Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
truc van » truc va, thuc van, truc ban
van hanh » van thanh, ban hanh, van anh
cao hoi » cau hoi, co hoi, cao hoc
cho hoc » co hoc, khoa hoc
hieu ve » hieu va, hieu van
luu tre » luu tru, cuu tre, luy tre
ve cau » ke cau, va cau, ve cac
vi luu » vi lua

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 (doc sach)) ky nang ((cao hoi) or (cho hoc)). hieu ve cau truc van hanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky nang ((cao hoi) OR (cho hoc)). hieu ve cau truc van hanh vi luu tre.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ky nang ((cao hoi) or (cho hoc)). hieu ve cau truc van hanh vi luu tre*.