Perhaps you should try some spelling variations:
van nang » van quang, van ban, van dung
cam thuc » am thuc, nam thuc, cam thu
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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 ((van nang) or (van dong)) xa hoi. hieu ve cam thuc van hanh ((vi cua) or (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((van nang) OR (van dong)) xa hoi. hieu ve cam thuc van hanh ((vi cua) OR (di cua)) tre.
• Adding a wildcard symbol may retrieve word variants: su sach ((van nang) or (van dong)) xa hoi. hieu ve cam thuc van hanh ((vi cua) or (di cua)) tre*.