Perhaps you should try some spelling variations:
dieu tra » dieu tri, kiem tra
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty hang » ly hang, ty xang, thi hang
hieu va » lieu va, hieu qua
duc ban » duc tan, dua ban, duc man
duc van » duc va, duc tan, duc manh
va hoi » xa hoi, va hoc, va hoa

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 va hoi. hieu va cac ((duc ban) or (duc van)) thanh ((dieu cua) OR (dieu tra)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty hang va hoi. hieu va cac ((duc ban) OR (duc van)) thanh ((dieu cua) OR (dieu tra)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty hang va hoi. hieu va cac ((duc ban) or (duc van)) thanh ((dieu cua) OR (dieu tra)) te".
• Adding a wildcard symbol may retrieve word variants: tu sach ty hang va hoi. hieu va cac ((duc ban) or (duc van)) thanh ((dieu cua) OR (dieu tra)) te*.