全文获取类型
收费全文 | 100523篇 |
免费 | 1252篇 |
国内免费 | 1144篇 |
专业分类
安全科学 | 3956篇 |
废物处理 | 3863篇 |
环保管理 | 15052篇 |
综合类 | 21568篇 |
基础理论 | 27688篇 |
环境理论 | 75篇 |
污染及防治 | 19309篇 |
评价与监测 | 6159篇 |
社会与环境 | 4603篇 |
灾害及防治 | 646篇 |
出版年
2022年 | 919篇 |
2021年 | 929篇 |
2020年 | 691篇 |
2019年 | 902篇 |
2018年 | 1404篇 |
2017年 | 1398篇 |
2016年 | 2379篇 |
2015年 | 1895篇 |
2014年 | 2699篇 |
2013年 | 9415篇 |
2012年 | 2716篇 |
2011年 | 3332篇 |
2010年 | 3536篇 |
2009年 | 3678篇 |
2008年 | 2955篇 |
2007年 | 2807篇 |
2006年 | 3003篇 |
2005年 | 2830篇 |
2004年 | 3074篇 |
2003年 | 2937篇 |
2002年 | 2458篇 |
2001年 | 2829篇 |
2000年 | 2271篇 |
1999年 | 1636篇 |
1998年 | 1396篇 |
1997年 | 1393篇 |
1996年 | 1527篇 |
1995年 | 1646篇 |
1994年 | 1508篇 |
1993年 | 1369篇 |
1992年 | 1357篇 |
1991年 | 1338篇 |
1990年 | 1280篇 |
1989年 | 1242篇 |
1988年 | 1089篇 |
1987年 | 1023篇 |
1986年 | 1005篇 |
1985年 | 1075篇 |
1984年 | 1178篇 |
1983年 | 1179篇 |
1982年 | 1182篇 |
1981年 | 1112篇 |
1980年 | 946篇 |
1979年 | 960篇 |
1978年 | 834篇 |
1977年 | 731篇 |
1976年 | 649篇 |
1974年 | 629篇 |
1973年 | 672篇 |
1972年 | 671篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Christopher E. Rushton James E. Tate Simon P. Shepherd David C. Carslaw 《Journal of the Air & Waste Management Association (1995)》2018,68(2):111-122
Emissions of nitrogen oxides (NOx) by vehicles in real driving environments are only partially understood. This has been brought to the attention of the world with recent revelations of the cheating of the type of approval tests exposed in the dieselgate scandal. Remote-sensing devices offer investigators an opportunity to directly measure in situ real driving emissions of tens of thousands of vehicles. Remote-sensing NO2 measurements are not as widely available as would be desirable. The aim of this study is to improve the ability of investigators to estimate the NO2 emissions and to improve the confidence of the total NOx results calculated from standard remote-sensing device (RSD) measurements. The accuracy of the RSD speed and acceleration module was also validated using state-of-the-art onboard global positioning system (GPS) tracking. Two RSDs used in roadside vehicle emissions surveys were tested side by side under off-carriageway conditions away from transient pollution sources to ascertain the consistency of their measurements. The speed correlation was consistent across the range of measurements at 95% confidence and the acceleration correlation was consistent at 95% confidence intervals for all but the most extreme acceleration cases. VSP was consistent at 95% confidence across all measurements except for those at VSP ≥ 15 kW t?1, which show a small underestimate. The controlled distribution gas nitric oxide measurements follow a normal distribution with 2σ equal to 18.9% of the mean, compared to 15% observed during factory calibration indicative of additional error introduced into the system. Systematic errors of +84 ppm were observed but within the tolerance of the control gas. Interinstrument correlation was performed, with the relationship between the FEAT and the RSD4600 being linear with a gradient of 0.93 and an R2 of 0.85, indicating good correlation. A new method to calculate NOx emissions using fractional NO2 combined with NO measurements made by the RSD4600 was constructed, validated, and shown to be more accurate than previous methods.Implications: Synchronized remote-sensing measurements of NO were taken using two different remote-sensing devices in an off-road study. It was found that the measurements taken by both instruments were well correlated. Fractional NO2 measurements from a prior study, measurable on only one device, were used to create new NOx emission factors for the device that could not be measured by the second device. These estimates were validated against direct measurement of total NOx emission factors and shown to be an improvement on previous methodologies. Validation of vehicle-specific power was performed with good correlation observed. 相似文献
12.
13.
14.
15.
Moonsammy Stephan Oyedotun Temitope D. Timothy Renn-Moonsammy Donna-Marie Oyedotun Temitayo Deborah Ally Nasrudeen Kasim Oluwasinaayomi Faith Famewo Ayomide 《Journal of Material Cycles and Waste Management》2021,23(4):1678-1687
Journal of Material Cycles and Waste Management - The novel COVID-19 pandemic has disrupted the functioning of solid waste management globally as households experience an increase in their waste... 相似文献
16.
17.
Maheswari C. Ramya A. S. Priya B. Meenakshi Sudhahar S. Prabhu Raj B. Lokesh B. Ramani G. 《Journal of Material Cycles and Waste Management》2021,23(6):2255-2265
Journal of Material Cycles and Waste Management - The present research work focused on fabricating Biodegradable Plate (BD plate) composed of rice husk ash, bagasse and corn starch which is... 相似文献
18.
Abstract: Introduction of artificial light into wildlife habitat represents a rapidly expanding form of human encroachment, particularly in coastal systems. Light pollution alters the behavior of sea turtles during nesting; therefore, long-wavelength lights—low-pressure sodium vapor and bug lights—that minimize impacts on turtles are required for beach lighting in Florida (U.S.A.). We investigated the effects of these two kinds of lights on the foraging behavior of Santa Rosa beach mice ( Peromyscus polionotus leucocephalus ). We compared patch use and giving-up densities of mice for experimental food patches established along a gradient of artificial light in the field. Mice exploited fewer food patches near both types of artificial light than in areas with little light and harvested fewer seeds within patches near bug lights. Our results show that artificial light affects the behavior of terrestrial species in coastal areas and that light pollution deserves greater consideration in conservation planning. 相似文献
19.
20.
Jürgen Tomiuk Lutz Bachmann Michael Leipoldt Jörg U. Ganzhorn Reiner Ries Michaela Weis & Volker Loeschcke 《Conservation biology》1997,11(2):491-497
The genetic polymorphism of natural populations of Lepilemur mustelinus ruficaudatus was studied by protein electrophoresis. We sampled blood from 72 individuals from four populations separated by geographic or anthropogenic barriers from southwestern Madagascar. Six out of 22 enzyme loci showed genetic variation with a degree of polymorphism of 0.273. The expected and observed degree of genetic heterozygosity over all loci is similar to that of other primates (He = 0.058, Ho = 0.036). The F-statistics revealed that the four subpopulations were similar with respect to gene structure (FST = 0.065, p = 0.016), but the genotypic structures within subpopulations were inconsistent with random mating. For the total of the four subpopulations the proportion of heterozygous individuals was significantly smaller than expected under random mating (FIS = 0.373, FIT = 0.414, p < 0.01). These results correspond closely to what is expected considering the low migration ability of individuals of L. m ruficaudatus leading to small and rather isolated inbred populations. 相似文献