Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
cac tuc » cac toc, cac tu, cac tac
hang vi » hang va, hanh vi, khang voi
hang di » hang doi, hang dien, hang dich
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
tuc va » thuc va, truc va, tuc xa
y lang » _ lang, tay lang, yen lang
o lang » hoa lang, hoi lang
thiet* » thieu*

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 ((y lang) or (o lang)) xa hoi. hieu ve cac tuc va ((hang di) OR (hang vi)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y lang) OR (o lang)) xa hoi. hieu ve cac tuc va ((hang di) OR (hang vi)) va thiet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y lang) or (o lang)) xa hoi. hieu ve cac tuc va ((hang di) OR (hang vi)) va thiet*".