Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
sach tao » sach dao, sach bao, sach tai
tao nano » tao nganh, cao nang, tao cao
nano cau » nang cau, bang cau, nano va
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cuu tre, cua triet
hanh va » hang va, hanh vi
vu sach » vu bach, su sach, vu khach
cam duc » cao duc, pham duc, nam duoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach tao nano cau hoi. hieu qua ((cam duc) OR (cam xuc)) van hanh va ((cua tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach tao nano cau hoi. hieu qua ((cam duc) OR (cam xuc)) van hanh va ((cua tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach tao nano cau hoi. hieu qua ((cam duc) OR (cam xuc)) van hanh va ((cua tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: vu sach tao nano cau hoi. hieu qua ((cam duc) OR (cam xuc)) van hanh va ((cua tre) or (cau tren))*.