Perhaps you should try some spelling variations:
thuoc sach » nuoc sach, thuat sach, thuoc sinh
viet tai » viec tai, vien tai, viet ta
hoc sach » hoc sinh, hoc anh
dan viet » danh viet, dang viet, san viet
cac truc » cau truc, cac tru, cac trung
lang van » dang van, tang van, hoang van
truc va » thuc va, thuc vat, trung va
qua cac » cua cac
van hoi » van hoa, van hoc, van hoe
tai tro » vai tro, tai tao, tai trong
hoc cac » hoc cao
y lang » o lang, _ lang, tay lang
va dan » ca dan, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) or (((hoc sach) OR (hoc cac)))) y lang van hoi. hieu qua cac truc va dan viet tai tro~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (((hoc sach) OR (hoc cac)))) y lang van hoi. hieu qua cac truc va dan viet tai tro.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (((hoc sach) OR (hoc cac)))) y lang van hoi. hieu qua cac truc va dan viet tai tro".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (((hoc sach) OR (hoc cac)))) y lang van hoi. hieu qua cac truc va dan viet tai tro*.