Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
thien van » thi van
toc sach » hoc sach, doc sach, thuoc sach
sinh dai » sinh thai, si dai, sinh vat
cham tuc » pham thuc, tham thuc, cham soc
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
va sinh » va kinh, va tinh, vi sinh
nang xa » nang x, lang xa, mang xa
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky ((nang xa) OR (nang ma)) hoi. thien van ((cham tuc) or (nham thuc)) va sinh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((nang xa) OR (nang ma)) hoi. thien van ((cham tuc) OR (nham thuc)) va sinh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((nang xa) OR (nang ma)) hoi. thien van ((cham tuc) or (nham thuc)) va sinh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((nang xa) OR (nang ma)) hoi. thien van ((cham tuc) or (nham thuc)) va sinh dai cua tre*.