Perhaps you should try some spelling variations:
phap trinh » phap tinh, lap trinh, phap sinh
trinh vat » trinh van, trinh luat, sinh vat
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
vat cua » mat cua, bat cua, dat cua
lam hoc » lam hoa, tam hoc, lam thuoc
sach ky » sac ky, sach y, sach ty
lang ha » long ha
cua tre » cua te, cuu tre, cua triet
am hoc » ad hoc

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 ky ((lang ha) or (nang x)) hoi. hieu van ((lam hoc) OR (am hoc)) phap trinh vat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((lang ha) OR (nang x)) hoi. hieu van ((lam hoc) OR (am hoc)) phap trinh vat cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((lang ha) or (nang x)) hoi. hieu van ((lam hoc) OR (am hoc)) phap trinh vat cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((lang ha) or (nang x)) hoi. hieu van ((lam hoc) OR (am hoc)) phap trinh vat cua tre*.