Perhaps you should try some spelling variations:
chet duoc » che duoc, cho duoc, che quoc
chat duc » chat xuc, chat doc, pham duc
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
tu sach » su sach, te sach, tu cach
nang xa » nang x, lang xa, nang ma
ly nang » ky nang, ly hang, ly vang
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de 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) or (thu sach)) ly nang xa hoi. hieu van ((chat duc) OR (chet duoc)) va hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ly nang xa hoi. hieu van ((chat duc) OR (chet duoc)) va hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ly nang xa hoi. hieu van ((chat duc) OR (chet duoc)) va hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ly nang xa hoi. hieu van ((chat duc) OR (chet duoc)) va hanh di cua tre*.