Perhaps you should try some spelling variations:
thu mach » thu sach, thuat mach, thu hoach
mach hoc » cach hoc, dich hoc, anh hoc
pho hong » pho thong, pho uong, pho dong
hong duc » dang duc, ton duc
van luan » van quan, von luan, vay luan
van tuan » van quan, van ban, anh tuan
mo hoc » mon hoc, co hoc
duc ma » duoc ma, duc mau, duc man

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu mach hoc tap, nghien cuu mo hoc pho hong duc ma hoa ((van luan) OR (van tuan)) van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu mach hoc tap, nghien cuu mo hoc pho hong duc ma hoa ((van luan) OR (van tuan)) van".
• Adding a wildcard symbol may retrieve word variants: thu mach hoc tap, nghien cuu mo hoc pho hong duc ma hoa ((van luan) OR (van tuan)) van*.