全文获取类型
收费全文 | 6370篇 |
免费 | 432篇 |
国内免费 | 3篇 |
出版年
2022年 | 33篇 |
2021年 | 87篇 |
2020年 | 45篇 |
2019年 | 69篇 |
2018年 | 99篇 |
2017年 | 100篇 |
2016年 | 145篇 |
2015年 | 195篇 |
2014年 | 258篇 |
2013年 | 353篇 |
2012年 | 354篇 |
2011年 | 424篇 |
2010年 | 246篇 |
2009年 | 215篇 |
2008年 | 335篇 |
2007年 | 333篇 |
2006年 | 331篇 |
2005年 | 298篇 |
2004年 | 350篇 |
2003年 | 305篇 |
2002年 | 275篇 |
2001年 | 162篇 |
2000年 | 168篇 |
1999年 | 134篇 |
1998年 | 71篇 |
1997年 | 70篇 |
1996年 | 48篇 |
1995年 | 66篇 |
1994年 | 46篇 |
1993年 | 50篇 |
1992年 | 101篇 |
1991年 | 90篇 |
1990年 | 83篇 |
1989年 | 89篇 |
1988年 | 80篇 |
1987年 | 91篇 |
1986年 | 67篇 |
1985年 | 74篇 |
1984年 | 56篇 |
1983年 | 39篇 |
1982年 | 38篇 |
1981年 | 27篇 |
1979年 | 40篇 |
1978年 | 19篇 |
1977年 | 20篇 |
1975年 | 16篇 |
1974年 | 24篇 |
1973年 | 29篇 |
1971年 | 16篇 |
1966年 | 17篇 |
排序方式: 共有6805条查询结果,搜索用时 31 毫秒
991.
M Fujita 《Journal of theoretical biology》1982,99(1):9-13
We show numerical evidence of continuous and discontinuous transitions between entrainment (frequency-locking) and beating regimes in a driven non-linear oscillator. 相似文献
992.
993.
994.
SERUM DOPAMINE-β-HYDROXYLASE IN SCHIZOPHRENIC PATIENTS 总被引:2,自引:2,他引:0
K. Fujita T. Ito K. Maruta R. Teradaira H. Beppu Y. Nakacami Y. Kato T. Nagatsu T. Kato 《Journal of neurochemistry》1978,30(6):1569-1572
Abstract— Dopamine-β-hydroxylase (DBH) activity in serum was decreased significantly in schizophrenic patients (16.17 ± 12.60 μmol/min/1 of serum, mean ± S.D., n = 149) when compared with that of normal controls (42.53 ± 30.94 μmol/min/1 of serum, mean ± S.D., n= 153) and neurotic patients. Long duration of disease did not cause any significant changes in serum DBH activity except a tendency for increase in patients of lodger than 18 years duration. We also examined the possibility that the serum DBH deficiency in the schizophrenic group was an artifact of treatment with antipsychotic drugs, especially phenothiazines. No significant difference was observed between the patients treated with the drugs and the patients not receiving the drugs. 相似文献
995.
Akitoshi Nakashima Mikiko Yamanaka-Tatematsu Naonobu Fujita Keiichi Koizumi Tomoko Shima Toshiko Yoshida Toshio Nikaido Aikou Okamoto Tamotsu Yoshimori Shigeru Saito 《Autophagy》2013,9(3):303-316
In early pregnancy, trophoblasts and the fetus experience hypoxic and low-nutrient conditions; nevertheless, trophoblasts invade the uterine myometrium up to one third of its depth and migrate along the lumina of spiral arterioles, replacing the maternal endothelial lining. Here, we showed that autophagy, an intracellular bulk degradation system, occurred in extravillous trophoblast (EVT) cells under hypoxia in vitro and in vivo. An enhancement of autophagy was observed in EVTs in early placental tissues, which suffer from physiological hypoxia. The invasion and vascular remodeling under hypoxia were significantly reduced in autophagy-deficient EVT cells compared with wild-type EVT cells. Interestingly, soluble endoglin (sENG), which increased in sera in preeclamptic cases, suppressed EVT invasion by inhibiting autophagy. The sENG-inhibited EVT invasion was recovered by TGFB1 treatment in a dose-dependent manner. A high dose of sENG inhibited the vascular construction by EVT cells and human umbilical vein endothelial cells (HUVECs), meanwhile a low dose of sENG inhibited the replacement of HUVECs by EVT cells. A protein selectively degraded by autophagy, SQSTM1, accumulated in EVT cells in preeclamptic placental biopsy samples showing impaired autophagy. This is the first report showing that impaired autophagy in EVT contributes to the pathophysiology of preeclampsia. 相似文献
996.
The presence of rhodopsin-like protein was detected in the head of the freshwater planarian Dugesia japonica japonica Ichikawa et Kawakatsu by use of anti-frog-rhodopsin rabbit IgG. Two membrane proteins of molecular weights 65000 and 62000 were separated by sodium-dodecyl-sulfate polyacrylamide gel electrophoresis and found to react with the anti-rhodopsin IgG. The antibody may be useful for monitoring regeneration of the planarian eye. 相似文献
997.
998.
H Sugiya Y Fujita E Fukushima T Yamazaki S Furuyama 《The International journal of biochemistry》1988,20(3):237-241
1. Regulation of phosphofructokinase in rat submandibular gland was non-Michaelis-Menten type at physiological pH. 2. At pH 7.3, ATP played a dual role on phosphofructokinase acting as a substrate and inhibitor at high concentration of ATP. 3. The activator of phosphofructokinase was present in cytosol fraction, and its properties were resemble to those of fructose 2,6-bisphosphate. 4. Both the activator and authentic fructose 2,6-bisphosphate relieved the inhibition of phosphofructokinase by ATP, and increased the affinity for fructose 6-phosphate. 5. Concentration of fructose 2,6-bisphosphate in rat submandibular gland was 8.22 nmol/g tissue, and which was about the half of that in liver. 6. Phosphofructokinase in rat submandibular gland was found to be regulated synergistically by ATP, fructose 6-phosphate and fructose 2,6-bisphosphate. 相似文献
999.
1000.