全文获取类型
收费全文 | 2095篇 |
免费 | 79篇 |
国内免费 | 149篇 |
专业分类
林业 | 96篇 |
农学 | 101篇 |
基础科学 | 48篇 |
110篇 | |
综合类 | 807篇 |
农作物 | 145篇 |
水产渔业 | 139篇 |
畜牧兽医 | 692篇 |
园艺 | 139篇 |
植物保护 | 46篇 |
出版年
2024年 | 6篇 |
2023年 | 28篇 |
2022年 | 65篇 |
2021年 | 88篇 |
2020年 | 75篇 |
2019年 | 75篇 |
2018年 | 46篇 |
2017年 | 86篇 |
2016年 | 98篇 |
2015年 | 91篇 |
2014年 | 126篇 |
2013年 | 114篇 |
2012年 | 173篇 |
2011年 | 181篇 |
2010年 | 154篇 |
2009年 | 172篇 |
2008年 | 122篇 |
2007年 | 142篇 |
2006年 | 118篇 |
2005年 | 77篇 |
2004年 | 53篇 |
2003年 | 32篇 |
2002年 | 38篇 |
2001年 | 30篇 |
2000年 | 17篇 |
1999年 | 25篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 9篇 |
1995年 | 11篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2323条查询结果,搜索用时 0 毫秒
241.
大豆肽是大豆蛋白质的水解产物,主要功能性营养物质包括多肽、寡肽、游离氨基酸和糖类,其相对分子质量低,易于消化吸收。丰富的小肽能调节矿物质、脂类代谢,降低胆固醇,提高免疫力。文章综述了大豆肽的生理功能和制备工艺。 相似文献
242.
小红豆淀粉颗粒性质研究 总被引:1,自引:0,他引:1
[目的]为小红豆淀粉资源的开发提供理论依据。[方法]研究了小红豆淀粉的颗粒性质,包括颗粒的形貌、X光-衍射图样、溶解度与膨胀度,链淀粉含量、葡聚糖结构等,并与大红豆及荷包豆淀粉进行了对比。[结果]小红豆淀粉颗粒多为卵圆形,少数不规则,溶解度与膨胀度随温度变化程度不大,总体趋势平缓上升,X光-衍射呈现A型晶体图样,结晶度为18.01%,相对链淀粉含量为36.5%。[结论]该研究对于开发食用豆类淀粉资源具有启发作用。 相似文献
243.
银杏GGPPS转运肽与GFP融合基因表达载体的构建(摘要) 总被引:1,自引:0,他引:1
[目的]构建银杏GGPPS转运肽与GFP融合基因表达载体。[方法]以银杏为材料,采用DNA重组技术克隆GGPPS基因质体转运肽(TP)序列,并将其与高效植物表达载体p1304+连接形成融合表达载体(p1304+-TP);冻融法转化根瘤农杆菌EHA105,构建工程菌(EHA105-p1304+-TP)。[结果]成功构建了银杏GGPPS转运肽与GFP融合基因表达载体及农杆菌工程菌。[结论]为进一步研究TP转运肽的亚细胞定位奠定基础,有助于阐明银杏内酯前体生物合成关键步骤的分子机理,同时为银杏内酯的代谢工程研究提供重要依据。 相似文献
244.
本文通过最新考古成果——澧县《澧阳平原原始社会遗址群》及《城头山文化遗址》的综合剖析,粗略论述了澧阳平原一万年的文明起步与城头山六千年古文化的演进,同时也考证了"澧县小叶"野茶漫长的进化起源与发展,提出了发掘、弘扬中国茶史的紧迫性和使命感。 相似文献
245.
246.
本文证明培育牛黄对乙酰胆硷与氯化钡所引起的小白鼠离体小肠痉挛有解痉作用。培育牛黄的成份中去氧胆酸具有较强的抗乙酰胆硷与氯化钡作用,其浓度与效应呈直线相关。其成分中的胆酸仅有较弱的抗乙酰胆硷作用,且浓度与效应不呈直线相关,也无抗氯化钡作用。 相似文献
247.
248.
Roberta Teta Elena Irollo Gerardo Della Sala Giuseppe Pirozzi Alfonso Mangoni Valeria Costantino 《Marine drugs》2013,11(11):4451-4463
An in-depth study of the secondary metabolites contained in the Caribbean sponge Smenospongia aurea led to the isolation of smenamide A (1) and B (2), hybrid peptide/polyketide compounds containing a dolapyrrolidinone unit. Their structures were elucidated using high-resolution ESI-MS/MS and homo- and heteronuclear 2D NMR experiments. Structures of smenamides suggested that they are products of the cyanobacterial metabolism, and 16S rRNA metagenomic analysis detected Synechococcus spongiarum as the only cyanobacterium present in S. aurea. Smenamides showed potent cytotoxic activity at nanomolar levels on lung cancer Calu-1 cells, which for compound 1 is exerted through a clear pro-apoptotic mechanism. This makes smenamides promising leads for antitumor drug design. 相似文献
249.
Bin Wang Yu-Mei Wang Chang-Feng Chi Hong-Yu Luo Shang-Gui Deng Jian-Yin Ma 《Marine drugs》2013,11(11):4641-4661
Acid soluble collagen (ASC) from scales of croceine croaker (ASC-C) was successfully isolated with the yield of 0.37% ± 0.08% (dry weight basis), and characterized as type I collagen on the basis of amino acid analysis and electrophoretic pattern. The antioxidant hydrolysate of ASC-C (ACH) was prepared through a two-stage in vitro digestion (4-h trypsin followed by 4-h pepsin), and three antioxidant peptides (ACH-P1, ACH-P2, and ACH-P3) were further isolated from ACH using ultrafiltration, gel chromatography, and RP-HPLC, and their amino acid sequences were identified as GFRGTIGLVG (ACH-P1), GPAGPAG (ACH-P2), and GFPSG (ACH-P3). ACH-P1, ACH-P2, and ACH-P3 showed good scavenging activities on hydroxyl radical (IC50 0.293, 0.240, and 0.107 mg/mL, respectively), DPPH radical (IC50 1.271, 0.675, and 0.283 mg/mL, respectively), superoxide radical (IC50 0.463, 0.099, and 0.151 mg/mL, respectively), and ABTS radical (IC50 0.421, 0.309, and 0.210 mg/mL, respectively). ACH-P3 was also effectively against lipid peroxidation in the model system. The antioxidant activities of three collagen peptides were due to the presence of hydrophobic amino acid residues within the peptide sequences. The collagen peptides might be used as antioxidant for the therapy of diseases associated with oxidative stress, or reducing oxidative changes during storage. 相似文献
250.
Costas E. Stathopoulos Amalia A. Tsiami Bodgan J. Dobraszczyk J. David Schofield 《Journal of Cereal Science》2006,43(3):322-330
Flours from wheat varieties of differing bread-making quality were fractionated using a sequential salt precipitation technique. The gluten fractions in the different varieties varied in the proportion of HMW, LMW glutenins and gliadins. Their rheological behaviour was examined using constant strain (2%) small deformation oscillation tests over frequencies ranging from 0.005 to 10 Hz, before and after heating at 90 °C. The fractions containing a higher proportion of HMW glutenins were associated with a predominantly elastic character, whereas fractions containing mostly gliadins exhibited a viscous-like behaviour. The frequency dependent rheological behaviour of fractions containing HMW proteins was less susceptible to heat, and their elastic character was maintained after heating, whereas the rheology of intermediate fractions and fractions containing mostly gliadins was more susceptible to heating, indicating a rapid change from viscous to elastic behaviour after heating. 相似文献