Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hanh ca » hanh cac, hanh cat, hanh cua
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
cuu tre » cua tre, cau tren, cau treo
ma hoi » mai hoi, xa hoi, ma hoa
ca cuu » cap cuu, cua cuu, 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) OR (ty hang)) ma hoi. hieu va ((tac tu) or (cac du)) va hanh ca cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty hang)) ma hoi. hieu va ((tac tu) OR (cac du)) va hanh ca cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ty hang)) ma hoi. hieu va ((tac tu) or (cac du)) va hanh ca cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) OR (ty hang)) ma hoi. hieu va ((tac tu) or (cac du)) va hanh ca cuu tre*.