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The Science of Nature - 相似文献
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The Science of Nature - 相似文献
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Bercaru O Gawlik BM Ulberth F Vandecasteele C 《Journal of environmental monitoring : JEM》2003,5(4):697-705
During recent years, the awareness of quality assurance and quality control in environmental analyses has constantly increased, especially due to the implementation of new guidelines and regulations at both the national and international level. Achieving comparable results by using certified reference materials is one of the primary concerns of the scientific community. As a result, there is a growing demand for certified reference materials to cover different matrices and pollutants. Moreover, these CRMs should be in close relationship to the determinants and target concentrations required by environmental bodies and European Directives as well. Supplementary information to this paper presents an inventory of reference materials available on the market from different suppliers against the priority pollutants listed in the Water Framework Directive. These CRMs cover matrices such as water, sediment and biota. The use of CRMs in relationship to appropriate analytical methods and relevant determinants is discussed and the need for matrix-CRMs, particularly for organic pollutants is emphasised. The use of proficiency testing schemes as an alternative for the lack of appropriate CRMs and future trends in the production of CRMs within the BCR framework are also discussed. 相似文献
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D. R. Franz 《Marine Biology》1986,91(4):553-560
Seasonal changes in pyloric caecum and gonad indices were studied in a population of the seastar Asterias forbesi (Desor) from East Rockaway Inlet (Long Island, New York) during two annual cycles (1980/81, 1982/83). Pyloric caeca indices increased during fall, reached a maximum about April, and declined sharply to a minimum in mid-summer. Gonad indices increased during fall and winter and reached a maximum about May. Judging from gonad size analysis, spawning occurred in late June to early July, at bottom temperatures of 16° to 18°C. There was no long-term inverse relationship between pyloric caecum and gonad indices. Since nutrients and energy ingested during the important fall feeding period are utilized simultaneously for body growth and gonad development, it is unnecessary for the pyloric caeca to store nutrients over long periods as occurs in A. rubens and many other species. The specific caeca-gonad relationship is probably an adaptation to the extreme seasonal thermal fluctuations of the NW Atlantic, which constrain the feeding activity of A. forbesi and limit the possibility of long-term storage. In this population, most individuals grow rapidly in their first year (including first two summers) and spawn in their third summer. Few seastars survive to spawn again in their fourth summer. However, gametogenesis may take place in some individuals in their second summer. Year-to-year variability in mean size at spawning may reflect temporal variation in environmental conditions (weather, food availability) at this site. 相似文献
149.
Laura Scrano Sabino A. Bufo Franz Menzinger Philippe Schmitt-Kopplin 《Environmental Chemistry Letters》2006,4(4):225-228
Two new intermediates rising from the photolytic reaction of the sulfonylurea herbicide oxasulfuron have been identified in aqueous environment. The higher concentrations of the two derivatives oxetan-3-yl 2-(formilsulfamoyl) benzoate and N-(4,6-dimethyl-pyrimidin-2-yl) formamide were reached within 8 h of UV-irradiation. Here we demonstrate that an optimal separation and analysis of such compounds can be achieved by using a novel analytical method based on “non-aqueous” capillary electrophoresis (CE) system joined to an electrospray ionisation-mass spectrometry equipment. Using such a separation method and a particular electrophoretic solution a high reproducibility of migration times and peak areas can be obtained. 相似文献
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Zusammenfassung Durch r?umlich integrale Bestimmung der Schadstofffrachten [1] und zeitlich integrales Monitoring mit Schadstoff-Dosimetern
[1] l?sst sich Topographie und Bewegung von Schadstofffahnen im Grundwasser bestimmen. Konventionelle Methoden der Entnahme
und Untersuchung von Wasserproben sind ungeeignet zur Erfüllung dieser Anforderungen. Sorptionsaktive Passivsammler, die für
entsprechende Untersuchungen in der Gasphase konzipiert sind, eignen sich nicht zur Aquiferuntersuchung.
Die Passivsammler zur Untersuchung im ungest?rten Aquifer sind zentraler Bestandteil eines Systems von Probenahme- und Messsonden,
das die Autoren für das Monitoring chemischer und hydraulischer Wasser-Parameter entwickelt haben.
Mit den Passivsammlern lassen sich die relativen Schadstofffrachten in beliebig enger tiefenorientierter Anordnung der Messpunkte
und auch zeitlich integriert zur Gewinnung von vertikalen relativen Schadstofffracht-Profilen ermitteln. Organische und anorganische
relative Schadstofffrachten k?nnen damit bestimmt werden.
Die gaiasafe-Passivsammler sind einfach handhabbar und lassen sich nach standardisierten chemischen Analysenmethoden auswerten.
Damit erfüllen sie eine Reihe wesentlicher Anforderungen an das zielführende Monitoring von Schadstofffahnen. Die Passivsammler
sind auch geeignet für die In-situ-Untersuchung von ruhigen und bewegten Gew?ssern auch in gro?er Tiefe z.B. Abw?sserkan?le,
Kl?ranlagen, Flüsse und Meere und insbesondere zum Nachweis von Kontaminanten und Spurenstoffen in Wasserproben.
Online First: 10. 01. 2001 相似文献