Perhaps you should try some spelling variations:
thuoc sach » nuoc sach, thuat sach, thuoc sinh
hoc sach » hoc sinh, hoc cac, hoc anh
hanh tai » thanh tai, hang tai, han tai
hieu van » hieu va, thien van, lieu va
cau loc » hau loc, cau hoc, cau luc
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
van cau » van dau, van hau, van chat
nang ma » tang ma, sang ma, nang cao
loc va » hoc va, luc va
ma hoi » mai hoi, xa hoi, ma hoa
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) OR (hoc sach)) ky nang ma hoi. hieu van cau loc va hanh tai ((cua tre) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (hoc sach)) ky nang ma hoi. hieu van cau loc va hanh tai ((cua tre) OR (cua tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) OR (hoc sach)) ky nang ma hoi. hieu van cau loc va hanh tai ((cua tre) or (cua tu))".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) OR (hoc sach)) ky nang ma hoi. hieu van cau loc va hanh tai ((cua tre) or (cua tu))*.