Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nhiem huu, chien huu
nguyen huu » nguyen duc
hoc khanh » hoc nhanh, hoc thanh, hoc hanh
mach hoc » cach hoc, dich hoc, anh hoc
tu mach » tu cach, tu manh, tu hach
mot hoc » mon hoc, mo hoc, mot goc
va han » va phan, van han, va hanh
han va » hang va, hanh va, nhan va
phong » thong

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu mach hoc tap, ((nghien huu) or (nguyen huu)) mot hoc khanh phong (tuc or thuc) xa hoi va han va~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu mach hoc tap, ((nghien huu) OR (nguyen huu)) mot hoc khanh phong (tuc OR thuc) xa hoi va han va.
• Adding a wildcard symbol may retrieve word variants: tu mach hoc tap, ((nghien huu) or (nguyen huu)) mot hoc khanh phong (tuc or thuc) xa hoi va han va*.