Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
lang hai » lang chai, lang thai, lang ha
hai khoi » mai khoi, tai khoi, thai khoa
hieu van » hieu va, thien van, lieu va
cham luc » nhan luc, cham cuu, chat lua
hanh tai » thanh tai, hang tai, han tai
va hanh » van hanh, va thanh, va danh
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

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 hai khoi. hieu van ((cham luc) OR (cham soc)) va hanh tai ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky lang hai khoi. hieu van ((cham luc) OR (cham soc)) va hanh tai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky lang hai khoi. hieu van ((cham luc) OR (cham soc)) va hanh tai ((cuu tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky lang hai khoi. hieu van ((cham luc) OR (cham soc)) va hanh tai ((cuu tre) or (cau tren))*.