全文获取类型
收费全文 | 396篇 |
免费 | 4篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 33篇 |
废物处理 | 6篇 |
环保管理 | 107篇 |
综合类 | 65篇 |
基础理论 | 59篇 |
环境理论 | 1篇 |
污染及防治 | 101篇 |
评价与监测 | 15篇 |
社会与环境 | 15篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 59篇 |
2012年 | 12篇 |
2011年 | 19篇 |
2010年 | 16篇 |
2009年 | 18篇 |
2008年 | 16篇 |
2007年 | 23篇 |
2006年 | 18篇 |
2005年 | 13篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1990年 | 3篇 |
1989年 | 8篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 12篇 |
1977年 | 2篇 |
1974年 | 3篇 |
1966年 | 2篇 |
1932年 | 4篇 |
1924年 | 1篇 |
1923年 | 1篇 |
1916年 | 1篇 |
1913年 | 1篇 |
排序方式: 共有406条查询结果,搜索用时 765 毫秒
91.
Finkelstein PL Davison AW Neufeld HS Meyers TP Chappelka AH 《Environmental pollution (Barking, Essex : 1987)》2004,131(2):295-303
Although there has been a great deal of research on ozone, interest in exposure of native, herbaceous species is relatively recent and it is still not clear what role the pollutant has in their ecological fitness. The ozone exposure of a plant is usually expressed in terms of the concentration above the canopy or as a time-weighted index. However, to understand the physiological effects of ozone it is necessary to quantify the ozone flux to individual leaves as they develop, which requires knowing the deposition velocity and concentration of the pollutant as a function of height throughout the plant canopy. We used a high-order closure model of sub-canopy turbulence to estimate ozone profiles in stands of cutleaf coneflower (Rudbeckia laciniata L.) located in the Great Smoky Mountains National Park, USA. The model was run for periods coinciding with a short field study, during which we measured vertical concentration profiles of ozone along with measurements of atmospheric turbulence and other meteorological and plant variables. Predictions of ozone profiles by the model are compared with observations throughout the canopy. 相似文献
92.
Summary Although present constitutively in large amounts, furanocoumarins in leaves of wild parsnip,Pastinaca sativa, are inducible to even higher concentrations by mechanical and insect damage. We conducted several experiments in order to characterize the nature and extent of xanthotoxin inducibility inP. sativa foliage. In order to determine the extent to which induction is localized, we mechanically damaged a single leaflet of a compound leaf on seven plants. Xanthotoxin concentrations increased significantly only in the damaged leaflet and in the half of the terminal leaflet closest to the damaged leaflet; thus, xanthotoxin induction is localized to the immediate vicinity of damage. To determine whether xanthotoxin induction results fromin situ biosynthesis or translocation from other plant parts, we detached individual leaflets from ten plants, damaged half of these detached leaflets, and compared xanthotoxin concentrations after 6 h in damaged and intact leaflets. We found that xanthotoxin concentrations increased 41% in damaged leaflets compared to detached leaflets that were not damaged. We also determined the rapidity and duration of the induction response. In leaflets that were damaged and then harvested after 0, 3, 24, 72, 120 and 168 h, xanthotoxin concentrations increased rapidly compared to undamaged leaflets on the opposite side of the leaf, reaching maximum levels within 24 h. This response was of comparatively short duration; concentrations declined to preinduction levels after seven days. To determine whether availability of resources influences the induced response, we performed two experiments, one in which soil nutrients were manipulated and one in which light level was manipulated. The low nutrient treatment was sufficiently extreme to cause cessation of aboveground growth, and the low light treatment caused etiolation. Extremes of resource limitation notwithstanding, leaflets significantly increased xanthotoxin production (2 to 3-fold increase under nutrient limitation and 3-fold increase under light limitation) in response to damage in both experiments. 相似文献
93.
Summary. Many species of insects sabotage the pressurized defense vessels of their host plants prior to feeding. This behavior, however,
does not render leaves indefinitely suitable, as some species employing this behavior eventually abandon uneaten portions
of sabotaged leaves. In this study, we examined whether and to what degree wild parsnip, Pastinaca sativa, is capable of restoring its pressurized defenses and whether cabbage loopers, Trichoplusa ni, which normally trench parsnip leaflets, benefit from their trenching behavior. The pressurized oil tubes of parsnip leaves
are rich in toxic terpenoids and furanocoumarins. A disruption of the integrity of the tubes (via razor blade nicks) in leaflets
revealed that that some of their contents were expelled at the break and that some movement of oil from outside the leaflet
(i.e., the midvein) occurred, bolstering furanocoumarin levels in the leaflet within minutes. Pressure and chemical content
in a leaflet’s oil tubes were also shown to be restored within 24 hours of depressurization. This recovery ability allowed
parsnip leaflets to respond to daily depressurizations by mechanical damage for up to at least 5 assaults, cumulatively causing
an approximate ten-fold increase in furanocoumarins. Cabbage loopers fed parsnip leaflets that were artificially trenched
accumulated twice as much body mass as larvae fed leaflets augmented with furanocoumarins equivalent to the quantity that
would be avoided through trenching, indicating that trenching does benefit the herbivore. Although parsnip recovers from trenching
rapidly, it does not do so within the time that cabbage loopers consume trenched leaflets 相似文献
94.
Paul B Conn Anthony D Arthur Larissa L Bailey Grant R Singleton 《Ecological applications》2006,16(2):829-837
Knowledge of animal abundance is fundamental to many ecological studies. Frequently, researchers cannot determine true abundance, and so must estimate it using a method such as mark-recapture or distance sampling. Recent advances in abundance estimation allow one to model heterogeneity with individual covariates or mixture distributions and to derive multimodel abundance estimators that explicitly address uncertainty about which model parameterization best represents truth. Further, it is possible to borrow information on detection probability across several populations when data are sparse. While promising, these methods have not been evaluated using mark-recapture data from populations of known abundance, and thus far have largely been overlooked by ecologists. In this paper, we explored the utility of newly developed mark-recapture methods for estimating the abundance of 12 captive populations of wild house mice (Mus musculus). We found that mark-recapture methods employing individual covariates yielded satisfactory abundance estimates for most populations. In contrast, model sets with heterogeneity formulations consisting solely of mixture distributions did not perform well for several of the populations. We show through simulation that a higher number of trapping occasions would have been necessary to achieve good estimator performance in this case. Finally, we show that simultaneous analysis of data from low abundance populations can yield viable abundance estimates. 相似文献
95.
Sarah S. Tzilkowski Anthony R. Buda Elizabeth W. Boyer Ray B. Bryant Peter J.A. Kleinman Casey D. Kennedy Arthur L. Allen Gordon J. Folmar Eric B. May 《Journal of the American Water Resources Association》2019,55(1):228-246
Urea‐N is a component of bioavailable dissolved organic nitrogen (DON) that contributes to coastal eutrophication. In this study, we assessed urea‐N in baseflow across land cover gradients and seasons in the Manokin River Basin on the Delmarva Peninsula. From March 2010 to June 2011, we conducted monthly sampling of 11 streams (4 tidal and 7 nontidal), 2 wastewater treatment plants, an agricultural drainage ditch, and groundwater underlying a cropped field. At each site, we measured urea‐N, DON, dissolved organic carbon (DOC), total dissolved nitrogen (TDN), NO3?‐N, and NH4+‐N. In general, urea‐N comprised between 1% and 6% of TDN, with the highest urea‐N levels in drainage ditches (0.054 mg N/L) and wetland‐dominated streams (0.035–0.045 mg N/L). While urea‐N did not vary seasonally in tidal rivers, nontidal streams saw distinct urea‐N peaks in summer (0.038 mg N/L) that occurred several months after cropland fertilization in spring. Notably, the proportion of wetlands explained 78% of the variance in baseflow urea‐N levels across the Manokin watershed. In wetland‐dominated basins, we found urea‐N was positively related to water temperature and negatively related to DOC:DON ratios, indicating short‐term urea‐N dynamics at baseflow were more likely influenced by instream and wetland‐driven processes than by recent agricultural urea‐N inputs. Findings demonstrate important controls of wetlands on baseflow urea‐N concentrations in mixed land‐use basins. 相似文献
96.
97.
98.
Edmarlon Girotto Maira Sayuri Sakai Bortoletto Alberto Durán González Arthur Eumann Mesas Tiago Severo Peixe Camilo Molino Guidoni 《Traffic injury prevention》2019,20(5):504-509
Objective: The objective of this study is to identify the role of working conditions as predictors of sleepiness while driving among truck drivers.Methods: This was a cross-sectional study carried out among truck drivers who transported grains to Paranaguá Port, Paraná, Brazil. The truck drivers were interviewed and completed a self-administered questionnaire to collect data on sociodemographic and behavioral variables, working conditions, consumption of illicit psychoactive substances, and sleep patterns. Drivers were considered to be sleepy while driving if they reported a medium or high probability of napping while driving at night, during the daytime, or while stopped in traffic. The statistical analysis used logistic regression models progressively adjusted for age, behavioral variables, sleep duration, and other working conditions.Results: In total, 670 male drivers, with a mean age of 41.9 (±11.1) years, were enrolled. The prevalence of sleepiness while driving was 31.5%. After model adjustments, the following working conditions were associated with sleepiness while driving: Distance from the last shipment of more than 1,000?km (odds ratio [OR]?=?1.54; 95% confidence interval [CI], 1.07–2.23) and a formal labor contract with a productivity-based salary (OR = 2.65; 95% CI, 1.86–3.78). Consumption of illicit psychoactive substances (OR = 1.99; 95% CI, 1.14–3.47) was also associated with sleepiness while driving.Conclusions: Distance traveled and a formal labor contract with productivity-based earnings were the working conditions associated with sleepiness while driving, regardless of other working or behavioral characteristics, age, consumption of illicit psychoactive substances, and sleep duration. 相似文献
99.
100.
Gero Leson Arthur M. Winer 《Journal of the Air & Waste Management Association (1995)》2013,63(8):1045-1054
Biofiltration is a relatively recent air pollution control (APC) technology in which off-gases containing biodegradable volatile organic compounds (VOC) or inorganic air toxics are vented through a biologically active material. This technology has been successfully applied in Germany and The Netherlands in many full-scale applications to control odors, VOC and air toxic emissions from a wide range of industrial and public sector sources. Control efficiencies of more than 90 percent have been achieved for many common air pollutants. Due to lower operating costs, biofiltration can provide significant economic advantages over other APC technologies if applied to off-gases that contain readily biodegradable pollutants in low concentrations. Environmental benefits include low energy requirements and the avoidance of cross media transfer of pollutants. This paper reviews the history and current status of biofiltration, outlines its underlying scientific and engineering principles, and discusses the applicability of biofilters for a wide range of specific emission sources. 相似文献