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11.
中国全新世的环境演化   总被引:1,自引:1,他引:1  
全新世是地球历史中全新的一页,年龄为10×103年,测定全新世年龄的最佳方法为14C法,按照环境演化综合分析,全新世可以分为:前北方期(9300aBP以前)、北方期(7500-9300aBP)、大西洋期(5000-7500aBP)、亚北方期(2500-5000aBP)、亚大西洋期(2500aBP至现在).全新世环境的主要特征是:现代人使用的新石器不断革新;全球性的大冰盖已经消逝,只有一些高山冰川和极地冰川,所以称为冰后期;海平面有多次的缓慢升降,总的趋势是不断升高;现代地壳运动是三大板块继续移动,并有多次的地震和火山喷发期;构造地貌和气候地貌的三大地貌单元已经形成;现代人的出现是全新世环境演化的最基本特征。这些特征的相互作用,构成了全新世的环境演化。  相似文献   
12.
Coping with recent heritage is troublesome for history of science museums, since modern scientific artefacts often suffer from a lack of esthetic and artistic qualities and expressiveness. The traditional object-oriented approach, in which museums collect and present objects as individual showpieces is inadequate to bring recent heritage to life. This paper argues that recent artefacts should be regarded as “key pieces.” In this approach the object derives its meaning not from its intrinsic qualities but from its place in an important historical event or development. The “key pieces” approach involves a more organic way of collecting and displaying, focussing less on the individual object and more on the context in which it functioned and its place in the storyline. Finally, I argue that the “key pieces” approach should not be limited to recent heritage. Using this method as a general guiding principle could be a way for history of science museums to appeal to today’s audiences.  相似文献   
13.
《Journal of Natural History》2012,46(35-36):2209-2226
Catenicella paradoxa sp. nov. is described from Mediterranean shallow bottoms. Colonies are small, rooted, erect and articulated, each segment either sterile unizooidal or bizooidal, or fertile bizooidal. Basal parts consist of an “articulated basal complex”, sometimes related to thick encrusting tubes, invariably followed by morphologically ordinary zooids belonging to each type of segment. The hypotheses of small separate colonies or subcolonies from a network of encrusting tubes are discussed, but relationships with the substratum remain unclear. The species represents the first known Mediterranean catenicellid, a family taxon with a warm, mostly Australasian present-day distribution. Nevertheless, catenicellids and Catenicella species have a long history in the European area from the Middle Eocene to the Early Pleistocene, with at least four different species. In this context, the meaning of C. paradoxa sp. nov. is discussed, bearing in mind problems of species spreading in relation to global warming and human activities.  相似文献   
14.
The anatomy and morphology of the pars jugularis skull region in cichlid fishes has been used recently, and for the first time, as a crucial character to establish intrafamilial phylogenies for these African, Malagasian and Neotropical freshwater teleosts. The new phylogeny cuts across relationships postulated in previous schemes, and suggests novel and geographically disjunct intrafamilial groups. It does not, however, seem tenable.

A detailed investigation of the cichlid pars jugularis, involving many more taxa and wider outgroup comparisons than were used to formulate the new classification, is described here. Apart from clarifying certain misconceptions about the anatomy of the pars jugularis in the Cichlidae, this study shows, at least in that family, that the character is valueless as an indicator of higher level intrafamilial relationships, and is of very limited value for establishing phyletic affinities at lower levels.

Other osteological features used in the new classification were also tested on a larger scale. None of these, either, refutes the two other and recent hypotheses-one of intrarelationships amongst Neotropical cichlids and the second for the family as a whole.  相似文献   
15.
《西藏地方近代史》在整个中国近代史中占有十分重要的地位,是“中国近代史”的重要组成部分。但西藏地方近代史的起始时间、社会性质和基本特点尚无定论,该就这一问题进行了研究和探讨。  相似文献   
16.
The bulk of the significant recent scientific heritage of universities is not to be found in accredited science museums or collections employed in research. Rather it is located in a wide variety of more informal collections, assemblages and accumulations. The selection and documentation of such materials is very often unsystematic and many of them are vulnerable to changes of staff, relocation and, above all, shortage of space. Following a survey of views on the values of the recent material heritage of the sciences, I consider the many advantages—for teaching, engagement with wider communities, enhancement of institutional identity and work experience, celebration of scientific achievements, study of the recent history of the practices and fruits of the sciences, etc.—of “multi-site museums” formed through the coordination of such varied and scattered collections. I go on to reflect on ways in which the preservation and display of scientific heritage in dispersed collections may be enhanced and protected through institutional recognition and through provision of guidance and assistance in selection, documentation and digitisation, preservation and conservation, and display. The importance of adequate documentation of the contexts of production and use of objects is stressed, as are the benefits that can result from involvement of student “taskforces” and heritage-concerned scientists.  相似文献   
17.
《Journal of Natural History》2012,46(13):1635-1663
Fossil Cyclocypris diebeli Absolon, 1973 Absolon, A. 1973. Ostracoden aus einigen Profilen spät- und postglazialer Karbonatablagerungen in Mitteleuropa,. Mitteilungen der Bayerischen Staatssammlung für Paläontologie und Historische Geologie, 13: 4794.  [Google Scholar] from Europe are redescribed, utilizing material with chitinous preservation of the appendages and carapace. These are compared with living C. diebeli from Kushiro Marsh, Hokkaido, Japan, representing the first living population of this species ever found. The fossil material is associated with strongly calcareous sediments, whereas the living material is found in weakly calcareous to acidic waters. Reasons for the different ecological requirements are discussed. Detailed study of soft parts of both living and fossil material using SEM is compared with other Cyclocypris species and it is shown that C. diebeli is more closely related to the North American Cyclocypris cruciata Furtos, 1935 Furtos, N. C. 1935. Fresh-water Ostracoda from Massachusetts,. Journal of the Washington Academy of Sciences, 25: 530544.  [Google Scholar] than to any European congeneric species. Furthermore, the comparison with other Cyclocypris species with left>right valve overlap results in the conclusion that the subgenus Laevicypris Krsti?, 1995 Krsti? N 1995 A new Cyclocypris subgenus—Laevicypris, in J. Ríha (ed.) Ostracoda and Biostratigraphy. Proceedings of the 12th International Symposium on Ostracoda (Rotterdam: A. Balkema), pp.?37–42  [Google Scholar] is not a useful division of the genus.  相似文献   
18.
With the interest in studying science as practice came an interest in the material artefacts and things that form part of scientific activities in the laboratory, the field, the classroom, or the political arena. This shift in interest in connection with new modes of knowledge production raises new questions regarding the “archive” of science: what should be preserved and where to make it possible to reconstruct scientific practices in the desired detail? While digital media may be able to bridge some of the traditional divisions between the collection of scientific artefacts in museums and the written archival depositories, the move to performing science in silico produces new challenges in respect to establishing the material archives of current science. The paper will discuss these and related questions with special reference to the archives of the contemporary life sciences.  相似文献   
19.
The characters of the genus Lunulites Lamarck, and of some closely related genera are described and discussed. The genus Lunularia Busk is reintroduced, and three species from Australasia are described. One species, L. parvicella, is known only as an Australian Tertiary fossil, but the remaining two, L. capulus and L. repandus, have an extensive Tertiary-to-Recent Australasian distribution. L. capulus is apparently confined to Australian waters and deposits, but L. repandus has now been found in the Miocene and Recent of New Zealand, as well as off the southern and western Australian coasts.  相似文献   
20.
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