Perhaps you should try some spelling variations:
trinh xuan » trinh quan, trinh luat, trinh xay
trinh luan » trinh luat, trinh quan, trinh han
nhan tuong » nhan trong, nhan thong, nhan tong
doi chieu » doc hieu, doi chi, mot chieu
tuong dan » huong dan, tung dan, xuong dan
ho chieu » theo chieu, hoc thieu, mot chieu
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((ho chieu) or (doi chieu)) sach - hanh ((trinh xuan) OR (trinh luan)) nhan tuong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (doi chieu)) sach - hanh ((trinh xuan) OR (trinh luan)) nhan tuong dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (doi chieu)) sach - hanh ((trinh xuan) OR (trinh luan)) nhan tuong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (doi chieu)) sach - hanh ((trinh xuan) OR (trinh luan)) nhan tuong dan toan cau*.