Perhaps you should try some spelling variations:
trinh vat » trinh van, trinh luat, sinh vat
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
thuc va » thuc vat, thuc day
vat cua » mat cua, bat cua, dat cua
cua tre » cua te, cuu tre, cua triet
van cau » van dau, van hau, van chat
ky dang » ky danh
vu sac » vu sach, vu san, va sac

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sac ((ky dang) or (ky nang)) xa hoi. hieu van cau ((thuc va) OR (thuc dan)) trinh vat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sac ((ky dang) OR (ky nang)) xa hoi. hieu van cau ((thuc va) OR (thuc dan)) trinh vat cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sac ((ky dang) or (ky nang)) xa hoi. hieu van cau ((thuc va) OR (thuc dan)) trinh vat cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sac ((ky dang) or (ky nang)) xa hoi. hieu van cau ((thuc va) OR (thuc dan)) trinh vat cua tre*.