Fluoride injury often is characterized by tip burn of leaves .
氟化物危害的特点是叶片顶尖灼燃现象。
Fluoride injury often is characterized by tip burn of leaves.
氟化物危害的特点是叶片顶尖灼燃现象。
The invention relates to a pen core, which comprises a core pipe with a pen tip. The pen core is characterized in that the pen tip is connected to the pen core through screw threads.
本发明的笔芯，包括带有笔尖的芯管，其特殊之处在于：笔尖通过螺纹连接在笔芯上。
The invention relates to a pen core, which comprises a core pipe with a pen tip. The pen core is characterized in that the pen tip is connected to the pen core through screw threads.
本发明的笔芯，包括带有笔尖的芯管，其特殊之处在于：笔尖通过螺纹连接在笔芯上。
应用推荐