全文获取类型
收费全文 | 3786篇 |
免费 | 396篇 |
国内免费 | 1904篇 |
专业分类
安全科学 | 364篇 |
废物处理 | 136篇 |
环保管理 | 305篇 |
综合类 | 3086篇 |
基础理论 | 668篇 |
污染及防治 | 886篇 |
评价与监测 | 248篇 |
社会与环境 | 263篇 |
灾害及防治 | 130篇 |
出版年
2024年 | 23篇 |
2023年 | 116篇 |
2022年 | 238篇 |
2021年 | 257篇 |
2020年 | 266篇 |
2019年 | 203篇 |
2018年 | 206篇 |
2017年 | 255篇 |
2016年 | 253篇 |
2015年 | 289篇 |
2014年 | 284篇 |
2013年 | 356篇 |
2012年 | 382篇 |
2011年 | 368篇 |
2010年 | 305篇 |
2009年 | 324篇 |
2008年 | 316篇 |
2007年 | 313篇 |
2006年 | 279篇 |
2005年 | 156篇 |
2004年 | 150篇 |
2003年 | 130篇 |
2002年 | 123篇 |
2001年 | 91篇 |
2000年 | 99篇 |
1999年 | 74篇 |
1998年 | 43篇 |
1997年 | 41篇 |
1996年 | 31篇 |
1995年 | 24篇 |
1994年 | 22篇 |
1993年 | 20篇 |
1992年 | 11篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1970年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有6086条查询结果,搜索用时 31 毫秒
11.
采用两步水热法制备了新型磁性纳米Fe3O4@α-MnO2复合材料作为催化剂,用于活化过一硫酸盐(PMS)产生强氧化性的硫酸根自由基(SO4-·)氧化降解偶氮染料活性黑5(RBK5).采用透射电子显微镜(TEM),X射线粉末衍射仪(XRD)和振动样品磁强计(VSM)对制备的催化剂进行表征,证明成功合成了纳米α-MnO2包覆Fe3O4形态的Fe3O4@α-MnO2催化剂,催化剂的饱和磁化强度为39.89emu/g.Fe3O4@α-MnO2催化剂活化PMS与单一的Fe3O4和α-MnO2活化PMS相比,具有更高的催化效率,说明铁锰双金属存在协同作用.同时研究了催化剂的投加量、PMS的浓度和初始pH值等各种因素对RBK5的降解效率以及反应动力学的影响.实验结果表明,Fe3O4@α-MnO2催化剂活化PMS降解RBK5的过程符合准一级反应动力学,在催化剂投加量为1.2g/L,PMS的浓度为4mmol/L,初始pH值为7.0,反应时间为60min的情况下,浓度为30mg/L的RBK5的降解效率可达到91%,此时RBK5的降解速率常数也达到最高值0.023min-1.此外,通过加入自由基淬灭剂甲醇、叔丁醇和硝基苯判断了Fe3O4@α-MnO2/PMS体系中起主要氧化降解作用的活性物种为SO4-·. 相似文献
12.
Ji Hu Jianmin Wang Shuxia Liu Zhechao Zhang Haifeng Zhang Xiaoxia Cai Jianming Pan Jingjing Liu 《环境科学学报(英文版)》2018,30(4):208-215
TiO_2 nanoparticles(NPs) could adversely impact aquatic ecosystems. However, the aggregation of these NPs could attenuate this effect. In this work, the biological effects of TiO_2 NPs on a marine microalgae Isochrysis galbana were investigated. The aggregation kinetics of TiO_2 NPs under different conditions was also investigated to determine and understand these effects. Results showed that, though TiO_2 NPs had no obvious impact on the size and reproducibility of algal cells under testing conditions, they caused a negative effect on algal chlorophyll, which led to a reduction in photosynthesis. Furthermore, fast aggregation of TiO_2 NPs occurred under all conditions, especially at the pH close to the p Hzpc. Increasing ionic strength and NP concentration also enhanced the aggregation rate.The aggregation and the following sedimentation of TiO_2 NPs reduced their adverse effects on I. galbana. 相似文献
13.
The toxic effects of the composites of Fe~0 and Cu~0 with different percentages of CNTs were examined based on the activity of bacterial bioluminescence and seed germination. In terms of the EC_50 values, the toxic effects of Cu~0 on bacterial bioluminescence and seed germination were approximately 2 and 180 times greater than that of Fe~0, respectively. The toxicity increased with increasing CNT content in the Cu-CNT mixtures for both organisms,whereas opposite results were observed with Fe-CNT mixtures. The mean toxic effects of Cu-CNT(6%) were approximately 1.3–1.4 times greater than that of Cu-CNT(0%), whereas the toxic effects of Fe-CNT(6%) were approximately 2.1–2.5 times lower than that of Fe-CNT(0%) for both the bioluminescence activity and seed germination. The causes of this phenomenon are unclear at this point. More research will be needed to elucidate the mechanism of the toxicity of nano-mixture materials and the causes of the different patterns of toxicity with Cu-and Fe-CNT mixtures. 相似文献
14.
目的研究不同p H值海水中阴极极化对X80管线钢应力腐蚀及氢脆的抑制作用。方法采用慢应变速率拉伸试验、电化学测试、微观组织观察等分析方法。结果 X80钢在天然海水中的析氢电位约为-940m V(vs.SCE,下同),海水p H为3.5时析氢电位发生正移。其应力腐蚀敏感性与极化电位有很大关系,随着极化电位负移,X80钢的氢脆敏感性增加。天然海水中当极化电位负于-950 m V时,断口出现准解理断裂特征形貌。在-1050 m V极化电位下,钢材进入氢脆断裂区发生脆性断裂。海水p H为3.5时,-900 m V钢材有发生氢脆的危险。结论与天然海水相比,X80钢在p H为3.5的酸性海水中具有较高的应力腐蚀敏感性,两种海水介质中X80钢的应力腐蚀敏感性均随极化电位负移而增加。 相似文献
15.
目的研究碳纤维增强复合材料贮存条件下的性能变化趋势和寿命评估。方法对碳纤维增强复合材料开展四个不同温度条件下的热氧老化试验,按试验周期定期取样开展冲击性能测试,对试验数据采用寿命预估方法进行处理,对材料性能进行预估。结果通过数据计算分别得到我国热带海洋、干热沙漠等典型气候条件下的碳纤维增强复合材料贮存寿命分别为17.21~35.89年。结论碳纤维增强复合材料具有较好的贮存性能,在较为严酷的热带海洋气候和给定的失效判据条件下,寿命预计为17.21年。试验和数据处理方法可以较好地预计材料的性能变化趋势和开展寿命评估。 相似文献
16.
研制了一种测定水中Mg2 + 的测试管 ,测定范围为 0 .5mg/L~ 2 .0mg/L。该测试管适用于现场应急监测 ,具有快速、简便、抗干扰能力强和价格低廉等特点 相似文献
17.
The emission of the dioxin-like compounds from on-site waste incinerators of seven schools in Kyonggi Province of Korea was evaluated by determination of the cytochrome P4501A(CYP1A) catalytic activity and antiestrogenic activity using cell culturemicrobioassay. The residue samples were extracted in a Soxhlet apparatus using toluene for 20 hr. The concentrated crude extractswere fractionated with a basic alumina column. Dioxin-like compounds were then extracted. Induction of CYP1A activity in a rat(H4IIE) hepatoma cell line was used as indicator of biologicaleffect of incinerator residues and measured as 7-ethoxyresorufin-O-deethylase(EROD) activities. The EROD activities of fraction II extracts (one of the two extracts) in the H4IIE cells were from 0.044±0.002 to 4.424±0.351 ng-TEQ g-1 (TCDD Toxicity equivalent), showing relatively high inducing capacity. Antisetrogenicity of the extracts was measured as decrease in E2-induced cell proliferation. Most of the extracts showed antiestrogenic activity in MCF7-BUS cell.The TEQ levels of the incinerator residues and the antiestrogenicactivities were in good correlation, strongly suggesting that thepotent toxic emissions were indeed produced from the on-site school waste semi-incinerators and could cause the antiestrogenicity. 相似文献
18.
19.
Determination of Trace Organochlorinated Pesticides and Polychlorinated Biphenyls in Water 总被引:1,自引:0,他引:1
Zou Shichun Zhang Zhanxia Sheng Guoying Min Yushun Fu Jiamo 《Environmental monitoring and assessment》1997,44(1-3):563-568
A modified steam distillation liquid-liquid extraction (SDE) device is developed for the enrichment of trace organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) in up to one litre of water samples. One ml of n-hexane is sufficient to extract the analytes. The extract can be analysed directly by a capillary gas chromatography-electron capture detector. The recoveries range from 84.6 to 102.3% for OCPs and 80.5 to 106.2% for PCBs, respectively. Matrice materials such as lipids and humic substances were removed by the SDE method from the extract and no further cleanup and concentration steps were needed. 相似文献
20.