Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
qua pham » quan pham, quy pham, qua cham
pham duy » pham duc
van hanh » van thanh, ban hanh, van anh
so sach » so sanh, bo sach, co sach
duy van » duy vat, dung van
vi cua » vai cua, di cua
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: so sach thu ((trong van) OR (trong cac)) hoi. hieu qua pham duy van hanh vi cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach thu ((trong van) OR (trong cac)) hoi. hieu qua pham duy van hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: so sach thu ((trong van) OR (trong cac)) hoi. hieu qua pham duy van hanh vi cua te*.