28444010 under HS Code Others, 90309090 under HS Code OSCILLOSCOPES, SPECTRUM ANALYSERS AND OTHER INSTRUMENTS AND APPARATUS FOR MEASURING OR CHECKING ELECTRICAL QUANTITIES, EXCLUDING METERS OF HEADING 9028; INSTRUMENTS AND APPARATUS FOR MEASURING OR DETECTING ALPHA, BETA, GAMMA, X-RAY, COSMIC OR OTHER IONISING RADIATIONS-PARTS AND ACCESSORIES: OTHER, and 38220090 under HS Code DIAGNOSTIC OR LABORATORY REAGENTS ON A BACKING, PREPARED DIAGNOSTIC OR LABORATORY REAGENTS WHETHER OR NOT ON A BACKING, OTHER THAN THOSE OF HEADING 3002 OR 3006; CERTIFIED REFERENCE MATERIALS DIAGNOSTIC OR LABORATORY REAGENTS ON A BACKING, PREPARED DIAGNOSTIC OR LABORATORY REAGENTS WHETHER OR NOT ON A BACKING, OTHER THAN THOSE OF HEADING 3002 OR 3006; CERTIFIED REFERENCE MATERIALS: OTHER were the top imported HS Codes by NUCLEAR RESEARCH INSTITUTE in 2021.