Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
cau tren » dau tren, ca tren, cau treo
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
hieu ve » hieu va, hieu van
sang ma » tang ma, nang ma, sang tao
cu tren » tu tren, dua tren
ma hoi » mai hoi, xa hoi, ma hoa
ve dat » de dat, va dat, ve dao
y sang » _ sang, duy sang
nuoc » quoc, duoc, ngoc

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) OR (thuoc sach)) y sang ma hoi. hieu ve dat nuoc va danh vi ((cau tren) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) y sang ma hoi. hieu ve dat nuoc va danh vi ((cau tren) OR (cu tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (thuoc sach)) y sang ma hoi. hieu ve dat nuoc va danh vi ((cau tren) or (cu tren))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (thuoc sach)) y sang ma hoi. hieu ve dat nuoc va danh vi ((cau tren) or (cu tren))*.