Perhaps you should try some spelling variations:
dung tren » dung trong, dung trung
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
thu sach » tu sach, thuat sach, thuoc sach
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 dung » di dong, da dung, di ung

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