Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh tai » thanh tai, hang tai, han tai
dat tren » dat trong, dua tren
lang mai » lang dai, lang hai, lang man
mai khoi » mai khoa, tai khoa, cac khoi
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
cham duc » pham duc, cham soc, pham duy
cuu tre » cua tre, cau treo
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
va hanh » van hanh, va thanh, va danh

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 ky lang mai khoi. hieu van cham duc va hanh tai ((cuu tre) or (((dat tren) or (cau tren))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang mai khoi. hieu van cham duc va hanh tai ((cuu tre) OR (((dat tren) OR (cau tren)))).
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang mai khoi. hieu van cham duc va hanh tai ((cuu tre) or (((dat tren) or (cau tren))))*.