Perhaps you should try some spelling variations:
trung van » truong van, trong van, trung va
cac trung » cac truong, dac trung, bac trung
toc sach » hoc sach, thuoc sach, nuoc sach
van hanh » van thanh, ban hanh, van anh
doc sach » hoc sach, nuoc sach, dac sac
hieu ve » hieu va, hieu van
cho hoc » co hoc, khoa hoc
luu tre » luu tru, cuu tre, luy tre
cao hoi » cau hoi, co hoi, cao hoc
ve cac » va cac, vien cac
y nang » ky nang, ly nang, v nang
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)) y nang ((cao hoi) or (cho hoc)). hieu ve cac trung van hanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) y nang ((cao hoi) OR (cho hoc)). hieu ve cac trung van hanh vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) y nang ((cao hoi) or (cho hoc)). hieu ve cac trung van hanh vi luu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) y nang ((cao hoi) or (cho hoc)). hieu ve cac trung van hanh vi luu tre*.