全文获取类型
收费全文 | 80897篇 |
免费 | 4571篇 |
国内免费 | 9篇 |
专业分类
85477篇 |
出版年
2023年 | 463篇 |
2021年 | 942篇 |
2020年 | 848篇 |
2019年 | 828篇 |
2018年 | 2198篇 |
2017年 | 1929篇 |
2016年 | 2615篇 |
2015年 | 3457篇 |
2014年 | 3540篇 |
2013年 | 4660篇 |
2012年 | 5469篇 |
2011年 | 4789篇 |
2010年 | 3119篇 |
2009年 | 2300篇 |
2008年 | 3845篇 |
2007年 | 3619篇 |
2006年 | 3587篇 |
2005年 | 3000篇 |
2004年 | 3017篇 |
2003年 | 2679篇 |
2002年 | 2456篇 |
2001年 | 2021篇 |
2000年 | 1889篇 |
1999年 | 1449篇 |
1998年 | 631篇 |
1996年 | 505篇 |
1992年 | 906篇 |
1991年 | 831篇 |
1990年 | 815篇 |
1989年 | 888篇 |
1988年 | 728篇 |
1987年 | 749篇 |
1986年 | 685篇 |
1985年 | 749篇 |
1984年 | 620篇 |
1983年 | 543篇 |
1982年 | 453篇 |
1979年 | 668篇 |
1978年 | 488篇 |
1977年 | 488篇 |
1975年 | 584篇 |
1974年 | 623篇 |
1973年 | 595篇 |
1972年 | 547篇 |
1971年 | 491篇 |
1970年 | 536篇 |
1969年 | 610篇 |
1968年 | 573篇 |
1967年 | 479篇 |
1966年 | 466篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
141.
142.
Marie Lipoldová Helena Havelková Jana Badalová Jarmila Vojtíšková Lei Quan Magdaléna Krulová Yahya Sohrabi Alphons P. Stassen Peter Demant 《Cancer immunology, immunotherapy : CII》2010,59(2):203-213
Low infiltration of lymphocytes into cancers is associated with poor prognosis, but the reasons why some patients exhibit
a low and others a high infiltration of tumors are unknown. Previously we mapped four loci (Lynf1–Lynf4) controlling lymphocyte infiltration of mouse lung tumors. These loci do not encode any of the molecules that are involved
in traffic of lymphocytes. Here we report a genetic relationship between these loci and the control of production of IFNγ
in allogeneic mixed lymphocyte cultures (MLC). We found that IFNγ production by lymphocytes of O20/A mice is lower than by
lymphocytes of OcB-9/Dem mice (both H2
pz
) stimulated in MLC by irradiated splenocytes of C57BL/10SnPh (H2
b
) or BALB/cHeA (H2
d
) mice, or by ConA. IFNγ production in MLCs of individual (O20 × OcB-9)F2 mice stimulated by irradiated C57BL/10 splenocytes and genotyped for microsatellite markers revealed four IFNγ-controlling
loci (Cypr4-Cypr7), each of which is closely linked with one of the four Lynf loci and with a cluster of susceptibility genes for different tumors. This suggests that inherited differences in certain
lymphocyte responses may modify their propensity to infiltrate tumors and their capacity to affect tumor growth. 相似文献
143.
Using gas chromatography, the authors studied the development of the proportion of 25 saturated and non-saturated fatty acids in the plasma of Wistar rats of their own breed aged 5, 10, 14 and 25 days and adult (both sexes), and in three age groups (5 and 14 day and adult) they determined the effect of acute altitude hypoxia. Fatty acids were determined as methylesters (FAME) (Base 1978), using the method already described by Smídová et al. (1984a), in mixed blood plasma obtained from decapitated control and experimental animals. Altitude hypoxia, which corresponded to 9 000 m, lasted 20 min. The temperature was kept stable at 25 degrees C. Marked changes occurred during ontogenesis in the proportion of total fatty acids (TFA) in the plasma; the proportion of sigma non-saturated FA fell significantly during maturation, chiefly in favour of monoene FA, with a resultant significant drop in their reciprocal index (sigma saturated/sigma monoene). The proportion of all saturated FA amounted in 5-day-old rats to 54% of the total quantity, but in adult rats to only 40%. Acute hypoxia had a demonstrable effect in all three age categories. In 5-day-old rats it led to significant changes in 7 FA and in adult rats in 10. In both 5-day-old and adult animals it produced an increase in the arachidonic acid level. The results are discussed in relation to previous findings on the effect of the same hypoxia on FA proportion in various parts of the CNS of rats of different ages. 相似文献
144.
145.
Csercsik D Farkas I Hrabovszky E Liposits Z 《Journal of computational neuroscience》2012,32(1):119-136
In this paper a modular model of the GnRH neuron is presented. For the aim of simplicity, the currents corresponding to fast time scales and action potential generation are described by an impulsive system, while the slower currents and calcium dynamics are described by usual ordinary differential equations (ODEs). The model is able to reproduce the depolarizing afterpotentials, afterhyperpolarization, periodic bursting behavior and the corresponding calcium transients observed in the case of GnRH neurons. 相似文献
146.
Flávio Resende 《Planta》1936,25(4):665-666
Ohne ZusammenfassungMit 1 Textabbildung (3 Einzelbildern). 相似文献
147.
148.
149.
D Hernández S Guerrero M Morales 《Comparative biochemistry and physiology. A, Comparative physiology》1987,87(3):649-656
1. The cardiac pacemaker cells of the frog Caudiverbera caudiverbera are centrally located in the sinus venosus. These cells are rounded, smaller than contractile fibres and have large nuclei. 2. Intracellular recording confirmed the existence of primary and transitional pacemaker cells. 3. Action potentials from primary cells were resistant to blockade by tetrodotoxin (TTX), but were abolished by verapamil suggesting that their bioelectric activity is dependent on a slow inward current. 4. Transitional cells appeared to have two different inward currents contributing to the upstroke: a fast TTX-sensitive and a slow verapamil-sensitive current. 相似文献
150.
F Escrivá A M Pascual-Leone J Hernández P Ferré J Girard 《Comparative biochemistry and physiology. A, Comparative physiology》1987,87(4):1041-1043
1. The feeding pattern influences the inhibitory effects of malonyl-CoA on carnitine palmitoyltransferase-I. 2. The sensitivity of liver carnitine palmitoyltransferase-I to malonyl-CoA is increased in rats meal-fed when compared to rats fed ad libitum. 3. Moreover, liver carnitine palmitoyltransferase-I of meal-fed rats remains more sensitive to inhibition by malonyl-CoA during a 24 hour fast than liver carnitine palmitoyltransferase-I of rats previously fed ad libitum. 相似文献