Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
than cua » thai cua, ban cua, gian cua
nhan cua » nhat cua, nhan luc, nhan su
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
van cac » van hac, van cau, van bac
va nang » van nang, da nang, cam nang
sac ky » cac ky, sai ky

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 xa hoi. hieu van cac nuoc va nang ((than cua) OR (nhan cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sach ky) OR (sac ky)) nang xa hoi. hieu van cac nuoc va nang ((than cua) OR (nhan cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat ((sach ky) or (sac ky)) nang xa hoi. hieu van cac nuoc va nang ((than cua) OR (nhan cua)) te".
• Adding a wildcard symbol may retrieve word variants: thuat ((sach ky) or (sac ky)) nang xa hoi. hieu van cac nuoc va nang ((than cua) OR (nhan cua)) te*.