Perhaps you should try some spelling variations:
dau tien » van tien
sach ky » sach y, sach ty, sach kem
danh du » danh dau, danh tu, dinh du
va danh » va dinh, va dan, va hanh
nam xua » nam cua, nam mua, nam qua
hieu va » lieu va, hieu qua
nang co » nang cao, nang doc, nang noi
nang ro » nang ho, nang ra, nang rong
va nam » van nam, ha nam, va nay
sac ky » cac ky, sai ky
xua va » xuat va, vua va, sua va
du dau » tu dau, dung dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ky) OR (sac ky)) ((nang ro) or (nang co)) hoi. hieu va nam xua va danh du dau tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sac ky)) ((nang ro) OR (nang co)) hoi. hieu va nam xua va danh du dau tien*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) OR (sac ky)) ((nang ro) or (nang co)) hoi. hieu va nam xua va danh du dau tien*".