Perhaps you should try some spelling variations:
trong thoi » trong thi, trong tho, trong trot
ngoc ngoai » nuoc ngoai, ngoc ngoc, noi ngoai
thoi trung » thoi trang, hoi trung, khoi truong
hoc ngoai » nuoc ngoai, hoc giai, hoc noi
tac giao » tac gia, tac giai, tac giam
tac pham » thuc pham, san pham

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

• Performing a fuzzy search may retrieve terms with similar spellings: tac giao, tac pham ((van hoc) OR (van hoa)) ((ngoc ngoai) or (hoc ngoai)) trong thoi trung~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tac giao, tac pham ((van hoc) OR (van hoa)) ((ngoc ngoai) OR (hoc ngoai)) trong thoi trung.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tac giao, tac pham ((van hoc) OR (van hoa)) ((ngoc ngoai) or (hoc ngoai)) trong thoi trung".
• Adding a wildcard symbol may retrieve word variants: tac giao, tac pham ((van hoc) OR (van hoa)) ((ngoc ngoai) or (hoc ngoai)) trong thoi trung*.