全文获取类型
收费全文 | 11584篇 |
免费 | 521篇 |
国内免费 | 3931篇 |
专业分类
安全科学 | 747篇 |
废物处理 | 713篇 |
环保管理 | 847篇 |
综合类 | 6176篇 |
基础理论 | 1958篇 |
污染及防治 | 4164篇 |
评价与监测 | 473篇 |
社会与环境 | 501篇 |
灾害及防治 | 457篇 |
出版年
2024年 | 15篇 |
2023年 | 188篇 |
2022年 | 545篇 |
2021年 | 460篇 |
2020年 | 367篇 |
2019年 | 349篇 |
2018年 | 381篇 |
2017年 | 495篇 |
2016年 | 506篇 |
2015年 | 602篇 |
2014年 | 831篇 |
2013年 | 1131篇 |
2012年 | 950篇 |
2011年 | 984篇 |
2010年 | 752篇 |
2009年 | 705篇 |
2008年 | 820篇 |
2007年 | 663篇 |
2006年 | 621篇 |
2005年 | 441篇 |
2004年 | 363篇 |
2003年 | 419篇 |
2002年 | 392篇 |
2001年 | 324篇 |
2000年 | 368篇 |
1999年 | 383篇 |
1998年 | 333篇 |
1997年 | 317篇 |
1996年 | 297篇 |
1995年 | 224篇 |
1994年 | 180篇 |
1993年 | 165篇 |
1992年 | 144篇 |
1991年 | 99篇 |
1990年 | 49篇 |
1989年 | 44篇 |
1988年 | 34篇 |
1987年 | 23篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
镰刀菌HJ01对对氯苯酚的降解特性 总被引:2,自引:0,他引:2
采用实验室分离的一株镰刀菌HJ01,以对氯苯酚(4-CP)为降解底物,以蔗糖为外加碳源,考察了蔗糖质量浓度、降解温度、初始pH对4-CP降解效果的影响,初步探讨了镰刀菌HJ01对4-CP的降解动力学和降解机理.实验结果表明:该菌株能以4-CP为惟一碳源和能源生长;在外加蔗糖为碳源,蔗糖质量浓度为3 g/L、降解温度为30℃、初始pH为8的条件下,50 mg/L4-CP能在6 d内被完全降解.以4-CP为惟一碳源和外加蔗糖下的降解动力学分别符合Haldane模型和一级动力学方程. 相似文献
942.
943.
944.
945.
以电解锰阳极泥与电解锌生产中产生的含SO_2尾气为原料,经过反应、浸出、浸出液两次净化和浓缩结晶制备硫酸锰,考察了反应时间、含SO_2尾气的流量及反应温度对Mn~(4+)转化率的影响.实验结果表明:在反应时间45 min、反应温度20~30 ℃、含SO_2尾气流量16 L/min的条件下,Mn~(4+)转化率达90%以上;尾气中SO_2利用率随尾气流量增加而降低;所得MnSO_4·H_2O产品质量达到GB1622-86<工业级硫酸锰标准>. 相似文献
946.
利用第一次全国污染源普查“火力发电行业产排污系数核算”工作中现场监测得到的数据,首次采用偏相关分析的方法,对固态排渣煤粉炉中机组规模、空气过剩系数、煤中挥发分和发电负荷率等因素对NOx产生浓度的影响进行定性分析,结论:NOx产生浓度与前三种因素存在显著的相关。而与发电负荷率的关系受锅炉是否采用低氮燃烧技术的影响。空气过剩系数越大,煤的挥发分越高,NOx产生浓度越低;采用低氮燃烧装置的锅炉中,机组规模越大,产生的NOx越少,且对于同一锅炉来说,NOx产生浓度随着发电负荷率的升高而增大;未采用燃烧控制的锅炉中,机组规模越大,NOx产生浓度越高,且与发电负荷率不相关。根据分析结果,提出了控制燃煤电厂固态排渣煤粉炉NOx排放的优化措施和建议。 相似文献
947.
Uptake of organic contaminants by plant roots consists of two consecutive steps: sorption to plant roots and entrance into root xylem tissues through epidermal and endodermic membranes. Most research pertaining to phytoremediation assumed that sorption to plant roots is linear and non-competitive. A growing body of evidence, however, is suggesting that sorption to plant roots is nonlinear and competitive. The objective of this study was to examine the concentration effects of chemical constituents on the competitive sorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) to the roots of Typha latifolia. Competitive sorption was clearly demonstrated by the reduced sorption of TCE and PCE in bi-solute systems than in single-solute systems. Concentration is an important factor affecting the extent of competition. In bi-solute systems, the PCE/TCE ratio on root surface approximately reflected the contaminant footprints in solution. The result was attributed to limited high energetically favorable sorption sites on the root surface and similar sorption mechanisms of TCE and PCE. The results hold significant importance for the application of phytomonitoring of organic contaminant mixtures. 相似文献
948.
Qinghao Meng Jinlian Hu KaiChiu Ho Fenglong Ji Shaojun Chen 《Journal of Polymers and the Environment》2009,17(3):212-224
The shape memory behavior of PLLA (poly(l-lactide)) and chitosan/PLLA composites was studied. PLLA and chitosan were compounded to fabricate novel materials which
may have biodegradability and biocompatibility. Chitosan does not significantly affect the glass and melting transition temperature
of the PLLA. Both the pure PLLA and chitosan/PLLA composites showed shape memory effect arising from the viscoelastic properties
of PLLA comprised of semi crystalline structures. The shape recovery ratio of the chitosan/PLLA composites decreased significantly
with increasing chitosan contents due to the incompatibility between PLLA and chitosan. Phase separation structures of the
composites were observed by using atomic force microscopy. To obtain good shape memory effect, the chitosan content should
be below 15 wt%. 相似文献
949.
Hangzhou Wang Bingzhen Chen Xiaorong He Qiu Tong Jinsong Zhao 《Process Safety and Environmental Protection》2009,87(1):40-46
As modern chemical plants are becoming more complex and bigger in scale, the associated chance of things going wrong is also increasing rapidly. Due to the flammable, explosive, toxic and corrosive nature of chemical process, any single accident may trigger a major catastrophe that brings tremendous environmental, social and economical loss. In order to prevent any accident from happening, hazard and operability (HAZOP) analysis has been brought in to monitor chemical process and provide early warning for signs of accident. However, most existing HAZOP is carried out manually, and there are always obstacles in terms of cost overrun and incompleteness of the analysis. To address the difficulties in current HAZOP method, this paper proposes a signed digraph (SDG)-based HAZOP analysis method. It is used to identify the most likely operating mistakes that may cause certain process variable deviating from its normal value, which is the main source of safety concern. A case study on polyvinyl chloride (PVC) plant is presented to demonstrate the effectiveness of SDG-based HAZOP analysis method in providing complete analysis result. 相似文献
950.