Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
thanh di » thanh doi, thanh de, thanh do
sach ky » sach y, sach ty, sach kem
hieu va » lieu va, hieu qua
cao suc » cao su, cao duc
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat ((sach ky) OR (sac ky)) nang x hoi. hieu va ((cao suc) or (giao duc)) va thanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sach ky) OR (sac ky)) nang x hoi. hieu va ((cao suc) OR (giao duc)) va thanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat ((sach ky) OR (sac ky)) nang x hoi. hieu va ((cao suc) or (giao duc)) va thanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: thuat ((sach ky) OR (sac ky)) nang x hoi. hieu va ((cao suc) or (giao duc)) va thanh di cua tre*.