全文获取类型
收费全文 | 15631篇 |
免费 | 117篇 |
国内免费 | 189篇 |
专业分类
安全科学 | 361篇 |
废物处理 | 679篇 |
环保管理 | 1686篇 |
综合类 | 3360篇 |
基础理论 | 3557篇 |
环境理论 | 8篇 |
污染及防治 | 4045篇 |
评价与监测 | 1315篇 |
社会与环境 | 853篇 |
灾害及防治 | 73篇 |
出版年
2023年 | 113篇 |
2022年 | 287篇 |
2021年 | 212篇 |
2020年 | 101篇 |
2019年 | 142篇 |
2018年 | 259篇 |
2017年 | 281篇 |
2016年 | 385篇 |
2015年 | 261篇 |
2014年 | 455篇 |
2013年 | 1165篇 |
2012年 | 512篇 |
2011年 | 649篇 |
2010年 | 519篇 |
2009年 | 564篇 |
2008年 | 614篇 |
2007年 | 612篇 |
2006年 | 581篇 |
2005年 | 521篇 |
2004年 | 461篇 |
2003年 | 471篇 |
2002年 | 451篇 |
2001年 | 600篇 |
2000年 | 378篇 |
1999年 | 264篇 |
1998年 | 150篇 |
1997年 | 165篇 |
1996年 | 176篇 |
1995年 | 189篇 |
1994年 | 182篇 |
1993年 | 134篇 |
1992年 | 166篇 |
1991年 | 172篇 |
1990年 | 168篇 |
1989年 | 143篇 |
1988年 | 159篇 |
1987年 | 96篇 |
1986年 | 128篇 |
1985年 | 129篇 |
1984年 | 122篇 |
1983年 | 118篇 |
1982年 | 124篇 |
1981年 | 121篇 |
1979年 | 101篇 |
1978年 | 102篇 |
1976年 | 92篇 |
1974年 | 105篇 |
1972年 | 87篇 |
1967年 | 100篇 |
1964年 | 94篇 |
排序方式: 共有10000条查询结果,搜索用时 432 毫秒
991.
Kovacevic R. Teodorovic I. Kaisarevic S. Planojevic I. Fa S. Dakic V. Pogrmic K. Virijevic S. 《Environmental science and pollution research international》2009,16(1):130-131
Environmental Science and Pollution Research - 相似文献
992.
K D Knape J B Carey S C Ricke 《Journal of environmental science and health. Part. B》2001,36(2):219-227
The objective of this study was to determine the effectiveness of an iodine based disinfectant (IBD, Iocide, Biomedical Development Corporation, San Antonio, TX) on Salmonella enteritidis and S. typhimurium inoculated on egg shell surfaces under simulated industry egg processing conditions with a commercial egg washer used as the sanitizer delivery system. Re-circulated egg washer water containing 1.40-2.85 g/l total dissolved solids was obtained from a commercial egg processing. Sanitizing treatments consisted of distilled deionized water (DDW), IBD, and chlorine (CL; 200 ppm). All treatments (DDW, IBD and CL) significantly (p < 0.05) decreased Salmonella spp. populations on the shell compared to dry (no spray) egg controls. However, efficacy of egg sanitizers appeared to be dependent on the level of total dissolved solids in the egg wash water. 相似文献
993.
994.
Douglas A. Wolfe K. John Scott John R. Clayton Jr. John Lunz James R. Payne Timothy A. Thompson 《Chemistry and Ecology》2013,29(1-2):137-156
Abstract Standardized tests were applied to aromatic and polar fractions of sediment extracts to determine whether polar constituents or oxidative degradation products contributed significantly to the toxicity of sediments oiled by the Exxon Valdez spill. Intertidal sediment and pore-water samples were collected in September 1990 from two heavily oiled sites and an unoiled site in Prince William Sound (PWS). Methylene chloride extracts from these samples were fractionated by liquid chromatography into aliphatic, aromatic and polar fractions, and the aromatic and polar fractions were tested for toxicity using the MicrotoxR test, bivalve larval mortality and development (Mytilus); several measures of genotoxicity in Mytilus, including SOS ChromotestR, anaphase aberrations and sister chromatid exchange; and survival, anaphase aberrations and teratogenicity in coho salmon (Onchorhynchus kisutch). MicrotoxR and SOS ChromotestR protocols were applied in a screening mode to all samples, whereas other tests were applied only to selected fractions from two sites. Samples from Bay of Isles (oiled) were consistently more toxic (usually only 2 to 5-fold) than the Mooselips Bay (unoiled) samples, which gave very low responses in all tests. for both sites, however, responses to polar and aromatic fractions were about the same in most tests, suggesting that while the overall toxicity of the oil was low in these samples, at least part of that toxicity was derived from polar constituents. Compared to the parent hydrocarbons, polar oxidation products partition preferentially into pore-water and are more rapidly diluted and dispersed in the water column. These results suggest that polar oxidation products of petroleum hydrocarbons pose little risk to marine organisms, except possibly for infauna continuously exposed to pore-water in heavily oiled sediments. Independent surveys showed that sediment toxicity in PWS declined during 1989–1991 to near background levels, in accord with previous understanding of oil weathering and toxicity. 相似文献
995.
Diana Sietz Sabino Edgar Mamani Choque Matthias K. B. Lüdeke 《Regional Environmental Change》2012,12(3):489-505
Smallholder livelihoods in the Peruvian Altiplano are frequently threatened by weather extremes, including droughts, frosts and heavy rainfall. Given the persistence of significant undernourishment despite regional development efforts, we propose a cluster approach to evaluate smallholders’ vulnerability to weather extremes with regard to food security. We applied this approach to 268 smallholder households using information from two existing regional assessments and from our own household survey. The cluster analysis revealed four vulnerability patterns that depict typical combinations of household attributes, including their harvest failure risk, agricultural resources, education level and non-agricultural income. We validated the identified vulnerability patterns by demonstrating the correlation between them and an independently reported damage: the purchase of food and fodder resulting from exposure to weather extremes. The vulnerability patterns were then ranked according to the different amounts of purchase. A second validation aspect accounted for independently reported mechanisms explaining smallholders’ sensitivity and adaptive capacity. Based on the similarities among the households, our study contributes to the understanding of vulnerability beyond individual cases. In particular, the validation strengthens the credibility and suitability of our findings for decision-making pertaining to the reduction of vulnerability. 相似文献
996.
K.R. Spurny 《Environment international》1980,4(1):39-46
A size-selective procedure was developed for the preparation of fiber fractions of uniform size of chrysotile, crocidolite, amosite, and glass. The raw material was first ground to a suitable fineness, then suspended in liquids by ultrasonic agitation and separated by fiber diameter by means of slow sedimentation. The fractionation by fiber length was done by a vibrating sieve method. Fibrous aerosols of different size distributions could be prepared by using a vibrating bed aerosol generator. 相似文献
997.
998.
999.
An Edge Effect Caused by Adult Corn-Rootworm Beetles on Sunflowers in Tallgrass Prairie Remnants 总被引:1,自引:0,他引:1
Mark J. McKone Kendra K. McLauchlan † Edward G. Lebrun ‡ Andrew C. McCall§ 《Conservation biology》2001,15(5):1315-1324
Abstract: The once-extensive tallgrass prairie community of North America has been reduced to small remnants, many of which are surrounded by intensive corn ( Zea mays ) agriculture. We investigated adult corn-rootworm beetles (Chrysomelidae : Diabrotica spp.), important pests of corn, on sunflowers (Asteraceae : Helianthus spp . ) in prairie remnants in southeast Minnesota. Large numbers of beetles invaded the prairie from surrounding corn fields in late summer. D. barberi and D. virgifera were captured on sticky traps in all locations in the prairie, but abundance was much greater near the edge adjacent to corn. We observed D. barberi ( but not D. virgifera ) feeding extensively on sunflower pollen and occasionally on other flower parts, such as petals. Sunflowers located nearer corn fields sustained more floral damage than those farther from corn. To determine the effect of beetle damage on seed set, we enclosed sunflower heads in bags with either zero, two, or four D. barberi adults. Seed set was reduced in heads enclosed with D. barberi . Thus, this agricultural pest may interfere with the successful reproduction of sunflowers and possibly other prairie composites that flower in late summer. Given the small size of most prairie remnants and the abundance of this flower-feeding beetle in landscapes dominated by corn agriculture, D. barberi may affect the sustainability of prairie plant populations. 相似文献
1000.
We examined the vertical distributions of scallop (Placopecten magellanicus) veligers in deep (0.6 m diameter, 9.5 m deep) polyethylene mesocosms from December 1991 to January 1992. In the mesocosms
temperature stratification varied from 0 to 1.5 °C. Profiles of vertical distribution revealed several repeated patterns.
Peaks in veliger numbers often appeared at the water surface and just above the thermocline. Higher density patches were seen
below the surface peaks, and revealed the presence of bio-convective cells. Distribution away from these discontinuities was
usually even. Distribution of veligers was affected by thermoclines above 1.0 °C. Responses to thermoclines varied with larval
age and time of day, and 28 to 30 d veligers passed in both directions through a 1.5 °C thermocline. We conclude that larval
behaviour is a major determinant of whether veligers pass through a thermocline. Kinematic viscosity may play a role in perception
of temperature changes. Two potential consequences of such behaviour are (1) remaining in more productive upper water layers,
where feeding opportunities are enhanced, and (2) increased horizontal transport in the region of the thermocline, which may
enhance recruitment.
Received: 15 May 1996 / Accepted: 11 May 2000 相似文献