全文获取类型
收费全文 | 276篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 16篇 |
环保管理 | 89篇 |
综合类 | 44篇 |
基础理论 | 54篇 |
污染及防治 | 53篇 |
评价与监测 | 16篇 |
社会与环境 | 11篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 2篇 |
2021年 | 1篇 |
2019年 | 3篇 |
2018年 | 7篇 |
2017年 | 8篇 |
2016年 | 4篇 |
2015年 | 12篇 |
2014年 | 6篇 |
2013年 | 25篇 |
2012年 | 13篇 |
2011年 | 14篇 |
2010年 | 9篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 31篇 |
2006年 | 12篇 |
2005年 | 15篇 |
2004年 | 8篇 |
2003年 | 13篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1971年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有286条查询结果,搜索用时 15 毫秒
61.
Summary This research concerned the relative potential for signaling and priming incompatibilities to promote reproductive isolation in rodents. Signaling is defined here as involving behavioral responses, while priming involves endocrine responses. Compatibility of both types of communications was tested between two widely separated and markedly diverging populations of deermice, and between equally separated but much less divergent populations of house mice. Signaling compatibility was assessed by comparing the amount of aggression toward young females by adult males when the two sexes were of the same vs the different stock of the same species. Priming compatibility was tested by measuring the relative amounts of uterine growth induced in young females by exposure to adult males.No signaling or priming incompatibilities were detected during cross-testing of the house mouse stocks. A degree of developing reproductive isolation was observed between the two deermouse populations, however, and this isolation was reinforced by independently occurring incompatibilities of both the signaling and the priming type. The signaling incompatibility was particularly dramatic, manifesting itself in the killing of young females by adult males.The present results provide the first demonstration of a priming incompatibility supporting reproductive isolation in diverging populations of a mammal. Furthermore, our results suggest that signaling and priming systems are independently subject to evolutionary change even when both systems probably operate through the same sensory modality. 相似文献
62.
Adjustment costs from environmental change 总被引:4,自引:0,他引:4
David L. Kelly Charles D. Kolstad Glenn T. Mitchell 《Journal of Environmental Economics and Management》2005,50(3):468-495
The paper is concerned with the case whereby the distribution of a firm's productivity shocks changes without the knowledge of the firm. Over time the firm learns about the nature and extent of the change in the distribution of the shock and adjusts, incurring adjustment costs in the process. The long-run loss in profits (±) due to the shift in the distribution we term the equilibrium response. The transitory loss in profits, incurred while the firm is learning about the distribution shift, is termed the adjustment cost. The theory is then applied to the problem of measuring adjustment costs in the face of imperfectly observed climate change in agriculture. The empirical part of the paper involves estimating a restricted profit function for agricultural land in a five-state region of the Midwest US as a function of prices, land characteristics, actual weather realizations and expected weather. We then simulate the effect of an unobserved climate shock, where learning about the climate shock is by observing the weather and updating prior knowledge using Bayes Rule. We find adjustment costs to climate change are 1.4% of annual land rents. 相似文献
63.
This study assesses the reliability of estimating gestational age via crown-rump or gestational sac measurements obtained at 8 weeks' gestation or earlier as part of routine physician office practice. To accomplish this, we studied 88 pregnancies managed at 45 different sites in which both an early first-trimester ultrasonically-derived gestational age estimate and a second-trimester biparietal diameter (BPD) estimate were available. The first-and second-trimester determinations were highly correlated, but the first-trimester determinations were, on average, 0.43 weeks earlier than the second. The first-trimester estimates were satisfactory for use in interpreting maternal serum alpha-fetoprotein (MSAFP) screening measurements, but second-trimester BPD measurements obtained prior to MSAFP screening should be the method of choice for interpreting MSAFP values, due to the increased sensitivity for detecting open spina bifida. 相似文献
64.
65.
Patrick J. Dugan Chris Barlow Angelo A. Agostinho Eric Baran Glenn F. Cada Daqing Chen Ian G. Cowx John W. Ferguson Tuantong Jutagate Martin Mallen-Cooper Gerd Marmulla John Nestler Miguel Petrere Robin L. Welcomme Kirk O. Winemiller 《Ambio》2010,39(4):344-348
The past decade has seen increased international recognition of the importance of the services provided by natural ecosystems. It is unclear however whether such international awareness will lead to improved environmental management in many regions. We explore this issue by examining the specific case of fish migration and dams on the Mekong river. We determine that dams on the Mekong mainstem and major tributaries will have a major impact on the basin’s fisheries and the people who depend upon them for food and income. We find no evidence that current moves towards dam construction will stop, and consider two scenarios for the future of the fisheries and other ecosystems of the basin. We conclude that major investment is required in innovative technology to reduce the loss of ecosystem services, and alternative livelihood strategies to cope with the losses that do occur. 相似文献
66.
Development of a novel mathematical model using a group contribution method for prediction of ionic liquid toxicities 总被引:2,自引:0,他引:2
Ismail Hossain M Samir BB El-Harbawi M Masri AN Abdul Mutalib MI Hefter G Yin CY 《Chemosphere》2011,85(6):990-994
A new mathematical model has been developed that expresses the toxicities (EC50 values) of a wide variety of ionic liquids (ILs) towards the freshwater flea Daphnia magna by means of a quantitative structure-activity relationship (QSAR). The data were analyzed using summed contributions from the cations, their alkyl substituents and anions. The model employed multiple linear regression analysis with polynomial model using the MATLAB software. The model predicted IL toxicities with R2 = 0.974 and standard error of estimate of 0.028. This model affords a practical, cost-effective and convenient alternative to experimental ecotoxicological assessment of many ILs. 相似文献
67.
Valtcho D. Zheljazkov Glenn W. Stratton James Pincock Stephanie Butler Ekaterina A. Jeliazkova Nedko K. Nedkov Patrick D. Gerard 《Waste management (New York, N.Y.)》2009,29(7):2160-2164
A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6–5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2–5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and basil tissue N, and NO3–N and NH4–N in growth medium relative to the unamended control. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis of wool fibers sampled at the end of the experiments indicated various levels of decomposition, with some fibers retaining their original surface structure. Furthermore, most of the wool fibers’ surfaces contained significant concentrations of S and much less N, P, or K. SEM/EDX revealed that some plant roots grow directly on wool-waste fibers suggesting either (1) root directional growth towards sites with greater nutrient concentration and/or (2) a possible role for roots or root exudates in wool decomposition. Results from this study suggest that uncomposted wool wastes can be used as soil amendment, growth medium constituent, and nutrient source for container-grown plants. 相似文献
68.
Changsub Shim Qinbin Li Ming Luo Susan Kulawik Helen Worden John Worden Annmarie Eldering Glenn Diskin Glen Sachse Andy Weinheimer David Knapp Deedee Montzca Teresa Campos 《Atmospheric environment (Oxford, England : 1994)》2009,43(8):1540-1547
Concurrent tropospheric O3 and CO vertical profiles from the Tropospheric Emission Spectrometer (TES) during the MILAGRO/INTEX-B aircraft campaigns over the Mexico City Metropolitan Area (MCMA) and its surrounding regions were used to examine Mexico City pollution outflow on a regional scale. The pollution outflow from the MCMA occurred predominantly at 600–800 hPa as evident in O3, CO, and NOx enhancements in the in situ aircraft observations. TES O3 and CO are sensitive to the MCMA pollution outflow due to their relatively high sensitivities at 600–800 hPa. We examined O3, CO, and their correlation at 600–800 hPa from TES retrievals, aircraft measurements, and GEOS-Chem model results. TES captures much of the spatial and day-to-day variability of O3 seen in the in situ data. TES CO, however, shows much less spatial and day-to-day variability compared with the in situ observations. The ΔO3/ΔCO slope is significantly higher in the TES data (0.43) than the in situ data (0.28) due partly to the lack of variability in TES CO. Extraordinarily high ΔO3/ΔCO slope (0.81) from TES observations at 618 hPa over the Eastern U.S. was previously reported by Zhang et al. [Zhang, L., Jacob, D.J., Bowman, K.W., et al., 2006. Ozone–CO correlations determined by the TES satellite instrument in continental outflow regions. Geophys. Res. Lett. 33, L18804. 10.1029/2006GL026399.]. Thus the application of TES CO–O3 correlation to map continental pollution outflow needs further examination. 相似文献
69.
70.
McFarland MJ Rasmussen SL Stone DA Palmer GR Olivas AC Wander JD Spencer M 《Journal of the Air & Waste Management Association (1995)》2007,57(1):31-38
The Digital Opacity Compliance System (DOCS) is an innovative method that uses digital imaging technology to quantify visible opacity of stationary sources. DOCS, which has been demonstrated at pilot and full scale as a technically defensible and economically attractive alternative to U.S. Environmental Protection Agency (EPA) Reference Method 9 (Method 9), uses commercial-off-the-shelf (COTS) digital cameras in combination with a user-friendly computer software package to determine opacity. To date, all DOCS field testing has been conducted using two models of digital cameras, notably, Kodak Models DC265 and DC290, both of which are no longer commercially available. To ensure that field-validated digital cameras will be available to future DOCS users, a suite of new digital cameras was evaluated with the opacity determination software including the following: (1) Sony Model Cybershot Model DSC-WI, (2) Nikon Model Coolpix 5200, (3) Fuji Finepix Model E500, and (4) Kodak Model DX6490. Within the opacity range of regulatory interest, that is, 0-40%, the Sony Cybershot Model DSC-WI and Nikon Coolpix Model 5200 digital cameras were found to generate plume photographs of which the DOCS opacity analysis yielded results that were statistically equivalent to the previously field-validated Kodak Model DC290. In contrast, the Fuji Finepix Model E500 generated plume photographs of which the DOCS opacity analysis were, on average, 2.2% less than those generated by the Kodak Model DC290 photographs, a difference that was determined to be statistically significant. Over the same opacity range, photographs taken by the Kodak Model DX6490 yielded DOCS opacity readings that were found to be statistically equivalent to a Method 9-certified transmissometer. Based on the results from the current digital camera validation testing approach, EPA has developed a new camera-based visible opacity measurement method titled "Determination of Visible Emission Opacity from Stationary Sources Using Computer-Based Photographic Analysis Systems." The proposed method is expected to be promulgated after closure of the public comment period. 相似文献