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61.
Christian C. Voigt Gerald Heckel Frieder Mayer 《Behavioral ecology and sociobiology》2005,57(5):457-464
We investigated how morphological traits of territorial males in the polygynous bat Saccopteryx bilineata were related to their reproductive success. Because of the frequency of aerial courtship displays and defence manoeuvres, and the high energetic costs of flight, we expected small and symmetric males to be better able to court females on the wing and to monopolize copulations with females in their harems. We predicted that small and symmetric males would sire more offspring within the colony and a larger portion of the young born within their harem than large or asymmetric males. We measured size and fluctuating asymmetry of 21 territorial males and analysed their reproductive success in 6 offspring cohorts (n=209 juveniles) using 11 microsatellite loci. As predicted, small and symmetric males had, on average, a higher reproductive success in the colony than large and asymmetric males. The percentage of young sired by males within their harem increased as males decreased in size, but was not influenced by fluctuating asymmetry. As fluctuating asymmetry of males correlated with their reproductive success within the colony but not within their harems, we infer that fluctuating asymmetry is probably related to female choice, whereas male size is probably important for harem defence on the wing.Communicated by G. Wilkinson 相似文献
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Sonia Rombout Daniel Sartenaer Benoît Parmentier Christian Dugauquier Yves Gillerot 《黑龙江环境通报》2004,24(10):822-827
We present a case of de novo trisomy of distal 19q diagnosed prenatally by cytogenetics and FISH analysis. The autopsy performed after termination of the pregnancy showed major internal and external malformations that are associated with this chromosome abnormality. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Rainer Brüggemann Gerhard Ginzel Christian Steinberg 《Environmental Sciences Europe》1997,9(6):339-343
Conflict are frequently observed when drinking water protection areas are to be defined and when many variants of how to protect these area are to be found. Using ten potential scenarios, a method is presented here which shows how such conflicts concerning these variants may be handled in a systematic manner. The technique is derived from the use of partially ordered sets and their visualization by Hasse diagrams. The first step is to define rankings of different variants according to each aim of protection. A further step is to define an appropriate relationship of order. It is then possible to visualize the extent of consensus and of dissension through the use of a Hasse diagram. The final step is to quantify the importance of each protection aim and the initialization of an iteration. Should a complete consensus be found, this would result in a chain of (connected) variants. Should a complete dissension be found on the other hand, an antichain would then result (i.e. where all variants are isolated). 相似文献
66.
We conducted breeding bird surveys in Minnesota, Wisconsin, and South Dakota in 12 hybrid poplar plantations and surrounding landscapes from 1992 to 1994. Plantations varied in age, shape, composition of surrounding landscape, and internal vegetative heterogeneity. Numbers of breeding bird individuals and species in plantations were lower than in surrounding forest/shrub habitat, but higher than in row crops. Numbers of individuals observed within several bird groups based on migratory status and habitat preference also differed among plantations and surrounding land-use types. Most differences were between numbers in plantations and row crops. Year-to-year changes in bird species composition in plantations were more likely in plantations between ages 2 and 4 years than in younger or older plantations. Correlative evidence from canonical correspondence analysis illustrated that plantation bird communities were related to habitat in surrounding landscapes, plantation age, size, latitude, and longitude. Additionally, more heterogeneous plantations had more species, individuals, and numbers of long-distance migrants. Plantations will likely not support bird communities that are comparable to natural forests in either species composition or species diversity. A goal would be to position them in the landscape to minimize impacts on regional biodiversity. This could be accomplished by maintaining structural diversity of plantations by creating a broad range of successional stages (ages) throughout plantations within a region. Size and connectivity of existing forest fragments may be increased by plantations, but fragmentation of natural open areas should be avoided. 相似文献
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The mining industry has been one of the backbones of the socialist countries of Eastern Europe, not only in economic, but also in political, terms. Three years after the beginning of economic reforms, the mining industry in all the Eastern European countries is facing dramatic changes. Most mines are mining ores below acceptable cut-off grades, and there is no hope of finding new, richer deposits. Downstream metallurgical industries will need to replace their former suppliers. In addition, the social contract that had been maintained under the socialist governments is about to be undone and a new form of internal organization must be found. The success of the economic reforms in Eastern Europe depends upon the capacity to develop new industrial relations: the large mining combinates will have to be transformed into competitive capitalist enterprises and the role of the state must be redefined. Prospects for this transformation vary greatly, from metal to metal and from country to country. Finally, restructuring in Eastern Europe will also affect European and world markets, both on the supply and demand sides. The integration of the Eastern European mining industries into the international mining community should be the medium-term goal of all the participants . 相似文献
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Radioniobium is present in long-lived nuclear waste as a result of the activation of zirconium pellets associated with the nuclear fuel. The behaviour of niobium (Nb) in the environment and especially its fate in the soil-plant system has not been thoroughly investigated so far. In safety assessment of French long-lived nuclear waste disposal, data concerning the mobility and the bioavailability of Nb in soils are needed as well as general trends of its fate in the specific environment around the site of French underground research laboratory. Therefore, we investigated the mobility of 95Nb in three different soils typical of the area of north-eastern France and its uptake by two plants, rye grass (Lolium perenne L.) and winter wheat (Triticum aestivum L.). Soil:solution distribution of 95Nb was observed in 1:10 batch experiments with deionized water for a 3-day period. Results showed that K(d) values were high (in the order of 10(3) L kg(-1)) and were still significantly increasing after 3 days. A mathematical model, fitted to describe the decrease of the radioactivity after 3 days, is proposed to calculate sorption ratios--SR--(rather than K(d) values as equilibrium was not reached) over longer periods. Soil-to-plant concentration ratios (CR) were measured in shoots and roots of the two plants after cultivation on two soils spiked with (95)Nb (406kBqkg(-1)). Soil-to-root dry weight CR were high (0.30-1.52) and could probably be due to efficient uptake into the roots. However, no transfer of Nb to plant shoots was detected in any of the soils. Nb is thus a rather immobile element in soils and its transfer to plants seems limited to underground parts. It would therefore tend to accumulate in surface horizons of soils in case of long-term continuous surface release. 相似文献