Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
viet cua » viec cua, viet qua, biet cua
anh danh » anh anh, anh dang, anh dinh
thuc anh » thuc hanh, thuy anh, thu anh
viet ca » viet ha, viet co, viet a
va cham » va chat, va tham
sach ky » sach y, sach ty, sach kem
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
sac ky » cac ky, sai ky

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 ky) or (sac ky)) nang xa hoi. hieu va cham thuc anh danh ((viet cua) or (viet ca)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ky) OR (sac ky)) nang xa hoi. hieu va cham thuc anh danh ((viet cua) OR (viet ca)) tre.
• Adding a wildcard symbol may retrieve word variants: doc ((sach ky) or (sac ky)) nang xa hoi. hieu va cham thuc anh danh ((viet cua) or (viet ca)) tre*.