The Eastern Scientific approach in general, and 1984 Bridge World Standard in particular, produce difficulties for responder with a long suit lower in rank than the opening bid. If partner's opening is a major, you cannot bid your suit directly without forcing to game unless you plan to rebid it. Often, however, you cannot show both your long suit and game-invitational strength after responding one notrump. Use of five-card majors does not substantially affect the response with this hand type. You are too weak for two clubs, even if you intend to follow with three clubs showing invitational strength.
Most experts choose one spade here, intending to pass two diamonds.
Here you are strong enough to bid two clubs, then three clubs, but that will lose a four-four spade fit. There are possible problems, but here we think the best shot is to bid two clubs, planning to rebid three clubs. This aims at the most likely contracts, three clubs and three notrump. Although there is no major to worry about, things could get out of hand. This hand, considering the misfit and the lack of strong secondary clubs, is really fractionally below the values need to force to game.