Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
danh da » danh dau, dan da, danh ca
va danh » va dinh, va dan, va hanh
cham so » cham soc, cham o, ham so
hieu so » thieu so
cau tre » cau tren, cau treo, cau tra
hieu vu » hieu va, hieu ve, hieu su
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
da cau » dat cau, va cau
so va » so van, so vat, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach y ((nang xa) or (nang ma)) hoi. ((hieu vu) or (hieu so)) cham so va danh da cau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach y ((nang xa) OR (nang ma)) hoi. ((hieu vu) OR (hieu so)) cham so va danh da cau tre.
• Adding a wildcard symbol may retrieve word variants: doc sach y ((nang xa) or (nang ma)) hoi. ((hieu vu) or (hieu so)) cham so va danh da cau tre*.