* C$ at C$0.9922 vs US$, or $1.0078 * U.S. jobless claims fall back to 4-year lows * Bond prices lower across the curve By Jon Cook TORONTO, March 15 (Reuters) - The Canadian dollar turned slightly positive against the greenback on Thursday after data showed U.S. jobless claims fell back to a four-year low last week but it slid against other major currencies. Canada's role as the largest U.S. trading partner has recently helped it outperform other commodity-linked currencies as strong U.S. data and a more optimistic economic tone from the Federal Reserve have boosted North American sentiment. In further signs of U.S. economic strength, initial claims for state unemployment benefits dropped 14,000 to a seasonally adjusted 351,000, falling back to a four-year low reached in February, the Labor Department said on Thursday. The Canadian dollar touched a session high at C$0.9915 versus the U.S. dollar, or $1.0085, shortly after the data was released, but failed to test this week's low at C$0.9881, as the U.S. jobless claims came in below Reuters estimates of 356,000. At 9:00 a.m. (1300 GMT), the Canadian dollar was at C$0.9922 versus the U.S. dollar, or $1.0078, up slightly from Wednesday's North American session close at C$0.9930 versus the U.S. dollar, or $1.0070. On Wednesday the Canadian dollar hit its strongest level against the Australian currency this year, breaking through the 200-day moving average and testing an overnight high at C$1.0450. But after testing technical thresholds against the Australian and New Zealand currencies and against the euro, Canada's dollar retreated on Thursday. "That might have caused a few of the short Canadian dollar positions to get squeezed on the move back up on the cross," said David Bradley, a director of foreign exchange trading at Scotia Capital. Canada's resource-reliant dollar was also held back after top consumer China said on Wednesday it must embrace slower growth to keep its economy from faltering, hurting industrial metals prices such as copper. Canadian bond yields rose above their yearly highs set on Wednesday as risk appetite improved. The two-year bond was down 3 Canadian cents to yield 1.259 percent, while the 10-year bond dropped 42 Canadian cents to yield 2.202 percent.