全文获取类型
收费全文 | 25388篇 |
免费 | 922篇 |
国内免费 | 5544篇 |
专业分类
安全科学 | 1293篇 |
废物处理 | 1739篇 |
环保管理 | 2525篇 |
综合类 | 10404篇 |
基础理论 | 5456篇 |
污染及防治 | 6546篇 |
评价与监测 | 1723篇 |
社会与环境 | 1481篇 |
灾害及防治 | 687篇 |
出版年
2024年 | 25篇 |
2023年 | 254篇 |
2022年 | 798篇 |
2021年 | 732篇 |
2020年 | 593篇 |
2019年 | 513篇 |
2018年 | 2035篇 |
2017年 | 2015篇 |
2016年 | 1832篇 |
2015年 | 1030篇 |
2014年 | 1302篇 |
2013年 | 1639篇 |
2012年 | 1831篇 |
2011年 | 2725篇 |
2010年 | 1842篇 |
2009年 | 1747篇 |
2008年 | 2105篇 |
2007年 | 2247篇 |
2006年 | 1028篇 |
2005年 | 676篇 |
2004年 | 518篇 |
2003年 | 613篇 |
2002年 | 601篇 |
2001年 | 377篇 |
2000年 | 455篇 |
1999年 | 397篇 |
1998年 | 318篇 |
1997年 | 335篇 |
1996年 | 293篇 |
1995年 | 227篇 |
1994年 | 174篇 |
1993年 | 143篇 |
1992年 | 131篇 |
1991年 | 73篇 |
1990年 | 69篇 |
1989年 | 27篇 |
1988年 | 29篇 |
1987年 | 21篇 |
1986年 | 15篇 |
1985年 | 9篇 |
1984年 | 18篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1958年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
571.
Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting 总被引:1,自引:0,他引:1
572.
Hou Jiaqi Li Mingxiao Xi Beidou Tan Wenbing Ding Jie Hao Yan Liu Dongming Liu Hongliang 《Environmental science and pollution research international》2017,24(26):21283-21297
Environmental Science and Pollution Research - Soil conditioners can be used to compensate for the insufficient soil nutrition and organic matter (OM) of arable soils. However, the traditional... 相似文献
573.
Jung-Kwang Kim Sun-Kee Han Geon-Ha Kim Ji-Tae Kim Chae-Young Lee 《Journal of Material Cycles and Waste Management》2017,19(1):118-123
This study was aimed to investigate the biodegradation characteristics of organic matters in swine carcasses. The lysimeters were simulated with different initial operating conditions: 30 % volumetric moisture content and no sludge addition for lysimeter A (control), 30 % volumetric moisture content and anaerobic sludge addition for lysimeter B, and 40 % volumetric moisture content and anaerobic sludge addition for lysimeter C. The degradation efficiency (18.4 %) of lysimeter B was higher than that (15.2 %) of lysimeter A due to anaerobic sludge addition. Lysimeter B showed higher CH4 yield (15.6 L/kg VS) and CH4 production rate (0.41 L/kg VS days) compared to lysimeter A by 31 % and 14 %, respectively. In addition, the degradation efficiency improved from 18.4 % (lysimeter B) to 26.3 % (lysimeter C) by increasing volumetric moisture content. The CH4 yield (22.9 L/kg VS) and CH4 production rate (0.68 L/kg VS days) of lysimeter C were higher than those of lysimeter B, respectively. Total organic carbon (TOC) removed in lysimeter C was converted to leachate (20.3 %) and gas (6.0 %), whose values were higher than those of lysimeter A and B. These results demonstrated that the proper control of initial operating conditions could accelerate the anaerobic degradation of organic matters in swine carcasses. 相似文献
574.
575.
Li Jintao Jiang Changjun Xing Zhanjun 《Environment, Development and Sustainability》2021,23(8):12151-12168
Environment, Development and Sustainability - With the rapid development of industrialization and urbanization and the continuous improvement of social productivity, people are increasingly... 相似文献
576.
随着车辆技术进步和燃油品质提升,河南省在用柴油车加载减速污染物现行排放限值已不能对高排放车辆进行有效监控。依据《确定压燃式发动机在用汽车加载减速法排气烟度排放限值的原则和方法》(HJ/T 241—2005),采用相对光吸收系数与累积频率法,对9 458份在用柴油车检测数据进行统计分析,提出符合河南省的在用柴油车排放限值。建议河南省在用国三、国四、国五轻型柴油车尾气光吸收系数限值分别为0.98、0.89、0.76m~(-1),而相应重型柴油车尾气光吸收系数限值分别为0.66、0.62、0.48m~(-1);依据该限值,河南省在用柴油车的年检合格率控制在82.6%,高排放柴油车比例为17.4%,符合HJ/T 241—2005的要求。 相似文献
577.
Xueqi Fan Jie Gao Wenchao Li Jun Huang Gang Yu 《Frontiers of Environmental Science & Engineering》2020,14(1):8
578.
Nikolay A. Vinnichenko Yulia Yu. Plaksina Ksenia M. Baranova Alexey V. Pushtaev Alexander V. Uvarov 《Environmental Fluid Mechanics》2018,18(5):1045-1056
Dynamics of the surface layer in different liquids is examined by means of infrared thermography of the surface and simultaneous velocity fields measurements using surface and infrared Particle Image Velocimetry. This technique allows measurements and comparison of two velocity fields—at the surface and at small depth about 50–200 μm. In distilled water the velocity fields at the surface and at small depth exhibit significant dissimilarity. The flow field below the surface is essentially 3D, whereas the surface flow is characterized by vanishing 2D divergence of velocity, indicating predominantly planar motion. In contrast, in ethanol–butanol mixture two velocity fields are well correlated, both corresponding to 3D flow with continuous surface renewal. Thermal patterns, observed at the surface, and the flow field structure in different liquids are associated with different boundary conditions for velocity at the surface. Water surface is seldom renewed, which inhibits heat and mass exchange between the liquid and atmosphere. However, absence of vertical advection also enables organisms to live within the surface layer, to stand and walk on the free surface. This is illustrated by the difficulties a water strider faces on the surface of ultrapure water, which exhibits Marangoni convection. 相似文献
579.
The Mekong River Delta in Vietnam plays a crucial role for the region in terms of food security and socioeconomic development; however, it is one of the most low-lying and densely populated areas in the world. It is vulnerable to seawater incursion, flood risk, and shoreline change, exacerbated as a consequence of sea-level rise (SLR) related to climate change. This study examined the Kien Giang coast in the western part of the delta, comprising seven coastal districts (namely Ha Tien, Kien Luong, Hon Dat, Rach Gia, Chau Thanh, An Bien, and An Minh), the economy of which is important in terms of agriculture and aquaculture. The analytical hierarchical process (AHP) method of multi-criteria decision making was integrated directly into geographic information systems (GIS) to derive a composite vulnerability index that indicated areas most likely to be vulnerable to SLR. The hierarchical structure comprised three key components: exposure (E), sensitivity (S), and adaptive capacity (A), at level 1. At the next level, 8 sub-components were mapped: seawater incursion, flood risk, shoreline change, population characteristics, land use/land cover, and socioeconomic, infrastructure, and technological capability, beyond which a further 22 variables (level 3) and 24 sub-variables (level 4) related to vulnerability were also mapped. Variables were assigned weights for incorporation into AHP pairwise comparisons after discussion with stakeholders. Maps were generated to visualise areas where the relative vulnerability was very low, low, moderate, high, and very high. Societal data were generally only available at district level; however, several regional patterns emerged. Relatively high exposure to flooding and inundation, salinity, and moderate loss of mangroves occurred along the coastal fringe of each district. This western section of the delta, which is low-lying and remote from the distributaries that carry sediment to the coast, appears to be particularly vulnerable. The most sensitive areas tended to be ethnic households engaged in rice cultivation and with moderate population density. The least adaptable areas consisted of high numbers of poor households, with low income, and moderate densities of transport, irrigation and drainage systems. Most coastal districts were determined to be moderately to relatively highly vulnerable, with scattered hotspots along the coast. 相似文献
580.
Sergio Santiago Deborah M. Roll Chittaranjan Ray Clinton Williams Philip Moravcik Allan Knopf 《Environmental science and pollution research international》2016,23(20):20257-20268
Agricultural crops have a long history of being irrigated with recycled wastewater (RW). However, its use on vegetable crops has been of concern due to the potential prevalence of microcontaminants, such as pharmaceuticals and personal care products (PPCPs) in the latter, which represents a possible health hazard to consumers. We investigated the uptake of three PPCPs (atenolol, diclofenac, and ofloxacin), at three different concentrations in irrigation water (0.5, 5, and 25 μg L?1) in relation to three varying volumetric soil moisture depletion levels of 14 % (?4.26 kPa), 10 % (?8.66 kPa), and 7 % (?18.37 kPa) by various vegetable crop species. Experiments were conducted in a split-split block completely randomized design. PPCPs were extracted using a developed method of accelerated solvent extraction and solid phase extraction and analyzed via liquid chromatography mass spectrometry (LCMS). Results indicate that all treated crops were capable of PPCP uptake at nanogram per gram concentrations independent of the applied soil moisture depletion levels and PPCP concentrations. Ofloxacin was the chemical with the highest uptake amounts, followed by atenolol and then diclofenac. Although the results were not statistically significant, higher concentrations of PPCPs were detected in plants maintained under higher soil moisture levels of 14 % (?4.26 kPa). 相似文献