Perhaps you should try some spelling variations:
trinh di » trinh do, trinh dien, trinh dinh
va trinh » van trinh, va tinh, lap trinh
luat tuc » luat thue
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
lam tuc » lam thuoc, lam truoc, nam thuc
hoc hai » hoc dai, hoc bai, hoc tai
y nang » ky nang, ly nang, v nang
ho hai » pho hai, cho hai, ho hap
di cua » dai cua, doi cua, de cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y nang ((ho hai) OR (hoc hai)). hieu van ((lam tuc) or (luat tuc)) va trinh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang ((ho hai) OR (hoc hai)). hieu van ((lam tuc) OR (luat tuc)) va trinh di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang ((ho hai) OR (hoc hai)). hieu van ((lam tuc) or (luat tuc)) va trinh di cua te".
• Adding a wildcard symbol may retrieve word variants: so sach y nang ((ho hai) OR (hoc hai)). hieu van ((lam tuc) or (luat tuc)) va trinh di cua te*.