Perhaps you should try some spelling variations:
can trinh » can tranh, dan trinh, van trinh
trinh co » trinh do, trinh cong, trinh hoa
hoc sach » hoc sinh, hoc cac, hoc anh
kinh hoa » kinh khoa, minh hoa, kinh hoc
co sach » bo sach, cuon sach
tu can » tu ban, tu cac, thu canh
hoa hi » hoa phi, hoa hoi, hoa thi

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu can trinh co khi đong luc ) or ( ((hoc sach) or (co sach)) kinh hoa hi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu can trinh co khi đong luc ) OR ( ((hoc sach) OR (co sach)) kinh hoa hi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (( tu can trinh co khi đong luc ) or ( ((hoc sach) or (co sach)) kinh hoa hi đong luc ))*.