Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trang, lanh tranh
hanh trinh » canh tranh, hanh chinh
nhung song » nhung cong, nhung bong, nhung chong
hieu cach » chieu sach, hieu ca, biet cach
hieu cac » hieu luc, hieu va, hieu van
song van » hoang van, trong van, duong van
van tuan » van quan, van ban, anh tuan
tuan cau » toan cau, quan cau, tuan cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu cach) OR (hieu cac)) - ((hanh tranh) or (hanh trinh)) va nhung song van tuan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu cach) OR (hieu cac)) - ((hanh tranh) OR (hanh trinh)) va nhung song van tuan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu cach) OR (hieu cac)) - ((hanh tranh) or (hanh trinh)) va nhung song van tuan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu cach) OR (hieu cac)) - ((hanh tranh) or (hanh trinh)) va nhung song van tuan cau*.