Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
cau tren » cu tren, dau tren, ca tren
tai hai » thi hai, dai hai, tai ha
cac tuc » cac toc, cac tu, cac nuoc
cac tac » cac toc, cac bac, cac dac
va hanh » van hanh, va thanh, va danh
y sang » duy sang
_ sang » _ san
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach ((y sang) OR (_ sang)) tai hai. hieu qua ((cac tuc) or (cac tac)) va hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ((y sang) OR (_ sang)) tai hai. hieu qua ((cac tuc) OR (cac tac)) va hanh vi cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ((y sang) OR (_ sang)) tai hai. hieu qua ((cac tuc) or (cac tac)) va hanh vi cau tren*".