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31.
皖南不同类型土壤植烟成熟期烟叶的基因差异表达和显微结构的比较 总被引:4,自引:0,他引:4
以烟草品种云烟97为材料,在皖南烟区典型的植烟土壤麻沙土、麻沙泥、粉沙土种植,以水稻土种植作对照,应用基因芯片技术和显微观察技术对生长成熟期烟叶的基因表达谱和细胞结构进行比较。结果表明,与水稻土相比,麻沙土植烟成熟期烟叶上调表达的基因主要有细胞增殖、生长和分化的基因,以及与氧化胁迫有关的基因,而下调表达的基因主要是光合作用和蛋白质、磷脂合成的基因。麻沙泥植烟成熟期烟叶上调表达的基因主要有与生长素运输和多糖合成有关的基因及与蛋白质和氨基酸分解有关的基因。粉沙土植烟成熟期烟叶与干旱胁迫有关的基因和与纤维素、果胶质、淀粉和蛋白质分解有关的基因上调。叶片的显微和超显微结构表明,粉沙土和水稻土植烟,烟叶长势差,生长衰退迹象明显;而麻沙土和麻泥土植烟,尤其是麻沙土,烟叶生长势较好,生长衰退迹象不明显。 相似文献
32.
Li-Jia ZhuHulya Dogan Hyma GajulaMing-Hong Gu Qiao-Quan Liu Yong-Cheng Shi 《Journal of Cereal Science》2012,55(1):1-5
Rice kernels of a transgenic high-amylose rice line and its wild type were examined by a high-resolution X-ray microtomography (XMT) and an environmental scanning electron microscope. Two-dimensional (2-D) cross-sectional images and 3-D objects from XMT were reconstructed and analyzed to elucidate their structural features. The lack of two isoforms of starch branching enzyme, termed SBEI and SBEIIb in high-amylose rice (HAR), resulted in a distinctly different grain inner density than wild-type rice (WTR). HAR had smaller, elongated starch granules with air spaces inside the kernels resulting in an opaque grain, whereas WTR had a tight endosperm with little air space and polygonal starch granules. XMT allowed a full 3-D characterization of the rice kernel structure and revealed that air space distribution was not uniform in the HAR kernel. 相似文献
33.
玉米自交系茎秆显微结构及其与茎节抗折强度的相关与通径分析 总被引:2,自引:0,他引:2
通过测定黄淮海地区22个常用玉米自交系的玉米茎节抗折强度(节折强度,NSS),并利用光学显微镜观察其茎节显微结构,对维管束各项显微指标与节折强度进行相关及通径分析,研究玉米节折强度与茎秆显微结构之间的关系。结果表明,不同自交系间节折强度差异达显著或极显著水平;对各自交系维管束显微指标进行统计分析表明,单个维管束面积的变异系数最大,为25.06%,其次是维管束数目,为19.97%;茎节维管束数目增多不利于节折强度的提高(r=-0.54**,r=-0.55**),单个维管束面积增大有助于节折强度的提高(r=0.48*,r=0.43*)。通径分析表明,抽雄后6 d及15 d两个测定时期均为维管束个数对节折强度的直接效应最大,单个维管束面积效应次之;在花后6 d,维管束最小直径、平均直径等指标对于节折强度的贡献也主要通过维管束数目的间接效应起作用。 相似文献
34.
To study dough microstructure, epifluorescence light microscopy (EFLM) combined with digital image processing software was used, which enabled an improved image quality. A comparison was made between EFLM and confocal scanning laser microscopy (CSLM) methods. Both techniques were satisfactorily able to demonstrate changes in the dough microstructure upon different stages of z-blade mixing. Dough mixed for a shorter time (under-mixed) showed a heterogeneous structure with coarse protein domains and clusters of starch due to local segregation or de-mixing effect. Increasing mixing time (optimal mixing) led to development of interconnected gluten network covering starch granules throughout the dough, representing optimal development. Over-mixing led to formation of a homogeneous dough microstructure in which the gluten phase showed a fine distribution throughout the dough. Using a double staining method in the preparation of samples for both microscopic techniques it was possible to observe gluten network structures together with starch granules. Moreover, special features of image processing software described in this study enabled us to improve EFLM images and to obtain comparable images with CSLM. This could favour a low cost and a convenient microscopic observation of biomaterials. 相似文献
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37.
针铁矿-高岭石二元体的微观结构与形成机制 总被引:3,自引:0,他引:3
制备了针铁矿-高岭石复合物,以其混合物为对照,分析了它们的微观结构与形成机制。结果表明,复合物中的针铁矿较好地包被在高岭石表面,而混合物中两固相之间的包被作用微弱。相对针铁矿和高岭石两单体而言,二元体中针铁矿和高岭石的主要晶面间距没有明显变化;复合物的孔体积增多、平均孔径减小,混合物的孔体积和平均孔径都接近两单体的平均值;两种二元体的表面分形度(D)增大,且D混合物>D复合物。红外光谱显示,二元体中≡Fe-OH的振动频率升高,而≡Al-OH、Al-O、Si-O和Fe-O的振动频率降低;高岭石与针铁矿胶结后,核磁共振波谱中29Si和27Al的化学位移均向正方向移动。根据波谱分析的结果推断,针铁矿与高岭石的胶结主要通过针铁矿表面≡FenOH2(n/2)+(n=1,2,3)与高岭石表面≡Si-OH、≡Al-OH02.5+等Lewis酸之间的阳离子交换、高岭石表面≡Si-O-和≡Al-OH0.5-与针铁矿表面铁羟基(≡Fe-OH)间的阴离子交换以及高岭石表面O与针铁矿表面Fe间的配位等作用而实现,其胶结力主要为氢键和静电引力。复合物中≡Fe-OH、≡Al-OH等主要基团的振动频率以及29Si、27Al的化学位移的漂移均大于混合物中的变化量,说明复合物中针铁矿与高岭石间的胶结强度大于混合物中两固相间的胶结作用。 相似文献
38.
Gluten is a fundamental component for the overall quality and structure of breads. The replacement of the gluten network in the development of gluten-free cereal products is a challenging task for the cereal technologist. The functionality of proteins from gluten-free flours could be modified in order to improve their baking characteristics by promoting protein networks. Transglutaminase (TGase) has been successfully used in food systems to promote protein cross-linking. In this study, TGase was investigated for network forming potential on flours from six different gluten-free cereals (brown rice, buckwheat, corn, oat, sorghum and teff) used in breadmaking. TGase was added at 0, 1 or 10 U/g of proteins present in the recipe. The effect of TGase on batters and breads was evaluated by fundamental rheological tests, Texture Profile Analysis and standard baking tests. Three-dimensional elaborations of Confocal Laser Scanning Microscopy (CLSM) images were performed on both batters and breads to evaluate the influence of TGase on microstructure. Fundamental rheological tests showed a significant increase in the pseudoplastic behaviour of buckwheat and brown rice batters when 10 U of TGase were used. The resulting buckwheat and brown rice breads showed improved baking characteristics as well as overall macroscopic appearance. Three-dimensional CLSM image elaborations confirmed the formation of protein complexes by TGase action. On the other side, TGase showed negative effects on corn flour as its application was detrimental for the elastic properties of the batters. Nevertheless, the resulting breads showed significant improvements in terms of increased specific volume and decreased crumb hardness and chewiness. Under the conditions of this study, no effects of TGase could be observed on breads from oat, sorghum or teff. Overall, the results of this study show that TGase can be successfully applied to gluten-free flours to improve their breadmaking potentials by promoting network formation. However, the protein source is a key element determining the impact of the enzyme. 相似文献
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本文运用扫描电镜(KYKY—1000B)对室内配制的黄土状粉土液化的微结构分析表明:粘粒含量为9%的粉土微结构为支架式胶结,在力的作用下,抗液化能力最差。其原因为以支架接触式胶结粉粒的粘土颗粒所起的“润滑作用”所致。此理论为今后进一步研究粉土液化机理提供了重要依据。 相似文献