Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dan viet » danh viet, dang viet, san viet
dan vien » nhan vien, danh viet, dang viet
truc va » thuc va, thuc vat, trung va
sach ty » sach y, sach tu, sach thu
qua cau » quan cau, qua cac, qua ca
dang ha » dong ha, dung ha, lang ha
dang xa » dang xay, lang xa, dang va
dai tro » vai tro, tai tro, dai tho

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty ((dang xa) or (dang ha)) hoi. hieu qua cau truc va ((dan vien) OR (dan viet)) dai tro~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty ((dang xa) OR (dang ha)) hoi. hieu qua cau truc va ((dan vien) OR (dan viet)) dai tro.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty ((dang xa) or (dang ha)) hoi. hieu qua cau truc va ((dan vien) OR (dan viet)) dai tro".
• Adding a wildcard symbol may retrieve word variants: thu sach ty ((dang xa) or (dang ha)) hoi. hieu qua cau truc va ((dan vien) OR (dan viet)) dai tro*.