Perhaps you should try some spelling variations:
trinh vat » trinh van, trinh luat, sinh vat
hoc thuoc » hoc thuc, hoc thuong, hoc nuoc
doc thuc » hoc thuc, do thuc, dan thuc
va trinh » van trinh, va tinh, lap trinh
lang van » dang van, tang van, hoang van
su sach » vu sach
vat cua » mat cua, bat cua, dat cua
hieu ve » hieu va, hieu van
van hoi » van hoa, van hoc, van hoe
ky lang » ky nang, ky dang, ky tang
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sach)) ky lang van hoi. hieu ve ((doc thuc) or (hoc thuoc)) va trinh vat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ky lang van hoi. hieu ve ((doc thuc) OR (hoc thuoc)) va trinh vat cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky lang van hoi. hieu ve ((doc thuc) or (hoc thuoc)) va trinh vat cua tre*.