期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
“维普”中文科技期刊数据库的检索 被引量:1
1
作者 杜伟 王君 《云南图书馆》 1999年第1期47-49,共3页
结合“维普”中文科技期刊数据库的检索实践,介绍该数据库的检索方法,研究如何提高检索效率。
关键词 “维普”数据库 中文科技期刊 数据库检索 关键词 检索策略 后截词检索
下载PDF
Study on Direct Seeding Density of Brassica napus 被引量:1
2
作者 Jixian ZHAO Xianglai DAI Tingbo REN Guizhou 《Agricultural Science & Technology》 CAS 2017年第10期1860-1866,共7页
The statistical analysis of 97 literatures shows that there is a quadratic parabolic relationship between direct seeding density and yield of rape: Y = 2 213,058 9 + 14,556 9 X- 0.145 5 X2. The optimum density is 3.... The statistical analysis of 97 literatures shows that there is a quadratic parabolic relationship between direct seeding density and yield of rape: Y = 2 213,058 9 + 14,556 9 X- 0.145 5 X2. The optimum density is 3.413 × 10^5 - 5,001 × 10 ^5 plants/hm2. Compared with conventional rape, hybrid rape has higher yield (by 3.71%) and lower density (by 4,97%), To obtain a high yield, conventional rape (or lines) needs to be planted more densely compared with hybrid rape, 展开更多
关键词 VIP database Brassica napus Direct seeding DENSITY YIELD
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部