Perhaps you should try some spelling variations:
tham thuc » pham thuc, tam thuc, thai thuc
nham thuc » nhan thuc, nam thuc, nham thu
viet cua » viec cua, viet ca, viet qua
cua viet » ca viet, hoa viet, cua vat
doc sai » doc hai, do sai, doc sach
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu va » hieu qua
anh anh » thanh anh, hinh anh, minh anh
sai ky » sac ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sai ky lang xa hoi. ((hieu va) or (lieu va)) ((tham thuc) OR (nham thuc)) anh anh viet cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sai ky lang xa hoi. ((hieu va) OR (lieu va)) ((tham thuc) OR (nham thuc)) anh anh viet cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sai ky lang xa hoi. ((hieu va) or (lieu va)) ((tham thuc) OR (nham thuc)) anh anh viet cua viet".
• Adding a wildcard symbol may retrieve word variants: doc sai ky lang xa hoi. ((hieu va) or (lieu va)) ((tham thuc) OR (nham thuc)) anh anh viet cua viet*.