Perhaps you should try some spelling variations:
phuong thao » phuong phap, phuong thuc
nhanh lang » nhanh quang, nhanh thang, nhan dang
chieu sang » chieu sach, chieu xanh, hieu lang
hanh mang » nhanh mang, hanh trang, thanh hang
ho chieu » theo chieu, hoc thieu, doi chieu
va bang » va nang, va lang, va ban
san cau » van cau, ban cau, can cau
van dau » van dao, phan dau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ho chieu sang - ((hanh mang) OR (nhanh lang)) va bang phuong thao ((san cau) OR (van dau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho chieu sang - ((hanh mang) OR (nhanh lang)) va bang phuong thao ((san cau) or (van dau))~".
• Adding a wildcard symbol may retrieve word variants: ho chieu sang - ((hanh mang) OR (nhanh lang)) va bang phuong thao ((san cau) or (van dau))*.