Perhaps you should try some spelling variations:
sach dong » sach dung, sach song, sach rong
khoa quan » khoan quan, khoa luan, hoa quan
toc sach » hoc sach, doc sach, thuoc sach
dong tac » cong tac, dong tai, dong bac
hoc danh » hoc dan, hoc anh, hoc nganh
hoc hanh » hoc nhanh, hoc thanh, hoc anh
khoa hoc » hoa hoc
quan van » luan van, quan va, quan luan
cuu mot » cua mot, cuu mo, huu mot
van van » van ban, tan van, san van
hoc da » hoc dan, hoc dai, hoc dat

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach dong tac, nghien cuu mot ((hoc danh) or (hoc hanh)) khoa hoc da khoa quan van van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach dong tac, nghien cuu mot ((hoc danh) OR (hoc hanh)) khoa hoc da khoa quan van van.
• Adding a wildcard symbol may retrieve word variants: toc sach dong tac, nghien cuu mot ((hoc danh) or (hoc hanh)) khoa hoc da khoa quan van van*.