse steps in the spillway, and they are in very satisfactory agreement
for water levels along the spillway. In addition, the numerical results provide information on the turbulence statistics of
the flow. This work also discusses important aspects of the flow, such as the values of the exponents of the power-law velocity
profiles, and the characteristics of the development of the boundary layer in the spillway. 相似文献
775.
中国废水排放量预测研究 总被引:2,自引:0,他引:2
文章在综合分析中国废水排放量影响因素的基础上,结合ARMA、多元线性回归方法构建了中国废水排放量预测模型,并对2013年-2015年中国废水排放量进行了预测,结果表明:2013年-2015年中国废水排放量将分别达到729.98亿吨、768.97亿吨、810.71亿吨;造纸印刷及文教用品制造业、化学工业等行业废水排放量及单位增加值废水排放量均较大,相关部门需对减排的各个过程进行规范和严格的监督。 相似文献
776.
In Jae Shin 《Journal of Loss Prevention in the Process Industries》2013,26(4):803-814
This paper examines effectiveness of a regulatory enforcement organization (Major industrial Accident Prevention Center, MAPC), and a grading system for implementation of the Process Safety Management (PSM) regulation in Korea. A lot of chemical installations have been built in Korea since the 1960s. The frequent occurrence of major industrial accidents had made people's concerns grow. The Korean government enacted PSM regulations in 1996 in order to curb these accidents.However, a key question is how to make sure companies comply with the PSM regulations. In order to improve company’ compliance with PSM regulations the Ministry of Employment and Labor (MOEL) responsible for the regulation introduced a grading management system in 2001 and then established special supervisory centers for enforcement of PSM regulations in 2005. This paper reviews the role and effectiveness of the system in term of PSM enforcement. The author found that the grade-based approach has encouraged employers to implement the requirements of the PSM regulations. MAPCs play an effective role in enhancing enforcement performance. Although the more chemical plants have been established in Korea, the fewer major industrial accidents have occurred since the introduction of the system. The results may be useful for the policy maker to build an effective and efficient enforcement system. 相似文献
777.
Yong-Ku Kong Andris Freivalds Dae-Min Kim 《International journal of occupational safety and ergonomics》2013,19(2):214-224
This study examined two conversion methods, M1 and M2, to predict finger/phalange bone lengths based on finger/phalange surface lengths. Forty-one Korean college students (25 males and 16 females) were recruited and their finger/phalange surface lengths, bone lengths and grip strengths were measured using a vernier caliper, an X-ray generator and a double-handle force measurement system, respectively. M1 and M2 were defined as formulas able to estimate finger/phalange bone lengths based on one dimension (i.e., surface hand length) and four finger dimensions (surface finger lengths), respectively. As a result of conversion, the estimation errors by M1 presented mean 1.22?mm, which was smaller than those (1.29?mm) by M2. The bone lengths estimated by M1 (mean r?=?0.81) presented higher correlations with the measured bone lengths than those estimated by M2 (0.79). Thus, the M1 method was recommended in the present study, based on conversion simplicity and accuracy. 相似文献
778.
孔繁德 《中国环境管理干部学院学报》2013,(6):19-22
《生态文明的中国觉醒》首先说明当今中国出现了环境严重污染的“生态墙”;进而阐述环境保护的严峻形势及建设生态文明的艰巨任务;然后论述我国正处环境问题的激化期,应借鉴世界各大工业国的经验教训,指明经济与生态双赢的方向;最后阐述生态文明建设势在必行。这篇重要文章提出了以下启示:中国发展打“消耗战”的路已经行不通,必须由传统工业文明向生态文明转型;必须坚持又好又快的发展,保持适当速度;提倡“合理消费”;大力实施“创新驱动战略”,为生态文明建设提供强大动力。 相似文献
779.
With the rapid social and economic development of the Tibet Autonomous Region,the situation in regard to energy supply and demand is increasingly tense.Meanwhile,the development of renewable energy in Tibet has been given considerable practical significance by its peculiar ecological environment.Given the complementarity of renewable energies in Tibet,using the method of factor analysis,we derived four major factors:level of economic development,social development,industrial development,and energy endowment,which help to evaluate development conditions in different regions of Tibet.Treating these four factors equally,we used the hierarchical clustering method to determine the order of regional development.Thus we acquire a three-stage planning project for renewable energy.In the first stage,Lhasa plays a leading role in promoting the development of renewable energy,particularly that based on solar and wind energy.There are two phases in the second stage,the first being to simultaneously develop solar and wind energy in Xigaze and Nyingchi.The second is to develop solar and wind energy in accordance with the time of year in Qamdo,Nagqu,and Ali,with 1.145billion kWh electricity to be generated.The third stage is to develop energy production in Lhoka Prefecture,with 1.369billion kWh electricity to be generated.At the end of the three-stage project,consumption of available electricity will have reached 4.045 billion kwh,with major social and economic benefits. 相似文献
780.
This study evaluates and compares the trends in CO2 emissions for the manufacturing industries of three countries: two developed countries (Germany and Sweden) that have applied several measures to promote a shift towards a low-carbon economy and one developing country (Colombia) that has shown substantial improvements in the reduction of CO2 emissions. This analysis is conducted using panel data cointegration techniques to infer causality between CO2 emissions, production factors and energy sources. The results indicate a trend of producing more output with less pollution. The trends for these countries’ CO2 emissions depend on investment levels, energy sources and economic factors. Furthermore, the trends in CO2 emissions indicate that there are emission level differences between the two developed countries and the developing country. Moreover, the study confirms that it is possible to achieve economic growth and sustainable development while reducing greenhouse gas emissions, as Germany and Sweden demonstrate. In the case of Colombia, it is important to encourage a reduction in CO2 emissions through policies that combine technical and economic instruments and incentivise the application of new technologies that promote clean and environmentally friendly processes. 相似文献