Perhaps you should try some spelling variations:
thien van » thi van
thuc dan » thuc hanh, hoc dan, thuc vat
su sach » so sach, vu sach
hanh va » hang va, hanh vi
sach ty » sach y, sach tu, sach thu
van cam » van nam, van lam, van cau
lang ha » long ha
lang xa » dang xay, lang van
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, truc va, tuc xa
va cua » va chua, via cua, ca 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 ty ((lang xa) OR (lang ha)) hoi. thien van cam ((tuc va) or (thuc dan)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang xa) OR (lang ha)) hoi. thien van cam ((tuc va) OR (thuc dan)) hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((lang xa) OR (lang ha)) hoi. thien van cam ((tuc va) or (thuc dan)) hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang xa) OR (lang ha)) hoi. thien van cam ((tuc va) or (thuc dan)) hanh va cua tre*.