Perhaps you should try some spelling variations:
sach hoc » cach hoc, sach hoi, mach hoc
cuu hoan » luu hoang, cuu van, cau hoa
khoa hoc » hoa hoc
dan khoa » dang khoa, da khoa, san khoa
nhan dan » phan dau, gian dan, nhan tai
te sach » toc sach
hoc xa » hoc ma
hoi ca » hoi cua, hoi cac, hoi cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach hoc tap, nghien ((cuu hoan) OR (cuu khoa)) hoc dan khoa hoc xa hoi ca nhan dan~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach hoc tap, nghien ((cuu hoan) OR (cuu khoa)) hoc dan khoa hoc xa hoi ca nhan dan".
• Adding a wildcard symbol may retrieve word variants: te sach hoc tap, nghien ((cuu hoan) OR (cuu khoa)) hoc dan khoa hoc xa hoi ca nhan dan*.