Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
cam thuc » am thuc, nam thuc, cam thu
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
su sach » so sach, vu sach
ve cam » ve cham, ve cac, va cam
den su » dan su, nen su
de su » ve su, de tu, da su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((nang xa) or (nang x)) hoi. hieu ve cam thuc van hanh ((de su) OR (den su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (nang x)) hoi. hieu ve cam thuc van hanh ((de su) OR (den su)) triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (nang x)) hoi. hieu ve cam thuc van hanh ((de su) OR (den su)) triet*".