Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang co » nang cao, nang doc, nang noi
nang ra » nang ma, lang ra, nang ro
qua cac » cua cac
cac tru » ca tru, cac tro, cac thu
va hanh » van hanh, va thanh, va danh
tru va » truc va, tu va, trung va
vi cua » vai cua, di cua
cua su » qua su

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 ky ((nang co) or (nang ra)) hoi. hieu qua cac tru va hanh vi cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang co) OR (nang ra)) hoi. hieu qua cac tru va hanh vi cua su.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang co) or (nang ra)) hoi. hieu qua cac tru va hanh vi cua su*.