Perhaps you should try some spelling variations:
thao hoc » thai hoc, than hoc, thao khoa
phan lap » phan dau
toc sac » toc sach, toc san, hoc sach
hieu va » lieu va, hieu qua
lap cua » lai cua, tap cua, lam cua
va phan » van phan, va phat, va phap
hieu ve » hieu van
ky sang » ky nang, ky dang, ky tang
tay hoi » tay ho, tao hoi, tay thai
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 sang ((thao hoc) or (tay hoi)). ((hieu ve) or (hieu va)) pham duc va phan lap cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky sang ((thao hoc) OR (tay hoi)). ((hieu ve) OR (hieu va)) pham duc va phan lap cua te.
• Adding a wildcard symbol may retrieve word variants: toc sac ky sang ((thao hoc) or (tay hoi)). ((hieu ve) or (hieu va)) pham duc va phan lap cua te*.