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901.
Chengbin Xiao Hai Yan Junfeng Wang Wei Wei Jun Ning Gang Pan 《Frontiers of Environmental Science & Engineering in China》2011,5(4):526-532
A promising bacterial strain for biodegrading microcystin-LR (MC-LR) as the sole carbon and nitrogen source was successfully
isolated from Lake Dianchi, China. The strain was identified as Sphingopyxis sp. USTB-05, which was the first isolated MCs-biodegrading Sphingopyxis sp. in China. The average biodegradation rate of MC-LR by Sphingopyxis sp. USTB-05 was 28.8 mg·L−1 per day, which was apparently higher than those of other bacteria reported so far. The optimal temperature and pH for both
strain USTB-05 growth and MC-LR biodegradation were 30°C and 7.0, respectively. The release of MC-LR from the cyanobacterial
cells collected from Lake Guishui and the biodegradation of MC-LR by both strain and cell-free extract (CE) were investigated.
The results indicated that MC-LR with the initial concentration of 4.0 mg·L−1 in water was biodegraded by Sphingopyxis sp. USTB-05 within 4 d, while MC-LR with the initial concentration of 28.8 mg·L−1 could be completely removed in 3 h by CE of Sphingopyxis sp. USTB-05 containing 350 mg·L−1 protein. During enzymatic biodegradation of MC-LR, two intermediate metabolites and a dead-end product were observed on an
HPLC chromatogram. Moreover, the similar scanning profiles of MC-LR and its metabolic products indicate that the Adda side-chain
of MC-LR was kept intact in all products. 相似文献
902.
本文探讨了突发性大气污染事故状态下进行快速、科学、规范、有效的应急环境监测的作用、工作程序、监测方法,以防止目前应急监测中措手不及、手忙脚乱、无章可循的工作弊病,具有一定的现实意义。 相似文献
903.
904.
905.
通过对浑善达克沙地桑根达来地段1km2范围的详细调查,发现204种维管植物,35个群系。与同属典型草原地带相同地段乌力雅斯太草原,只有11个群系。沙地是最好的冬季牧场,是干旱区的地下水库。相关资料显示,我国沙漠和沙地目前比较稳定,不像是某些媒体所说的在强烈扩大。另外,沙漠和沙地不是沙尘源。因此,不得不审视我们对沙地和沙漠的错误看法。 相似文献
906.
我国养猪业废弃物中四环素类、磺胺类抗生素及相关抗性基因污染研究进展 总被引:2,自引:0,他引:2
我国是世界养猪第一大国,生猪饲养量和猪肉产量均位居世界第一。养猪业每年所产生的粪便、废水中含有大量畜用抗生素及其代谢产物,使养猪业废弃物成为环境中重要的抗生素污染源之一,随之产生的抗性基因污染及传播问题也不容忽视。本文结合近年来国内外的研究数据,对我国养猪业废弃物中四环素类、磺胺类抗生素及其相关抗性基因的检测方法、污染状况及影响抗性基因传播的因素进行了分析,并基于控制我国养猪行业抗生素及抗性基因污染的目的,提出了今后的研究重点。 相似文献
907.
本文旨在检测健康人群与前列腺癌患者血清中重金属锑的含量,并对重金属锑在前列腺癌发生发展中的作用和相关机制进行初步探索。本实验使用电感耦合等离子体质谱仪(ICP-MS)对健康人群和前列腺癌患者血清中重金属锑的含量进行了检测;此外,分别通过MTT和Alamar-Blue方法对于重金属锑对人前列腺癌PC-3细胞的毒性效应进行了评价,并进一步探讨了非毒性剂量的重金属锑对前列腺癌细胞增殖能力(细胞计数及克隆形成实验)及脂类代谢过程(细胞内甘油三酯)的影响。研究结果显示:重金属锑在前列腺癌组患者血清中含量明显高于健康人群组且差异具有统计学意义;毒性实验结果表明高剂量的重金属锑能够显著抑制细胞活力且呈浓度依赖型方式,而非毒性剂量重金属锑能够显著促进前列腺癌细胞增殖,并导致细胞内甘油三酯的含量增加(P0.05)。综上所述,重金属锑在前列腺癌患者血清中具有相对较高水平,其机制可能是通过影响细胞脂类代谢从而促进前列腺癌的进展,这将对未来前列腺癌的预防和治疗提供一定的理论依据。 相似文献
908.
含油率对餐厨垃圾干式厌氧发酵的影响 总被引:3,自引:1,他引:2
餐厨垃圾含油率高,且随着地域的变化有显著差别,含油率的高低对餐厨垃圾厌氧消化产气有一定影响.在中温(35℃)和高温(55℃)条件下,研究了不同含油率(0、2%、4%、6%、8%、10%)对餐厨垃圾干式厌氧发酵过程中日产气量、累计产气量、总固体(TS)、挥发性固体(VS)及甲烷产量的影响.结果表明:在中温和高温条件下,当含油率为6%时,200 g餐厨垃圾的累计产气量达最大值,分别为1391.6 m L和2165.9 m L.此时,TS和VS的去除率也最高,中温时去除率分别为29.4%(TS)和33.9%(VS),高温时去除率分别为33.2%(TS)和38.0%(VS).在餐厨垃圾干式厌氧发酵过程中,甲烷的产量占可燃气的体积分数逐渐升高.在中温厌氧发酵条件下,含油率为10%的餐厨垃圾发酵进行到26 d时,甲烷的体积分数最高,为80.5%.在高温干式厌氧发酵条件下,含油率为10%的餐厨垃圾发酵进行到23 d时,甲烷的体积分数最高,为84.2%. 相似文献
909.
Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria (PNSB). This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg2 + under the light-anaerobic condition. Results showed that with the optimal Mg2 + dosage of 10 mg/L, biomass production was improved by 70% to 3630 mg/L, and biomass yield also was improved by 60%. Chemical Oxygen Demand (COD) removal reached above 86% and hydraulic retention time was shortened from 96 to 72 hr. The mechanism analysis indicated that Mg2 + could promote the content of bacteriochlorophyll in photosynthesis because Mg2 + is the bacteriochlorophyll active center, and thus improved adenosine triphosphate (ATP) production. An increase of ATP production enhanced the conversion of organic matter in wastewater into PNSB cell materials (biomass yield) and COD removal, leading to more biomass production. With 10 mg/L Mg2 +, bacteriochlorophyll content and ATP production were improved by 60% and 33% respectively. 相似文献
910.
Using chitosan modified soil to flocculate and sediment algal cells has been considered as a promising strategy to combat cyanobacteria blooms in natural waters. However, the flocculation efficiency often varies with algal cells with different zeta potential (ZP) attributed to different growth phases or water conditions. This article investigated the relationship between ZP of Microcystis aeruginosa and its influence to the flocculation efficiency using chitosan modified soil. Results suggested that the optimal removal efficiency was obtained when the ZP was between − 20.7 and − 6.7 mV with a removal efficiency of more than 80% in 30 min and large floc size of > 350 μm. When the algal cells were more negatively charged than − 20.7 mV, the effect of chitosan modified soil was depressed (< 60%) due to the insufficient charge density of chitosan to neutralize and destabilize the algal suspension. When the algal cells were less negative than − 6.7 mV or even positively charged, a small floc size (< 120 μm) was formed, which may be difficult to sink under natural water conditions. Therefore, manipulation of ZP provided a viable tool to improve the flocculation efficiency of chitosan modified soil and an important guidance for practical engineering of cyanobacteria bloom control. 相似文献