Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach thieu
thi hanh » thi thanh
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
tu sach » thu sach, su sach, te sach
hanh xa » hanh va, hanh ma, hanh xu
ve cam » ve cham, ve cac, ve cai
lam va » nam va, lam ha, am va
dam va » dam van, nam va, dam ha
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach thi hanh xa hoi. hieu ((ve cam) or (va cam)) thuc van hanh ((lam va) OR (dam va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thi hanh xa hoi. hieu ((ve cam) OR (va cam)) thuc van hanh ((lam va) OR (dam va)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thi hanh xa hoi. hieu ((ve cam) or (va cam)) thuc van hanh ((lam va) OR (dam va)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach thi hanh xa hoi. hieu ((ve cam) or (va cam)) thuc van hanh ((lam va) OR (dam va)) triet*.