全文获取类型
收费全文 | 13918篇 |
免费 | 32篇 |
国内免费 | 10篇 |
专业分类
安全科学 | 106篇 |
废物处理 | 948篇 |
环保管理 | 1428篇 |
综合类 | 2480篇 |
基础理论 | 3967篇 |
环境理论 | 8篇 |
污染及防治 | 2769篇 |
评价与监测 | 1202篇 |
社会与环境 | 1046篇 |
灾害及防治 | 6篇 |
出版年
2022年 | 37篇 |
2021年 | 33篇 |
2020年 | 34篇 |
2019年 | 48篇 |
2018年 | 1520篇 |
2017年 | 1426篇 |
2016年 | 1267篇 |
2015年 | 217篇 |
2014年 | 127篇 |
2013年 | 222篇 |
2012年 | 575篇 |
2011年 | 1496篇 |
2010年 | 806篇 |
2009年 | 731篇 |
2008年 | 1062篇 |
2007年 | 1371篇 |
2006年 | 172篇 |
2005年 | 163篇 |
2004年 | 160篇 |
2003年 | 177篇 |
2002年 | 230篇 |
2001年 | 100篇 |
2000年 | 83篇 |
1999年 | 60篇 |
1998年 | 52篇 |
1997年 | 41篇 |
1996年 | 50篇 |
1995年 | 55篇 |
1994年 | 51篇 |
1993年 | 35篇 |
1992年 | 48篇 |
1991年 | 40篇 |
1990年 | 45篇 |
1989年 | 35篇 |
1986年 | 32篇 |
1984年 | 38篇 |
1976年 | 35篇 |
1967年 | 34篇 |
1965年 | 47篇 |
1964年 | 38篇 |
1963年 | 37篇 |
1962年 | 31篇 |
1961年 | 44篇 |
1960年 | 40篇 |
1959年 | 43篇 |
1958年 | 46篇 |
1957年 | 41篇 |
1956年 | 40篇 |
1955年 | 40篇 |
1954年 | 41篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Anne Niedbala Mario Schaffer Tobias Licha Karsten Nödler Hilmar Börnick Hans Ruppert Eckhard Worch 《Chemosphere》2013,90(6):1945-1951
The aim of this study was to systematically investigate the influence of the mono- and divalent inorganic ions Na+ and Ca2+ on the sorption behavior of the monovalent organic cation metoprolol on a natural sandy sediment at pH = 7. Isotherms for the beta-blocker metoprolol were obtained by sediment–water batch tests over a wide concentration range (1–100 000 μg L?1). Concentrations of the competing inorganic ions were varied within freshwater relevant ranges. Data fitted well with the Freundlich sorption model and resulted in very similar Freundlich exponents (n = 0.9), indicating slightly non-linear behavior. Results show that the influence of Ca2+ compared to Na+ is more pronounced. A logarithmic correlation between the Freundlich coefficient KFr and the concentration or activity of the competing inorganic ions was found allowing the prediction of metoprolol sorption on the investigated sediment at different electrolyte concentrations. Additionally, the organic carbon of the sediment was completely removed for investigating the influence of organic matter on the sorption of metoprolol. The comparison between the experiments with and without organic carbon removal revealed no significant contribution of the organic carbon fraction (0.1%) to the sorption of metoprolol on the in this study investigated sediment. Results of this study will contribute to the development of predictive models for the transport of organic cations in the subsurface. 相似文献
992.
Fatih Büyüksönmez Robert Rynk Asli Yucel Matt Cotton 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1423-1430
Emissions of malodors are considered to be the greatest threat to the compost industry. In work presented here, several simple odor mitigation alternatives were investigated for their effectiveness in preventing the release of common odorants, such as terpenes, ammonia, and reduced sulfur compounds. The mitigation methods studied included the use of a blanket of finished compost, compost amendment mixed within the feedstock, odor neutralizing agents (ONAs), and oxygen release compounds (ORCs). Among the mitigation alternatives investigated in this study, the use of finished compost as a blanket and finished compost as an amendment yielded the most conclusive and significant results. Both of these alternatives yielded a substantial emission reduction for terpenes, ammonia, and reduced sulfur compounds. The application of finished compost blanket resulted in up to 95% reduction of terpene and 25% reduction of ammonia emissions. Blending the feedstock with finished compost also provided substantial reduction of terpene emissions ranging from 73.6 to 93.1% at the 24% blending ratio, and up to 85% ammonia reduction a the 35% blending ratio. Use of finished compost also provided 75% lower reduced sulfur compound emissions at the 12% blending ratio. Misting and application of odor neutralizing agents did not result in any consistent reduction in emissions for any of the odorous compounds tested.
Implications The odor emissions from composting are often considered to be the biggest threat to composting facilities. Because most facilities cannot afford enclosures and contained composting vessels, there is a need to inexpensively and effectively control the odor emissions from composting facilities. The findings of this research can lead the way for efforts to control odor easily and cost effectively. In fact, the application of a compost blanket for odor control is already gaining acceptance by the composting industry. 相似文献
993.
Sara Persson Anna Rotander Bert van Bavel Björn Brunström Britt-Marie Bäcklin Ulf Magnusson 《Chemosphere》2013,90(5):1664-1671
The wild mink has gained acceptance as a sentinel species in environmental monitoring. However, only limited data are available in the literature on factors driving variability in concentrations of organic pollutants in this species. This study characterizes the differences in contaminant concentrations in subcutaneous fat of male mink from four different areas in Sweden and demonstrates how age, season and body condition influence concentrations of polychlorinated biphenyl (PCB) congeners, polybrominated diphenyl ether (PBDE) congeners (including methoxylated forms, MeO-PBDEs), as well as the pesticides dichlorodiphenyldichloroethylene (DDE), chlordane and hexachlorobenzene (HCB). The data were statistically treated using multiple regression and principal component analysis. The ∑PCB concentration and concentrations of PCB congeners 138, 156, 157, 180, 170/190, 189, 194, 206, 209 as well as PBDE 153/154 varied with age. Season had an influence on ∑PCB, PBDE 47 and PBDE 153/154 concentrations, as well as concentrations of most PCB congeners, with the exception of PCB 101, 110, 141 and 182/187. Lean mink had higher concentrations of most PCBs and PBDEs than mink with larger fat depots. The analyzed pesticides (DDE, oxychlordane, HCB) showed no systematic variation with season, age or body condition. The concentrations of MeO-PBDEs were generally low and 6MeO-PBDE 47 was the most commonly detected MeO-PBDE in mink from marine, brackish and freshwater areas. The results indicate that age, season and body condition are factors that may influence the concentrations of PCBs and PBDEs, and it is thus recommended to take these factors into account when analyzing mink exposure data. 相似文献
994.
Anders Berglund Gunilla Rosenqvist Sarah Robinson-Wolrath 《Behavioral ecology and sociobiology》2006,60(2):281-287
In a sex role reversed pipefish, Syngnathus typhle, we found that basic life history allocations were directly influenced by sexual selection. We investigated time allocation to foraging and mating, respectively, in a choice experiment, giving males and females, of small or large body size, a choice between food and a potential partner. We found that males were more interested in foraging than mating, i.e., were more frequently observed in front of the food than in front of the partner, whereas females were more interested in the potential partner. This reflects sexual selection operating differently on the two sexes, as males and females are relatively similar in other life history traits, such as growth, mortality, age of maturity, dispersal, and parental expenditure. Moreover, large individuals allocated more time to mating activities, small to feeding. Individuals more interested in mating compared to food were subsequently more critical when given a choice between a large (high-quality) and a small (low-quality) partner, whereas individuals more interested in food were not selective. These findings are consistent with our predictions: sex-role reversed males can be relatively sure of achieving one or more matings, and should allocate more time to feeding and, hence, to parental investment, growth and/or future reproduction. Females, on the other hand, have more uncertain mating prospects and should allocate time to imminent reproductive activities, thereby foregoing other life history traits such as growth and future egg production. By this, they also sacrifice future fecundity and attractiveness. 相似文献
995.
996.
András Bardossy Arne Färber Steffen Schönau Bernhard Westrich Thomas Jancke Gerhard Schmid Sven Wurms Karl Stahr Thomas Gaiser Harald Frauenknecht Thilo Streck Joachim Ingwersen Claudia Kreschnak Ulrich Kern Hilke Heppelmann Ekkehard Christoffels Ulrich Förstner Patrick Jacobs 《Environmental Sciences Europe》2006,18(1):67-69
997.
In ant societies, workers do not usually reproduce but gain indirect fitness benefits from raising related offspring produced
by the queen. One of the preconditions of this worker self-restraint is sufficient fertility of the queen. The queen is, therefore,
expected to signal her fertility. In Camponotus floridanus, workers can recognize the presence of a highly fertile queen via her eggs, which are marked with the queen's specific hydrocarbon
profile. If information on fertility is encoded in the hydrocarbon profile of eggs, we expect workers to be able to differentiate
between eggs from highly and weakly fertile queens. We found that workers discriminate between these eggs solely on the basis
of their hydrocarbon profiles which differ both qualitatively and quantitatively. This pattern is further supported by the
similarity of the egg profiles of workers and weakly fertile queens and the similar treatment of both kinds of eggs. Profiles
of queen eggs correspond to the cuticular hydrocarbon profiles of the respective queens. Changes in the cuticular profiles
are associated with the size of the colony the queen originates from and her current egg-laying rate. However, partial correlation
analysis indicates that only colony size predicts the cuticular profile. Colony size is a buffered indicator of queen fertility
as it is a consequence of queen productivity within a certain period of time, whereas daily egg-laying rate varies due to
cyclical oviposition. We conclude that surface hydrocarbons of eggs and the cuticular profiles of queens both signal queen
fertility, suggesting a major role of fertility signals in the regulation of reproduction in social insects. 相似文献
998.
Petra Köpf-Maier 《Die Naturwissenschaften》1987,74(8):374-382
Non-platinum-group metal antitumor agents are represented by inorganic and organometallic compounds which contain either main-group metals such as gallium, germanium, and tin, or transition metals such as titanium, vanadium, iron, copper, and gold. Their antiproliferative properties have been detected during the past years, the spectrum of antitumor activity not being identical with that of cytostatic platinum complexes. In the case of germanium complexes, the antitumor activity is obviously not based on direct cytotoxic effects, but on host-mediated immunopotentiating mechanisms. The toxic properties of most non-platinum-group metal antitumor agents differ fundamentally from those of platinum compounds. Thus, non-platinum-group metal antitumor agents may open new perspectives for the clinical therapy of human malignancies. 相似文献
999.
1000.