下列关于癌细胞的表面结构的描述,说法错误的是()。
A. 接触抑制丧失
B. 黏着作用消失
C. 细胞膜组成的异常
D. 抗原性维持不变
E. 与外源性凝集素的反应
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下列哪种询问调查方法的回收率低且容易产生理解差错:()
A. 面谈调查法
B. 邮寄调查法
C. 电话调查法
D. 留置问卷调查法
按信息资料的形态划分,市场信息的类型有原始信息和加工信息。
A. 正确
B. 错误
The EMP table contains these columns: LAST_NAME VARCHAR2 (25) SALARY NUMBER (6,2) DEPARTMENT_ID NUMBER (6) You need to display the employees who have not been assigned to any department. You write the SELECT statement: SELECT LAST_NAME, SALARY, DEPARTMENT_ID FROM EMP WHERE DEPARTMENT_ID = NULL; What is true about this SQL statement ?()
A. The SQL statement displays the desired results.
B. The column in the WHERE clause should be changed to display the desired results.
C. The operator in the WHERE clause should be changed to display the desired results.
D. The WHERE clause should be changed to use an outer join to display the desired results.
纳税人提供建筑业劳务(不含装饰劳务)的,其营业额应当包括工程所用原材料、设备及其他物资和动力价款在内。()
A. 正确
B. 错误