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941.
The effect of the characteristics of the surface on the phototransformation of acridine, one of the most abundant azapolycyclic compounds encountered in urban atmospheres, and of one of its principal photoproducts, acridone, was studied when adsorbed onto models of the atmospherice particulate matter. For this purpose, relative photodegradation rates were determined from absorption or emission intensities as a function of irradiation times, and some products were isolated and characterized. The relative photodegradation rates of adsorbed acridine show the tendency (NH(4))(2) SO(4) > MgO > Al(2)O(3) >SiO(2). In general, the rates decrease as the fraction of protonated acridine species on the surface increases in MgO, Al(2)O(3), and SiO(2), except for (NH(4))(2) SO(4) where a fast surface reaction occurs. Oxygen reduces the photodestruction rates by as much as 40 to 60% when compared to an inert atmosphere, implying the participation of an acrideine triplet state in the transformation processes on all surfaces except on (NH(4))(2)SO(4). Acridone, a major product, undergoes a photoinduced tautomerization to 9-hydroxy acridine. The formation of a dihydrodiol, another photoproduct of acridine, is suggested by comparison to reported spectral properties of these compounds. This is formed through a singlet oxygen reaction. Photoproducts showing the absence of the narrow absorption band of 250 nm, characteristic of the pi -->pi* transition in tricyclic aromatics, were detected in small yields but not identified. These results suggest possible photochemical transformation pathways that could lead to the ultimate fate of these pollutants in the environment. 相似文献
942.
943.
Simões Marta Filipa Maiorano Alfredo Eduardo dos Santos Jonas Gomes Peixoto Luciana de Souza Rodrigo Fernando Brambilla Neto Almir Oliveira Brito António Guerreiro Ottoni Cristiane Angélica 《Environmental Chemistry Letters》2019,17(3):1413-1420
Environmental Chemistry Letters - The anthraquinone dye Remazol Brilliant Blue R is largely used in the textile industry. However, its removal from wastewaters is costly and complex. Many methods... 相似文献
944.
Nicolás-López Porfirio Macías-Cruz Ulises Avendaño-Reyes Leonel Valadez-García Karen M. Mellado Miguel Meza-Herrera Cesar A. Díaz-Molina Raúl Castañeda Vielka J. Vicente-Pérez Ricardo Luna-Palomera Carlos 《Environmental science and pollution research international》2023,30(5):11562-11571
Environmental Science and Pollution Research - Free ferulic acid (FA) is a natural compound with antioxidant properties which mitigates the negative effects of cold stress in sheep; however, its... 相似文献
945.
J. M. Mancilla-Leytón A. Martín Vicente C. Parejo-Farnés R. Fernández-Ales M. J. Leiva 《Russian Journal of Ecology》2014,45(5):384-390
We have studied the effect of goat grazing on the shrub understory of a pine forest situated in a protected area (Doñana Natural Park). Along three years we have studied the changes in phytovolume, flammability, species richness and diversity in a grazed shrubland and in a control area not grazed by the goats. We studied also food preferences of the goats and the ability of the goats to disperse the seeds of the plants they eat. Goat grazing significantly reduced shrub biomass and flammability, decreasing the risk of forest fire. Goats selected the species they eat, changing the pattern of selection throughout the year. Grazing reduced shrub diversity, but did not affected species richness. The goats can also potentially disperse the seeds of some of the species they eat, since the seeds were able to pass through the goat’s gut and germinated afterwards. Goat grazing on scrub vegetation can be used as an effective tool for the control of shrubs in protected forest areas, without losing biodiversity. 相似文献
946.
Ortega Zaida Mencía Abraham Pérez-Mellado Valentín 《Behavioral ecology and sociobiology》2017,71(1):1-10
Behavioral Ecology and Sociobiology - Pre-copulatory sexual cannibalism (Pre-SC), where females attack and consume courting males, is considered an extreme case of sexual conflict. Different... 相似文献
947.
The availability of lithium resources for a transition to electric vehicles is a vital topic for transport technology strategy. Recent debate seems to have concluded that there is ‘sufficient’ lithium available, but for the purposes of a technological transition, time matters. It is not simply the quantity of resource that is relevant—the flow rate into society may be a much more difficult constraint and transient events have disrupted heavily concentrated material supply chains in the past. Furthermore, critical assumptions such as the presence of recycling systems may not be justified without policy support. Complacency is therefore not an appropriate stance for a robust evaluation of material risks in the case of lithium. 相似文献
948.
A. Marin M. D. López M. A. Esteban J. Meseguer J. Muñoz A. Fontana 《Marine Biology》1998,131(4):639-645
The marine sponge Dysidea fragilis from El Mar Menor, a hypersaline coastal lagoon (Murcia, Spain), contains the furanosesquiterpenoid ent-furodysinin as the major secondary metabolite. D. fragilis emits a defensive white fluid when it is disturbed. Electron micrographs of this fluid revealed intact vesiculated cells
together with other amorphous material. Dissociated cells are more rounded in shape but maintain the same ultrastructural
features as cells observed in ultra-thin sections of the whole sponge. The defensive secretion is composed mainly of sponge
cells with abundant light vesicles. Sometimes these light vesicles appear to open into the intercellular space; this correlates
with surface blebs on these cells observed under scanning electron microscopy. The intracellular location of ent-furodysinin was confirmed by Erlich staining. In laboratory assays, we examined the role of ent-furodysinin as a feeding deterrent to generalist fish predators. It was isolated from D. fragilis and incorporated into a carrageenan-based artificial diet. The addition of ent-furodysinin to the artificial diet reduced feeding by the fish Thalassoma pavo. Similarly, fish did not feed on artificial diet above which defensive secretion of D. fragilis had been ejected with a small syringe.
Received: 4 June 1997 / Accepted: 28 January 1998 相似文献
949.
950.
J.J. Cerón E. Sancho MD. Ferrando C. Gutierrez E. Andreu 《Journal of environmental science and health. Part. B》2013,48(5):1029-1040
Abstract Eels were exposed to a sublethal diazinon concentration of 0.042 mg/L for exposure times of 6, 24, 48, 72 and 96 hours. Biochemical analyses of blood composition, such as plasma glucose, total plasma cholesterol and triglycerides, plasma lactate, plasma urea and uric acid, showed significant differences between treated and control animals. Plasma glucose and lactate increased after 6 hours exposure to the insecticide. Plasma cholesterol and triglycerides content decreased during 96 hours treatment. Urea levels increased at 72 hours while uric acid content decreased significantly at 24, 72 and 96 hours exposure to the pesticide. The observed effects of diazinon on eel metabolism suggested that the treated fish was faced with a serious metabolic crisis, and the fish looked for alternative methods of metabolism to overcome the toxic stress. 相似文献