Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuc dan » thuc hanh, thuc vat
dien cua » dieu cua, dien cuc, dien cu
tiep cua » tiep can, dieu cua, tap cua
sach ky » sac ky, sach y, sach ty
va cham » va chat, va tham
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky nang o hoi. lieu va cham ((thuc dan) OR (hoc dan)) danh ((dien cua) or (tiep cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky nang o hoi. lieu va cham ((thuc dan) OR (hoc dan)) danh ((dien cua) OR (tiep cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky nang o hoi. lieu va cham ((thuc dan) OR (hoc dan)) danh ((dien cua) or (tiep cua)) te".
• Adding a wildcard symbol may retrieve word variants: doc sach ky nang o hoi. lieu va cham ((thuc dan) OR (hoc dan)) danh ((dien cua) or (tiep cua)) te*.