Perhaps you should try some spelling variations:
truong dong » trong dong, truong dang, tuong dong
doi chieu » doc hieu, doi chi, ho chieu
sinh cua » manh cua, dinh cuu
dong bai » dong tai, dong bac, dong ban
bai toan » bai tap
toan cau » toan cao, toan ban, toan tap
sinh va » sinh vat, tinh va, dinh van

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi chieu) or (hoc hien)) tinh - hanh ((sinh cua) OR (sinh va)) truong dong bai toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (hoc hien)) tinh - hanh ((sinh cua) OR (sinh va)) truong dong bai toan cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) or (hoc hien)) tinh - hanh ((sinh cua) OR (sinh va)) truong dong bai toan cau*".