Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cap nuoc » dat nuoc
hieu van » hieu va, thien van, lieu va
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
sach ty » sach y, sach tu, sach thu
van cap » van cau, van dap, van ca
va danh » va dinh, va dan, va hanh
va anh » van anh, va hanh, va banh
vi cua » vai cua, di cua
cua cu » cua chu, cua cau, cua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty ((nang xa) or (nang ma)) hoi. hieu van cap nuoc ((va anh) OR (va danh)) vi cua cu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty ((nang xa) OR (nang ma)) hoi. hieu van cap nuoc ((va anh) OR (va danh)) vi cua cu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty ((nang xa) or (nang ma)) hoi. hieu van cap nuoc ((va anh) OR (va danh)) vi cua cu".
• Adding a wildcard symbol may retrieve word variants: toc sach ty ((nang xa) or (nang ma)) hoi. hieu van cap nuoc ((va anh) OR (va danh)) vi cua cu*.