全文获取类型
收费全文 | 864篇 |
免费 | 15篇 |
国内免费 | 27篇 |
专业分类
安全科学 | 34篇 |
废物处理 | 96篇 |
环保管理 | 91篇 |
综合类 | 141篇 |
基础理论 | 136篇 |
环境理论 | 2篇 |
污染及防治 | 303篇 |
评价与监测 | 66篇 |
社会与环境 | 29篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 14篇 |
2022年 | 11篇 |
2021年 | 16篇 |
2020年 | 12篇 |
2019年 | 17篇 |
2018年 | 23篇 |
2017年 | 37篇 |
2016年 | 39篇 |
2015年 | 27篇 |
2014年 | 34篇 |
2013年 | 82篇 |
2012年 | 45篇 |
2011年 | 73篇 |
2010年 | 53篇 |
2009年 | 55篇 |
2008年 | 58篇 |
2007年 | 50篇 |
2006年 | 49篇 |
2005年 | 34篇 |
2004年 | 42篇 |
2003年 | 21篇 |
2002年 | 20篇 |
2001年 | 16篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1957年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有906条查询结果,搜索用时 15 毫秒
871.
Sexual selection in a monomorphic lek-breeding bird: correlates of male mating success in the great snipe Gallinago media 总被引:2,自引:0,他引:2
Summary In the lek-breeding great snipe, male morphology, behaviour, and territory features were recorded for individually marked birds on two adjacent leks. Partial correlation sshowed that male mating success, expressed as the number of female solicitations and copulations, was negatively correlated with the distance of a display territory to the lek center and positively correlated with the number of displays per unit time given by a male. No other variables were directly correlated with male matin success. Thus, central males obtain more matings than peripheral males and successful males display more per unit time than do less successful males, independently of position on the lek. Central males were found to be older than peripheral ones and were present more often on the lek. Furthermore, central males had a larger number of white tail feathers, which are usea as visual signals in the displays, but this may be explained by the fact that these males were older. It is suggested that male great snipe are subject to sexual selection mainly in behavioural and vocal cues and that this may explain the absence of size and plumage dimorphism in this species. 相似文献
872.
Oil concentrations in the seawater, seabed sediments, and shoreline sediments were measured from the samples collected 165 days after the Keumdong oil spill accident, which had occurred in Kwangyang Bay of the South Sea, Korea in September 1993. Distribution patterns of the concentrations in the seabed and shoreline sediments have allowed us to hindcast the transport and fate of the spilled oil. Overall, the patterns agree better with the southward (seaward) surface water circulation than with the northward (landward) bottom water circulation over the region. Rapid, initial dispersal of the spilled oil to the south and its subsequent grounding onto the intertidal seabed sediments, as well as onto the shorelines, appear to have made ineffective the subsurface oil transport by the bottom current. 相似文献
873.
Character refers to qualities within individuals that lead them to desire and to pursue the good. We propose that strengths of character are a neglected but critically important resource for organizations. Character matters because it leads people to do the right thing, and the right thing can be productive and profitable. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
874.
Jung Hyun Choi Seon‐A. Jeong Seok Soon Park 《Journal of the American Water Resources Association》2007,43(6):1444-1454
Abstract: This research investigates possible impacts of enlarged water body according to dam reconstruction on the hydrodynamics and water quality of the reservoir using a laterally averaged, two‐dimensional hydrodynamic and transport model, CE‐QUAL‐W2. The lake was formed by the artificial dam in 1983 for agricultural water supply and is currently under consideration of reconstruction so as to expand the volume of reservoir for flood control as well as water supply in downstream areas. To calibrate and validate the model, field‐collected data were compared with model predictions for water level fluctuations and water temperature during the years of 2001 (from January to December) and 2003 (from March to November). The model results showed a good agreement with field measurements both in calibration and verification. Utilizing the model, impacts of dam reconstruction on the thermal hydrodynamics and turbid current were predicted. From the model results, dam reconstruction limited the depth of thermal stratification below 10 meter and formed steep temperature gradient between epilimnion and hypolimnion. The restricted thermal stratification persisted up to the end of September. This result indicated that thermal stratification would become stronger during summer and stay longer after dam reconstruction. In addition, the restricted thermal stratification caused vertical circulation of water mixing lower than 10 meter and isolated the upper water layer from the lower water layer which increased the volume of hypolimnetic water with low temperature. The vertical circulation near the surface also mitigated propagation of density plume within the depth of 10 m which would remain the hypolimnetic water clean. 相似文献
875.
Mikyung Park Jinkwan Oh Kihong Park 《Frontiers of Environmental Science & Engineering in China》2011,5(3):313-319
A continuous flow streamwise thermal gradient cloud condensation nuclei (CCN) counter with an aerosol focusing and a laser-charge-coupled
device (CCD) camera detector system was developed here. The counting performance of the laser-CCD camera detector system was
evaluated by comparing its measured number concentrations with those measured with a condensation particle counter (CPC) using
polystyrene latex (PSL) and NaCl particles of varying sizes. The CCD camera parameters (e.g. brightness, gain, gamma, and
exposure time) were optimized to detect moving particles in the sensing volume and to provide the best image to count them.
The CCN counter worked well in the particle number concentration range of 0.6–8000 #·cm−3 and the minimum detectable size was found to be 0.5 μm. The supersaturation in the CCN counter with varying temperature difference
was determined by using size-selected sodium chloride particles based on K?hler equation. The developed CCN counter was applied
to investigate CCN activity of atmospheric ultrafine particles at 0.5% supersaturation. Data showed that CCN activity increased
with increasing particle size and that the higher CCN activation for ultrafine particles occurred in the afternoon, suggesting
the significant existence of hygroscopic or soluble species in photochemically-produced ultrafine particles. 相似文献
876.
Misun Park Hyeon Yoon Cheolho Yoon Jae-Young Yu 《Environmental geochemistry and health》2011,33(1):49-53
Although numerous hypotheses have been proposed to explain geophagy, the primary driver of this behaviour remains elusive.
Supplementation of scarce nutrients is one commonly cited explanation. We examined the element concentration of three licks
relative to adjacent topsoils to infer the possible reasons for geophagy at Loskop Dam Nature Reserve. Lick samples had greater
concentrations of B, Co, Zn, Se, Mo and Mn (Loskop Main Lick); Cu (Klopperskloof Lick); and Na (Klopperskloof Lick and Rhenosterhoek
Lick) than those of adjacent topsoil. We suggest that supplementation with all or some of these nutrients is a likely driver
of geophagy in this fenced reserve, with different licks providing herbivores with different suites of nutrients. 相似文献
877.
Soil salinization is a potentially negative side effect of irrigation with reclaimed water. While optimization schemes have been applied to soil salinity control, these have typically failed to take advantage of real-time sensor feedback. This study incorporates current soil observation technologies into the optimal feedback-control scheme known as Receding Horizon Control (RHC) to enable successful autonomous control of soil salinization. RHC uses real-time sensor measurements, physically-based state prediction models, and optimization algorithms to drive field conditions to a desired environmental state by manipulating application rate or irrigation duration/frequency. A simulation model including the Richards equation coupled to energy and solute transport equations is employed as a state estimator. Vertical multi-sensor arrays installed in the soil provide initial conditions and continuous feedback to the control scheme. An optimization algorithm determines the optimal irrigation rate or frequency subject to imposed constraints protective of soil salinization. A small-scale field test demonstrates that the RHC scheme is capable of autonomously maintaining specified salt levels at a prescribed soil depth. This finding suggests that, given an adequately structured and trained simulation model, sensor networks, and optimization algorithms can be integrated using RHC to autonomously achieve water reuse and agricultural objectives while managing soil salinization. 相似文献
878.
Concomitant rock phosphate dissolution and lead immobilization by phosphate solubilizing bacteria (Enterobacter sp.) 总被引:1,自引:0,他引:1
This paper examines the potential value of phosphate solubilizing bacteria (Enterobacter cloacae) in the dissolution of rock phosphate (RP) and subsequent immobilization of lead (Pb) in both bacterial growth medium and soils. Enterobacter sp. showed resistance to Pb and the bacterium solubilized 17.5% of RP in the growth medium. Enterobacter sp. did not enhance Pb immobilization in solution because of acidification of bacterial medium, thereby inhibiting the formation of P-induced Pb precipitation. However, in the case of soil, Enterobacter sp. increased Pb immobilization by 6.98, 25.6 and 32.0% with the RP level of 200, 800 and 1600 mg P/kg, respectively. The immobilization of Pb in Pb-spiked soils was attributed to pyromorphite formation as indicated by XRD analysis. Inoculation of phosphate solubilizing bacteria with RP in soil can be used as an alternative technique to soluble P compounds which can cause eutrophication of surface water. 相似文献
879.
Kiwon Park Karl S. Rosengren Gavin P. Horn Denise L. Smith Elizabeth T. Hsiao-Wecksler 《Safety Science》2011,49(5):719-726
Each year, roughly 11,000 firefighters are injured as a result of slips, trips and falls, which account for over 25% of all fireground injuries. Wearing personal protective equipment (PPE) can increase risk of fall-related injuries due to its weight, restrictiveness, and increased heat stress. Modification of PPE may serve to mitigate firefighter injuries related to loss of balance and falls. We examined the effects of choosing ‘enhanced’ protective clothing (lightweight, breathable, and less restrictive compared to typical firefighting PPE) and simulated firefighting tasks (18-min bout over four activities) on subsequent gait performance. To assess the effect of wearing protective clothing and firefighting activity, seven gait parameters and three movement errors were assessed during level and obstacle-crossing walking tasks. Forty-four firefighters wore one of two types of PPE (‘Standard’, ‘Enhanced’) during three testing conditions (baseline in station uniform, pre-firefighting activity in PPE, and post-firefighting activity in PPE). The effect of donning any PPE was found to significantly impair gait performance. Fatigue may impact effective mobility since more movement errors were observed during post-activity than pre-activity assessments. Although the Enhanced PPE did not lead to any significant differences in gait parameters compared to Standard PPE, participants in Enhanced PPE made twice as many movement errors, potentially attributed to lack of familiarity with the gear. These results suggest that wearing firefighting PPE and heat-stress induced fatigue are associated with reduced gait performance and increased risk for tripping over obstacles. 相似文献
880.
Ighalo Joshua O. Ajala Oluwaseun Jacob Adeniyi Adewale George Babatunde Esther O. Ajala Mary A. 《Environmental science and pollution research international》2021,28(3):2655-2668
Environmental Science and Pollution Research - Glyphosate (N-[phosphonomethyl]glycine) is one of the most popular herbicides now used in agricultural practice. The aim of this paper was to discuss... 相似文献