First-quarter underlying results at Smiths Group were lower than last year, but the technology and engineering firm said it still remains on track for the full year.Underlying revenues and headline operating profits in the three months to 1 November were below the same period last year, though the company said this was expected.Growth in Smiths Medical was outweighed by declines in Smiths Detection and Smiths Interconnect, while John Crane results were broadly similar to last year.Foreign exchange is estimated to have a 3% adverse impact on group headline operating profits in the first half. However, the company said that this headwind is "expected to reverse" during the second half if current rates are maintained."More generally, as previously guided, the group's underlying performance will be weighted towards the second half," Smiths Group said.Smiths Detection, which makes sensors that detect explosives and radioactive material, is continuing to be affected by constraints on government spending.The electronic components division, Smiths Interconnect, started the year "more slowly than expected" due to spending delays by wireless telecoms customers, order timings and continued softness in some end markets such as defence.John Crane, which provides technology for the energy services sectors, delivered a flat result as growth in the rotating equipment business was offset by declines in the upstream energy unit. The company said it is monitoring the trading environment closely due to concerns over the outlook for oil and gas spending given the recent slump in oil prices.