Perhaps you should try some spelling variations:
thuat trinh » thuat tinh, thuyet trinh, thuat trong
sach thien » sach thieu, cach thien, sach tren
phat trinh » phat trien, phat thanh, phat minh
giao tinh » giao trinh, gia tinh, giao thanh
sach tien » sach tren, sach thieu
giap tinh » gia tinh, diep tinh, tap tinh
hoc phat » hoc phan
minh te » minh ve, minh tu, minh tien
minh de » menh de, minh ve, sinh de

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (((( kinh te ((hoc phat) OR (hoc pho)) thien giap tinh ) OR ( kinh te hoc ((sach thien) OR (sach tien)) giap tinh ))) OR ( ((minh te) OR (minh de)) hoc ((phat trinh) OR (thuat trinh)) giao tinh ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( kinh te ((hoc phat) or (hoc pho)) thien giap tinh ) or ( kinh te hoc ((sach thien) or (sach tien)) giap tinh ))) or ( ((minh te) OR (minh de)) hoc ((phat trinh) or (thuat trinh)) giao tinh ))~".
• Adding a wildcard symbol may retrieve word variants: (((( kinh te ((hoc phat) or (hoc pho)) thien giap tinh ) or ( kinh te hoc ((sach thien) or (sach tien)) giap tinh ))) or ( ((minh te) OR (minh de)) hoc ((phat trinh) or (thuat trinh)) giao tinh ))*.