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高莹 《安徽农业科学》2011,39(29):18325-18326,18331
阐述了新生代农民工劳动权益现状及其劳动权益被侵害的原因,并提出通过实现农民工"公平流动"、提高农民工综合素质、树立正确的政绩观、健全和完善有关劳动法律法规等途径保护新生代劳民工劳动权益。  相似文献   
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The lumbosacral-canal system in birds most likely operates as a sense organ involved in the control of balanced walking and perching, but our knowledge of it is superficial. Penguins constitute interesting objects for the study of this system due to their upright walking, but only the Humboldt penguin, Spheniscus humboldti, and some incomplete fossil penguin synsacra have been studied in this respect. Here, we give an integrative comparative insight into the synsacral canal of extant Emperor penguin, Aptenodytes forsteri, Adelie penguin, Pygoscelis adeliae, and Eocene giant Anthropornis and/or Palaeeudyptes Antarctic penguins, using computed tomography imaging and associated data-extraction methodologies, complemented by analytical approaches ranging from geometric morphometrics to modularity, curvature, and wavelet analyses. We document that the variability in the number of synsacro-lumbar vertebrae is evolutionarily conserved, and all studied synsacra possess osteological correlates of the lumbosacral-canal system. We also found that Eocene and extant Antarctic penguins were separable on the basis of the main direction of the shape-related (size-independent) variability within said system, and A. forsteri was unique in the entire studied set in terms of the relative cranial shift of this compound structure. Moreover, we suggest that the evolutionary processes, shaping both the terrestrial posture and gait, were responsible, in extant penguins, for the increased simplicity and stability of the synsacral canal cross-sectional periodic patterns, as well as pave the way for the lumbosacral-canal system modularity characterized by reduced atomization/complexity.  相似文献   
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Following the discovery of the first living polypterid, Polypterus bichir, in 1802, almost two centuries later we now know of 15 living species (including four subspecies), 14 belonging to the genus Polypterus and one to the genus Erpetoichthys (Calamoichthys) all inhabiting intertropical Africa. The polypterid fossil record was for a long time reduced to some scarce, disarticulated bones, mainly scales, found in various African deposits covering a wider area than the actual geographical distribution. With the discovery, on one hand, of polypterid scales, vertebrae, dermal bones of the cranium and dorsal spiny rays in South America and, on the other hand, of scales and numerous dorsal spiny rays in Niger and Sudan, and two articulated fossils in Morocco, the story of the polypteriforms has revealed some of its mysteries. The discovery of isopedine between dentine and bony basal plate in the scales of living and fossil polypterid species is considered a synapomorphy of the group, and has been an important aid in discriminating polypterid scales from other ganoid scales. A review of the main findings during the last 20 years is presented.  相似文献   
4.
Cenozoic terrestrial mammals from Sardinia contribute substantial information for reconstructing the complex history of the western Mediterranean. The occurrence of endemic perissodactyls in Eocene marine and marsh deposits suggests the existence of ecological or physical barriers between the Corso‐Sardinian massif and the Iberian‐Occitanic area. At the end of the Oligocene, isolation of Sardinia was almost complete, although a migration from Europe occurred at the beginning of the Early Miocene, as indicated by the unbalanced endemic fauna from Oschiri. During the Late Miocene, the Tusco‐Sardinian palaeobioprovince came into existence as an isolated region inhabited by the quite diversified, but notably endemic, Oreopithecus fauna. Sardinia was definitely isolated from Tuscany by the Messinian, but temporary connections with the European mainland possibly allowed the colonization of forerunners of some Sardinian Pliocene taxa. During the Plio‐Pleistocene, Sardinia maintained permanent isolation. However, sea level drop, resulting in a relatively short distance between Sardinia and the European mainland, allowed different migratory events. From the Late Pliocene to the Late Pleistocene‐Holocene, two main mammalian faunal complexes (FC) can be recognized: the Nesogoral FC (Late Pliocene‐Early Pleistocene) and the Microtus (Tyrrhenicola) FC (late Early Pleistocene‐Early Holocene). At the transition from Nesogoral to Microtus (Tyrrhenicola) FC, approximately 47% of the genera and 76% of the species disappeared, while approximately 58% of the genera and 71% of the species appeared. A noticeable turnover followed the arrival of Neolithic man and his accompanying fauna. Nonetheless, Praemegaceros was still present at about 7000 years BP, while Microtus (Tyrrhenicola) and Prolagus are respectively recorded in the Bronze and Iron Ages.  相似文献   
5.
新生代农民工边缘化研究综述   总被引:1,自引:0,他引:1  
郭立场 《安徽农业科学》2011,(19):11839-11841
通过对政府及学术界已有成果的梳理和归纳,基于社会发展现状及新生代农民工自身情况,提出应从观念转变、制度保障、氛围营造、条件改善及新生代农民工自身能力提升等多方面维护新生代农民工的基本权益。政府政策的支持、社会组织的介入、农民工主体作用的发挥是破解新生代农民工边缘化的有效措施。  相似文献   
6.
运用植物区系地理学的研究方法,根据古植物学资料及与现代植物区系的对比分析,对陕北黄土高原植物区系的演变及新生代植物区系进行了研究,对深入了解陕北黄土高原植物区系、植被的起源和发展具有重要意义,同时为指导本区目前实施的退耕还林还草、植被恢复等生态环境建设方面可以提供参考。文中论述了自白垩纪以来各时期陕北黄土高原植物区系的演变发展过程,对陕北黄土高原植物区系的演变和现代与新生代孢粉植物群进行了比较分析,认为本区植物区系主要来源于4个方面:一是起源于本地及邻近地区晚白垩纪-早第三纪植物群,一些草本植物和湿生植物主要发生于晚第三纪,耐寒和耐旱的种类主要发生于第四纪;二是来源于地中海区-中亚和欧亚草原;三是来源于东北亚、西伯利亚温-寒地区;四是来源于我国西南、西北、华北及秦岭、华中地区。  相似文献   
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