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81.
This study aims to analyse how vegetation, and in particular the degree of openness of the landscape, is reflected in pollen assemblages from surface sediment in lakes. Modern analogues of ancient cultural landscapes in southern Sweden were selected. Surface sediments from 22 small lakes (0.5–20 ha) located mainly in the forest region of southern Sweden were collected and analysed for pollen in order to enlarge and complement an earlier data set of 13 lakes collected in the open, agricultural region of southernmost Sweden. The composition of the landscape surrounding the lakes was mapped within 1000-m and 500-m radii around the lakes using Colour InfraRed (CIR) aerial photographs. The pollen and landscape data were analysed using numerical ordination techniques. The results show that, despite the large variation of landscape openness, the variation in non-arboreal pollen (NAP) is low between the sites which was not the case for the 13 lakes of the previous study. It is hypothesised that this may be due to differences in the major characteristics of the two regions in which the sites were selected, i.e. mainly treeless and intensively farmed in the previous study and mainly forested in the present investigation. The difference in background pollen appears to play a decisive role on the relative representation of NAP. This implies that the background pollen should be estimated before NAP percentages can be used for quantitative reconstruction of past landscape openness. In the 22 lakes studied, Gramineae, Cerealia (excludingSecale),Filipendula andSalix are positively correlated to cultivated land within both radii, and with open land (tree cover not exceeding 20%) within the 1000-m radius.Quercus andFagus have some positive correlation with deciduous orest within 1000-m radius. We conclude that the landscape units cultivated land, open land and deciduous forest within 1000-m radius are reasonably well reflected in the pollen assemblages and could be predicted within this area.  相似文献   
82.
林柳  张婷  史海涛 《动物学杂志》2023,58(4):481-485
旗舰物种的“明星效应”对生物多样性保护和国家公园建设具有很好的推动作用。我国对海洋保护高度重视,选择理想的代表物种作为旗舰物种,对海洋保护具有重要的推动作用。国家一级重点保护野生动物海龟是大型的海洋爬行动物和海洋活化石物种,对海洋生物多样性和生态系统的平衡稳定具有重要作用;海龟的独特外形特征使其具有很高的识别度,憨态可掬的形象和特殊的生活史使其充满魅力;海龟在我国被利用的历史悠久,具有很高的文化价值;海龟在沿海地区可遇见性和可接触性高,与人类有很好的关系。综上所述,本文认为海龟是海洋保护理想的旗舰物种。  相似文献   
83.
The dearth of socio-perceptual information on urban green spaces is not only limiting for ecosystem service research, but also for effective planning and management of these spaces. Previous studies have assessed perceived CES at single urban parks or across wider spans in rural areas but citywide coverage is missing. This paper explores perceptions of cultural ecosystem services (CES) and various uses of urban green spaces in the case study city of Berlin in relation to the values people place on these CES. Results indicate spatial differentiation of CES across an urban-rural gradient whereby: (1) the density of CES perceived decreased from the inner to the outer edges of the city and (2) recreational, social and cultural heritage and identity services were concentrated more heavily in the inner-city, while perceived biodiversity and spiritual, inspirational, and nature experience and educational services exhibited a more scattered pattern. We also uncovered two distinct clusters of CES—one that is more recreation and social-based and one that is more immaterial and nature-based. CES and their associated uses demonstrated complex relationships that should be explored in further research, though the study indicates that recreation as an indicator is too coarse for assessments at this level. Further research could more pointedly elaborate the potential of such mapping for planning, design and management.  相似文献   
84.
A new actinomycete strain designated as BT-408 producing polyketide antibiotic SBR-22 and showing antibacterial activity against methicillin resistant Staphylococcus aureus has been characterized and found to be a novel strain of Streptomyces psammoticus. Nutritional and cultural conditions for the production of antibiotic by this organism under shake-flask conditions have been optimized. Glucose and ammonium nitrate were found to be best carbon and nitrogen sources respectively for growth and antibiotic production. Similarly initial medium pH of 7.2, incubation temperature of 30 degrees C and incubation time of 96 h were found to be optimal. Optimization of medium and cultural conditions resulted in 1.82-fold increase in antibiotic yield.  相似文献   
85.
Moe  Bjørn  Botnen  Astri 《Plant Ecology》2000,151(2):143-159
The epiphytic vegetation on 24 pollarded trees of Fraxinus excelsior at the farm Grinde, Leikanger, western Norway was investigated. Each trunk was divided into a basal zone, a middle zone and a top zone. In each zone the four different aspects were analysed (12 sampling units from each trunk). Within a total of 276 sampling units, 162 taxa were recorded (99 lichens, 56 bryophytes, 7 vascular plants). The trunks were covered mainly by an old, thick and occasionally swollen bark, but decaying wood did not occur. Their habitats were different, and each trunk was classified into one of four categories: open meadow, wooded hay meadow, deciduous wood, and spruce plantation. A climate station was established in each habitat to measure important parameters. The floristic and environmental data were analysed by canonical correspondence analysis (CCA). The floristic data were classified into eight TWINSPAN groups that have been taken into account in the CCA diagrams. At Grinde all the pollarded trunks grew under fairly homogeneous conditions during a more extensive agricultural period until about 1962. The deciduous wood developed by tree colonization on old meadows and wooded hay meadows, whilst spruce has been planted in a small part of the area. Floristic differences in the epiphytic vegetation between the four different habitats were found, which suggests that changes in the vegetation have developed during the last two or three decades. The spruce plantation was the most shady habitat having a very sparse epiphytic vegetation, mainly remnants from vegetation established during more open area conditions.  相似文献   
86.
K. Kouli 《Plant biosystems》2013,147(1):195-204
The Neolithic settlement of Dispilió (lake Orestiás, northern Greece) is a unique site due to its continual inhabitation from the Middle Neolithic (5400 BC) to the Chalcolithic (3600 BC) and its exceptional location at the shore of Lake Orestiás (also known as Lake Kastoria). The plant landscape shaping of the area has been examined by correlating pollen and non-pollen palynomorphs from both on-site and off-site records. The examined pollen profiles bear concrete evidence of agricultural activities and land use in the area. The local pollen assemblages identified, each of them corresponding either to a different kind or intensity of exploitation of natural resources, display the diachronic evolution of the cultural landscape during more than 2000 years of human activity. The successive phases of intense human impact on vegetation patterns are in good accordance with the periods of major constructing activities described by the archaeological study of the Dispilió settlement. Finally, the differences on palynomorph accumulation pathways of the examined records made possible the distinction between local and “regional” plant landscapes and related human activities.  相似文献   
87.
台湾虫草子实体人工培养条件的初步研究   总被引:4,自引:0,他引:4  
目的研究人工培养条件对台湾虫草子实体形成的影响。方法通过黄山被毛孢的液体摇瓶培养,确定摇瓶种子的最佳培养时间,并研究了在人工诱导下台湾虫草子实体的形成条件,即子实体形成与营养液pH、营养液量、培养温度及光照时间之间的关系。结果黄山被毛孢液体摇瓶最佳培养时间为12 d,人工固体培养子实体所需营养液最佳pH为6.0,营养液量为40 mL,培养温度为25℃,菌丝培养阶段为完全黑暗培养,原基出现后给予光照,可获得较多的子实体。结论人工培养条件对台湾虫草菌丝体生长、原基形成、子实体产量具有显著影响。  相似文献   
88.
Humans exhibit a rich and complex material culture with no equivalent in animals. Also, social learning, a crucial requirement for culture, is particularly developed in humans and provides a means to accumulate knowledge over time and to develop advanced technologies. However, the type of social learning required for the evolution of this complex material culture is still debated. Here, using a complex and opaque virtual task, the efficiency of individual learning and two types of social learning (product‐copying and process‐copying) were compared. We found that (1) individuals from process‐copying groups outperformed individuals from product‐copying groups or individual learners, whereas access to product information was not a sufficient condition for providing an advantage to social learners compared to individual learners; (2) social learning did not seem to affect the exploration of the fitness landscape; (3) social learning led to strong within‐group convergence and also to between‐group convergence, and (4) individuals used widely variable social learning strategies. The implications of these results for cumulative culture evolution are discussed.  相似文献   
89.
Previous research on black students attending predominantly white colleges has emphasized race-based differences with white students while downplaying differences in social class. This research indicates that class-based differences are an important component of many black students’ discomfort at ‘Northern College’, a school that has traditionally served wealthy white students. Drawing on interviews and participant observation done on campus, I apply cultural capital theory to explain how differences in class-specific cultural styles make campus life difficult for non-affluent blacks and discuss the implications of the findings for future research on black college experiences.  相似文献   
90.
Litigation involving the R.M.S. Titanic highlights the critical need for a more stable legal regime to protect shipwrecks, their cargo, and other aspects of underwater cultural heritage. The general maritime law, as articulated by admiralty courts in the United States, has begun to qualify salvage awards in terms of compliance with archaeological standards. Salvage law, however, does not provide language and rules readily applicable to historic wreck and related material. We are, therefore, in a period of transition between a heavy reliance on the common law of "treasure" salvage and the development of a truly general, universal regime to govern underwater heritage. At the center of this development is the Draft UNESCO Convention on the Protection of the Underwater Heritage, based upon the Buenos Aires Draft Convention of the International Law Association. The emerging regime of conventional law provides authority, bases of jurisdiction and other forms of international cooperation, to enforce a set of rules for protection and scientific management of heritage. Critical issues await further negotiations, including the definition of protected heritage, an accommodation of commercial salvage interests within the prescribed conservation and management standards, the status of warships, and the terms of coastal state jurisdiction within the permissible limits of the 1982 UNCLOS.  相似文献   
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