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41.
In the Zoom Erlebniswelt Gelsenkirchen the third and last biogeographical area dedicated to the Asian fauna was opened in March 2010 covering a total area of five hectares. In May 2013 a new enclosure for tigers was added. The emphasis of the Asia area lies on a 4700 m2 tropical hall with mammals and birds, and Asian gastronomic facilities as well. Included is a mixed species exhibit for orangutans (Pongo abelii), northern plains grey langurs (Semnopithecus entellus) and Asian small clawed otters (Aonyx cinerea). Along a 1.3 km outside path enclosures for some species of colder climates were built, too. The transformation of the former Ruhr Zoo Gelsenkirchen to the modern ZOOM Erlebniswelt herewith is brought to a close.  相似文献   
42.

Background and Aims

Mycorrhizal specialization has been shown to limit recruitment capacity in orchids, but an increasing number of orchids are being documented as invasive or weed-like. The reasons for this proliferation were examined by investigating mycorrhizal fungi and edaphic correlates of Microtis media, an Australian terrestrial orchid that is an aggressive ecosystem and horticultural weed.

Methods

Molecular identification of fungi cultivated from M. media pelotons, symbiotic in vitro M. media seed germination assays, ex situ fungal baiting of M. media and co-occurring orchid taxa (Caladenia arenicola, Pterostylis sanguinea and Diuris magnifica) and soil physical and chemical analyses were undertaken.

Key Results

It was found that: (1) M. media associates with a broad taxonomic spectrum of mycobionts including Piriformospora indica, Sebacina vermifera, Tulasnella calospora and Ceratobasidium sp.; (2) germination efficacy of mycorrhizal isolates was greater for fungi isolated from plants in disturbed than in natural habitats; (3) a higher percentage of M. media seeds germinate than D. magnifica, P. sanguinea or C. arenicola seeds when incubated with soil from M. media roots; and (4) M. media–mycorrhizal fungal associations show an unusual breadth of habitat tolerance, especially for soil phosphorus (P) fertility.

Conclusions

The findings in M. media support the idea that invasive terrestrial orchids may associate with a diversity of fungi that are widespread and common, enhance seed germination in the host plant but not co-occurring orchid species and tolerate a range of habitats. These traits may provide the weedy orchid with a competitive advantage over co-occurring orchid species. If so, invasive orchids are likely to become more broadly distributed and increasingly colonize novel habitats.  相似文献   
43.
权秋梅 《广西植物》2013,(4):516-520
对不同生境中巫山淫羊藿结实特性进行比较研究。结果表明:(1)三个种群在繁殖时期中不同花部特征的植株繁殖投资差异不大,如每株分枝数、每株花序数和每株开花数差异均不显著;(2)三个种群中每株结实数、每株结实率、每花序结实数在不同花部特征中差异显著,PLS和SAA要显著大于PESS;(3)三种花部特征在不同生境中单株分枝数和单株花序数均无显著差异。在不同花部特征中种群1开花数量相较少,因而在结实方面均值均要小于种群2和种群3;(4)不同花部特征的果实饱满种子数、败育数和败育率均具有显著差异,而种子数差异不大,但在种群间均无显著的差异。说明种子的多少更多地受到花部特征的影响。总之,巫山淫羊藿的结实特性受到生境和花部特征的双重影响,其中花型比生境对巫山淫羊藿结实特性的影响更为明显。  相似文献   
44.
随着人类和其他生物赖以生存的环境破碎化程度的加剧,许多以前是连续分布的物种,目前不得不在破碎化生境(斑块)中求生存,所以,种群在破碎化生境(斑块)中分布问题的研究对生物保护和生境重建意义重大.本文运用Leslie矩阵和Markov链建立了一个具年龄结构的种群在破碎化生境中随时间动态变化的分布模型,讨论了种群在该生境中持续存在以及灭绝的条件.  相似文献   
45.
South–west Australia contains extensive seagrass meadows along 2,500 km of coastline from the shallow subtidal to 50+ m water depths, and in many of the 51 bar-built estuaries along the coast. There are geomorphological differences between the south and west coasts that result in different patterns of swell exposure influencing the processes that structure seagrass habitats. In this paper, ‘sheltered’, ‘exposed’ and ‘estuarine’ seagrass habitat types are defined for south–west Australia to synthesize processes influencing seagrass communities. Sheltered habitats in south–west Australia are characterized by high light, low to moderate water motion and sporadic disturbance from storms, making them ideal habitats for a diversity of seagrass assemblages. Exposed seagrass habitats are characterized by the presence of strong and consistent ocean swells (3–8 m), predominantly from the south or south–west and seagrasses exhibit a suite of adaptive traits to survive the effects of exposure to ocean swell and associated sand movement. These include morphological features such as heavy fiber reinforcement to strengthen the aboveground stems or leaves, deep vertical rhizomes and life history traits such as rapid growth and high seed set. Within estuarine habitats highly dynamic seagrass communities are the result of fluctuating annual cycles in temperature, light and salinity. Compared to global seagrass meadows, coastal south–west Australian seagrass habitats experience high light, low nutrients and high water movement. Despite these differences, similarities with other regions do exist and here we place the habitats of south–west Australia into a global context using comparative data. The wide array of morphology and life history traits displayed among seagrass species of south–west Australia are presented in a conceptual model including habitat type, physical stressors and seagrass responses. The combination of adaptations to the habitats and processes that define them make south–west Australia a region where there is an unusually high number of co-occurring seagrass species, the highest in the world for a temperate environment (19 species), and approaching the species diversity of many tropical environments. Linking aspects of seagrass habitat, physical aspects of the environment and seagrass life history provides a context for applying knowledge gained from seagrasses in south–west Australia to other coastal ecosystems throughout the world.  相似文献   
46.
Fungal biodiversity in freshwater, brackish and marine habitats was estimated based on reports in the literature. The taxonomic groups treated were those with species commonly found on submerged substrates in aquatic habitats: Ascomycetes (exclusive of yeasts), Basidiomycetes, Chytridiomycetes, and the non-fungal Saprolegniales in the Class Oomycetes. Based on presence/absence data for a large number and variety of aquatic habitats, about 3,000 fungal species and 138 saprolegnialean species have been reported from aquatic habitats. The greatest number of taxa comprise the Ascomycetes, including mitosporic taxa, and Chytridiomycetes. Taxa of Basidiomycetes are, for the most part, excluded from aquatic habitats. The greatest biodiversity for all groups occurs in temperate areas, followed by Asian tropical areas. This pattern may be an artifact of the location of most of the sampling effort. The least sampled geographic areas include Africa, Australia, China, South America and boreal and tropical regions worldwide. Some species overlap occurs among terrestrial and freshwater taxa but little species overlap occurs among freshwater and marine taxa. We predict that many species remain to be discovered in aquatic habitats given the few taxonomic specialists studying these fungi, the few substrate types studied intensively, and the vast geographical area not yet sampled.  相似文献   
47.
We developed broad-scale habitat selection models for the distribution of red-legged partridge Alectoris rufa in a low-density area in northwestern Spain, the Baixa-Limia site of community importance (SCI). The fieldwork consisted of ground surveys in 1 × 1 km squares. For habitat selection analysis, we used a 2 × 2 km grid integrating the information obtained in the 1 × 1 km squares. As predictors we used environmental variables measured on digital 1:50,000 scale cartography using a geographical information system (GIS). The red-legged partridge was scarce in the study area. The logistic regression analysis carried out on data from the squares with probable and confirmed breeding included the area of scrubland and pastureland with a positive sign. Using the breeding index category (BIC) three variables produced a slightly positive response: area of scrubland and pastureland, length of border between scrublands and forests, and length of border between forests and dams. The difficulty for modelling the habitat selection of this species could be due to human activities (hunting, habitat loss, restocking of hunt species), and may have modified their habitat preferences. Furthermore, the occupation of suboptimal habitats would distort the real habitat preferences.  相似文献   
48.
Endemic freshwater finfish of Asia: distribution and conservation status   总被引:2,自引:1,他引:1  
Freshwater finfish species richness and level of endemism in East, and South and South‐East Asia that included 17 nations were studied using available databases, and included nation‐wise distribution, habitat types, and conservation status. The number of endemic finfish species in the region was 559, belonging to 47 families. Families Cyprinidae and Balitoridae accounted for 43.5% and 16.2% of the total number of endemic species in the region, respectively, followed by Sisoridae (25), Gobiidae (20), Melanotaeniidae (19), and Bagridae (16), and the other 41 families had at least one endemic species. Nation‐wise the most number of endemic freshwater finfish species occur in India (191), followed by China (88), Indonesia (84), and Myanmar (60). In India, the endemic species accounted for 26.4% of the native freshwater fish fauna, followed by South Korea (16.9%), the Philippines, (16.3%) and Myanmar (15.7%). Statistically significant relationships discerned between the number of indigenous and endemic species richness to land area (Xla in 103 km2) of the nations in the region were, Yin = 218.961 Ln(Xla) – 843.1 (R2 = 0.735; P < 0.001) and Ye = 28.445 Ln Xla?134.47 (R2 = 0.534; P < 0.01), respectively, and between indigenous and endemic species richness was Ye = 0.079Xn? 1.558 (R2 = 0.235; P < 0.05). The overall conservation status of endemic finfish in Asia was satisfactory in that only 92 species were in some state of vulnerability, of which 37 species (6.6%) are endangered or critically endangered. However, the bulk of these species (83.7%) were cave‐ and or lake‐dwelling fish. However, nation‐wise, the endemic freshwater finfish fauna of the Philippines and Sri Lanka, based on the imperilment index, were found to be in a highly vulnerable state. Among river basins, the Mekong Basin had the highest number of endemic species (31.3%). The discrepancies between databases are highlighted and the need to consolidate information among databases is discussed. It is suggested that the Mekong Basin be considered as a biodiversity hotspot, and appropriate management strategies be introduced in this regard.  相似文献   
49.
Global biodiversity is decreasing as a result of human activities. In many parts of the world, this decrease is due to the destruction of natural habitats. The European perspective is different. Here, traditional agricultural landscapes developed into species-rich habitats. However, the European biodiversity heritage is strongly endangered. One of the countries where this biodiversity is best preserved is Romania. We analyse the possible changes in Romania's land-use patterns and their possible benefits and hazards with respect to biodiversity. As model group, we used butterflies, whose habitat requirements are well understood. We determined the ecological importance of different land-use types for the conservation of butterflies, underlining the special importance of Romania's semi-natural grasslands for nature conservation. We found that increasing modern agriculture and abandonment of less productive sites both affect biodiversity negatively — the former immediately and the latter after a lag phase of several years. These perspectives are discussed in the light of the integration of Romania into the European Union.  相似文献   
50.
Movement is the process by which individual organisms are displaced over time to eat, reproduce and defend resources. Fractal analysis is a technique used to study animal movement that measures spatial complexity of path tortuosity; here, we apply it to characterize the movement patterns of the Eurasian badger (Meles meles) in a Mediterranean landscape. We calculated path tortuosity overall and seasonally, and for individuals of different sexes and social groups. The influence of variables related to badgers’ resources (food, shelter, water), human infra-structures and weather conditions were analysed with respect to the tortuosity of each badger’s path. A total of 55 search paths from six badgers were considered for this study. Although badgers generally displayed convoluted movement, there were two exceptions: (a) males overall and (b) all badgers in summer; for both, movements had a lower fractal value, i.e. were less tortuous. The convoluted movement pattern generally observed is probably adapted to the clumped distribution of food in the study area. Nevertheless, our results suggest that the use of dens and latrines were the principal determinants of tortuosity of badgers’ paths while foraging.  相似文献   
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