Perhaps you should try some spelling variations:
cai tren » cai tien, ca tren, cau tren
sach ky » sac ky, sach y, sach ty
hanh ve » hanh vi, hanh va, hanh kem
va hanh » van hanh, va thanh, va danh
ve caic » ve cac
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
ve caim » ve chim
ve cai » va cai, ve cac, ve tai

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 ((nang ma) or (nang x)) hoi. hieu ((ve caim) or (ve caic)) duc va hanh ve cai tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (nang x)) hoi. hieu ((ve caim) OR (ve caic)) duc va hanh ve cai tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) or (nang x)) hoi. hieu ((ve caim) or (ve caic)) duc va hanh ve cai tren*.