Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
va hanh » van hanh, va thanh, va danh
cac dac » cac dan, cac dai, cac bac
cac duc » cac du, cao duc, cac nuoc
te sach » toc sach
tu lang » cu lang, tu lanh, xu lang
tu sang » thu sang, tu san, tu quang
vi cua » vai cua, di cua
cua tu » cua tuc, cua su, cua cu

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 ((tu sang) or (tu lang)) xa hoi. hieu vien ((cac duc) OR (cac dac)) va hanh vi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((tu sang) OR (tu lang)) xa hoi. hieu vien ((cac duc) OR (cac dac)) va hanh vi cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((tu sang) or (tu lang)) xa hoi. hieu vien ((cac duc) OR (cac dac)) va hanh vi cua tu".
• Adding a wildcard symbol may retrieve word variants: te sach ((tu sang) or (tu lang)) xa hoi. hieu vien ((cac duc) OR (cac dac)) va hanh vi cua tu*.