Perhaps you should try some spelling variations:
danh tai » doanh tai, dinh tai, hanh tai
thu sach » thuat sach, thuoc sach, thu hoach
sang mai » sang ma, sang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
tu sach » su sach, te sach, tu cach
hieu su » hieu sau, tieu su, hieu so
va danh » va dinh, va dan, va hanh
hieu vu » hieu va, hieu ve, dieu vu
ky sang » ky nang, ky dang, ky tang
soc va » hoc va, loc va, doc va
tai va » thai va, mai va, tri va
thiet » thieu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thu sach)) ky sang mai khoi. ((hieu vu) or (hieu su)) cham soc va danh tai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky sang mai khoi. ((hieu vu) OR (hieu su)) cham soc va danh tai va thiet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky sang mai khoi. ((hieu vu) or (hieu su)) cham soc va danh tai va thiet*.