Perhaps you should try some spelling variations:
sach van » sach va, bach van, cach van
sach han » sach tham, sach danh, sach nang
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
cam truc » cau truc, nam truc, lam truoc
hieu ve » hieu va, hieu van
de cua » le cua, dieu cua
te cua » tue cua, le cua
ve cam » ve cham, ve cac, va cam
o hoi » co hoi, o hoc, o hai
ban o » ban do, ban co, ban bo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach van) OR (sach han)) ban o hoi. hieu ve cam truc van hanh ((de cua) or (te cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach van) OR (sach han)) ban o hoi. hieu ve cam truc van hanh ((de cua) OR (te cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach van) OR (sach han)) ban o hoi. hieu ve cam truc van hanh ((de cua) or (te cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach van) OR (sach han)) ban o hoi. hieu ve cam truc van hanh ((de cua) or (te cua)) tre*.