全文获取类型
收费全文 | 633篇 |
免费 | 67篇 |
国内免费 | 159篇 |
专业分类
安全科学 | 68篇 |
废物处理 | 38篇 |
环保管理 | 32篇 |
综合类 | 337篇 |
基础理论 | 87篇 |
污染及防治 | 130篇 |
评价与监测 | 143篇 |
社会与环境 | 8篇 |
灾害及防治 | 16篇 |
出版年
2024年 | 7篇 |
2023年 | 9篇 |
2022年 | 20篇 |
2021年 | 23篇 |
2020年 | 26篇 |
2019年 | 25篇 |
2018年 | 21篇 |
2017年 | 27篇 |
2016年 | 28篇 |
2015年 | 33篇 |
2014年 | 34篇 |
2013年 | 82篇 |
2012年 | 54篇 |
2011年 | 46篇 |
2010年 | 32篇 |
2009年 | 32篇 |
2008年 | 24篇 |
2007年 | 42篇 |
2006年 | 42篇 |
2005年 | 29篇 |
2004年 | 41篇 |
2003年 | 32篇 |
2002年 | 28篇 |
2001年 | 27篇 |
2000年 | 23篇 |
1999年 | 15篇 |
1998年 | 9篇 |
1997年 | 21篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有859条查询结果,搜索用时 670 毫秒
581.
Summary. Male locust borers, Megacyllene robiniae
(Förster), responded to females only after contacting them
with their antennae, indicating that mate recognition was
mediated by a contact sex pheromone. GC-MS analyses of
whole-body extracts of males and females determined that the
profiles of compounds in the extracts were qualitatively similar,
but differed considerably in the ratios of compounds
between sexes. Biological activities of reconstructed blends
of the most abundant straight-chain (nC23, nC24, nC25, nC26),
methyl-branched (3me-C23, 3me-C25), and unsaturated
(Z9:C23, Z9:C25, Z9:C27 compounds in extracts from females
were assessed in arena bioassays, assessing four distinct steps
in the mating behavior sequence of males (orientation, arrestment,
body alignment, mounting and attempting to couple the
genitalia). Males were unresponsive to freeze-killed, solventwashed
females treated with blends of straight-chain and
methyl-branched alkanes, but responded strongly to females
treated with the blend of alkenes. Further trials determined
that the complete sequence of mating behaviors, up to and
including coupling the genitalia, was elicited by Z9:C25 alone.
Z9:C25 comprised 16.4 ± 1.3% of the total hydrocarbons in
whole-body hexane extracts of females and was co-dominant
with two other hydrocarbons that were not active. In contrast,
in solid phase microextraction (SPME) wipe samples from
several areas of the cuticle, Z9:C25 appeared as the single
dominant peak, comprising 34.6 – 37.8% of the sampled
hydrocarbons. Our data indicate that Z9:C25 is a contact sex
pheromone of M. robiniae, being the most abundant hydrocarbon
on the surface of the cuticular wax layer of females
where it is readily accessible to the antennae of males. 相似文献
582.
工业废水和城市污水中邻苯二甲酸酯残留分析 总被引:3,自引:0,他引:3
建立了以HLB固相萃取柱和反相液相色谱法测定水体中8种邻苯二甲酸酯的方法,并对方法的回收率、灵敏度进行了评价,同时分析了北京市七类典型污染点源50个采样点位邻苯二甲酸酯的浓度,检出的邻苯二甲酸酯包括DBP、DEHP、BBP、DEP和DCHP,它们的检出率分别为66%、62%、36%、10%和6%,工业废水和城市污水中主要邻苯二甲酸酯残留为DBP和DEHP。检出邻苯二甲酸酯的浓度范围为0.20~848.14μg/L。方法对邻苯二甲酸酯的回收率达到75.1%~115.5%,最低检出限0.10~0.62μg/L。 相似文献
583.
污水中新精神活性物质的分析方法优化及验证 总被引:2,自引:2,他引:0
随着对传统毒品打击力度的增大,各种为规避现行法律管制而合成的新精神活性物质(new psychoactive substances,NPS)层出不穷.NPS被滥用后,经人体新陈代谢所生成的代谢产物和未被代谢的原药随尿液进入生活污水,从而汇入污水处理厂,经处理后被排入自然水体.因此在国内外以往相关研究的基础上,应用固相萃取和UPLC-MS/MS技术,建立并优化了污水中11种常见NPS的前处理及检测方法.比较了污水前处理条件(如SPE柱、样品p H值、淋洗和复溶等)对目标物回收率的影响.结果表明最优前处理条件为:选用Oasis MCX柱,在p H=2的条件下加载样品,用2 m L p H=2的超纯水和2m L甲醇淋洗SPE柱,400μL 20%的甲醇水溶液复溶.通过对目标物的保留时间、回收率、基质效应、检出限和定量限、精密度等指标的评价,说明优化后的前处理方法和C18-UPLC-MS/MS检测方法高效可靠.应用优化后的方法对北京市11家污水处理厂的进、出水样进行了分析,验证了方法的可靠性,为进一步开展NPS的污水流行病学研究及健康风险评价提供了参考依据. 相似文献
584.
Gd2O3-NiO 共掺对钇稳定氧化锆材料热物理性能的影响 总被引:3,自引:0,他引:3
目的研究Gd_2O_3-NiO共掺对钇稳定氧化锆材料热物理性能的影响。方法采用高温固相反应法制得Gd_2O_3-NiO共掺YSZ陶瓷材料。分别利用XRD、扫描电镜观察、激光导热仪、傅立叶红外光谱仪对陶瓷材料的晶体结构、微观结构、热扩散系数及红外透过率进行表征,并对其热导率进行分析。结果 Gd_2O_3-NiO共掺YSZ后,陶瓷材料单斜相含量减少,室温至1300℃的热导率相比YSZ降低,在2.5~5μm波长范围内红外透过率降低。结论 Gd_2O_3-NiO共掺对YSZ陶瓷材料热导率的影响机理为掺杂Gd_2O_3和NiO导致YSZ中单斜相(M)、四方相(T)和立方相(C)含量发生变化,同时YSZ晶格发生畸变。对YSZ辐射传热的影响机理为通过在YSZ中掺杂过渡金属元素Ni使陶瓷材料吸收特定波长的光,进而有效地降低在2.5~5μm短波长的红外透过率,降低其高温下的红外辐射传热。 相似文献
585.
空间碎片超高速碰撞的数值方法研究 总被引:1,自引:0,他引:1
应用非线性动力学数值仿真软件AUTODYN-2D对空间碎片的超高速碰撞问题进行模拟,研究不同数值计算方法和材料模型的适用范围,空间碎片形状对碎片云的影响,冲击相变等问题。结果表明,在研究超高速碰撞中普遍采用的SPH方法可以很好地模拟碎片云的情况,但是难以对冲击相变问题进行模拟,而采用侵蚀模型的拉格朗日方法可较好地反映冲击相变现象。Tilloston状态方程适用于描述冲击相变问题,包括汽化问题。Johnson-Cook强度模型用来对应变硬化、应变率硬化以及熔化等问题进行模拟。因此,在当速度足以使材料发生相变时,Tilloston状态方程和Johnson-Cook强度模型是比较好的选择。 相似文献
586.
Shahabuddin Memon Ezgi Akceylan Begum Sap Mustafa Tabakci D. Max Roundhill Mustafa Yilmaz 《Journal of Polymers and the Environment》2003,11(2):67-74
Three newly synthesized polymer supported calix[4]arene ionophores (7–9) were synthesized, and their ion binding properties toward selected alkali (Li+, Na+, K+, Cs+) and transition metal (Hg2+, Ni2+, Cu2+, Co2+, Cd2+, and Pb2+) cations were investigated. It has been observed that these ionophores are not selective toward a particular metal cation but show better ion binding property as compared to monomeric calixarene derivatives (2 and 6). Ionophore 6 and its supported polymer were also employed in dichromate anion extraction experiments. The polymeric ionophore (9) was found an effective extractant for dichromate anion even at pH 7. 相似文献
587.
Ahmed I. El-Seesy Hamdy Hassan Latif Ibraheem Manzoore Elahi M Soudagar 《International Journal of Green Energy》2020,17(12):793-804
ABSTRACT The main challenge of utilizing ethanol in diesel engines in blending mode is the phase separation issue. Therefore, an attempt has been performed to enhance the stability feature of ethanol/Jatropha biodiesel (JME) blends by using n-butanol as co-solvent. The 10% by volume of n-butanol is added to the mixtures of 10% and 20% ethanol and 70% and 80% JME, which is denoted as JME10Bu10E and JME10Bu20E, respectively. The phase stability of the evaluated fuels is examined employing visual approach and Thermogravimetric analysis. These methods confirm that there is no phase separation for more than 2 months under ambient conditions. Then, the combustion and emission features are investigated utilizing a diesel engine run with different loads and constant speed. The findings demonstrate that the pmax. and HRR are increased by adding ethanol. The ignition delay is extended with the addition of ethanol while the combustion period is almost the same. The bsfc is decreased by adding ethanol compared to JME fuel. The CO, UHC, and NOx formations are reduced markedly by 40%, 40%, and 40%, respectively, with adding ethanol. Finally, using n-butanol and JME as co-solvents with ethanol supports the growth of renewable energy in the CI engine. 相似文献
588.
P. Manoj Kumar K. Mylsamy Karthick Alagar K. Sudhakar 《International Journal of Green Energy》2020,17(13):872-883
ABSTRACT This work explores the opportunities to address the setback in thermal energy storage of solar-based water heaters by uniting it with a suitable hybrid-nano composite phase change material (HNCPCM) in a static mode of operation. The experiments were conducted on a natural circulation all-glass evacuated solar water heating system (AGSWH). The investigation was steered in five cases such that the first case without any phase change material (PCM), the second with pure paraffin as PCM, and remaining three cases with three different mass percentage of HNCPCMs (0.5%, 1.0%, and 2.0% mass fraction of hybrid nanoparticles within PCM) in real-time solar exposure. The system was analyzed based on the first and second law of thermodynamics to assess the performance in all the five cases. Erstwhile, the hybrid nanoparticles were prepared by blending equal mass of SiO2 and CeO2 nanoparticles and characterized to gauge its thermal storage properties. The achieved results substantiated that the thermal conductivity had boosted with the accumulation of hybrid nanoparticles within the paraffin matrix, and maximum enhancement of 65.56% was attained with 2.0% mass fraction. The first law and second law investigations revealed that the incorporation of hybrid-nano composites improved the energy and exergy content of the system, distinctly. Among the experimented cases, HNCPCM with 1.0 mass% of hybrid nanoparticles remarkably yielded a better result of 19.4% and 1.28% improvement in energy and exergy efficiencies, respectively. Besides, it evidenced the necessity of choosing the right quantity of nanoparticles for achieving better overall results. 相似文献
589.
液相法芒硝制碱中苛化废渣的利用 总被引:2,自引:0,他引:2
研究了用液相法芒硝制碱的苛化废渣制取轻质CaCO3的工艺及用轻质CaCO3填充母料对聚乙烯进行改性。试验结果表明,本研究所制取的轻质CaCO3的质量符合GB4794-84一级品规格,用其制成母料对低密度聚乙烯填充改性,不仅可消除苛化废渣对环境的污染,降低聚乙烯制品的生产成本,而且可在制品的拉伸强度、断裂伸长率和冲击强度降低不多的情况下,提高制品的硬度、弹性模量、热稳定性及耐蠕变性。 相似文献
590.
Estrogen-related receptor
disruption of source water and drinking water
treatment processes extracts
Na Li Weiwei Jiang Kaifeng Rao Mei M Zijian Wang Satyanarayanan Senthik Kumaran 《环境科学学报(英文版)》2011,23(2):301-306
Environmental chemicals in drinking water can impact human health through nuclear receptors. Additionally, estrogen-related
receptors (ERRs) are vulnerable to endocrine-disrupting e ects. To date, however, ERR disruption of drinking water potency has
not been reported. We used ERR
two-hybrid yeast assay to screen ERR
disrupting activities in a drinking water treatment plant
(DWTP) located in north China and in source water from a reservoir, focusing on agonistic, antagonistic, and inverse agonistic activity
to 4-hydroxytamoxifen (4-OHT). Water treatment processes in the DWTP consisted of pre-chlorination, coagulation, coal and sand
filtration, activated carbon filtration, and secondary chlorination processes. Samples were extracted by solid phase extraction. Results
showed that ERR
antagonistic activities were found in all sample extracts, but agonistic and inverse agonistic activity to 4-OHT
was not found. When calibrated with the toxic equivalent of 4-OHT, antagonistic e uent e ects ranged from 3.4 to 33.1 g/L. In the
treatment processes, secondary chlorination was e ective in removing ERR
antagonists, but the coagulation process led to significantly
increased ERR
antagonistic activity. The drinking water treatment processes removed 73.5% of ERR
antagonists. To our knowledge,
the occurrence of ERR
disruption activities on source and drinking water in vitro had not been reported previously. It is vital, therefore,
to increase our understanding of ERR
disrupting activities in drinking water. 相似文献