Perhaps you should try some spelling variations:
trinh van » trinh han, trinh quan, trinh toan
dan trinh » dan tinh, van trinh, hanh trinh
thu sach » thuat sach, thuoc sach, thu hoach
thuc dan » thuc hanh, hoc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
tu sach » su sach, te sach, tu cach
van cua » vang cua, ban cua, dan cua
cua tre » cua te, cuu tre, cua triet
nang xa » lang xa, nang ma, mang xa

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

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