Perhaps you should try some spelling variations:
thanh phan » thanh pho, thanh san, thanh toan
toc sach » hoc sach, doc sach, thuoc sach
tay lang » tai lang, tay tang, tay quang
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
phan cua » nhan cua, than cua, phat cua
ky tang » ky nang, ky dang, kho tang
thu dan » thu dang, thu ban, thu san
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: toc sach ((tay lang) or (ky tang)) xa hoi. hieu van nam ((thu dan) OR (thuc dan)) thanh phan cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((tay lang) OR (ky tang)) xa hoi. hieu van nam ((thu dan) OR (thuc dan)) thanh phan cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((tay lang) or (ky tang)) xa hoi. hieu van nam ((thu dan) OR (thuc dan)) thanh phan cua te".
• Adding a wildcard symbol may retrieve word variants: toc sach ((tay lang) or (ky tang)) xa hoi. hieu van nam ((thu dan) OR (thuc dan)) thanh phan cua te*.