Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
cau luc » cau truc, cau phuc
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
ly hang » ly quang
ly nang » ky nang, ly vang, ly quang
luc va » duc va, tuc va, loc va
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ly nang) OR (ly hang)) ma hoa. ((hieu ve) or (hieu va)) cau luc va tinh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ly nang) OR (ly hang)) ma hoa. ((hieu ve) OR (hieu va)) cau luc va tinh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ly nang) OR (ly hang)) ma hoa. ((hieu ve) or (hieu va)) cau luc va tinh di cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ly nang) OR (ly hang)) ma hoa. ((hieu ve) or (hieu va)) cau luc va tinh di cua tre*.