全文获取类型
收费全文 | 9446篇 |
免费 | 123篇 |
国内免费 | 77篇 |
专业分类
安全科学 | 375篇 |
废物处理 | 448篇 |
环保管理 | 1253篇 |
综合类 | 1287篇 |
基础理论 | 2334篇 |
环境理论 | 4篇 |
污染及防治 | 2298篇 |
评价与监测 | 707篇 |
社会与环境 | 873篇 |
灾害及防治 | 67篇 |
出版年
2023年 | 73篇 |
2022年 | 116篇 |
2021年 | 106篇 |
2020年 | 85篇 |
2019年 | 109篇 |
2018年 | 158篇 |
2017年 | 209篇 |
2016年 | 250篇 |
2015年 | 176篇 |
2014年 | 274篇 |
2013年 | 764篇 |
2012年 | 345篇 |
2011年 | 472篇 |
2010年 | 389篇 |
2009年 | 415篇 |
2008年 | 462篇 |
2007年 | 464篇 |
2006年 | 442篇 |
2005年 | 385篇 |
2004年 | 342篇 |
2003年 | 351篇 |
2002年 | 310篇 |
2001年 | 350篇 |
2000年 | 230篇 |
1999年 | 164篇 |
1998年 | 89篇 |
1997年 | 122篇 |
1996年 | 103篇 |
1995年 | 113篇 |
1994年 | 120篇 |
1993年 | 104篇 |
1992年 | 97篇 |
1991年 | 92篇 |
1990年 | 95篇 |
1989年 | 79篇 |
1988年 | 78篇 |
1987年 | 71篇 |
1986年 | 72篇 |
1985年 | 64篇 |
1984年 | 65篇 |
1983年 | 75篇 |
1982年 | 71篇 |
1981年 | 57篇 |
1980年 | 49篇 |
1979年 | 49篇 |
1978年 | 41篇 |
1977年 | 33篇 |
1976年 | 34篇 |
1974年 | 34篇 |
1973年 | 32篇 |
排序方式: 共有9646条查询结果,搜索用时 15 毫秒
951.
952.
953.
Blake T. Dotta Nirosha J. Murugan Lukasz M. Karbowski Robert M. Lafrenie Michael A. Persinger 《Die Naturwissenschaften》2014,101(2):87-94
During the first 24 h after removal from incubation, melanoma cells in culture displayed reliable increases in emissions of photons of specific wavelengths during discrete portions of this interval. Applications of specific filters revealed marked and protracted increases in infrared (950 nm) photons about 7 h after removal followed 3 h later by marked and protracted increases in near ultraviolet (370 nm) photon emissions. Specific wavelengths within the visible (400 to 800 nm) peaked 12 to 24 h later. Specific activators or inhibitors for specific wavelengths based upon Cosic’s resonant recognition model elicited either enhancement or diminishment of photons at the specific wavelength as predicted. Inhibitors or activators predicted for other wavelengths, even within 10 nm, were less or not effective. There is now evidence for quantitative coupling between the wavelength of photon emissions and intrinsic cellular chemistry. The results are consistent with initial activation of signaling molecules associated with infrared followed about 3 h later by growth and protein-structural factors associated with ultraviolet. The greater-than-expected photon counts compared with raw measures through the various filters, which also function as reflective material to other photons, suggest that photons of different wavelengths might be self-stimulatory and could play a significant role in cell-to-cell communication. 相似文献
954.
V. A. Romanenkov J. U. Smith P. Smith O. D. Sirotenko D. I. Rukhovitch I. A. Romanenko 《Regional Environmental Change》2007,7(2):93-104
The Model of Humus Balance was used to estimate the influence of climate effects and changing agricultural practices on carbon
(C) levels in soddy–podzolic soils in the Russian Federation for the years 2000–2050. The model was linked with a spatial
database containing soil, climate and farming management layers for identification of spatial change of C sequestration potential.
Analysis of relationships between C, soil texture and climate indicated that compared with a business-as-usual scenario, adaptation
measures could increase the number of polygons storing soil organic carbon (SOC) by 2010–2020. The rate of possible C loss
is sensitive to the different climate scenarios, with a maximum potential for SOC accumulation expected in 2030–2040, thereafter
decreasing to 2050. The effect is most pronounced for the arid part of the study area under the emission scenario with the
highest rate of increase in atmospheric CO2 concentration, supporting findings from the dynamic SOC model, RothC. C sequestration during the study period was permanent
for clay and clay loam soils with a C content of more than 2%, suggesting that C sequestration should be focused on highly
fertile, fine-textured soils. We also show that spatial heterogeneity of soil texture can be a source of uncertainty for estimates
of SOC dynamics at the regional scale.
Figures in color are available at 相似文献
955.
It has traditionally been accepted that people structure their cognitive map of the city through the five Lynch categories: path, edge, district, node and landmark. This study confirms empirically the existence of these categories in two different experiments applying two forms of multivariate analysis: hierarchical cluster analysis and correspondence analysis based on Euclidean and χ2 distances, respectively. The problematic edge category is also discussed, as well as the influence of centre-periphery dimensions on these categories. 相似文献
956.
G.J. Schürmann A. Algieri I.M. Hedgecock G. Manna N. Pirrone F. Sprovieri 《Atmospheric environment (Oxford, England : 1994)》2009,43(29):4424-4434
A modelling study with the on-line coupled Eulerian chemical-weather model WRF/Chem for the Southern Italian region around Cosenza (Calabria) was conducted to identify the influences of synoptic scale meteorology, local scale wind systems and local emissions on ozone concentrations in this orographically complex region. Four periods of 5–7 days were chosen, one from each season, which had wind pattern characteristics representative of typical local climatological conditions, in order to study the local versus non-local impacts on ozone transport and formation. To account for the complex terrain, the horizontal resolution of the smallest modelling domain was 3 km. Model results were compared with measurements to demonstrate the capability of the model to reproduce ozone concentrations in the region. The comparison was favourable with a mean bias of ?1.1 ppb. The importance of local emissions on ozone formation and destruction was identified with the use of three different emission scenarios. Generally the influence of regional emissions on the average ozone concentration was small. However during periods when mountain-sea wind systems were well developed and synoptic scale winds were weak, the influence of local emissions from the urban area was at its greatest. The maximum influence of local emissions on ozone concentrations was 18 ppb. 相似文献
957.
958.
959.