Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
chieu sang » chieu sach, chieu xanh, hieu lang
doi chieu » doc hieu, doi chi, mot chieu
hanh sinh » hanh tinh, hanh dinh, hinh sinh
hang cong » dang cong, hang nong, bang cong
trinh bat » trinh ban, trinh bao, trinh bay
sinh va » sinh vat, tinh va, dinh van

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: doi chieu sang - hanh sinh va ((thong cong) OR (hang cong)) trinh bat dau~.
• Adding a wildcard symbol may retrieve word variants: doi chieu sang - hanh sinh va ((thong cong) or (hang cong)) trinh bat dau*.