Perhaps you should try some spelling variations:
danh viet » anh viet, ninh viet, nang viet
lam thuoc » nam thuoc, am thuc, cay thuoc
doc sach » toc sach, nuoc sach, dac sac
lam duoc » nam duoc, luat duoc, tao duoc
viet cua » viec cua, viet ca, viet qua
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
va danh » va dinh, va dan, va hanh
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc sach) OR (hoc sach)) ky lang xa hoi. hieu van ((lam duoc) or (lam thuoc)) va danh viet cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (hoc sach)) ky lang xa hoi. hieu van ((lam duoc) OR (lam thuoc)) va danh viet cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc sach) OR (hoc sach)) ky lang xa hoi. hieu van ((lam duoc) or (lam thuoc)) va danh viet cua te".
• Adding a wildcard symbol may retrieve word variants: ((doc sach) OR (hoc sach)) ky lang xa hoi. hieu van ((lam duoc) or (lam thuoc)) va danh viet cua te*.