Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
sang thai » sang tai, sang than, dang thai
hieu van » thien van, lieu va, hieu ve
cac nuoc » cap nuoc, hoc nuoc, cua nuoc
thai cua » than cua, tai cuc, tri cua
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va sang » van sang, vua sang, va nang
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 ty nang xa hoi. ((hieu van) or (hieu va)) ((cac nuoc) or (dat nuoc)) va sang thai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ty nang xa hoi. ((hieu van) OR (hieu va)) ((cac nuoc) OR (dat nuoc)) va sang thai cua te.
• Adding a wildcard symbol may retrieve word variants: thuat sach ty nang xa hoi. ((hieu van) or (hieu va)) ((cac nuoc) or (dat nuoc)) va sang thai cua te*.