Perhaps you should try some spelling variations:
thien van » thi van
hanh dai » hanh tai, hanh dao, vanh dai
thuc dan » thuc hanh, hoc dan, thuc vat
su sach » so sach, vu sach
van cac » van hac, van cau, van bac
y lang » _ lang, tay lang, yen lang
luc va » duc va, tuc va, loc va
o lang » hoa lang, hoi lang
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: su sach ((y lang) OR (o lang)) xa hoi. thien van cac ((luc va) or (thuc dan)) hanh dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y lang) OR (o lang)) xa hoi. thien van cac ((luc va) OR (thuc dan)) hanh dai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y lang) OR (o lang)) xa hoi. thien van cac ((luc va) or (thuc dan)) hanh dai cua te*".