Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
hang mai » hoang mai, hang tai, lang mai
hang hai » hoang hai, hang tai, thanh hai
sach thu » sach thue, sach thieu, sach tham
vu sach » vu bach, su sach, vu khach
tinh va » tich va, trinh van, trinh vat
va tinh » may tinh
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach thu ((hang mai) or (hang hai)) hoi. ((hieu va) OR (hieu qua)) pham thuc va tinh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach thu ((hang mai) OR (hang hai)) hoi. ((hieu va) OR (hieu qua)) pham thuc va tinh va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach thu ((hang mai) or (hang hai)) hoi. ((hieu va) OR (hieu qua)) pham thuc va tinh va cua tre*".