Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
van hanh » van thanh, ban hanh, van anh
sang ma » tang ma, sang tao, mang may
sach ty » sach y, sach tu, sach thu
hieu su » hieu sau, tieu su, hieu so
su kham » su pham, vu kham, so kham
kham ly » khao ly, khanh ly
nang ma » tang ma, nang cao, mang may
tai cua » thai cua, tri cua, dai cua
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 ma) OR (sang ma)) hoi. hieu su kham 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 ma) OR (sang ma)) hoi. hieu su kham 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 ma) OR (sang ma)) hoi. hieu su kham ly van hanh ((tai cua) or (tai cuc)) tre".
• Adding a wildcard symbol may retrieve word variants: thuat sach ty ((nang ma) OR (sang ma)) hoi. hieu su kham ly van hanh ((tai cua) or (tai cuc)) tre*.