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81.
对深圳地区9种母质和6种土类构成的16个母质─土类单元共83个土壤样品中12种微量元素的含量进行侧定。在此基础上分析了微量元素含量分布的成因。研究结果表明,成土母质是影响土壤微量元素含量和分布的首要因素,相同母质上的不同类型土壤中的微量元素含量大多无明显差异。土壤中微量元素的共生组合关系表现出明显的母质继承性特征,由于微量元素主要以同晶替代方式分散在硅酸盐矿物中,其分布与离子半径关系密切。第四周期过渡元家具有相似的分布格局,而Pb、Zn、Cd等另成一类。 相似文献
82.
83.
GONG Yue-hua LIU Ying-zhou GAO Jun-feng 《中国农业科学(英文版)》2005,4(12):903-908
Using Matlab software, the grain filling process of hybrid wheat 901 and its parents was fitted by Richards equation W = A/(1 + Be^-kt in order to study the characteristics of grain filling of the hybrid. The active grain growth period of the hybrid was 6 d longer than that of Shaan 229, and its final grain weight (43.7 g/1 000 grains) was higher than that of Shaan229 (36.3 g/1 000 grains). N values of 901 and R205 were both less than 1, and their grain growth was faster in the early filling stage, while slower in the middle-late stage. N value of Shaan 229 was 〉1~ and its growth was slower in the early stage and faster in the middle stage. The period of early stage of 901 was shorter and of middle-late stage was longer. The situation of Shaan 229 was totally reversed. For parents, the father plant R205 was similar to hybrid wheat 901, whereas its mother plant K3314A similar to Shaan 229. It has been found that Richards equation was more suitable for fitting the grain filling process of wheat than Logistic equation. 相似文献
84.
85.
应用系统分类体系和数值分类方法对汉中盆地土壤进行研究表明,发育在不同母质和海拔高度的土壤,剖面形态、发生特性和成土过程均存在明显差异,应在土类以上的等级上区分开来:其中发育在粘黄土母质上的土壤为淋溶土纲、铁质湿润淋溶土土类;发育在基岩风化物母质上的土壤为富铁土纲、粘化湿润富铁土土类;分布在中山区暖温带湿润地区的土壤为淋溶土纲、简育湿润淋溶土土类。 相似文献
86.
小麦育种工作40年回顾Ⅱ.杂交育种的亲本选配和后代处理 总被引:2,自引:0,他引:2
根据已定育种目标,着眼近期,考虑长远的需要,采取不同亲本选配方式。后代处理中既要考虑遗传因素,还要考虑生态、生理因素影响 相似文献
87.
中国不同年代玉米亲本自交系的灌浆特性与氮素运转 总被引:1,自引:1,他引:0
大田试验条件下,选择我国1960s、1980s、2000s三个年代在生产中大面积应用的玉米亲本自交系为试验材料,比较分析了遗传改良过程中玉米骨干自交系灌浆特性及氮素运转的演变特征。结果表明,当代玉米品种及其亲本自交系的产量显著高于其他年代品系(P<0.05),且不同年代品种产量提高与其亲本产量密切相关(P<0.05),亲本自交系产量提高与其穗粒数相关性不显著,而与粒重呈显著正相关(P<0.05)。对粒重变化研究表明,当代亲本自交系的灌浆速率呈先慢后快的趋势,籽粒灌浆的积累起始势(R0)较高,灌浆最大速率出现时间(Tmax)延迟,灌浆速率最大时生长量(Wmax)和最大灌浆速率(Gmax)明显较高。当代亲本自交系具有较高的干物质积累和日增干重,其茎鞘物质输出率和茎鞘物质贡献率均高于1960s自交系,且在高密度条件下优势更为明显。当代亲本自交系具有较高的氮素积累总量(P<0.05),氮素输出率、贡献率的优势不明显(P>0.05),而氮素利用效率及氮收获指数显著高于1960s自交系(P<0.05)。表明遗传改良过程中玉米骨干自交系籽粒产量及氮效率得到同步提高,这与其自身较高的籽粒灌浆能力和物质运转效率密切相关。 相似文献
88.
Ten soil colloids were obtained from three kinds of Fe-rich (> 50 g kg− 1) subtropical soil parent materials (Basalt, Sandshale, and Quaternary Period Red Earth) collected in nine sites in Guangdong of China. Effect of the Fe-rich soil colloids and adding Fe(II) and oxalic acid on reductive dechlorination transformation of pentachlorophenol (PCP) were studied on colloids interfaces of reaction suspension. Mineralogical properties and specific surface area of the soil colloids were characterized by X-ray powder diffraction and Brunauer-Emmett-Teller (BET) methods, respectively. A series of reductive experiments were designed to determine PCP transformation and chloride ion release, and to calculate rate constant (k values) of pseudo first-order kinetics. Our results showed that reductive transformation of PCP occurred with k values from 0.007 to 0.057 d− 1, and relevant chloride was released in the suspension of the ten soil colloids. Soil colloid developed from Basalt presented higher transformation rates (0.040-0.057 d− 1) than that from Sandshale (0.007-0.033 d− 1) and Quaternary Period red earth (0.012 d− 1). Two paddy soil colloids developed from Sandshale (0.032-0.033 d− 1) were more active than other three Sandshale soil colloids (0.007-0.011 d− 1). The k values were significantly and positively correlated to the BET surface area (P < 0.01, n = 10). Addition of oxalic acid (0.022-0.231 d− 1) or Fe(II) (0.029-0.256 d− 1) into suspension of soil colloids gave arise to increase by 1.2-9.4 times in the k values. The release of chloride ion was simultaneously elevated. The enhancement of oxalic acid or Fe(II) on reductive transformation of PCP was attributed to increase of surface-bound Fe(II), which possess high reductive reactivity. The k values adding 1.0 mM oxalic acid were significantly and positively correlated to BET surface area and soil pH (P < 0.01), while k values adding 1.0 mM Fe(II) were related to total Fe (P < 0.001). The results may give new insight to understand the contribution of PCP abiotic reductive transformation in subtropical and tropical soils, and also in permeable reactive barriers. 相似文献
89.
Emre Babur 《Scandinavian Journal of Forest Research》2019,34(2):94-101
Afforestation is economically and ecologically important for protecting land and improving soil quality. This study evaluates how soil basal respiration, physicochemical and microbiological characteristics are affected by parent material variety in afforesting degraded areas. For this, some soil physical and chemical parameters, microbial respiration (MR), soil microbial biomass carbon and microbial indexes (Cmic/Corg and MR/Cmic) were determined. The results showed that the physical, chemical and microbiological properties of the soil formed from limestone were better than those of the basaltic-andesite soil. An independent samples t-test demonstrated that the afforested area on the limestone parent material had significantly higher microbial biomass C than the basaltic-andesite parent material. The microbial quotient (Cmic/Corg) of the limestone soil was positively affected by afforestation. In addition, the highest basal respiration value (1.01?±?0.33 CO2–C 10?2?µg?g?1?h?1) was observed for the limestone at the topsoil. The lowest metabolic quotient values were determined for the basaltic-andesite parent material on both topsoil and subsoil (1.99 and 1.42?μg CO2-C mg Cmic?1 h?1, respectively). This study revealed the importance of determining the parent material and its soil characteristics for successfully managing forest applications in degraded areas. Limestone soil sequesters more carbon and promotes microbial activities with a higher Cmic/Corg than the basaltic-andesite soil. Furthermore, the microbial quotient remained low during the 10 years in which the forest was in its sapling stage. 相似文献
90.