Perhaps you should try some spelling variations:
thu sac » thu sach, thu san, thu xac
hieu va » lieu va, hieu qua
cac tac » cac toc, cac bac, cac dac
va dinh » van dinh, va kinh, va tinh
sac ky » cac ky, sai ky
me hoi » le hoi
tac va » tac da, tac xa, tuc va
ca cuu » cua cuu, ca cua, ca cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sac ky nang ((me hoi) or (ma hoa)). hieu va cac tac va dinh ((ca cuu) or (cap cuu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sac ky nang ((me hoi) OR (ma hoa)). hieu va cac tac va dinh ((ca cuu) OR (cap cuu)) tre.
• Adding a wildcard symbol may retrieve word variants: thu sac ky nang ((me hoi) or (ma hoa)). hieu va cac tac va dinh ((ca cuu) or (cap cuu)) tre*.