Perhaps you should try some spelling variations:
dong tren » dung tren, dong tien, dong truyen
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
toc sach » hoc sach, doc sach, thuoc sach
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
va lang » va nang, hoa lang
lang di » lang dai, hang di, lang du
di dong » dien dong, dao dong, hoi dong
tu sach » thu sach, su sach, te sach

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) or (toc sach)) ky lang xa hoi. hieu van ((pham duc) or (nam thuc)) va lang di dong tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) ky lang xa hoi. hieu van ((pham duc) OR (nam thuc)) va lang di dong tren.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky lang xa hoi. hieu van ((pham duc) or (nam thuc)) va lang di dong tren*.