Perhaps you should try some spelling variations:
trinh le » trinh ly, thinh le, trinh he
va trinh » van trinh, va tinh, lap trinh
vu sach » vu bach, su sach, vu khach
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hang ca » nang cao, hang tai, hang dau
so sanh » do sanh
le cua » ly cua

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 (so sanh)) thieu ((hang ca) OR (hang va)) hoi. hieu va cac duc va trinh le cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (so sanh)) thieu ((hang ca) OR (hang va)) hoi. hieu va cac duc va trinh le cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) or (so sanh)) thieu ((hang ca) OR (hang va)) hoi. hieu va cac duc va trinh le cua tre*".