全文获取类型
收费全文 | 303篇 |
免费 | 8篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 12篇 |
废物处理 | 7篇 |
环保管理 | 49篇 |
综合类 | 37篇 |
基础理论 | 90篇 |
污染及防治 | 81篇 |
评价与监测 | 20篇 |
社会与环境 | 18篇 |
灾害及防治 | 4篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2018年 | 9篇 |
2017年 | 13篇 |
2016年 | 12篇 |
2015年 | 12篇 |
2014年 | 11篇 |
2013年 | 31篇 |
2012年 | 11篇 |
2011年 | 11篇 |
2010年 | 16篇 |
2009年 | 8篇 |
2008年 | 17篇 |
2007年 | 15篇 |
2006年 | 17篇 |
2005年 | 12篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1968年 | 4篇 |
1967年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有318条查询结果,搜索用时 15 毫秒
251.
252.
B. H. Robinson J. R. Toone R. Petrova Benedict J. E. Dimmick J. Oei D. A. Applegartht 《黑龙江环境通报》1985,5(1):67-71
Prenatal diagnosis of pyruvate carboxylase (PC) deficiency was performed in a family at risk for the acute neonatal form of this disease which manifests secondary citrullinemia. The diagnosis of an affected child was confirmed by enzyme assay and 3H-biotin labelling of proteins in cultured fetal skin fibroblasts. Sufficient amniocytes were cultured in 3–4 weeks for enzyme analysis in two centres. Citrulline concentration in amniotic fluid (AF) was normal in the affected fetus. 相似文献
253.
254.
Division of labor during honey bee colony defense 总被引:5,自引:0,他引:5
Michael D. Breed Gene E. Robinson Robert E. Page Jr. 《Behavioral ecology and sociobiology》1990,27(6):395-401
Summary Some worker honey bees respond to major disturbances of the colony by flying around the assailant and possibly stinging; they are a subset of the bees involved in colony defense. These defenders have an open-ended age distribution similar to that of foragers, but defensive behavior is initiated at a younger age than foraging is. Behavioral and genetic evidence shows that defenders and foragers are distinct groups of older workers. Behaviorally, defenders have less worn wings than foragers, suggesting less flight activity. Genetically, defenders differ in allozyme frequencies, demonstrating different subfamily composition from foragers in the same colony. They also differ in allozyme frequencies from guards in the same colony, providing further evidence for division of labor associated with colony defense. We use this information to develop a model for honey bee colony defense involving at least two distinct groups of workers and we propose that the non-guard defenders be called soldiers, due to their important role in colony defense.Offprint requests to: M.D. Breed 相似文献
255.
Intracellular and extracellular granules are found in most bivalve kidneys. We examined the composition of kidney granules from the infaunal bivalveMercenaria mercenaria (L.) collected in 1985 from Cataumet Bay, Bourne, and Waquoit Bay, Falmouth, Massachusetts, USA. Small granules are numerically dominant, but large granules dominate the samples on the basis of weight. Large granules (estimated diam. >15 m) are composed primarily of metals (28% by weight) with Mn (8%), Ca (8%), Zn (4%) and Fe (4%) as the major contributors. Non-metal elements (P, C, H, N, S) together constituted 21% of the granule dry weight, though organic content (0.02% protein, 0.3% carbohydrate and 0.5% lipid) was low. Small kidney granules (10 m diam.) and digestive gland granules fromM. mercenaria had significantly higher C, H, and N contents than larger kidney granules. Our results, taken together with those from other bivalve species, suggest that kidney granule formation and subsequent increase in size is a continuous process of lysosomal maturation, residual body release and extracellular accumulation of predominately inorganic elements. 相似文献
256.
Parks as Shibboleths 总被引:1,自引:0,他引:1
257.
The Sustainability of Subsistence Hunting in the Neotropics 总被引:7,自引:0,他引:7
Michael S. Alvard John G. Robinson Kent H. Redford & Hillard Kaplan 《Conservation biology》1997,11(4):977-982
Hunting is an important component of native subsistence strategies in Amazonia. It is also a serious threat to biodiversity in some areas. We present data on the faunal harvests of two native Neotropical subsistence hunting peoples, Machiguenga bow-hunters and Piro shotgun hunters of Peru. The rate of annual harvest per square kilometer of catchment is estimated and compared to rates of sustainable harvest calculated by Robinson and Redford (1991). We used indicators of prey abundance to test for the depletion of species that hunters killed in numbers greater than what the model predicts to be sustainable. As predicted, we found the strongest evidence for local depletion of the large primates at the Piro site. The woolly monkey ( Lagothrix lagothricha) harvest at the Machiguenga village and the deer ( Mazama americana) and collared peccary (Tayassu tajacu) harvests at both sites were not predicted to be unsustainable and we found no evidence for depletion. Machiguenga bow hunters killed spider monkeys (Ateles paniscus) in quantities that were slightly above what the model predicted to be sustainable, yet we found no evidence for depletion. Differential species vulnerability, catchment size, and consumer population size could be important factors in determining sustainability. 相似文献
258.
John G. Robinson 《Conservation biology》1993,7(1):20-28
Caring for the Earth represents current middle-of-the-road thinking on the relationship between conservation and development. This IUCN/UNEP/WWF document has embraced a purely utilitarian perspective: it considers the conservation and development of natural resources to be the same process. In this analysis, I argue that the goal of creating the sustainable society, as defined in Caring for the Earth , is an unattainable utopia, and that the mechanisms proposed to attain this goal will lead irrevocably to the loss of biological diversity. I consider the history of the concept of sustainable development, and then document the constraints on sustainable use of natural resources. Sustainable use only occurs when both human needs are met and the losses of biodiversity and environmental degradation are acceptable. These conditions are not always met when natural resources are used, and I consider the fundamental contradictions between resource potential and human needs. I conclude by emphasizing that while sustainable use is a powerful approach to conservation, it is not the only one, and the conservation of many species and biological communities also requires a preservationist approach. 相似文献
259.
Gene E. Robinson Robert E. Page Jr. Naomi Arensen 《Behavioral ecology and sociobiology》1994,34(2):125-137
Summary Three experiments were performed to determine whether brood care in honey bee colonies is influenced by colony genetic structure and by social context. In experiment 1, there were significant genotypic biases in the relative likelihood of rearing queens or workers, based on observations of individually labeled workers of known age belonging to two visually distinguishable subfamilies. In experiment 2, no genotypic biases in the relative likelihood of rearing drones or workers was detected, in the same colonies that were used in experiment 1. In experiment 3, there again were significant genotypic differences in the likelihood of rearing queens or workers, based on electrophoretic analyses of workers from a set of colonies with allozyme subfamily markers. There also was an overall significant trend for colonies to show greater subfamily differences in queen rearing when the queens were sisters (half- and super-sisters) rather than unrelated, but these differences were not consistent from trial to trial for some colonies. Results of experiments 1 and 3 demonstrate genotypic differences in queen rearing, which has been reported previously based on more limited behavioral observations. Results from all three experiments suggest that genotypic differences in brood care are influenced by social context and may be more pronounced when workers have a theoretical opportunity to practice nepotism. Finally, we failed to detect persistent interindividual differences in bees from either subfamily in the tendency to rear queen brood, using two different statistical tests. This indicates that the probability of queen rearing was influenced by genotypic differences but not by the effect of prior queen-rearing experience. These results suggest that subfamilies within a colony can specialize on a particular task, such as queen rearing, without individual workers performing that task for extended periods of time. 相似文献
260.