Perhaps you should try some spelling variations:
tan hanh » tan thanh, tang hanh, toan hanh
phan duc » pham duc, phan tu, phan dau
mau van » ma van, mai van, mao van
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
ve phan » va phan, ke phan, ve phat
y lang » _ lang, tay lang, yen lang
o lang » hoa lang, hoi lang
mau va » dau va, lau va, cau va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((y lang) or (o lang)) xa hoi. hieu ve phan duc tan hanh ((mau va) OR (mau van)) trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y lang) OR (o lang)) xa hoi. hieu ve phan duc tan hanh ((mau va) OR (mau van)) trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y lang) or (o lang)) xa hoi. hieu ve phan duc tan hanh ((mau va) OR (mau van)) trien".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y lang) or (o lang)) xa hoi. hieu ve phan duc tan hanh ((mau va) OR (mau van)) trien*.