Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
vu nang » vuc nang, va nang, vu dang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
hau duc » huu duc, ha duc, pham duc
va dinh » van dinh, va kinh, va tinh
va hau » van hau, va chau, vat hau
di su » doi su, da su, de su
ki su » ky su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (thuoc sach)) vu nang xa hoi. hieu va hau duc va dinh ((di su) or (ki su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) vu nang xa hoi. hieu va hau duc va dinh ((di su) OR (ki su)) triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuoc sach)) vu nang xa hoi. hieu va hau duc va dinh ((di su) or (ki su)) triet*".