Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc van » thuc vat, thuc va, thuc hanh
thanh vi » hanh vi, thanh va, thanh ve
thuc dan » thuc hanh, hoc dan, thuc vat
hieu ve » hieu va, hieu van
vi cua » vai cua, di cua
ve cam » ve cham, ve cac, va cam
y lang » _ lang, tay lang, yen lang
o lang » hoa lang, hoi lang
cua te » cua tu

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 ((y lang) or (o lang)) xa hoi. hieu ve cam ((thuc van) or (thuc dan)) thanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((y lang) OR (o lang)) xa hoi. hieu ve cam ((thuc van) OR (thuc dan)) thanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: toc sach ((y lang) or (o lang)) xa hoi. hieu ve cam ((thuc van) or (thuc dan)) thanh vi cua te*.