Perhaps you should try some spelling variations:
sach thuat » sach tham, dich thuat, cac thuat
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
va cam » va cham, va cac, va cao
luc va » tuc va, loc va
cua te » cua tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach thuat ((nang xa) OR (nang ma)) hoi. hieu va cam ((luc va) or (duc va)) hanh vai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach thuat ((nang xa) OR (nang ma)) hoi. hieu va cam ((luc va) OR (duc va)) hanh vai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach thuat ((nang xa) OR (nang ma)) hoi. hieu va cam ((luc va) or (duc va)) hanh vai cua te".
• Adding a wildcard symbol may retrieve word variants: toc sach thuat ((nang xa) OR (nang ma)) hoi. hieu va cam ((luc va) or (duc va)) hanh vai cua te*.