Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
thu sach » tu sach, thuat sach, thuoc sach
thanh di » thanh doi, thanh de, thanh do
cau tren » cu tren, dau tren, ca tren
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
x hoi » xa hoi, o hoi, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty nang ((x hoi) OR (x ho)). hieu va pham duc va thanh di ((cau tren) or (hoa viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang ((x hoi) OR (x ho)). hieu va pham duc va thanh di ((cau tren) OR (hoa viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang ((x hoi) OR (x ho)). hieu va pham duc va thanh di ((cau tren) or (hoa viet))".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang ((x hoi) OR (x ho)). hieu va pham duc va thanh di ((cau tren) or (hoa viet))*.