Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cam thuc » am thuc, nam thuc, cam thu
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
ve cam » ve cham, ve cac, va cam
va han » va phan, van han, va hanh
tai su » tai tu, lai su, tai du
tai so » tai sao, dai so, tai co
x hoi » xa hoi, o hoi, x ho

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 ky nang x hoi. hieu ve cam thuc va han ((tai su) OR (tai so)) tien~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang x hoi. hieu ve cam thuc va han ((tai su) OR (tai so)) tien".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang x hoi. hieu ve cam thuc va han ((tai su) OR (tai so)) tien*.