Perhaps you should try some spelling variations:
thieu sach » thien hach, hieu cach, theo sach
chieu sach » chinh sach, chiet tach, chieu sang
nhung cong » dung cong, thong cong, hang cong
thang cua » thong cua, hang cua, than cua
cong tinh » cong trinh, cong vinh, long tinh
tang cua » mang cua, hang cua, tang luan
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: hoc ((thieu sach) OR (chieu sach)) - hanh ((thang cua) or (tang cua)) nhung cong tinh toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (chieu sach)) - hanh ((thang cua) OR (tang cua)) nhung cong tinh toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) OR (chieu sach)) - hanh ((thang cua) or (tang cua)) nhung cong tinh toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) OR (chieu sach)) - hanh ((thang cua) or (tang cua)) nhung cong tinh toan cau*.