Perhaps you should try some spelling variations:
thien van » thi van
toc sach » hoc sach, doc sach, thuoc sach
sach tay » xach tay, sach hay, sach nay
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
cam thuc » am thuc, nam thuc, cam thu
hieu van » hieu va, lieu va
lang van » dang van, tang van, hoang van
tay lang » tai lang, tay tang, tay quang
hieu ve » hieu va
van hoi » van hoa, van hoc, van hoe
vi cua » vai cua, di cua
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 tay lang van hoi. ((hieu ve) or (((hieu van) or (thien van)))) cam thuc van hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tay lang van hoi. ((hieu ve) OR (((hieu van) OR (thien van)))) cam thuc van hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: toc sach tay lang van hoi. ((hieu ve) or (((hieu van) or (thien van)))) cam thuc van hanh vi cua te*.