Perhaps you should try some spelling variations:
dan hanh » dang hanh, dan khanh, dan thanh
hang tai » hang va, dung tai
thuc dan » thuc hanh, hoc dan, thuc vat
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
tai hai » thi hai, dai hai, tai ha
ty hang » ly hang, ty xang, thi hang
se tam » se lam, su tam
va tam » van tam, va tham, va tac
vi su » va su, ki su, oi su
ve su » va su

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 ty hang tai hai. hieu ((se tam) or (va tam)) thuc dan hanh ((vi su) OR (ve su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty hang tai hai. hieu ((se tam) OR (va tam)) thuc dan hanh ((vi su) OR (ve su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty hang tai hai. hieu ((se tam) or (va tam)) thuc dan hanh ((vi su) OR (ve su)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty hang tai hai. hieu ((se tam) or (va tam)) thuc dan hanh ((vi su) OR (ve su)) triet*.