全文获取类型
收费全文 | 1840篇 |
免费 | 116篇 |
国内免费 | 315篇 |
专业分类
林业 | 72篇 |
农学 | 321篇 |
基础科学 | 36篇 |
232篇 | |
综合类 | 883篇 |
农作物 | 429篇 |
水产渔业 | 73篇 |
畜牧兽医 | 160篇 |
园艺 | 39篇 |
植物保护 | 26篇 |
出版年
2024年 | 7篇 |
2023年 | 17篇 |
2022年 | 55篇 |
2021年 | 64篇 |
2020年 | 72篇 |
2019年 | 85篇 |
2018年 | 49篇 |
2017年 | 103篇 |
2016年 | 94篇 |
2015年 | 88篇 |
2014年 | 92篇 |
2013年 | 120篇 |
2012年 | 133篇 |
2011年 | 158篇 |
2010年 | 136篇 |
2009年 | 153篇 |
2008年 | 113篇 |
2007年 | 109篇 |
2006年 | 99篇 |
2005年 | 91篇 |
2004年 | 58篇 |
2003年 | 44篇 |
2002年 | 38篇 |
2001年 | 41篇 |
2000年 | 32篇 |
1999年 | 22篇 |
1998年 | 29篇 |
1997年 | 35篇 |
1996年 | 23篇 |
1995年 | 21篇 |
1994年 | 15篇 |
1993年 | 9篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 3篇 |
排序方式: 共有2271条查询结果,搜索用时 312 毫秒
991.
孜然鹅肉火腿肠的研制 总被引:1,自引:1,他引:0
根据鹅肉的特点,加入环状糊精以除去鹅肉的腥味,用改性淀粉改善火腿肠的品质,在鹅肉中加入孜然,经斩拌、灌制、煮制,制成具有孜然风味的鹅肉火腿肠。 相似文献
992.
蔗糖和谷氨酰胺及植物激素对水稻离体培养穗淀粉积累的影响 总被引:11,自引:0,他引:11
采用离体穗培养技术研究了蔗糖、谷氨酰胺和不同植物激素对杂交稻组合汕优10号、KA/2469穗培4~6d籽粒的溶液、蔗糖吸收,以及籽粒淀粉积累和淀粉合成的酶活性的 影响。在5~15g/L蔗糖浓度范围内,随着培养液中蔗糖浓度的提高,籽粒吸收溶液、蔗糖的量及淀粉积累、蔗糖合成酶、ADPG焦磷酸化酶、淀粉合成的酶有促进作用,其余3种植物激素对离体穗培籽粒吸收溶液和蔗糖及淀粉合成的酶活笥有负效应。本研究认为, 相似文献
993.
A standard method for determining apparent amylose content was modified for use with samples of 2–3 cereal seeds. Starch was extracted by soaking the seeds overnight in dilute ammonia solution, grinding in NaCl solution in a microfuge tube with an appropriate pestle and decanting the starch slurry. The starch was then washed successively in acetic acid, ethanol and acetone. The amylose content was determined by dispersing 5·0 mg of the starch in ethanol, adding NaOH solution, heating until a clear gel was formed, diluting, neutralising with citric acid, staining with iodine and reading in a spectrophotometer at 620 nm. The method provided a very strong correlation with a standard method for much larger samples. The apparent amylose content was determined for 1083 accessions of Triticum monococcum (einkorn), T. turgidum (emmer), T. tauschii and Secale cereale (rye). The 10 extreme accessions of each species were re-analysed a further three times and the two most extreme individual lines were selected for genetic studies. Apparent amylose content of T. monococcum ranged from 15 to 28%; that of T. turgidum, 19–31%; T. tauschii, 21–34%; and rye 12–28%. These ranges are considered sufficiently broad to allow amylose content to be further diversified through breeding. 相似文献
994.
以3对卷叶近等基因系杂交组合为研究对象,设置两种施肥水平处理,研究Rl(t)卷叶基因对杂交稻稻米品质性状的影响。在正常肥力水平下,卷叶组合的精米率显著或极显著高于其对应组合,整精米率高于其对应组合,垩白率和垩白度均低于其对应组合。稻米淀粉RVA谱特征值中,卷叶组合的最高粘度、热浆粘度和崩解值均大于其对应组合,其他性状指标值在对应组合间的差异表现趋势不一致。增施穗肥,除汕优63外,各组合的糙米率、精米率和整精米率都有提高的趋势,各组合最高粘度、热浆粘度和崩解值均降低,消减值均增大,其他性状指标值变化趋势因组合而异。增施穗肥,卷叶组合的精米率和整精米率都高于其对应组合,其中卷叶汕优559与汕优559的整精米率差异达显著水平,其他性状指标值在对应组合间的差异没有明显的规律性,说明Rl(t)基因在一定条件下有利于提高稻米品质。 相似文献
995.
复合变性淀粉制备淀粉基异氰酸酯胶黏剂的研究 总被引:4,自引:0,他引:4
研究了复合变性玉米淀粉制备Ⅰ、Ⅱ型淀粉基水性高分子-异氰酸酯(API)胶黏剂的工艺.选择复合变性淀粉乳液、二元酸、聚乙烯醇、多异氰酸酯的用量作为影响因素,以压缩、拉伸剪切强度为评价目标,通过正交试验优化出满足日本JISK 6806-1995指标要求的Ⅰ、Ⅱ型淀粉基API胶黏剂的配方,对影响胶黏剂理化性能的因素进行了系统分析.验证实验证明,所优化出的最佳配方具有明显的生产可操作性,交联剂多异氰酸酯可不经封闭直接使用,完全能够满足现有的木材胶合制品生产工艺的要求. 相似文献
996.
Relationships between seed protein, lipid, starch and sugar concentrations and seed yield of 14 pea (Pisum sativum L.) cultivars were examined under rain-fed conditions in northern Jordan. Significant differences amongst cultivars for each character were noted. The cultivar-by-environment interaction was significant for each character except lipid and starch concentrations. A negative correlation was noted between seed yield and seed protein and fructose concentrations. Positive non-significant correlations between seed yield and seed lipid and starch concentrations were noted. The cultivars DMR-8, P 350-1 and 88P022-6 had similar seed yields, but varied seed chemical components. Seeds of the Praire No. 11 cultivar had the highest protein concentration amongst cultivars, although it produced the lowest seed yield. These results indicate that factors other than seed yield are important for determining the chemical composition of seeds, and that one-sided selection for high seed yield tends to reduce the nutritional quality of the pea seed. 相似文献
997.
998.
分别以普通玉米淀粉和海藻酸钠-普通玉米淀粉为研究对象,采用动态流变仪、差示扫描量热仪和红外光谱分析仪等,探讨了3种不同循环湿热处理方式对普通玉米淀粉(Normal Corn Starch,NCS)和海藻酸钠-普通玉米淀粉(Sodium Alginate-Normal Corn Starch,AG-NCS)流变性质、老化性质及结构的影响.结果表明,3种循环湿热处理均有利于AG-NCS黏弹性凝胶的形成,表现为tanδ减小.经过3种循环湿热处理,AG-NCS的增稠性减弱,表现为稠度系数k减小.老化性质表明,3种循环湿热处理能够抑制AG-NCS的短期回生,而只有经过25 ℃和4 ℃放置后再次进行湿热处理能够抑制AG-NCS的长期回生.经过3种循环湿热处理,AG-NCS中的结晶结构增加,表现在1047/1022 cm-1的比值增大;AG-NCS分子内、分子间水合羟基数增多,表现为AG-NCS的O-H伸缩振动峰、O-H弯曲振动峰波数降低. 相似文献
999.
Comparison of Starch Granule Size Distribution Between Hard and Soft Wheat Cultivars in Eastern China 总被引:1,自引:0,他引:1
LI Wen-yang YAN Su-hui YIN Yan-ping LI Yong LIANG Tai-bo GU Feng DAI Zhong-min WANG Zhen-lin 《中国农业科学(英文版)》2008,7(8):907-914
Granule size distribution of wheat starch is an important characteristic that can affect its chemical composition and functionality. Two types of wheat cultivars, the hard and soft wheat cultivars, grown at Tai'an Experimental Station of Shandong Agricultural University, Taian, Shandong, China, were examined in this study. The granule size distribution and amylose contents in wheat grains were studied and compared, and relationships between the properties were identified. A clear bimodal distribution of granule size was shown in all wheat cultivars. Volume distribution of starch granules shows the typical bimodal with peak values in the ranges of 5.6-6.1μm and 20.7-24.9μm, respectively. Also, granule surface area distribution was bimodal with peak values in the ranges of 2.4-3.2μm and 20.7-24.9μm, respectively. Number distribution of granules was a typical population with a peak value in the range of 0.54-1.05μm. Contributions from the granules 〈 2.8μm and 〈 9.9μm to the total volume were in the ranges of 94.2-95.1% and 99.7-99.9% of total number, respectively. Proportions of granules〈2.8μm, 2.8-9.9μm, 9.9-22.8μm, and 22.8-42.8μm were in the ranges of 12.9-14.3%, 28.4-31.1%, 33.5-35.6%, and 19.7-22.7% for hard wheat, and 10.3-13.9%, 26.6-28.1%, 32.7-34.6%, and 24.2-27% for soft wheat. Hard wheat had greater B-type granules ( 〈 9.9μm), and had fewer granules of 22.8-42.8μm than soft wheat. Amylose content was positively related to volume percentage of granules 22.8-42.8μm, and negatively related to volume percentage of granules 2.8-22.8μm. 相似文献
1000.
禾谷类作物胚乳淀粉的生物合成 总被引:6,自引:0,他引:6
综述了禾谷类作物胚乳淀粉合成生化过程的近期研究进展,对淀粉合成关键酶的生理和分子生物学研究现状做了重点介绍。 相似文献