Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
doc sach » hoc sach, toc sach, nuoc sach
sang ma » tang ma, nang ma, sang tao
hieu ve » hieu va, hieu van
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
cu tren » tu tren, dua tren
y sang » _ sang, duy sang
ve dat » de dat, va dat, ve dao
vi cu » vi su, vi xu, vi du

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) or (thuoc sach)) y sang ma hoa. hieu ve dat (nuoc or quoc) va danh vi cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (thuoc sach)) y sang ma hoa. hieu ve dat (nuoc OR quoc) va danh vi cu tren.
• Adding a wildcard symbol may retrieve word variants: ((doc sach) or (thuoc sach)) y sang ma hoa. hieu ve dat (nuoc or quoc) va danh vi cu tren*.