: , .
, .
,
. , a .
,
. , , c
,
s
s
. .
. 2
e e
1976
1981 a a
.
a
50 1981
. a
.
.
, a
, a
a .
55 .
a a
a
, ,
. a
a
a
a
a
a
.
8.4
3.7
.
,
6 a 5
.
.
, .
,
a
.
a
15
.
, .
26 21 .
a
.
24
a . a .
9
3 3 6
1992; 24:
.
.
Downloaded by: Chinese University of Hong Kong. Copyrighted material.
1975
42
1992;
24
1981
1988.
,
,
a
, .
2
.
1,000
a
96
,
;
, a a
.
, ; .
. a
a
.
a
e
a
. , 12.5
,
.
.
.
,
a
. a
a
.
.
, 22,
.
,
a
,
a a
a
. a .
.
a a
,
.
;
,
.
.
.
a ,
a
,
.
. , .
, .
,
.
,
a
.
.
.
, .
, a
.
.
a
.
,
,
.
a . .
. .
.
, a
,
a
, ,
.
a . ,
.
. 98.7
.
a . a
a
a
.
,
.
a a
. .
a a , 2
.
, a
a .
2
Downloaded by: Chinese University of Hong Kong. Copyrighted material.
a
:
43
1992; 24
a .
,
a
, ; a
45
.
42
, ;
30
.
, 10
.
,
.
, , .
a
a .
.
. a a
. . a
.
. 20
30
3
.
a a
.
: a
, ,
, ,
,
.
,
.
,
, .
. . , a
.
1
.
. .
, .
2
a
.
.
.
.
.
. a
.
.
a
2.
.
a
. 3
, 92
a
a
a
a
85
a ,
2
.
.
: 1990; 31:
4
. 39
.
a
.
.
. .
3.
, . 1989; 13:
.
.
. a
. . .
4.
7
. 2
.
.
1991; 100: a ,
. ;
.
. .
. . ,
Downloaded by: Chinese University of Hong Kong. Copyrighted material.
.
44
1992; 24 25 .
.
,
, 1980: 378
26
1 .
.
1976; 2:
.
6
1979; 54,
2 . 1985; 312:
:
3
27
.
.
1
1990; 12:
3
28
3 .
.
1984; 101:
1990; 19:
6
29
5 4
, a , 1986; 24:
à 1985; 107: 6
. 0
30
5 : .
1991; 178:
.
6
1988; 112:
5
31
6
:
a .
1989; 11:
, a
0 .
7
1987; 11:
9
32 1991; 302:
a 1987; 16: 966
2
8
a : 1990; 31:
a
.
.
33
a a
2
a
9 .
.
7
1988; 109: 664 34
670 10 11
.
1984; 25:
.
7 1991; 100:
. 30 ,
60 ,
,
.
a :
.
1
35 a
.
:
,
: .
, 1986:
: .
6
,
, 1989
12 .
1983: 85:
36
2
13 : 5
1986; 81:
.
. 1987; 34:
1
37
14 a
.
. .
1987; 11:
1987; 266:
7
7 38
15 .
.
1981; 81:
1989; 13:
41
7 39
16
7
. 1981;
22:
.
2
1991; 100:
4
40
17
, a
. 1983; 85:
.
4
1991; 100:
4
41
18 . :
.
:
a
.
, ,
,
1984; 30:
5
42
3
. 1991; 37
19 .
1977; 72: 838
43
841 .
20 1979; 2:
1990; 36:
1
44
4
a .
21 a 1991; 37: a
. 22 .
1986; 15: a
. 1983; 7:
.
6
23 .
1972; 4:
8
24 a
a .
1987; 11:
1
5
1
. 4
, ,
,
Downloaded by: Chinese University of Hong Kong. Copyrighted material.
a