Perhaps you should try some spelling variations:
nang khai » dang khai, nang hai, quang khai
hieu van » hieu va, thien van, lieu va
khai cua » thai cua, hai cua, khi cua
van nang » van quang, van ban, van dong
nuoc van » nuoc va, nuoc san, luoc van
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
sach ky » sach y, sach ty, sach kem
van cac » van hac, van cau, van bac
nang xa » lang xa, nang ma, mang xa
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: thuat ((sach ky) OR (sac ky)) ((nang xa) or (nang x)) hoi. hieu van cac nuoc van nang khai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sach ky) OR (sac ky)) ((nang xa) OR (nang x)) hoi. hieu van cac nuoc van nang khai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat ((sach ky) OR (sac ky)) ((nang xa) or (nang x)) hoi. hieu van cac nuoc van nang khai cua te".
• Adding a wildcard symbol may retrieve word variants: thuat ((sach ky) OR (sac ky)) ((nang xa) or (nang x)) hoi. hieu van cac nuoc van nang khai cua te*.