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排序方式: 共有366条查询结果,搜索用时 109 毫秒
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Participatory Development and Community-Based Conservation: Opportunities Missed for Lessons Learned? 总被引:1,自引:0,他引:1
Lisa M. Campbell Arja Vainio-Mattila 《Human ecology: an interdisciplinary journal》2003,31(3):417-437
This paper traces the evolution as well as key elements, and provides examples of implementation of participatory development and community-based conservation, two concepts that resemble distant cousins in the intersecting worlds of development assistance and environmental conservation. The paper examines the connections between the concepts, the implications of participatory development for community-based conservation, and the reasons for the differences in their conceptualization and implementation. The paper is based on a review of the literature in both fields and on the authors' research and experience with participatory development and community-based conservation. Several keys to understanding the disconnection between the concepts emerge; intellectual and pragmatic origins of and impetus for the concepts, the expertise and interests of their promoters, and the differing emphasis on participation as means versus end. Results may inform our understandings of why many participatory approaches to conservation have failed to achieve meaningful participation in practice. 相似文献
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A Marjam?ki H Frang M Pihlavisto A M Hoffrén T Salminen M S Johnson J Kallio J A Javitch M Scheinin 《The Journal of biological chemistry》1999,274(31):21867-21872
The substituted cysteine-accessibility method and two sulfhydryl-specific reagents, the methane-thiosulfonate derivative 2-aminoethyl methanethiosulfonate (MTSEA) and the alpha(2)-adrenergic receptor (alpha(2)-AR) agonist chloroethylclonidine (CEC), were used to determine the relative accessibility of engineered cysteines in the fifth transmembrane domain of the human alpha(2A)-AR (Halpha2A). The second-order rate constants for the reaction of the receptor with MTSEA and CEC were determined with the wild type Halpha2A (cysteine at position 201) and receptor mutants containing accessible cysteines at other positions within the binding-site crevice (positions 197, 200, and 204). The rate of reaction of CEC was similar to that of MTSEA at residues Cys-197, Cys-201, and Cys-204. The rate of reaction of CEC with Cys-200, however, was more than 5 times that of MTSEA, suggesting that these compounds may interact with two different receptor conformations. MTSEA, having no recognition specificity for the receptor, likely reacts with the predominant inactive receptor conformation (R), whereas the agonist CEC may stabilize and react preferentially with the active receptor conformation (R*). This hypothesis was consistent with three-dimensional receptor-ligand models, which further suggest that alpha(2A)-AR activation may involve the clockwise rotation of transmembrane domain 5. 相似文献
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Minna Miettinen Arja Kaitala Robert L. Smith Rogelio Macías Ordóñez 《Journal of Insect Behavior》2006,19(2):171-178
Golden egg bug Phyllomorpha laciniata (Heteroptera, Coreidae) females oviposit on male and female conspecifics that carry ova until they hatch. Embryos benefit from being carried because of diminished risks of predation. Female carriers are never the parents of carried eggs, and males are only rarely the fathers of any carried eggs. Eggs develop and hatch without being carried in the laboratory. Egg carriers may be viewed as victims, exploited by females that encumber them with eggs. The intensity of selection favouring resistance to egg carrying should be proportional to the costs of this behaviour. One possible cost could be a reduction in mobility caused by carried eggs. We compare movement rates among encumbered and unencumbered golden egg bugs of both sexes. Protracted copulations (often exceeding 20 h) typical of this species and mating may also cause reduction in bugs mobility. Therefore, we also evaluate rates of movement of coupled pairs of bugs. Our results indicate that egg loads do not affect the mobility and speed of either males or females. However, copulating pairs are significantly slowed as compared to single bugs. Thus protracted copulations have a clear cost in rates of movement and possibly risks of predation, but there are no apparent mobility costs for egg carrying. 相似文献