全文获取类型
收费全文 | 1197篇 |
免费 | 49篇 |
国内免费 | 133篇 |
专业分类
林业 | 38篇 |
农学 | 116篇 |
基础科学 | 10篇 |
155篇 | |
综合类 | 480篇 |
农作物 | 120篇 |
水产渔业 | 117篇 |
畜牧兽医 | 255篇 |
园艺 | 39篇 |
植物保护 | 49篇 |
出版年
2024年 | 4篇 |
2023年 | 12篇 |
2022年 | 21篇 |
2021年 | 26篇 |
2020年 | 35篇 |
2019年 | 32篇 |
2018年 | 26篇 |
2017年 | 40篇 |
2016年 | 48篇 |
2015年 | 45篇 |
2014年 | 64篇 |
2013年 | 69篇 |
2012年 | 104篇 |
2011年 | 82篇 |
2010年 | 81篇 |
2009年 | 78篇 |
2008年 | 74篇 |
2007年 | 96篇 |
2006年 | 57篇 |
2005年 | 49篇 |
2004年 | 43篇 |
2003年 | 27篇 |
2002年 | 14篇 |
2001年 | 27篇 |
2000年 | 31篇 |
1999年 | 15篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有1379条查询结果,搜索用时 15 毫秒
101.
本文通过水溶大豆粉凝固性试验对几种不同NSI值大豆粉凝胶形成性,以考察不同工艺生产的大豆食品中物理添加特性,证明了不同剂量高频处理工艺生产不同NSI值大豆粉凝胶形成性情况。同时证明只有NSI值>50%时,具有良好的凝胶性。 相似文献
102.
103.
从人工接种感染黄矮病毒(Rice Yellow Stunt Virus,RYSV)的水稻茎杆中提取得到了部分纯化的RYSV制品,病毒制品经Tricine-SDS-PAGE得到分子量分别为84 kD,60 kD,31 kD和29.5 kD的4条主要蛋白带和分子量为170kD和43kD的两条次要蛋白带。根据弹状病毒结构蛋白命名法,按分子量大小依次命名为L,G,N,NS,M_1和M_2蛋白。从电泳凝胶上切下G和N蛋白带,制成抗原免疫BALB/C小鼠;制得G和N蛋白小鼠腹水抗体。经Dot-blot试验测得N蛋白抗体效价为1:1000,G蛋白抗体效价为1:400。 相似文献
104.
褐藻酸钠涂膜剂的特性研究 总被引:9,自引:1,他引:9
对褐藻酸钠凝胶经冻结和解冻处理后的持水能力、凝胶强度、弹性、韧性及状态变化等特性进行了比较试验。结果表明;褐藻酸钠凝胶的这些性质与凝胶体内的钠和钙的比率直接相关;采用2%的褐藻酸钠溶液与5%的氯化钙溶液凝胶化2min,所形成的凝胶具有很好的涂膜性能。 相似文献
105.
不同凝胶电泳对玉米自交系DNA多态检测的影响 总被引:1,自引:0,他引:1
利用10个SSR(简单序列重复)引物对,对10个玉米自交系进行同源位点扩增,用琼脂糖凝胶及聚丙烯酰胺凝胶两种电泳方法分离,检测其DNA多态性。结果表明,其间的多态性检测结果差异较大。聚丙烯酰胺凝胶电泳较琼脂糖凝胶电泳能检出更多的等位基因位点,多态信息含量值亦较高,自交系间遗传相似系数的变幅小于琼脂糖凝胶检测中的相应值。聚丙烯酰胺凝胶电泳的分辨率高于琼脂糖凝胶电泳,对自交系的系统聚类更为准确、可靠,更能真实地反映自交系间的系谱关系。 相似文献
106.
醇溶蛋白酸性电泳及其在种质资源分析中的应用 总被引:5,自引:0,他引:5
建立了 1个新的醇溶蛋白酸性电泳方法 ,并用此方法对不同倍性小麦品种及黑麦、小黑麦品种的醇溶蛋白组成进行了分析。结果表明 ,此方法不仅适用于小麦醇溶蛋白分析 ,而且也适用于黑麦和小黑麦种质资源分析 相似文献
107.
Tuberization is a complex and multilevel developmental process. Many important metabolic changes in the early stage of tuberization are crucial to the tuber differentiation and development. In this study, we attempted to identify proteins differentially expressed in the early stage of in vitro tuberization in taro (Colocasia esculenta var. antiquorum) by two-dimensional polyacrylamide gel electrophoresis (2-DE) and mass spectrometry (MS). Protein samples from shoot tips cultured in 8% sucrose media at 0, 2, 4, 6 and 8 d were separated with 2-DE. A total of 13 differentially expressed proteins were analyzed with MS. Four proteins via, glyceraldehyde-3-phosphate dehydrogenase, alcohol dehydrogenase, chloroplast protein synthesis elongation factor (EF-Tu), and ankyrin repeat protein HBP1 were successfully identified during in vitro tuberization of taro. This implies that important metabolic changes, including sucrose metabolism, signal transduction and cell defense, occurred in the early stage of in vitro tuberization in taro. 相似文献
108.
Ji Hyung Kim Sun Young Hwang Jee Soo Son Jee Eun Han Jin Woo Jun Sang Phil Shin Casiano Choresca Jr Yun Jaie Choi Yong Ho Park Se Chang Park 《Journal of veterinary science (Suw?n-si, Korea)》2011,12(1):41-48
The antibiotic resistance of 16 Aeromonas (A.) salmonicida strains isolated from diseased fish and environmental samples in Korea from 2006 to 2009 were investigated in this study. Tetracycline or quinolone resistance was observed in eight and 16 of the isolates, respectively, based on the measured minimal inhibitory concentrations. Among the tetracycline-resistant strains, seven of the isolates harbored tetA gene and one isolate harbored tetE gene. Additionally, quinolone-resistance determining regions (QRDRs) consisting of the gyrA and parC genes were amplified and sequenced. Among the quinolone-resistant A. salmonicida strains, 15 harbored point mutations in the gyrA codon 83 which were responsible for the corresponding amino acid substitutions of Ser83→Arg83 or Ser83→Asn83. We detected no point mutations in other QRDRs, such as gyrA codons 87 and 92, and parC codons 80 and 84. Genetic similarity was assessed via pulsed-field gel electrophoresis, and the results indicated high clonality among the Korean antibiotic-resistant strains of A. salmonicida. 相似文献
109.
Yoo-Jeong?Yang Robert?S.?Dungan A.?Mark?Ibekwe Cesar?Valenzuela-Solano David?M.?Crohn David?E.?CrowleyEmail author 《Biology and Fertility of Soils》2003,38(5):273-281
The application of organic mulches as a soil cover is effective in improving the quality of soil. However, very little information is available on the effect of mulches on the soil microbial community. In this study, we investigated the effect of various organic mulches on soil dehydrogenase activity (DHA) and microbial community structures in the top 1 cm and 5 cm below the soil surface 1 year after application of the mulches. DHA was stimulated at both depths in plots mulched with grass clippings (GC), but was not significantly different from the control for the other mulch treatments. Fatty acid methyl ester (FAME) analysis and denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction-amplified 16S rDNA fragments were used to assess changes in the soil microbial community structure. Cluster analysis and principle component analysis of FAME profiles showed that only soil mulched with pine chips distinctively clustered from the other treatments. At the soil surface, bacterial DGGE profiles revealed that distinct shifts in several bacterial populations occurred in soils mulched with GC and eucalyptus yardwaste (EY), while DGGE profiles from soil at the 5 cm depth revealed no distinct changes. Changes in bacterial diversity at the soil surface under different mulches were calculated based on the number of bands in the DGGE profile using the Shannon-Weaver index of diversity ( H). Compared to the control ( H =0.9), the GC- and EY-treated soils showed slightly increased bacterial diversity, with an H of 1.1 and 1.0, respectively. These results indicate that the long-term effect of organic mulches on the soil microbial activity and community structure is highly dependent upon the type of mulch and is mostly exerted in the top few centimeters of the soil profile. 相似文献
110.
羧甲基纤维素凝胶对乙草胺的控制释放研究 总被引:3,自引:0,他引:3
羧甲基纤维素(CMC)经Fe3 交联得到的凝胶载体可以有效延缓除草剂乙草胺的释放速率,有助于减轻农药污染.采用50%乙草胺被释放所需时间(t50)衡量乙草胺的释放速率,结果表明乙草胺由水凝胶中释放的t50值不足8h.将CMC水凝胶干燥处理可以使t50值提高到100h以上,同时制剂中的载药量越少释放速度越慢.采用控制释放模型对释放动力学数据进行分析得到,乙草胺从干凝胶中的释放主要由扩散机理控制.红外光谱分析证实了乙草胺与CMC之间主要通过氢键结合. 相似文献