Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
trinh le » trinh ly, thinh le, trinh he
khang ca » hang ca, khang a, khang cu
va trinh » van trinh, va tinh, lap trinh
vu sach » vu bach, su sach, vu khach
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cua triet, dua tren
hieu va » lieu va, hieu qua
so sanh » do sanh
cuu tre » cau tren, cau treo
ca hoi » cau hoi, cua hoi, xa hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) or (so sanh)) thieu khang ca hoi. hieu va cac duc va trinh le ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (so sanh)) thieu khang ca hoi. hieu va cac duc va trinh le ((cua tre) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) or (so sanh)) thieu khang ca hoi. hieu va cac duc va trinh le ((cua tre) OR (cuu tre))*".