Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh va » hang va, hanh vi
hanh ve » hanh vi, hanh kem
cac duc » cac du, cao duc, cac dac
vu sach » vu bach, vu khach
hieu ve » hieu va, hieu van
su sach » so sach
hanh x » hanh xu, hanh _, hanh y
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) OR (su sach)) thuc hanh x hoi. hieu ve cac duc va ((hanh ve) or (hanh va)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (su sach)) thuc hanh x hoi. hieu ve cac duc va ((hanh ve) OR (hanh va)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) OR (su sach)) thuc hanh x hoi. hieu ve cac duc va ((hanh ve) or (hanh va)) cau tren".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) OR (su sach)) thuc hanh x hoi. hieu ve cac duc va ((hanh ve) or (hanh va)) cau tren*.