Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
van hanh » van thanh, ban hanh, van anh
ty nang » ty xang, ty hang, ly nang
hieu su » hieu sau, tieu su, hieu so
su khao » so khao, su khac, qua khao
khao ly » khanh ly
tai cua » thai cua, tri cua, dai cua
ma hoi » mai hoi, xa hoi, ma hoa
ly van » le van, ly va, ly von

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 ((ty nang) OR (ky nang)) ma hoi. hieu su khao ly van hanh ((tai cua) or (tai cuc)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ((ty nang) OR (ky nang)) ma hoi. hieu su khao ly van hanh ((tai cua) OR (tai cuc)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ((ty nang) OR (ky nang)) ma hoi. hieu su khao ly van hanh ((tai cua) or (tai cuc)) tre".
• Adding a wildcard symbol may retrieve word variants: thuat sach ((ty nang) OR (ky nang)) ma hoi. hieu su khao ly van hanh ((tai cua) or (tai cuc)) tre*.