Perhaps you should try some spelling variations:
nang mai » nang ma, nang tai, lang mai
cham loc » cham soc, chon loc, hau loc
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
sach ty » sach y, sach tu, sach thu
hieu ve » hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
cham o » cham soc
va cua » va chua, via cua, ca 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 ty nang mai hoi. ((hieu ve) OR (hieu va)) ((cham loc) or (cham o)) va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang mai hoi. ((hieu ve) OR (hieu va)) ((cham loc) OR (cham o)) va hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang mai hoi. ((hieu ve) OR (hieu va)) ((cham loc) or (cham o)) va hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang mai hoi. ((hieu ve) OR (hieu va)) ((cham loc) or (cham o)) va hanh va cua tre*.