Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
nang mai » nang ma, nang tai, lang mai
dinh dai » dinh dat, sinh dai, dinh dao
tham tuc » tham thuc, thai tuc, nham thuc
doc sach » hoc sach, nuoc sach, dac sac
ty nang » ky nang, ty xang, ty hang
mai hoi » mai khoi, dai hoi, lai hoi
va tham » van tham, va cham, va thanh
va dinh » van dinh, va kinh, va tinh
cua tre » cuu tre, cua triet, dua tren
tuc va » thuc va, truc va, tuc xa
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (doc sach)) ty nang mai hoi. lieu va tham tuc va dinh dai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ty nang mai hoi. lieu va tham tuc va dinh dai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ty nang mai hoi. lieu va tham tuc va dinh dai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ty nang mai hoi. lieu va tham tuc va dinh dai ((cua tre) OR (cua te))*.