Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
hanh di » hanh vi, hanh de, hang di
luc van » luoc van, luu van, duc van
cam luc » cam xuc, cau luc
qua cam » qua cham, qua cac, qua ca
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
di cua » dai cua, doi cua, de cua

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 x) or (((nang ma) OR (tang ma)))) hoi. hieu qua cam luc van hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang x) OR (((nang ma) OR (tang ma)))) hoi. hieu qua cam luc van hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((nang x) or (((nang ma) OR (tang ma)))) hoi. hieu qua cam luc van hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang x) or (((nang ma) OR (tang ma)))) hoi. hieu qua cam luc van hanh di cua tre*.