Perhaps you should try some spelling variations:
"complementary and alternative designs" » "complementary and alternative antigens" (Expand Search), "complementary and alternative tests" (Expand Search), "complementary and alternative depictions" (Expand Search)
"complementary and alternative splicing" » "complementary and alternative splitting" (Expand Search), "complementary and alternative pricing" (Expand Search), "complementary and alternative spacing" (Expand Search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("complementary and alternative designs") OR ("complementary and alternative splicing"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"complementary and alternative designs\") OR (\"complementary and alternative splicing\"))".
• Removing quotes may allow a broader search: (( complementary and alternative designs ) OR ( complementary and alternative splicing )).
• Adding a wildcard symbol may retrieve word variants: (("complementary and alternative designs") OR ("complementary and alternative splicing"))*.