Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh dan » thanh dan, hanh san, canh dan
ban hanh » ban hang
sang tao » hang tai
dan cua » dan ca, ban cua, dai cua
duc ban » duc tan, duc van, dua ban
hieu ve » hieu va
tao hoi » tao khoi, tao boi, tay hoi
sach ty » sach y, sach tu, sach thu
sac ky » cac ky, sai ky
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: toc ((sac ky) or (sach ty)) sang tao hoi. ((hieu ve) OR (hieu van)) pham duc ban hanh dan cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sac ky) OR (sach ty)) sang tao hoi. ((hieu ve) OR (hieu van)) pham duc ban hanh dan cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sac ky) or (sach ty)) sang tao hoi. ((hieu ve) OR (hieu van)) pham duc ban hanh dan cua te".
• Adding a wildcard symbol may retrieve word variants: toc ((sac ky) or (sach ty)) sang tao hoi. ((hieu ve) OR (hieu van)) pham duc ban hanh dan cua te*.