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61.
The Kahuzi-Biega National Park (KBNP), situated mainly in the Eastern Highlands Ecoregion of the Upper Congo basin, is drained by the Lowa and Ulindi rivers, and some western affluents of Lake Kivu. In this study, the first list of the fish diversity of these systems is provided based on museum collections and complemented, for the Lowa River system and the western Lake Kivu affluents, with recently collected specimens (2013–2017). A total of 118 species are reported from the Lowa basin, 22 from the Ulindi basin and seven from these Lake Kivu affluents. Within the Lowa and Ulindi, respectively, five and one species, all cichlids, have been introduced. Currently, 51 species are reported from within the park, only two of which have been reported from the highlands, i.e., Amphilius kivuensis from the Luha, the source of the Luka River, and Clarias liocephalus from the headwaters of the Lake Kivu’ affluents. With a total of 30 species, Cyprinidae is by far the largest family, representing 25% of the total species diversity of the Lowa basin. It is followed by Mormyridae with 13 species (11%), Alestidae and Mochokidae with 10 species each (8%), Clariidae and Amphiliidae with eight species (7%), and Distichodontidae with six species (5%). Seven new species for science were discovered and 11 species were found to be endemic to the Lowa system. Although further exploration is needed, this underscores the importance of the KBNP in protecting the fish fauna of the Lowa basin but also highlights the park's limited coverage of the fish fauna of the Lowa basin.  相似文献   
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Patterns of species-richness and endemism in the Gulf of Guinea reflect the region's biogeographic history. Bioko is a continental-shelf island that was recently connected to the African mainland, whereas Príncipe, São Tomé and Annobón are truly oceanic and have never been connected with each other or with the mainland. As a result, Bioko supports a much more diverse flora and fauna but with relatively low levels of endemism at the species level, whereas the oceanic islands are relatively depauperate because of their isolation but rich in endemic taxa. Species endemism is 0–3% on Bioko for angiosperms, bats, birds, reptiles and amphibians, compared with much higher values on Principe for these same taxa of 8% (plants) to 100% (amphibians), on São Tomé between 14% (plants) and 100% (amphibians), and on Annobón 0% (bats) to 71% (reptiles). On a global scale, for their size both Príncipe and São Tomé support unusually high numbers of single-island endemic species of birds, reptiles and amphibia. For its tiny size, Annobón is also notable for its endemic birds and reptiles. Among terrestrial molluscs the rates of endemism are in general higher than for plants and vertebrates, from ca 50% on Bioko to ca 80% on the oceanic islands. In contrast and as might be expected, only Bioko supports a rich freshwater fish fauna and it contains many endemic taxa, whereas the oceanic islands support only a few salt-tolerant species. The Gulf of Guinea islands are also important for their marine organisms, amongst which coral reef fish and marginellid molluscs show high levels of endemism, though they are not especially species-rich. The Gulf of Guinea islands are of great interest to conservationists and evolutionary biologists. Each island, of greatly differing size and degree of isolation, has acquired its unique sub-set of plants and animals separately from the neighbouring mainland, followed by adaptive radiations in situ. For this reason the conservation value of the archipelago as a whole is greater than the sum of the biodiversity contained in its individual islands. Conservation initiatives in the Gulf of Guinea should therefore ensure that representative terrestrial, freshwater and marine habitats and groups of organisms are targeted in a co-ordinated manner among the islands.  相似文献   
64.
Alien plants from psammophilous ecosystems have been studied in southern Spain. Sixteen sites, which are included in the Andalusian Network of Protected Spaces, have been chosen along 1100 km of Andalusian coasts in order to verify the degree of abundance and influence of these species on different communities. Out of the 26 localized species, the increase of some invasive plants, such as Arctotheca calendula, Agave americana, A. sisalana, Cortaderia selloana, Lantana camara and Opuntia dillenii, affects the conservation of some natural coastal ecosystems.  相似文献   
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成文青  陶宇  吴未  欧维新 《生态学报》2020,40(5):1789-1798
随着城市化进程的加快,对生态保护空间(Ecological Protect Area,EPA)进行优先级识别已经成为保护生物多样性,缓解城市生态压力,提高土地利用效率的重要方法之一。以苏锡常地区为例,通过形态空间格局分析(Morphological Spatial Pattern Analysis,MSPA)确定EPA,进而采用景观连接度方法对其优先级进行识别,以优先级较高的林地和水域为"源地",构建EPA网络;同时由于景观连接度方法在识别优先级时,未能体现EPA对物种决策的非等权重影响,因此本研究引入空间句法进一步对EPA进行优先级识别。结果显示:1)苏锡常地区EPA中编号1、2的林地以及太湖的优先级最高,是区域网络的3个中心,需要优先保护;2)引入空间句法的优先级识别结果与基于景观连接度的优先级识别结果存在明显差异,后者优先级较高的8个EPA,在引入空间句法后优先级降低1—2个等级;后者优先级较低的4个EPA的优先级则上升了2个等级。同时也表明:基于连接度-空间句法的EPA优先级识别方法能够反映不同景观要素对物种决策行为的非等权重影响,强化了生态要素的空间配置的生态效应,为明确关键性生态空间,提供了有效的方法补充,对保护生物多样性和维系区域生态安全具有重要意义。  相似文献   
66.
This study aimed to evaluate different vitrification methods using distinct cryoprotectants (CPAs) for the preservation of collared peccary ovarian preantral follicles (PFs). Ovarian pairs from six females were fragmented and three fragments (fresh control group) were immediately evaluated for morphology, viability, cell proliferation capacity (assessed by quantifying the number of argyrophilic nucleolus organizer regions – NORs), and apoptosis (by the identification of activated caspase-3 expression). The remaining 18 fragments were vitrified using the solid surface vitrification (SSV) method or the ovarian tissue cryosystem (OTC) with 3 M ethylene glycol (EG), 3 M dimethylsulfoxide (DMSO), or a combination of the two (1.5 M EG/1.5 M DMSO). After two weeks, samples were rewarmed and evaluated as described previously. The OTC with any of the CPAs provided a similar conservation of morphologically normal PFs as the fresh control group (75.6 ± 8.6%); however, the SSV was only efficient with DMSO alone (63.9 ± 7.6%). Regarding the viability or cell proliferation, all tested groups provided post rewarming values similar to those observed for the fresh control group, 84.0 ± 2.9% viable cells with 2.0 ± 0.2 NORs. Related to apoptosis analysis, only the OTC with EG (46.7%) and the SSV method with EG (43.4%) or the combination of EG and DMSO (33.4%) provided similar values to those found for the fresh control group (36.7%). Our findings indicate the utilization of a closed system, the OTC, with 3 M EG as the CPA for the vitrification of collared peccary ovarian tissue.  相似文献   
67.
Work aimed at assessing status and introducing water conservation regimes for coffee production in southern Saudi Arabian highlands. Data on farm locations, altitudes, areas, practices, irrigation, tree density, and annual coffee production were analyzed. Field experiment using chlorophyll fluorescence and different irrigation regimes was conducted to examine effects of reducing irrigation frequency on photosynthesis. Results indicated that Coffea arabica L. is commonly grown at altitudes of 1300–1400 m. Plants grown at 4–6 Trees m?2 using 100 kg ha?1 mineral fertilizer produce an average of 3 t ha?1. High frequency 2-day-intervals irrigation regime practiced by farmers during the dry season presents ecological challenge to limited local artesian water resources. Changes in chlorophyll fluorescence under 14-day-intervals irrigation regime initiated water stress that markedly inhibited Photosystem II efficiency and quantum yield and increased non-photochemical energy dissipation. Applying a 7-day-intervals irrigation regime induced less inhibitory effects on Photosystem II. Results also indicated that shifting from 2-day-intervals irrigation regime to 7-day-intervals regime improves coffee agroecology and directs coffee production towards sustainability.  相似文献   
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69.
  1. Many organisms contribute to the decomposition of carrion. For arthropods, many studies focus on the necrophagous community, those directly consuming carrion.
  2. Necrophagous arthropods use carrion as a shelter or food source. Therefore, carrion generally increases the abundance and biodiversity of necrophagous species. However, it is unclear if carrion has similar effects on detrital communities.
  3. This study examines changes in community structure and composition of necrophilous and detrital communities over the course of decomposition.
  4. Five pig head carrion were placed at least 7 m apart under cages in temperate mixed forest. Leaf litter was sampled 0 m, 1.5 m, and 3 m from each carrion weekly during summer, and monthly during autumn, until the first frost. Arthropods were extracted from leaf litter by using Berlese funnels.
  5. At the carrion site, necrophagous insects increased in abundance, species richness, and Shannon diversity during decomposition, and all decreased after dry decay.
  6. Detritus arthropods displayed a sharp increase in abundance during advanced decay, decreasing during dry decay, and a general increase over time for species richness and diversity.
  7. In conclusion, carrion can influence the surrounding, non-necrophagous arthropod community, highlighting the need to investigate carrion effects beyond typical necrophagous species to have a more holistic understanding of carrion ecology.
  相似文献   
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