Perhaps you should try some spelling variations:
khoa hoc » hoa hoc
toc sach » hoc sach, doc sach, thuoc sach
tu ngang » tu ngan, hu angang, vu ngan
van anh » van thanh, tuan anh, van minh
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
cho hoc » co hoc
cua chu » sua chua
anh di » danh di, xanh di, anh d
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) tu ngang ((cho hoc) or (khoa hoc)). hieu va cac duc van anh di cua chu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) tu ngang ((cho hoc) OR (khoa hoc)). hieu va cac duc van anh di cua chu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) tu ngang ((cho hoc) or (khoa hoc)). hieu va cac duc van anh di cua chu*".