全文获取类型
收费全文 | 15468篇 |
免费 | 2357篇 |
国内免费 | 5332篇 |
专业分类
安全科学 | 2493篇 |
废物处理 | 348篇 |
环保管理 | 1354篇 |
综合类 | 12094篇 |
基础理论 | 2514篇 |
污染及防治 | 1360篇 |
评价与监测 | 1007篇 |
社会与环境 | 1161篇 |
灾害及防治 | 826篇 |
出版年
2024年 | 149篇 |
2023年 | 421篇 |
2022年 | 1091篇 |
2021年 | 1048篇 |
2020年 | 1267篇 |
2019年 | 791篇 |
2018年 | 811篇 |
2017年 | 883篇 |
2016年 | 746篇 |
2015年 | 1024篇 |
2014年 | 965篇 |
2013年 | 1296篇 |
2012年 | 1482篇 |
2011年 | 1470篇 |
2010年 | 1296篇 |
2009年 | 1216篇 |
2008年 | 1173篇 |
2007年 | 1197篇 |
2006年 | 1091篇 |
2005年 | 875篇 |
2004年 | 626篇 |
2003年 | 496篇 |
2002年 | 392篇 |
2001年 | 339篇 |
2000年 | 323篇 |
1999年 | 221篇 |
1998年 | 92篇 |
1997年 | 52篇 |
1996年 | 59篇 |
1995年 | 74篇 |
1994年 | 51篇 |
1993年 | 38篇 |
1992年 | 39篇 |
1991年 | 20篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 176 毫秒
671.
Competition of three bloom-forming marine phytoplankton (diatom Skeletonema costatum, and dinoflagellates Prorocentrum
minimum and Alexandrium tamarense) was studied through a series of multispecies cultures with di erent nitrate (NaNO3) and
phosphate (NaH2PO4) levels and excess silicate to interpret red tide algae succession. S. costatum outgrew the other two dinoflagellates
in nitrate and phosphate replete cultures with 10 mol/L Na2SiO3. Under nitrate limited (8.82 mol/L NaNO3) conditions, the growth
of S. costatum was also dominant when phosphate concentrations were from 3.6 to 108 mol/L. Cell density of the two dinoflagellates
only increased slightly, to less than 400 and 600 cells/mL, respectively. Cell density of S. costatum decreased with time before day
12, and then increased to 4000 cells/mL (1.5 mg/L dry biomass) at NaNO3 concentrations between 88.2 and 882 mol/L with limited
phosphate (0.36 mol/L NaH2PO4) levels. In addition, P. minimum grew well with a maximal cell density of 1690–2100 cells/mL
(0.5–0.6 mg/L dry biomass). Although S. costatum initially grew fast, its cell density decreased quickly with time later in the growth
phase and the two dinoflagellates were dominant under the nitrate-limited and high nitrate conditions with limited phosphate. These
results indicated that the diatom was a poor competitor compared to the two dinoflagellates under limited phosphate; however, it grew
well under limited nitrate when growth of the dinoflagellates was near detection limits. 相似文献
672.
Biosorption of silver ions onto Bacillus cereus biomass was investigated. Overall kinetic experiments were performed for the
determination of the necessary contact time for the attainment of equilibrium. It was found that the overall biosorption process was
best described by pseudo second-order kinetic model. The crystals detected by scanning electron microscope and X-ray photoelectron
spectroscopy suggested the precipitation was a possible mechanism of biosorption. The molecular genetics of silver resistance of B.
cereus biomass was also detected and illustrated by a whole cell sensor tool. 相似文献
673.
The Cu2+-loaded montmorillonite clays (MMT-Cu) may be a good material for the adsorbed and eliminated pathogenic bacteria from aqueous solution. 相似文献
674.
大型溞母溞暴露于氨氮所产子代对氨氮毒性的耐受性 总被引:2,自引:0,他引:2
采用大型溞(Daphnia magna)作为受试生物,在测定了氨氮对大型溞的急慢性毒性效应的基础上,进一步研究了在慢性毒性试验中暴露于氨氮环境下的母溞所产子代对氨氮的毒性响应.急性毒性试验结果表明,氨氮对大型溞的24 h和48 h的LC50分别为165.97和69.54 mg/L.21 d慢性试验结果表明:大型溞的生长指标——脱皮数是对氨氮最为敏感的毒性参数;其慢性毒性下限值(LCL)和慢性毒性上限值(UCL)分别为1.88和3.75 mg/L;据此计算出的慢性毒性值(CHV)为2.66 mg/L,急慢性比(ACR)为26.14.在慢性试验中,暴露于毒物的母体所产的子代幼溞,与对照组相比,其48 h LC50都有所增大(增幅为13.7%~56.2%),说明对毒物的适应性有所增强. 相似文献
675.
676.
677.
678.
679.
680.