url = "http://define.cnki.net/WebForms/WebNavigationContent.aspx?name="+'{}'.format(subjectsName)+"&id=1&page=1"
r=requests.get(url)
r.raise_for_status()
r.encoding=r.apparent_encoding
soup=BeautifulSoup(r.text,"lxml")
p = str(soup.find_all("span",attrs = {'class':'txtspan'})[-1])
page = re.findall('[0-9]?[0-9]?[1-9]',p)[-1] #获取学科页码数
就是p = str(soup.find_all("span",attrs = {'class':'txtspan'})[-1])出错