maintain的名詞形式是什麼

maintainer例句：

Clinical application of positive pressure transparent space maintainer

壓膜式間隙保持器的臨床應用

We are a maintainer and builder of the international system.

我們是國際社會秩序的'維護者和建設者。

Male sterile line and maintainer line of S~ v type wheat

S~v型小麥雄性不育系及保持系的研究

A study on Breeding Corn Genetic Male Sterile Double Heterozygous Maintainer

玉米基因雄性不育雙雜合保持系的選育研究

You are the cause and the maintainer of the three worlds.

你是三個世界的原因和維繫者。