Perhaps you should try some spelling variations:
nang than » nang thanh, sang than, nang phan
hieu van » hieu va, thien van, lieu va
cac nuoc » cap nuoc, hoc nuoc, cua nuoc
than cua » nhan cua, thai cua, ban cua
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
va nang » van nang, da nang, cam nang
sac ky » cac ky, sai ky
cua te » cua tu

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) OR (dat nuoc)) va nang than 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) OR (dat nuoc)) va nang than 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) OR (dat nuoc)) va nang than cua te".
• Adding a wildcard symbol may retrieve word variants: thuat ((sach ky) or (sac ky)) nang xa hoi. hieu van ((cac nuoc) OR (dat nuoc)) va nang than cua te*.