Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
cuu tre » cua tre, cau treo
hanh de » hanh ve, hanh kem
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
van cam » van nam, van lam, van cau

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 ty ((nang xa) or (lang xa)) hoi. hieu van cam duc van hanh de ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang xa) OR (lang xa)) hoi. hieu van cam duc van hanh de ((cuu tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang xa) or (lang xa)) hoi. hieu van cam duc van hanh de ((cuu tre) or (cau tren))*.