Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
luc van » luoc van, luu van, duc van
y lang » o lang, _ lang, tay lang
ve cam » ve cham, ve cac, va cam
cua tu » cua tuc, cua su, cua te
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 y lang xa hoi. hieu ve cam ((luc van) or (thuc vat)) hanh vi ((cua tu) or (cua cu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y lang xa hoi. hieu ve cam ((luc van) OR (thuc vat)) hanh vi ((cua tu) OR (cua cu)).
• Adding a wildcard symbol may retrieve word variants: toc sach y lang xa hoi. hieu ve cam ((luc van) or (thuc vat)) hanh vi ((cua tu) or (cua cu))*.