Perhaps you should try some spelling variations:
thuoc sach » hoc sach, thuat sach, thuoc sinh
nuoc sach » nguoi sach, hoc sach, cuoc cach
hieu van » hieu va, thien van, lieu va
ly nang » ky nang, ly hang, ly vang
nang ma » tang ma, sang ma, nang cao
duoc va » duc va, duoc ma, duong va
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
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: ((thuoc sach) or (nuoc sach)) ly nang ma hoi. hieu van nam ((duoc va) OR (nuoc va)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (nuoc sach)) ly nang ma hoi. hieu van nam ((duoc va) OR (nuoc va)) hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (nuoc sach)) ly nang ma hoi. hieu van nam ((duoc va) OR (nuoc va)) hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (nuoc sach)) ly nang ma hoi. hieu van nam ((duoc va) OR (nuoc va)) hanh va cua tre*.