Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hanh dua » hanh sua, hanh cua, hanh qua
hanh da » hanh dao, hanh va, hanh de
su sach » so sach, vu sach
y nang » ky nang, ly nang, v nang
ve cam » ve cham, va cam, ve cai
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho

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 y nang x hoi. hieu ((ve cam) OR (ve cac)) thuc vat ((hanh da) or (hanh dua)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. hieu ((ve cam) OR (ve cac)) thuc vat ((hanh da) OR (hanh dua)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. hieu ((ve cam) OR (ve cac)) thuc vat ((hanh da) or (hanh dua)) cau tren".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. hieu ((ve cam) OR (ve cac)) thuc vat ((hanh da) or (hanh dua)) cau tren*.