Perhaps you should try some spelling variations:
truoc xay » thuc xay, truoc dam, truoc nam
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
truc xa » tuc xa, truc va, truc may
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ky) or (sach y)) nang ma hoa. hieu van nam ((truc xa) OR (truoc xay)) hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sach y)) nang ma hoa. hieu van nam ((truc xa) OR (truoc xay)) hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sach y)) nang ma hoa. hieu van nam ((truc xa) OR (truoc xay)) hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) or (sach y)) nang ma hoa. hieu van nam ((truc xa) OR (truoc xay)) hanh vi cuu tre*.