Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam duoc » nam thuoc, da duoc, dat duoc
va thanh » gia thanh, ban thanh, va tinh
sach ky » sach y, sach ty, sach kem
duoc va » nuoc va, duc va, duoc ma
vai cua » dai cua, hai cua, bai cua
lai cua » dai cua, hai cua, lai chau
sac ky » cac ky, sai ky
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: tu ((sach ky) or (sac ky)) nang x hoi. hieu van nam duoc va thanh ((vai cua) OR (lai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang x hoi. hieu van nam duoc va thanh ((vai cua) OR (lai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sac ky)) nang x hoi. hieu van nam duoc va thanh ((vai cua) OR (lai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) nang x hoi. hieu van nam duoc va thanh ((vai cua) OR (lai cua)) tre*.