全文获取类型
收费全文 | 574篇 |
免费 | 5篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 38篇 |
环保管理 | 31篇 |
综合类 | 103篇 |
基础理论 | 109篇 |
污染及防治 | 162篇 |
评价与监测 | 103篇 |
社会与环境 | 34篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 11篇 |
2020年 | 3篇 |
2019年 | 8篇 |
2018年 | 21篇 |
2017年 | 10篇 |
2016年 | 23篇 |
2015年 | 13篇 |
2014年 | 24篇 |
2013年 | 38篇 |
2012年 | 36篇 |
2011年 | 128篇 |
2010年 | 26篇 |
2009年 | 26篇 |
2008年 | 22篇 |
2007年 | 18篇 |
2006年 | 14篇 |
2005年 | 18篇 |
2004年 | 23篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1988年 | 4篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1967年 | 3篇 |
1966年 | 1篇 |
1965年 | 4篇 |
1964年 | 5篇 |
1962年 | 1篇 |
1961年 | 2篇 |
1959年 | 6篇 |
1958年 | 7篇 |
1957年 | 2篇 |
1956年 | 4篇 |
1955年 | 3篇 |
排序方式: 共有583条查询结果,搜索用时 15 毫秒
281.
Marcela Nováková Barbora Vašáková Hana Kutalová Katarina Galeštoková Klára Průšová Petr Šmilauer Radim Šumbera Daniel Frynta 《Behavioral ecology and sociobiology》2010,64(3):371-379
Spiny mice of the genus Acomys (Muridae) represent a very suitable mammalian model for studying factors influencing the secondary sex ratio (SSR). The maternal
effort in these rodents is extremely biased in favour of the prenatal period and, therefore, maternal manipulation of the
SSR is potentially more advantageous. We studied the SSR in four populations/species of spiny mice kept in family groups consisting
of two closely related females, one non-relative male and their descendants. The groups were established from founding animals
aged about 3 months (maturing age) and were allowed to breed freely for several months. Each litter was sexed after birth,
and relevant data were thoroughly recorded. Altogether, data were collected on 1684 litters: 189 of Acomys sp. from Iran, 203 of A. cilicicus, 875 of A. cahirinus, and 417 of A. dimidiatus. We recorded the sex of 4048 newborns of which 1995 were males and 2053 were females. The overall sex ratio was close to
1:1 (49.2%). Generalized linear mixed models and/or generalized linear models were constructed to evaluate the effect of four
life history and eight social variables on the sex ratio. No consistent effects of these variables on the sex ratio were found
and, interestingly, none of the variables associated with maternal life history had any effect on the sex ratio. Three factors
associated with group composition (i.e. the number of immature males, the number of immature females and the number of breeding
females) did have significant effects on the sex ratio, but these effects were not consistent across the studied species.
In conclusion, our evaluation of this large dataset revealed that the sex ratio in spiny mice is surprisingly stable. 相似文献
282.
Balázs Rosivall Eszter Szöllősi Dennis Hasselquist János Török 《Behavioral ecology and sociobiology》2010,64(10):1555-1562
The sex-dependent effect of environmental conditions on nestlings has been extensively studied in size dimorphic birds. Whether
males or females are more sensitive to poor conditions is not yet clear; however, the degree of sexual size-dimorphism, brood
size and their interactions seem to influence the pattern. Much less is known about sex-dependent environmental sensitivity
in size-monomorphic species, even though it may result in biased sex allocation. We altered the rearing conditions by brood
size manipulation in the size-monomorphic collared flycatcher and then examined the sex-specific development of the nestlings.
In all analyses, we controlled for the effect of paternity, because one may expect extra-pair young to be of better genetic
quality and perform better at least under poor conditions. However, this was not the case, because we did not find any difference
in growth rate or fledging size between extra- and within-pair young. We found that male nestlings had the potential for faster
growth under favourable conditions, but suffered more under poor conditions. We found no sex × environment interaction for
fledging size probably because the growth curves level off before fledging, and the disadvantaged nestlings can catch up with
their siblings. The larger sensitivity of males does not explain the previously found seasonal shift in brood sex ratios and
contradicts previous findings in another size-monomorphic species where females were more sensitive. This suggests that even
in size-monomorphic species, no general rule exists, which determines the more sensitive sex. 相似文献
283.
Attila?HettyeyEmail author Balázs?Vági János?T?r?k Herbert?Hoi 《Behavioral ecology and sociobiology》2012,66(2):201-208
The theory of life history evolution assumes trade-offs between competing fitness traits such as reproduction, somatic growth,
and maintenance. One prediction of this theory is that if large individuals have a higher reproductive success, small/young
individuals should invest less in reproduction and allocate more resources in growth than large/old individuals. We tested
this prediction using the common toad (Bufo bufo), a species where mating success of males is positively related to their body size. We measured testes mass, soma mass, and
sperm stock size in males of varying sizes that were either (1) re-hibernated at the start of the breeding season, (2) kept
without females throughout the breeding season, or (3) repeatedly provided with gravid females. In the latter group, we also
estimated fertilization success and readiness to re-mate. Contrary to our predictions, the relationship between testes mass
and soma mass was isometric, sperm stock size relative to testes mass was unrelated to male size, fertilization success was
not higher in matings with larger males, and smaller males were not less likely to engage in repeated matings than larger
males. These results consistently suggest that smaller males did not invest less in reproduction to be able to allocate more
in growth than larger males. Causes for this unexpected result may include relatively low year-to-year survival, unpredictable
between-year variation in the strength of sexual selection and low return rates of lowered reproductive investment. 相似文献
284.
Oral bioaccessibility of inorganic contaminants in waste dusts generated by laterite Ni ore smelting
Vojtěch Ettler Ladislav Polák Martin Mihaljevič Gildas Ratié Jérémie Garnier Cécile Quantin 《Environmental geochemistry and health》2018,40(5):1699-1712
The laterite Ni ore smelting operations in Niquelândia and Barro Alto (Goiás State, Brazil) have produced large amounts of fine-grained smelting wastes, which have been stockpiled on dumps and in settling ponds. We investigated granulated slag dusts (n = 5) and fly ash samples (n = 4) with a special focus on their leaching behaviour in deionised water and on the in vitro bioaccessibility in a simulated gastric fluid, to assess the potential exposure risk for humans. Bulk chemical analyses indicated that both wastes contained significant amounts of contaminants: up to 2.6 wt% Ni, 7580 mg/kg Cr, and 508 mg/kg Co. In only one fly ash sample, after 24 h of leaching in deionised water, the concentrations of leached Ni exceeded the limit for hazardous waste according to EU legislation, whereas the other dusts were classified as inert wastes. Bioaccessible fractions (BAF) of the major contaminants (Ni, Co, and Cr) were quite low for the slag dusts and accounted for less than 2 % of total concentrations. In contrast, BAF values were significantly higher for fly ash materials, which reached 13 % for Ni and 19 % for Co. Daily intakes via oral exposure, calculated for an adult (70 kg, dust ingestion rate of 50 mg/day), exceeded neither the tolerable daily intake (TDI) nor the background exposure limits for all of the studied contaminants. Only if a higher ingestion rate is assumed (e.g. 100 mg dust per day for workers in the smelter), the TDI limit for Ni recently defined by European Food Safety Authority (196 µg/day) was exceeded (324 µg/day) for one fly ash sample. Our data indicate that there is only a limited risk to human health related to the ingestion of dust materials generated by laterite Ni ore smelting operations if appropriate safety measures are adopted at the waste disposal sites and within the smelter facility. 相似文献
285.
Copper sulphate (0.2 ppm) has only a slight damaging effect on tissues as indicated by measurements of biochemical and haematological parameters. These effects are significantly increased in the presence of sulphuric acid at pH 6.5. 相似文献
286.
287.
288.
289.
290.