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41.
This paper deals with the pattern of energy flow through four major sub-systems (jhum, valley, animal and domestic) of a typical Khasi village ecosystem with ‘slash and burn’ agriculture (jhum) at an elevation of 1540 m in the north-eastern hill region of India. The energetic efficiency (output:input ratio) of jhum in 5 ha of land worked out at 7·53 and that of valley cultivation on 2 ha of land at 40·14. The animal husbandry sub-system had swine husbandry as its predominant component. This had an energetic efficiency of 3·04. The village ecosystem as a whole, however, had an efficiency of 1·57. Animal husbandry formed an important link in the detritus food chain by utilising the garbage and vegetable waste of the agricultural system. The forest, apart from providing the basis for agriculture, also meets part of the fuel requirement of the village. The compost pit is a very important component in the functioning of the village ecosystem as it provides feed for secondary production and generates organic manure both of plant and animal origin, which is cycled back into agriculture. The intricate relationship existing between the production and consumption compartments of the village ecosystem has been worked out from both the economic and the energetic points of view and is discussed. 相似文献
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Terrestrial plants lose water primarily through stomata, pores on the leaves. The hormone abscisic acid (ABA) decreases water loss by regulating opening and closing of stomata. Here, we show that phospholipase Dalpha1 (PLDalpha1) mediates the ABA effects on stomata through interaction with a protein phosphatase 2C (PP2C) and a heterotrimeric GTP-binding protein (G protein) in Arabidopsis. PLDalpha1-produced phosphatidic acid (PA) binds to the ABI1 PP2C to signal ABA-promoted stomatal closure, whereas PLDalpha1 and PA interact with the Galpha subunit of heterotrimeric G protein to mediate ABA inhibition of stomatal opening. The results reveal a bifurcating signaling pathway that regulates plant water loss. 相似文献
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OBJECTIVE: This study employed a multilevel design to test the contribution of individual, social and environmental factors to mediating socio-economic status (SES) inequalities in fruit and vegetable consumption among women. DESIGN: A cross-sectional survey was linked with objective environmental data. SETTING: A community sample involving 45 neighbourhoods. SUBJECTS: In total, 1347 women from 45 neighbourhoods provided survey data on their SES (highest education level), nutrition knowledge, health considerations related to food purchasing, and social support for healthy eating. These data were linked with objective environmental data on the density of supermarkets and fruit and vegetable outlets in local neighbourhoods. RESULTS: Multilevel modelling showed that individual and social factors partly mediated, but did not completely explain, SES variations in fruit and vegetable consumption. Store density did not mediate the relationship of SES with fruit or vegetable consumption. CONCLUSIONS: Nutrition promotion interventions should focus on enhancing nutrition knowledge and health considerations underlying food purchasing in order to promote healthy eating, particularly among those who are socio-economically disadvantaged. Further investigation is required to identify additional potential mediators of SES-diet relationships, particularly at the environmental level. 相似文献
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Mishra B Kizaki K Koshi K Ushizawa K Takahashi T Hosoe M Sato T Ito A Hashizume K 《Domestic animal endocrinology》2012,42(2):63-73
Extracellular matrix metalloproteinase inducer (EMMPRIN) and its induced matrix metalloproteinases (MMPs) play a crucial role in tissue remodeling during the peri-implantation period. However, the role of EMMPRIN in the bovine placenta is still unclear. We have postulated that EMMPRIN might play a regulatory role in trophoblastic cell functions during gestation by itself or through the regulation of MMP expression. In this study, EMMPRIN mRNA was detected in the bovine placentome and interplacentome throughout gestation, and its expression was significantly higher in the cotyledon during late gestation. In situ hybridization showed that EMMPRIN mRNA was expressed in the caruncular epithelium and the cotyledonary epithelium, including binucleate cells. Western blot analysis detected a band representing a protein of approximately 65 kDa in the caruncular and cotyledonary tissues, and the intensity of its expression was increased in both of these tissues during late gestation. The expression levels of MMP-2 and MMP-14 in the bovine placenta were higher during late gestation, as was observed for EMMPRIN. Therefore, EMMPRIN might regulate trophoblastic cell functions, especially those of binucleate cells, through MMP expression in the bovine placenta. 相似文献
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The polymer optical fiber with trade name Flexi was used in this research, because of its flexibility and the range of diameters available in the market. These fibers were dyed using commercial disperse dye under various conditions of dye concentration and dyeing time. Samples were analyzed for side emission of light with the use of an instrument which was specifically designed for the measurement of this nature. The results showed that the dye penetration is dependent on time, if dye concentration and temperature are kept constant. After 40 min of dyeing, the fiber core showed an increase in side emission with lower loss due to attenuation. Excessive time in the hot conditions also degraded the fiber, so that the fiber became very stiff and brittle. Fibers were also subjected to heat, in the form of boiling water bath, for selected periods of time, and it was found that the effect was similar to that of the prior experiments. Surface treatment of Flexi fibers was carried out using ethyl acetate as an etching agent, to possibly accept more disperse dye on the fiber surface. The results after dyeing showed a more significant improvement in both side emission and attenuation of light. 相似文献