Perhaps you should try some spelling variations:
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
trang xa » trang va, trang ha, trong xa
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va, hieu van
tang xa » tang ma, lang xa, tang ha
ve cam » ve cham, ve cac, va cam

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 ((tang xa) OR (trang xa)) hoi. hieu ve cam duc van hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((tang xa) OR (trang xa)) hoi. hieu ve cam duc van hanh vi ((dua tren) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((tang xa) OR (trang xa)) hoi. hieu ve cam duc van hanh vi ((dua tren) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((tang xa) OR (trang xa)) hoi. hieu ve cam duc van hanh vi ((dua tren) or (cuu tre))*.