Perhaps you should try some spelling variations:
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
cam thuc » am thuc, nam thuc, cam thu
hieu van » hieu va, thien van, lieu va
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau
vai cua » dai cua, hai cua, lai cua
sach v » sach va, sach y, sach vay
sach 2 » sach y
vi cua » di 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 v) or (sach 2)) nang xa hoi. hieu van cam thuc dan hanh ((vi cua) OR (vai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach v) OR (sach 2)) nang xa hoi. hieu van cam thuc dan hanh ((vi cua) OR (vai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach v) or (sach 2)) nang xa hoi. hieu van cam thuc dan hanh ((vi cua) OR (vai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: su ((sach v) or (sach 2)) nang xa hoi. hieu van cam thuc dan hanh ((vi cua) OR (vai cua)) triet*.