首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4434篇
  免费   215篇
  国内免费   1656篇
安全科学   313篇
废物处理   287篇
环保管理   340篇
综合类   2490篇
基础理论   751篇
污染及防治   1591篇
评价与监测   167篇
社会与环境   152篇
灾害及防治   214篇
  2024年   7篇
  2023年   66篇
  2022年   240篇
  2021年   191篇
  2020年   137篇
  2019年   147篇
  2018年   150篇
  2017年   238篇
  2016年   230篇
  2015年   249篇
  2014年   319篇
  2013年   486篇
  2012年   365篇
  2011年   436篇
  2010年   279篇
  2009年   274篇
  2008年   349篇
  2007年   273篇
  2006年   257篇
  2005年   165篇
  2004年   122篇
  2003年   169篇
  2002年   133篇
  2001年   105篇
  2000年   128篇
  1999年   112篇
  1998年   102篇
  1997年   115篇
  1996年   82篇
  1995年   86篇
  1994年   62篇
  1993年   61篇
  1992年   57篇
  1991年   45篇
  1990年   28篇
  1989年   9篇
  1988年   6篇
  1987年   6篇
  1986年   5篇
  1985年   3篇
  1984年   3篇
  1983年   3篇
  1982年   4篇
  1981年   1篇
排序方式: 共有6305条查询结果,搜索用时 78 毫秒
241.
结合石化企业装置生产特点,分析装置级突发事故应急预案编制中存在的不足和问题,并对应急预案编制的思路和处置对策进行了深入地探讨.  相似文献   
242.
随着石油工业的发展和科学技术的进步,在油气开发和加工的生产中已形成了一套完善、先进的工艺技术,但在生产现场的安全管理方面仍存在着许多薄弱环节和诸多不安全因素.这些不安全因素将导致各类事故的发生,直接威胁着油田的安全生产.  相似文献   
243.
石化行业职业健康危害因素影响与控制   总被引:1,自引:0,他引:1  
石化行业生产过程高温、高压、易燃、易爆、易腐蚀,生产工艺伴有毒有害气体、烟尘、工业粉尘、噪声等职业健康危害因素,生产原料、中间产品、最终产品、副产品大多为危险化学品,劳动环境中存在许多职业健康危害因素,作业人员急性职业中毒和慢性职业病多发.因此,做好职业健康防护,杜绝和减少职业健康事故发生将是石化企业一项长期而艰巨的任务.  相似文献   
244.
有机磷农药降解方法及应用研究新进展   总被引:1,自引:0,他引:1  
现代农业的发展和有机磷农药的使用密切相关,所造成的严重的农产品和环境污染是农业发展有待解决的关键问题之一。介绍了超声波技术、吸附、洗涤和辐照等物理方法,微生物、降解酶和工程菌等生物方法,水解、氧化分解和光化学降解等化学方法对有机磷农药的降解作用及其相关的应用研究。  相似文献   
245.
Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized kaolin (kaolin/CA), was prepared using a sol-gel method. The e ects of contact time, pH, adsorbent dose, and temperature on Cu2+ adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum Cu2+ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.  相似文献   
246.
This work was designed to explore the characteristics of photodegradation of herbicides in the copper-polluted water body. The results showed that Cu(II) alone could induce a photo Fenton-like reaction to enhance the degradation of atrazine, in which hydroxyl radical ( OH) was a main active species. Humic acids restrained atrazine degradation, nevertheless, when introducing Cu(II), the photodegradation was accelerated, in which singlet oxygen (1O2) replaced OH acting as the prevailing species. A feasible mechanism for the photochemical process was also proposed, which is helpful for better understanding the environmental photochemistry of atrazine in the copper-polluted water.  相似文献   
247.
The adsorption behaviors of heavy metals onto novel low-cost adsorbent, red loess, were investigated. Red loess was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectra. The results indicated that red loess mainly consisted of silicate, ferric and aluminum oxides. Solution pH, adsorbent dosage, initial metal concentration, contact time and temperature significantly influenced the efficiency of heavy metals removal. The adsorption reached equilibrium at 4 hr, and the experimental equilibrium data were fitted to Langmuir monolayer adsorption model. The adsorption of Cu(II) and Zn(II) onto red loess was endothermic, while the adsorption of Pb(II) was exothermic. The maximum adsorption capacities of red loess for Pb(II), Cu(II) and Zn(II) were estimated to be 113.6, 34.2 and 17.5 mg/g, respectively at 25°C and pH 6. The maximum removal efficiencies were 100% for Pb(II) at pH 7, 100% for Cu(II) at pH 8, and 80% for Zn(II) at pH 8. The used adsorbents were readily regenerated using dilute HC1 solution, indicating that red loess has a high reusability. All the above results demonstrated that red loess could be used as a possible alternative low-cost adsorbent for the removal of heavy metals from aqueous solution.  相似文献   
248.
The aim of the present work was to produce a polyaluminium ferric silicate chloride (PAFSiC) coagulant from acidic and alkaline wastewater of purifying graphite by roasting, and subsequently to evaluate coagulation efficiency of the reagent by treating surface water from the Yellow River as well as municipal wastewater in comparison with the conventional coagulant polyaluminium chloride (PAC). The PAFSiC coagulant was prepared by co-polymerization. The effects of (Al+Fe)/Si molar ratio, OH/(Al+Fe) molar ratio (i.e., value), coagulant dosage and pH value of test suspension on the coagulation behavior of FAFSiC and the stability of the PAFSiC were also examined. Results showed that PAFSiC performed more efficiently than PAC in removing turbidity, chemical oxygen demand (COD), and total phosphate (TP). The PAFSiC with a value of 2.0 and (Al+Fe)/Si ratio of 5 (PAFSiC 2.0/5) showed excellent coagulation effect for both turbidity and COD, while PAFSiC 1.0/5 was the best for TP. The optimum coagulation pH range of PAFSiC 2.0/5 was 5.0–9.0, slightly wider than that of PAC (6.0–8.0). The process can be easily incorporated into high-purity graphite production plants, thereby reducing wastewater pollution and producing a valuable coagulant.  相似文献   
249.
Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were studied. The amount of methanotrophs ranged 61.97 103–632.91 103 cells/g (in dry basis) in aged refuse from Shanghai Laogang Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I methanotrophs were detected in the presence of nitrate minimal salt medium (NMS). The clone sequences of the pmoA gene obtained from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum, and Methylocystis, and two clones were distinct with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane biological oxidation and over 93% conversions were obtained.  相似文献   
250.
The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was investigated in a sediment core from Lake Erhal in Southwest China using gas-chromatography/mass spectrometry (GC/MS) method.The total organic carbon (TOC) normalized total PAHs concentrations (sum of US Environmental Protection Agency proposed 16 priority PAHs) ranged from 31.9 to 269 μg/g dry weight (dw),and were characterized by a slowly increasing stage in the deeper sediments and a sharp increasing stage in the upper sediments.The PAHs in the sediments were dominated by low molecular weight (LMW) PAHs,suggesting that the primary source of PAHs was low- and moderate temperature combustion processes.However,both the significant increase in high molecular weight (HMW) PAHs in the upper sediments and the vertical profile of diagnostic ratios pointed out a change in the sources of PAHs from low-temperature combustion to high-temperature combustion.The ecotoxicological assessment based on consensus-based sediment quality guidelines implied that potential adverse biological impacts were possible for benzo(ghi)perylenelene and most LMW PAHs.In addition,the total BaP equivalent quotient of seven carcinogenic polycyclic aromatic hydrocarbons (BaA,CHr,BbF,BkF,BaP,DBA and INP) was 106.1 ng/g,according to the toxic equivalency factors.Although there was no great biological impact associated with the HMW PAlls,great attention should be paid to these PAH components based on their rapid increase in the upper sediments.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号