Perhaps you should try some spelling variations:
tu tieng » luc tieng, tu tuong, tu trong
hanh voi » hanh vi, hanh noi, hanh moi
dau truc » cau truc, dai truc, doan truc
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
nang xa » lang xa, nang ma, mang xa
tu tren » tu truyen, tu trong, dua tren
te sach » toc sach
va dau » va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky ((nang xa) or (nang x)) hoi. hieu va dau truc va hanh voi ((tu tren) OR (tu tieng))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((nang xa) OR (nang x)) hoi. hieu va dau truc va hanh voi ((tu tren) OR (tu tieng)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky ((nang xa) or (nang x)) hoi. hieu va dau truc va hanh voi ((tu tren) OR (tu tieng))".
• Adding a wildcard symbol may retrieve word variants: te sach ky ((nang xa) or (nang x)) hoi. hieu va dau truc va hanh voi ((tu tren) OR (tu tieng))*.