全文获取类型
收费全文 | 2558篇 |
免费 | 31篇 |
国内免费 | 165篇 |
专业分类
安全科学 | 129篇 |
废物处理 | 225篇 |
环保管理 | 303篇 |
综合类 | 435篇 |
基础理论 | 458篇 |
环境理论 | 1篇 |
污染及防治 | 860篇 |
评价与监测 | 222篇 |
社会与环境 | 90篇 |
灾害及防治 | 31篇 |
出版年
2023年 | 15篇 |
2022年 | 46篇 |
2021年 | 57篇 |
2020年 | 34篇 |
2019年 | 57篇 |
2018年 | 84篇 |
2017年 | 82篇 |
2016年 | 101篇 |
2015年 | 75篇 |
2014年 | 84篇 |
2013年 | 205篇 |
2012年 | 148篇 |
2011年 | 175篇 |
2010年 | 119篇 |
2009年 | 149篇 |
2008年 | 152篇 |
2007年 | 161篇 |
2006年 | 133篇 |
2005年 | 123篇 |
2004年 | 111篇 |
2003年 | 106篇 |
2002年 | 102篇 |
2001年 | 64篇 |
2000年 | 47篇 |
1999年 | 27篇 |
1998年 | 22篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 20篇 |
1994年 | 19篇 |
1993年 | 20篇 |
1992年 | 12篇 |
1991年 | 19篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1978年 | 6篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1969年 | 5篇 |
排序方式: 共有2754条查询结果,搜索用时 359 毫秒
991.
Measurement of flow speed in the channels of novel threadlike structures on the surfaces of mammalian organs 总被引:1,自引:0,他引:1
There have been several reports on novel threadlike structures (NTSs) on the surfaces of the internal organs of rats and rabbits
since their first observation by Bonghan Kim in 1963. To confirm this novel circulatory function, it is necessary to observe
the flow of liquid through the NTS as well as the structurally corroborating channels in the NTS. In this article, we report
on the measurement of the flow speed of Alcian blue solution in the NTSs on the organ surfaces of rabbits, and we present
electron microscopic images depicting the cribrous cross-section with channels. The speed was measured as 0.3 ± 0.1 mm/s,
and the flow distance was up to 12 cm. The flow was unidirectional, and the phase contrast microscopic images showed that
the NTSs were strongly stained with Alcian blue. The ultrastructure of the NTSs revealed by cryo-scanning electron microscopy
and high-voltage electron microscopy showed that (1) there were cell-like bodies and globular clumps of matter inside the
sinus of the channel with thin strands of segregated zones which is a microscopic evidence of the liquid flow, (2) the sinuses
have wall structures surrounded with extracellular matrices of collagenous fibers, and (3) there exists a cribriform structure
of sinuses. To understand the mechanism for the circulation, a quantitative analysis of the flow speed has been undertaken
applying a simplified windkessel model. In this analysis, it was shown that the liquid flow through the NTSs could be due
to peristaltic motion of the NTS itself.
Baeckkyoung Sung and Min Su Kim contributed equally to this work. 相似文献
992.
993.
南黄海中部表层沉积物中多环芳烃含量分布及来源分析 总被引:1,自引:0,他引:1
采用气相色谱与质谱联用(GC/MS)技术,在一个航次内对南黄海表层沉积物中16种优先监控的PAHs的污染状况进行了调查,采用菲/蒽、荧蒽/芘、荧蒽/(荧蒽+芘)、吲哚芘/(吲哚芘+苯并(g,h,i)菲)等特定比值对PAHs来源进行了分析.结果表明,南黄海表层沉积物中检出PAHs的总含量为90.4~732.65ng·g-1,各站点均以4~6环为主;与其它站位相比,倾废区的HOI站位受到PAHs污染较为明显,无论是16种PAHs总量还是高分子量组分最高值都出现在该站点,虽然该海区沉积物中PAHs的含量没有超出生物影响低值,但苯并(b)荧蒽、吲哚芘和苯并(g,h,i)芘等一些没有最低安全标准的PAHs也有不同程度的检出,对海洋生物具有潜在的毒副作用.PAHs可能来源于原油、生物和煤燃烧造成的污染. 相似文献
994.
Application of ferrate(VI) in the treatment of industrial wastes containing metal-complexed cyanides : A green treatment 总被引:2,自引:0,他引:2
Ferrate(VI) was employed for the oxidation of cyanide (CN) and simultaneous removal of copper or nickel in the mixed/complexed
systems of CN-Cu, CN-Ni, or CN-Cu-Ni. The degradation of CN (1.00 mmol/L) and removal of Cu (0.095 mmol/L) were investigated
as a function of Fe(VI) doses from 0.3–2.00 mmol/L at pH 10.0. It was found that Fe(VI) could readily oxidize CN and the reduction
of Fe(VI) into Fe(III) might serve e ciently for the removal of free copper ions. The increase in Fe(VI) dose apparently favoured the
CN oxidation as well as Cu removal. Moreover, the pH dependence study (pH 10.0–13.0) revealed that the oxidation of CN was almost
una ected in the studied pH range (10.0–13.0), however, the maximum removal e ciency of Cu was obtained at pH 13.0. Similarly,
treatment was carried out for CN-Ni system having the initial Ni concentration of 0.170 mmol/L and CN concentration of 1.00 mmol
with Fe(VI) dose 2.00 mmol at various pH values (10.0–12.0). Results showed a partial oxidation of CN and partial removal of Ni. It
can be observed that Fe(VI) can partially degrade the CN-Ni complex in this pH range. Further, Fe(VI) was applied for the treatment
of simulated industrial waste/e uent waters treatment containing CN, Cu, and Ni. 相似文献
995.
996.
MiSeon Lee GeunAe Park MinJi Park JongYoon Park JiWan Lee SeongJoon Kim 《环境科学学报(英文版)》2010,22(6):826-833
This study evaluated the reduction e ect of non-point source pollution by applying best management practices (BMPs) to a 1.21 km2
small agricultural watershed using a SWAT (Soil andWater Assessment Tool) model. Two meter QuickBird land use data were prepared
for the watershed. The SWAT was calibrated and validated using daily streamflow and monthly water quality (total phosphorus (TP),
total nitrogen (TN), and suspended solids (SS)) records from 1999 to 2000 and from 2001 to 2002. The average Nash and Sutcli e
model e ciency was 0.63 for the streamflow and the coe cients of determination were 0.88, 0.72, and 0.68 for SS, TN, and TP,
respectively. Four BMP scenarios viz. the application of vegetation filter strip and riparian bu er system, the regulation of Universal
Soil Loss Equation P factor, and the fertilizing control amount for crops were applied and analyzed. 相似文献
997.
Ku-Fan Chen Chih-Ming Kao Chiu-Wen Chen Rao Y. Surampalli Mu-Sheng Lee 《环境科学学报(英文版)》2010,22(6):864-871
In the first phase of this study, the e ectiveness of intrinsic bioremediation on the containment of petroleum hydrocarbons was
evaluated at a gasoline spill site. Evidences of the occurrence of intrinsic bioremediation within the BTEX (benzene, toluene,
ethylbenzene, and xylenes) plume included (1) decreased BTEX concentrations; (2) depletion of dissolved oxygen (DO), nitrate,
and sulfate; (3) production of dissolved ferrous iron, methane, and CO2; (4) deceased pH and redox potential; and (5) increased
methanogens, total heterotrophs, and total anaerobes, especially within the highly contaminated areas. In the second phase of this study,
enhanced aerobic bioremediation process was applied at site to enhance the BTEX decay rates. Air was injected into the subsurface
near the mid-plume area to biostimulate the naturally occurring microorganisms for BTEX biodegradation. Field results showed that
enhanced bioremediation process caused the change of BTEX removal mechanisms from anaerobic biodegradation inside the plume
to aerobic biodegradation. This variation could be confirmed by the following field observations inside the plume due to the enhanced
aerobic bioremediation process: (1) increased in DO, CO2, redox potential, nitrate, and sulfate, (2) decreased in dissolved ferrous iron,
sulfide, and methane, (3) increased total heterotrophs and decreased total anaerobes. Field results also showed that the percentage
of total BTEX removal increased from 92% to 99%, and the calculated total BTEX first-order natural attenuation rates increased
from 0.0092% to 0.0188% per day, respectively, after the application of enhanced bioremediation system from the spill area to the
downgradient area (located approximately 300 m from the source area). 相似文献
998.
Natarajan Velmurugan Grim Hwang Muthuswamy Sathishkumar Tae Kie Choi Kui-Jae Lee Byung-Taek Oh Yang-Soo Lee 《环境科学学报(英文版)》2010,22(7):1049-1056
A heavy metal contaminated soil sample collected from a mine in Chonnam Province of South Korea was found to be a source
of heavy metal adsorbing biosorbents. Chemical analyses showed high contents of lead (Pb) at 357 mg/kg and cyanide (CN) at 14.6
mg/kg in the soil. The experimental results showed that Penicillium sp. MRF-1 was the best lead resistant fungus among the four
individual metal tolerant fungal species isolated from the soil. Molecular characterization of Penicillium sp. MRF-1 was determined
using ITS regions sequences. E ects of pH, temperature and contact time on adsorption of Pb(II) by Penicillium sp. MRF-1 were
studied. Favorable conditions for maximum biosportion were found at pH 4 with 3 hr contact time. Biosorption of Pb(II) gradually
increased with increasing temperature. E cient performance of the biosorbent was described using Langmuir and Freundlich isotherms.
Adsorption kinetics was studied using pseudo first-order and pseudo second-order models. Biosorbent Penicillium sp. MRF-1 showed
the maximum desorption in alkali conditions. Consistent adsorption/desorption potential of the biosorbent in repetitive cycles validated
the e cacy of it in large scale. SEM studies given notes on surface modification of fungal biomass under metal stress and FT-IR results
showed the presence of amino groups in the surface structure of the biosorbent. In conclusion, the new biosorbent Penicillium sp.
MRF-1 may potentially be used as an inexpensive, easily cultivatable material for the removal of lead from aqueous solution. 相似文献
999.
Shaoyong Lu Xiangcan Jin Fengchang Wu Jianning Guo Jing Si 《Frontiers of Environmental Science & Engineering in China》2010,4(3):295-300
Effects of human activity on the distribution of phosphorus (P) forms were investigated for the sediments and porewaters in
Daqinghe Estuary of Dianchi Lake, China. The concentrations of total P (TP), inorganic-P (I-P),and organic-P (Org-P), and
the ratio of iron-bound P (Fe-P)/calcium-bound P (Ca-P) in the sediments decreased with the increasing distance from the sampling
site to the estuary. This is probably due to the flocculant materials, e.g., ferric and aluminous salts, usually being added
in the wastewater treatment processes. The concentration of ammonia in the sediment porewaters significantly decreased with
the increasing distance from the sampling site to the estuary. Both concentrations of total nitrogen and nitrogen in the sediment
porewaters decreased to some content with the increasing distance from the sampling site to the estuary. However, the concentrations
of nitrate, dissolved total P (DTP), and TP did not have strong relationship with the distances from the sampling sites to
the estuary. Pollution load and water quantity also had an important influence on the concentrations of P in sediments and
its interstitial water in estuary sedimentary area. 相似文献
1000.
为统一危险源和隐患的分歧,本文首先分析2个术语概念混乱的原因,然后根据2个术语的本质特征,给出它们的新定义、新分类和新分级,最后基于新的分类分级体系,给出新的隐患管理模式.研究表明:2个术语服从内外因作用原理,即危险源是内因,隐患是外因.危险源按源头可划分为3类,按载体形式可划分为4类;隐患按安全防护功能可划分为7类,根据产生阶段,可将这7类隐患再归为3类,若按内容和表现形式可将隐患划分为3类.根据隐患影响安全防护功能的程度将隐患分为1、2、3级.隐患管理新模式可简化现行隐患管理体制机制,有助于让政府、企业/单位等落实各自的安全生产主体责任. 相似文献