全文获取类型
收费全文 | 1801篇 |
免费 | 17篇 |
国内免费 | 27篇 |
专业分类
安全科学 | 46篇 |
废物处理 | 62篇 |
环保管理 | 246篇 |
综合类 | 406篇 |
基础理论 | 351篇 |
环境理论 | 1篇 |
污染及防治 | 514篇 |
评价与监测 | 95篇 |
社会与环境 | 110篇 |
灾害及防治 | 14篇 |
出版年
2023年 | 20篇 |
2022年 | 18篇 |
2021年 | 29篇 |
2020年 | 21篇 |
2019年 | 25篇 |
2018年 | 47篇 |
2017年 | 50篇 |
2016年 | 61篇 |
2015年 | 72篇 |
2014年 | 76篇 |
2013年 | 84篇 |
2012年 | 81篇 |
2011年 | 115篇 |
2010年 | 97篇 |
2009年 | 99篇 |
2008年 | 90篇 |
2007年 | 103篇 |
2006年 | 80篇 |
2005年 | 56篇 |
2004年 | 80篇 |
2003年 | 45篇 |
2002年 | 62篇 |
2001年 | 67篇 |
2000年 | 31篇 |
1999年 | 17篇 |
1998年 | 17篇 |
1997年 | 27篇 |
1996年 | 19篇 |
1995年 | 31篇 |
1994年 | 20篇 |
1993年 | 6篇 |
1992年 | 15篇 |
1991年 | 24篇 |
1990年 | 11篇 |
1989年 | 18篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1979年 | 9篇 |
1970年 | 6篇 |
1969年 | 4篇 |
1966年 | 3篇 |
1965年 | 4篇 |
1962年 | 3篇 |
1960年 | 4篇 |
1959年 | 3篇 |
1954年 | 3篇 |
排序方式: 共有1845条查询结果,搜索用时 15 毫秒
991.
van Oudenhove L Billoir E Boulay R Bernstein C Cerdá X 《Die Naturwissenschaften》2011,98(12):1009-1017
In Mediterranean habitats, temperature affects both ant foraging behaviour and community structure. Many studies have shown
that dominant species often forage at lower temperature than subordinates. Yet, the factors that constrain dominant species
foraging activity in hot environments are still elusive. We used the dominant ant Tapinoma nigerrimum as a model species to test the hypothesis that high temperatures hinder trail following behaviour by accelerating pheromone
degradation. First, field observations showed that high temperatures (> 30°C) reduce the foraging activity of T. nigerrimum independently of the daily and seasonal rhythms of this species. Second, we isolated the effect of high temperatures on pheromone
trail efficacy from its effect on worker physiology. A marked substrate was heated during 10 min (five temperature treatments
from 25°C to 60°C), cooled down to 25°C, and offered in a test choice to workers. At hot temperature treatments (>40°C), workers
did not discriminate the previously marked substrate. High temperatures appeared therefore to accelerate pheromone degradation.
Third, we assessed the pheromone decay dynamics by a mechanistic model fitted with Bayesian inference. The model predicted
ant choice through the evolution of pheromone concentration on trails as a function of both temperature and time since pheromone
deposition. Overall, our results highlighted that the effect of high temperatures on recruitment intensity was partly due
to pheromone evaporation. In the Mediterranean ant communities, this might affect dominant species relying on chemical recruitment,
more than subordinate ant species, less dependent on chemical communication and less sensitive to high temperatures. 相似文献
992.
Where clocks are redundant: weak circadian mechanisms in reindeer living under polar photic conditions 总被引:1,自引:0,他引:1
Biological rhythms are a result of interplay between endogenous clocks and the ambient light–dark (LD) cycle. Biological timing
in resident polar organisms presents a conundrum because these experience distinct daily LD cycles for only a few weeks each
year. We measured locomotor activity in reindeer, Rangifer tarandus platyrhynchus (SR, n = 5 and 6) and R. tarandus tarandus (NR, n = 6), ranging freely at 78 and 70°N, respectively, continuously throughout 1 year using data loggers. NR, but not SR, are
gregarious which enabled us to examine the integrated effects of differences in social organisation and the photic environment
at two different latitudes on the organisation of activity. In both sub-species, ultradian bouts of activity and inactivity
alternated across the 24-h day throughout the year. This pattern was modified by the LD cycle in NR but barely at all in SR.
Periodogram analysis revealed significant ultradian rhythmicity in both sub-species; the frequency of daily cycles of activity
increased from three per day in winter to nearly five in summer. We conclude that this increase, and a concomitant increase
in the level of daily activity, reflected the seasonal increase in the animals’ appetite and the quality of their forage.
Secondly, the combination, most evident in SR, of a weak photic response, weak circadian mechanisms and a weak social synchronization
reduces the constraints of biological timing in an environment which is effectively non-rhythmic most of the year and permits
expression of the basic ultradian pattern of ruminant activity. Third, the weaker 24-h rhythmicity in SR compared to NR indicates
a latitudinal decrease in circadian organization and photic responsiveness in Rangifer. 相似文献
993.
van Ginneken V Ballieux B Antonissen E van der Linden R Gluvers A van den Thillart G 《Die Naturwissenschaften》2007,94(2):128-133
In birds and mammals, the thyroid gland secretes the iodothyronine hormones of which tetraiodothyronine (T4) is less active
than triiodothyronine (T3). The action of T3 and T4 is calorigenic and is involved in the control of metabolic rate. Across
all vertebrates, thyroid hormones also play a major role in differentiation, development and growth. Although the fish thyroidal
system has been researched extensively, its role in thermogenesis is unclear. In this study, we measured overall heat production
to an accuracy of 0.1 mW by direct calorimetry in a free-moving European eel (Anguilla anguilla L.) with different thyroid status. Hyperthyroidism was induced by injection of T3 and T4, and hypothyroidism was induced
with phenylthiourea. The results show for the first time at the organismal level, using direct calorimetry, that neither overall
heat production nor overall oxygen consumption in eels is affected by hyperthyroidism. Therefore, we conclude that the thermogenic
metabolism-stimulating effect of thyroid hormones (TH) is not present with a cold-blooded fish species like the European eel.
This supports the concept that TH does not stimulate thermogenesis in poikilothermic species. 相似文献
994.
Oxidation of As(Ⅲ) by potassium permanganate 总被引:3,自引:1,他引:2
LI N FAN Maohong Van Leeuwen Johannes Saha Basude YANG Hongqun HUANG C. P. 《环境科学学报(英文版)》2007,19(7):783-786
The oxidation of As(Ⅲ) with potassium permanganate was studied under conditions including pH, initial As(Ⅲ) concentration and dosage of Mn(Ⅶ). The results have shown that potassium permanganate was an effective agent for oxidation of As(Ⅲ) in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As(Ⅲ) by Mn(Ⅲ). Although theoretical redox analyses suggest that Mn(Ⅶ) should have better performance in oxidization of As(Ⅲ) within lower pH ranges, the experimental results show that the oxidation efficiencies of As(Ⅲ) under basic and acidic conditions were similar, which may be due to the adsorption of As(Ⅲ) on the Mn(OH)2 and MnO2 resulting from the oxidation of As(Ⅲ). 相似文献
995.
Daniel J. A. Johansson Paul L. Lucas Matthias Weitzel Erik O. Ahlgren A. B Bazaz Wenying Chen Michel G. J. den Elzen Joydeep Ghosh Maria Grahn Qiao-Mei Liang Sonja Peterson Basanta K. Pradhan Bas J. van Ruijven P. R. Shukla Detlef P. van Vuuren Yi-Ming Wei 《Mitigation and Adaptation Strategies for Global Change》2015,20(8):1335-1359
996.
Seasonal and Regional Patterns in Performance for a Baltic Sea Drainage Basin Hydrologic Model
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Steve W. Lyon Roya Meidani Ype van der Velde Helen E. Dahlke Dennis P. Swaney Carl‐Magnus Mörth Christoph Humborg 《Journal of the American Water Resources Association》2015,51(2):550-566
This study evaluates the ability of the Catchment SIMulation (CSIM) hydrologic model to describe seasonal and regional variations in river discharge over the entire Baltic Sea drainage basin (BSDB) based on 31 years of monthly simulation from 1970 through 2000. To date, the model has been successfully applied to simulate annual fluxes of water from the catchments draining into the Baltic Sea. Here, we consider spatiotemporal bias in the distribution of monthly modeling errors across the BSDB since it could potentially reduce the fidelity of predictions and negatively affect the design and implementation of land‐management strategies. Within the period considered, the CSIM model accurately reproduced the annual flows across the BSDB; however, it tended to underpredict the proportion of discharge during high‐flow periods (i.e., spring months) and overpredict during the summer low flow periods. While the general overpredictions during summer periods are spread across all the subbasins of the BSDB, the underprediction during spring periods is seen largely in the northern regions. By implementing a genetic algorithm calibration procedure and/or seasonal parameterization of subsurface water flows for a subset of the catchments modeled, we demonstrate that it is possible to improve the model performance albeit at the cost of increased parameterization and potential loss of parsimony. 相似文献
997.
With the present paper, we aim to provide new conceptual insights and empirical evidence on ethical leadership contingencies: we analyze under what conditions ethical leadership can positively impact follower discretionary work behaviors (extra effort and helping). We argue that followers vary in terms of their sensitivity toward and processing of moral information, as conveyed by ethical leaders, and that these individual differences determine the strength of the link between ethical leadership and follower discretionary work behaviors. In a multisource study with 135 leader–follower dyads, we examine two prototypical examples of affective and cognitive individual differences that involve a heightened inclination toward morality: follower moral emotions and follower mindfulness. Our findings indicate that ethical leadership is more strongly related to follower extra effort and helping at higher levels of follower moral emotions and higher levels of follower mindfulness. We discuss the implications of this moral information processing perspective on ethical leadership for research and managerial practice. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
998.
Nivine H. Abbas Irna van der Molen Manal R. Nader Jon C. Lovett 《Journal of Environmental Planning and Management》2015,58(9):1511-1529
This research investigates how trust plays a role in environmental management in North Lebanon, which has suffered repeated episodes of armed conflict in recent times. Previous studies have shown that environmental problems have increased and that the government has been unable to address these, even during periods of relative peace. We examined trust as a factor that contributes to, or hampers, environmental management. Our analysis drew on a survey in 2011 involving 499 citizens. The results demonstrated that, according to citizens, the lack of trust between citizens, and between citizens and the public sector, is a key factor obstructing effective environmental management. The results indicate the level of correlation between how trusting people are; how citizens participate; and how people perceive government legitimacy. 相似文献
999.
Jeroen van der Heijden 《Journal of Environmental Planning and Management》2015,58(6):1034-1057
This paper addresses a current trend of New Environmental Governance (NEG). It examines whether NEG is able to overcome a series of complex regulatory barriers and market shortfalls that stand in the way of carbon emissions reductions in the building sector. Building on an evaluation of 20 NEG arrangements from Australia and the Netherlands, it discusses the limits of the effective implementation and use of NEG in this sector. The paper concludes by suggesting three strategies to improve the performance of NEG arrangements in the building sector. 相似文献
1000.
Pauline Vuarin Roland Allemand Joffrey Moiroux Joan van Baaren Patricia Gibert 《Die Naturwissenschaften》2012,99(11):903-912
Energy allocation is determined by resource availability and trade-offs among traits, and so organisms have to give some traits priority over others to maximize their fitness according to their environment. In this study, we investigated the geographic variations in life history traits and potential trade-offs in populations of the parasitoid Leptopilina heterotoma (Hymenoptera: Figitidae) originating from the north and the south of the Rh?ne–Sa?ne valley (over a gradient of 300?km, South-East France). We measured a set of traits related to reproduction, maintenance, and mobility using several estimators of each of these main functions determined at different times. We did not find any clear differences between populations from contrasting areas, whereas the southern populations, which were all assumed to be exposed to similar environmental conditions, displayed contrasting patterns of energy allocation. Thus, the most likely explanation seems to be that the evolution of the life history of L. heterotoma is probably shaped by local selective pressures, such as microclimate, microhabitats, or intensity of competition, rather than by regional ecological conditions. Using our study as an example, we discuss the interest of considering several traits and using different ways of measuring them, concluding that multiple measurements should be performed in future studies to ensure the robustness of the results. 相似文献