全文获取类型
收费全文 | 27052篇 |
免费 | 224篇 |
国内免费 | 356篇 |
专业分类
安全科学 | 473篇 |
废物处理 | 1213篇 |
环保管理 | 3284篇 |
综合类 | 5204篇 |
基础理论 | 6996篇 |
环境理论 | 6篇 |
污染及防治 | 6138篇 |
评价与监测 | 1880篇 |
社会与环境 | 2346篇 |
灾害及防治 | 92篇 |
出版年
2022年 | 228篇 |
2021年 | 211篇 |
2019年 | 189篇 |
2018年 | 801篇 |
2017年 | 771篇 |
2016年 | 859篇 |
2015年 | 412篇 |
2014年 | 572篇 |
2013年 | 1679篇 |
2012年 | 815篇 |
2011年 | 1556篇 |
2010年 | 1094篇 |
2009年 | 1202篇 |
2008年 | 1486篇 |
2007年 | 1710篇 |
2006年 | 858篇 |
2005年 | 792篇 |
2004年 | 795篇 |
2003年 | 823篇 |
2002年 | 826篇 |
2001年 | 898篇 |
2000年 | 574篇 |
1999年 | 384篇 |
1998年 | 274篇 |
1997年 | 278篇 |
1996年 | 313篇 |
1995年 | 339篇 |
1994年 | 304篇 |
1993年 | 285篇 |
1992年 | 271篇 |
1991年 | 283篇 |
1990年 | 259篇 |
1989年 | 227篇 |
1988年 | 221篇 |
1987年 | 212篇 |
1986年 | 199篇 |
1985年 | 205篇 |
1984年 | 231篇 |
1983年 | 221篇 |
1982年 | 220篇 |
1981年 | 201篇 |
1980年 | 174篇 |
1979年 | 164篇 |
1978年 | 164篇 |
1977年 | 147篇 |
1976年 | 133篇 |
1975年 | 138篇 |
1974年 | 145篇 |
1973年 | 131篇 |
1972年 | 135篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
952.
W. Holländer G. Morawietz D. Bake L. Laskus B. G. van Elzakker A. van der Meulen 《Journal of the Air & Waste Management Association (1995)》2013,63(6):881-886
The European Economic Community Council Directive 80/779/EEC1 describes air quality limit values and guide values for sulfur dioxide and suspended particulates. However, article 10, paragraph 1 does not define well enough the reference method required, amongst others, for the gravimetric measurement of suspended particulates. It is explicity stated in article 10, paragraph 5 of the directive, that “the commission shall, in selected locations in the member states and in cooperation with the latter, carry out studies on the sampling…of suspended particulates. These studies shall be designed in particular to promote the harmonization of methods of sampling and analysis of these pollutants.” Therefore, in a joint research program the Umweltbundesamt (grant #104 02263), the commission of European Communities (grant #84-B-6642-11-017-11-N) and the U.S. EPA (grant #2-43211-3580) funded the development of a reference dust sampler by the Fraunhofer-lnstitute of Toxicology and Aerosol Research (FhITA, in Hannover, Federal Republic of Germany) in order: ? to study the particle size distribution of ambient air aerosol at a number of selected sites; ? to compare the results obtained with the reference dust sampler with those of particle samplers operated in Europe and the United States; ? to verify the applicability of wind tunnel results to sampling behaviour in the free atmosphere. 相似文献
953.
María del Mar Delgado Vincenzo Penteriani Vilis O. Nams Letizia Campioni 《Behavioral ecology and sociobiology》2009,64(1):35-43
Moving and spatial learning are two intertwined processes: (a) changes in movement behavior determine the learning of the
spatial environment, and (b) information plays a crucial role in several animal decision-making processes like movement decisions.
A useful way to explore the interactions between movement decisions and learning of the spatial environment is by comparing
individual behaviors during the different phases of natal dispersal (when individuals move across more or less unknown habitats)
with movements and choices of breeders (who repeatedly move within fixed home ranges), that is, by comparing behaviors between
individuals who are still acquiring information vs. individuals with a more complete knowledge of their surroundings. When
analyzing movement patterns of eagle owls, Bubo bubo, belonging to three status classes (floaters wandering across unknown environments, floaters already settled in temporary
settlement areas, and territory owners with a well-established home range), we found that: (1) wandering individuals move
faster than when established in a more stable or fixed settlement area, traveling larger and straighter paths with longer
move steps; and (2) when floaters settle in a permanent area, then they show movement behavior similar to territory owners.
Thus, movement patterns show a transition from exploratory strategies, when animals have incomplete environmental information,
to a more familiar way to exploit their activity areas as they get to know the environment better. 相似文献
954.
This paper provides a preliminary assessment of the suitability of Tertiary sedimentary basins in Northern, Western and Eastern Greece in order to identify geological structures close to major CO2 emission sources with the potential for long-term storage of CO2. The term “emissions” refers to point source emissions as defined by the International Energy Agency, including power generation, the cement sector and other industrial processes. The Prinos oil field and saline aquifer, along with the saline formations of the Thessaloniki Basin and the Mesohellenic Trough have been identified as prospective CO2 geological storage sites. In addition, a carbonate deep saline aquifer occurring at appropriate depths beneath the Neogene-Quaternary sediments of Ptolemais-Kozani graben (NW Greece) is considered. The proximity of this geological formation to Greece's largest lignite-fired power plants suggests that it would be worthwhile undertaking further site-specific studies to quantify its storage capacity and assess its structural integrity. 相似文献
955.
The amine-modified polyhydroxyethylmethacrylate (poly(HEMA))-grafted biomaterial (tamarind fruit shell, TFS) carrying carboxyl functional groups at the chain end (PGTFS-COOH) was prepared and used as an adsorbent for the removal of uranium(VI) from water and nuclear industry wastewater. FTIR spectral analysis revealed that U(VI) ions and PGTFS-COOH formed a chelate complex. The adsorption process was relatively fast, requiring only 120 min to attain equilibrium. The adsorption kinetic data were best described by the pseudo-second-order equation. The equilibrium adsorption data were correlated with the Sips isotherm model. The maximum U(VI) ions uptake with PGTFS-COOH was estimated to be 100.79 mg/g. The complete removal of 10 mg/L U(VI) from simulated nuclear industry wastewater was achieved by 3.5 g/L PGTFS-COOH. The reusability of the adsorbent was demonstrated over 4 cycles using NaCl (1.0 M) + HCl (0.5 M) solution mixture to de-extract the U(VI). The results show that the PGTFS-COOH tested is very promising for the recovery of U(VI) from water and wastewater. 相似文献
956.
A major bottleneck for data-based policy making is that data sources are collected, managed, and distributed by different institutions, residing in different locations, resulting in conceptual and practical problems. The use of dispersed data for agricultural systems research requires the integration of data sources, which means to ensure consistency in data interpretations, units, spatial and temporal scales, to respect legal regulations of privacy, ownership and copyright, and to enable easy dissemination of data. This paper describes the SEAMLESS integrated database on European agricultural systems. It contains data on cropping patterns, production, farm structural data, soil and climate conditions, current agricultural management and policy information. To arrive at one integrated database, a shared ontology was developed according to a collaborative process, which facilitates interdisciplinary research. The paper details this process, which can be re-used in other research projects for integrating data sources. 相似文献
957.
This paper introduces a new stormwater quality improvement device, called the "Green Gully" that collects, purifies, and reuses stormwater throughout an automated system. The working principal of the Green Gully is divided into two parts. Firstly, diverting stormwater from roadways to the diverter channel by filtering litter and secondly, watering the gardens and roadside plants with the stormwater that is collected from diverter channel. Stormwater treatment is an important step before reusing the water for gardening purpose. Different treatment levels (primary, secondary, and tertiary) are applied depending on the application to make water suitable for long-term storage and watering purposes. In this study, stormwater samples from three sites of Rockhampton City have been tested and analyzed to determine the quality of water for reuse. The parameters tested were electrical conductivity, pH, salinity, concentration of oil and grease, total suspended solid, turbidity, alkalinity, sodium, and chloride. The results of on-site stormwater quality tests are compared with the Australian and New Zealand Environment Conservation Council (ANZECC) standards and quality data available in the literature for each parameter suitable for irrigating roadside plants and gardening. Although, the results of this study is comparable with the literature data, a significantly different quality data are found compared to ANZECC standards. However, the samples collected for this study gave a basic understanding of stormwater quality issues for potential inflows to the Green Gully. Further study is recommended in order to establish mathematical link between raw stormwater quality and water quality required for gardening and irrigating roadside plants and for adopting required level of treatment facility with Green Gully for purifying and reusing water through an automated network system. 相似文献
958.
A. C. Sheth J. Li D. G. Rasnake 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1466-1472
The interactions between potassium and sulfur-containing species are unique, yet important, phenomena for a coal-fired magnetohydrodynamics (MHD) system. An in-depth understanding of such phenomena will help in the future design of MHD systems. This paper deals with the modeling of potassium and sulfur interactions in DOE's Coal-Fired Flow Facility (CFFF), located in Tullahoma, Tennessee. 相似文献
959.
Abstract: The probability of persistence of many species of hibernating bats in the United States is greatly reduced by an emerging infectious disease, white‐nose syndrome (WNS). In the United States WNS is rapidly spreading and is associated with a psychrophilic fungus, Geomyces destructans. WNS has caused massive mortality of bats that hibernate. Efforts to control the disease have been ineffective. The culling of bats in hibernacula has been proposed as a way to break the transmission cycle or slow the spread of WNS. We formulated a disease model to examine the efficacy of culling to abate WNS in bat populations. We based the model dynamics on disease transmission in maternity roosts, swarms, and hibernacula, which are the arenas of contact among bats. Our simulations indicated culling will not control WNS in bats primarily because contact rates are high among colonial bats, contact occurs in multiple arenas, and periodic movement between arenas occurs. In general, culling is ineffective in the control of animal diseases in the wild. 相似文献
960.
This study examines the composition and activity of the planktonic community during the polar night in the high Arctic Kongsfjord,
Svalbard. Our results are the first published evidence of bioluminescence among zooplankton during the Arctic polar night.
The observations were collected by a bathyphotometer detecting bioluminescence, integrated into an autonomous underwater vehicle,
to determine the concentration and intensity of bioluminescent flashes as a function of time of day and depth. To further
understand community dynamics and composition, plankton nets were used to collect organisms passing through the bathyphotometer
along with traditional vertical net tows. Additionally, using a moored bathyphotometer closed to the sampling site, the bioluminescence
potential itself was shown not to have a diurnal or circadian rhythm. Rather, our results provide evidence for a diel vertical
migration of bioluminescent zooplankton that does not correspond to any externally detectable changes in illumination. 相似文献