Determination of nine kinds of nucleosides in Spirodelae Herba from different habitats by UPLC-MS/MS Determination of thymine, hypoxanthine and uracil contents in medical pipefish by HPLC DOSE EFFECT OF N~+ AND Ar~+ IMPLANTATION INTO THYMINE AND URACIL Study on chemical constituents of Typha angustifolia Study on chemical constituents in pollen of Typha angustifolia