Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
nam thuc » nam thuoc, am thuc, nam thu
cau tren » cu tren, ca tren, cau treo
hanh tai » thanh tai, hang tai, han tai
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
lieu ha » lieu nha, lieu va, liem ha

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 ky ((nang ma) or (sang ma)) hoi. lieu ha nam thuc day hanh tai ((cau tren) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (sang ma)) hoi. lieu ha nam thuc day hanh tai ((cau tren) OR (dau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) or (sang ma)) hoi. lieu ha nam thuc day hanh tai ((cau tren) or (dau tren))*.