Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thuc day » thuc dan, thuc vat
thuc va » thuc vat, thuc dan
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang o » nang co, nang ho, nang ro
vi cuu » vinh cuu
vi luu » vi lua
va ha » va hoa, va kha, va han
o hoi » co hoi, o hoc, o hai

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 ky nang o hoi. hieu va ha ((thuc va) OR (thuc day)) dinh ((vi cuu) or (vi luu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang o hoi. hieu va ha ((thuc va) OR (thuc day)) dinh ((vi cuu) OR (vi luu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang o hoi. hieu va ha ((thuc va) OR (thuc day)) dinh ((vi cuu) or (vi luu)) tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang o hoi. hieu va ha ((thuc va) OR (thuc day)) dinh ((vi cuu) or (vi luu)) tre*.