全文获取类型
收费全文 | 190篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 22篇 |
废物处理 | 1篇 |
环保管理 | 25篇 |
综合类 | 49篇 |
基础理论 | 66篇 |
污染及防治 | 22篇 |
评价与监测 | 3篇 |
灾害及防治 | 8篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 8篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 16篇 |
2008年 | 8篇 |
2007年 | 16篇 |
2006年 | 14篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1981年 | 2篇 |
排序方式: 共有196条查询结果,搜索用时 15 毫秒
41.
蚕豆根尖微核技术监测工业废水遗传毒性 总被引:3,自引:0,他引:3
用蚕豆根尖微核技术监测淮阴市冶金、化工、印染及制药行业废水的遗传毒性,结果表明淮明市部分工厂废水存在不同程度的遗传毒性。 相似文献
42.
C. Verlingue A. David M. P. Audrezet M. G. Le Roux B. Mercier J. P. Moisan C. Ferec MD Ph.D. 《黑龙江环境通报》1993,13(12):1143-1148
The cystic fibrosis (CF) gene has been observed to have the highest frequency of mutations in the Caucasian population. Prenatal diagnosis can now be performed with a high degree of accuracy since the identification of most of the gene's mutations, as well as the characterization of intragenic markers. However, the observation of a distribution of clinical phenotypes increases the need to identify a mild phenotype and avoid false-negative diagnosis. By screening most of the exons of the CFTR gene, we showed that a supposed obligate carrier of CF was in fact an asymptomatic affected woman. 相似文献
43.
The prenatal detection of a cystic hygroma (CH) in a fetus with a 45,X karyotype is described. The cystic hygroma underwent spontaneous resolution and a healthy baby with Turner syndrome was subsequently born. The implications for genetic counselling are discussed. 相似文献
44.
Two women not only lost relatively large amounts of amniotic fluid immediately following genetic amniocentesis, but continued to lose fluid for the remainder of their pregnancies. Periodic ultrasonographic assessment confirmed normal fetal growth and presence of some amniotic fluid. Both women were delivered at term of normal offspring who showed no evidence of fetal deformations. Although amnionitis is a risk, cautious surveillance may permit continuation of pregnancies complicated by copious or persistent amniotic fluid leakage following genetic amniocentesis. 相似文献
45.
Polyandry and enhanced reproductive success in the harlequin-beetle-riding pseudoscorpion 总被引:1,自引:0,他引:1
J. A. Zeh 《Behavioral ecology and sociobiology》1997,40(2):111-118
The growing molecular evidence that females of many species mate with several males calls for a critical reassessment of
the selective forces which act to shape female mating tactics. In natural populations of the harlequin-beetle-riding pseudoscorpion,
Cordylochernes scorpioides, females are polyandrous and typically produce mixed-paternity broods. Laboratory behavioral analyses and breeding experiments
indicate that polyandry in this pseudoscorpion is an active strategy which increases female reproductive success. Females
restricted to mating with a single male experienced a higher rate of embryo failure and produced significantly fewer offspring
than either females mated to more than one male in the laboratory or females naturally inseminated in the field. Forced copulation,
insufficient sperm from a single mating, male nutrient donations and variation in inherent male genetic quality cannot explain
the greater number of nymphs hatched by polyandrous females in this study. Evidence suggests that, by mating with several
males, C. scorpioides females may exploit postcopulatory mechanisms for reducing the risk and/or cost of embryo failure resulting from fertilization
by genetically incompatible sperm.
Received: 5 May 1996 / Accepted after revision: 16 October 1996 相似文献
46.
Mary K. Stapleton Oddmund Kleven Jan T. Lifjeld Raleigh J. Robertson 《Behavioral ecology and sociobiology》2007,61(11):1725-1733
Recent attention has focused on genetic compatibility as an adaptive function for why females engage in extrapair mating.
We tested the genetic compatibility hypothesis in tree swallows (Tachycineta bicolor) over five breeding seasons using data from ten microsatellite loci. Tree swallows are socially monogamous passerines exhibiting
high levels of extrapair paternity. Overall, we found that 47% of offspring were the result of extrapair fertilizations, and
83% of females produced at least one extrapair offspring. Consistently for all years, extrapair offspring were more heterozygous
than their maternal half-siblings, which is in accordance with the genetic compatibility hypothesis. The difference was largely
caused by the high heterozygosity of extrapair offspring sired by unknown males, suggesting that females are engaging in extrapair
copulations with geographically distant males to increase the likelihood of being inseminated by a more compatible mate. Our
findings support the idea that postcopulatory mechanisms are important for females when assessing potential sires for their
offspring. 相似文献
47.
Liselotte Sundström 《Behavioral ecology and sociobiology》1993,33(5):345-354
Summary The genetic population structure and the sociogenetic organization of the red wood ant Formica truncorum were compared in two populations with monogynous colonies and two populations with polygynous colonies. The genetic population structure was analysed by measuring allele frequency differences among local subsets of the main study populations. The analysis of sociogenetic organisation included estimates of nestmate queen and nestmate worker relatedness, effective number of queens, effective number of matings per queen, relatedness among male mates of nestmate queens and relatedness between queens and their male mates. The monogynous populations showed no differentiation between subpopulations, whereas there were significant allele frequency differences among the subpopulations in the polygynous population. Workers, queens and males showed the same genetical population structure. The relatedness among nestmate workers and among nestmate queens was identical in the polygynous societies. In three of the four populations there was a significant heterozygote excess among queens. The queens were related to their male mates in the polygynous population analysed, but not in the monogynous ones. The data suggest limited dispersal and partial intranidal mating in the populations with polygynous colonies and outbreeding in the populations having monogynous colonies. Polyandry was common in both population types; about 50% of the females had mated at least twice. The males contributed unequally to the progeny, one male fathering on average 75% of the offspring with double mating and 45–80% with three or more matings.
Correspondence to: L. Sundström 相似文献
48.
The overuse of rainforests in the last century and its consequences necessitate a rethinking of logging policies. To this end models have been developed to simulate rainforest dynamics and to allow optional management strategies to be evaluated. Parameterisation of presently existing models for a certain site needs a lot of work, thus the parameterisation effort is too high to apply the models to a wide range of rainforests. Hence, in this paper we introduce the simplified model FORREG using the knowledge we have gained from a more complex model, FORMIX3-Q. 相似文献
49.
Alternative male mating tactics in a cichlid, Pelvicachromis pulcher: a comparison of reproductive effort and success 总被引:2,自引:0,他引:2
Pelvicachromis pulcher is a small African cichlid which breeds in holes. Males may either reproduce monogamously (pair males), polygynously (harem
males), or be tolerated as helpers in a harem territory (satellite males). These helpers share in defence of the territory
against conspecifics, heterospecific competitors and predators. There are two male colour morphs that are fixed for life and
are apparently genetically determined. These differ in their potential mating strategy. Red morph males may become harem owners,
while yellow morph males may become satellite males, and males of both morphs may alternatively pair up monogamously. We compared
the reproductive effort and success of these three male reproductive strategies. Effort was measured as attack rates, time
expenditure and the risk of being injured or killed when attacking competitors or predators of three sympatric fish species.
Reproductive success was measured by observing how many eggs were fertilized by each male when this was possible, and by using
genetic markers. The number of fry surviving to independence of parental care was used as a criterion of success. The reproductive
success of harem males was 3.3 times higher than that of pair males and 7 times higher than that of the average satellite
male. Dominant satellite males, however, were as successful as monogamous pair males, using the measure of fertilized eggs.
To our knowledge, this has not been found previously in any fish species. Both harem and pair males had lower parental defence
costs per sired offspring, however, than males using the alternative satellite tactic. Defence effort was significantly related
to the risk of injury.
Received: 17 January 1996 / Accepted after revision: 9 June 1997 相似文献
50.
T.?FredstedEmail author C.?Pertoldi J.?M.?Olesen M.?Eberle P.?M.?Kappeler 《Behavioral ecology and sociobiology》2004,56(4):393-403
The objective of our study was to investigate the spatial distribution and genetic structure of a solitary primate at the microgeographical scale of adjacent local populations. We obtained spatial data and tissue samples for mtDNA analysis from 205 gray mouse lemurs (Microcebus murinus) captured along transects and within 3 grid systems within a 12.3 km2 area in Kirindy Forest, western Madagascar. Our capture data revealed that, even though the forest was continuous, gray mouse lemurs were not evenly distributed, and that daily and maximum dispersal distances were significantly greater in males. The frequency distribution of 22 mtDNA D-loop haplotypes was highly skewed. Nine haplotypes were unique to males, indicating male-mediated gene flow from surrounding areas. The geographic distribution of haplotypes revealed that males were also more dispersed than females. Females with the same haplotype showed a tendency towards spatial aggregation, and the correlation between genetic and geographic distances was higher in females. In several areas of the forest, however, spatially clustered females were not of the same haplotype, and females were not always found in clusters. Hence, in contrast to suggestions from previous studies, matrilineal clustering is not the only way females are socially organized. In addition, our study revealed heterogeneity and patterns in population structure that were not evident at smaller spatial scales, some of which may be relevant for designing conservation strategies.Communicated by C. Nunn 相似文献