全文获取类型
收费全文 | 1355篇 |
免费 | 43篇 |
专业分类
1398篇 |
出版年
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 17篇 |
2018年 | 28篇 |
2017年 | 27篇 |
2016年 | 25篇 |
2015年 | 29篇 |
2014年 | 44篇 |
2013年 | 63篇 |
2012年 | 62篇 |
2011年 | 65篇 |
2010年 | 43篇 |
2009年 | 47篇 |
2008年 | 53篇 |
2007年 | 43篇 |
2006年 | 51篇 |
2005年 | 49篇 |
2004年 | 44篇 |
2003年 | 29篇 |
2002年 | 45篇 |
2001年 | 67篇 |
2000年 | 44篇 |
1999年 | 32篇 |
1998年 | 28篇 |
1997年 | 17篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 12篇 |
1992年 | 25篇 |
1991年 | 27篇 |
1990年 | 22篇 |
1989年 | 33篇 |
1988年 | 25篇 |
1987年 | 20篇 |
1986年 | 26篇 |
1985年 | 19篇 |
1984年 | 18篇 |
1983年 | 14篇 |
1979年 | 12篇 |
1978年 | 8篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1974年 | 14篇 |
1973年 | 10篇 |
1972年 | 18篇 |
1971年 | 7篇 |
1970年 | 8篇 |
1969年 | 7篇 |
1968年 | 7篇 |
1967年 | 14篇 |
排序方式: 共有1398条查询结果,搜索用时 15 毫秒
81.
82.
83.
Statistical analysis of the low-frequency (1.0 sec-1 and lower) neuronal impulse activity (IA) meets a few fundamental difficulties. Among them, the most significant is the small number of measurements (interspike intervals) recorded within an acceptable analysis epoch. In our study, we examined the possibility of using the normalized (by its maximum value) informational entropy (Hn) for estimation of the significance of changes in the IA generated by low-frequency neurons of the rostral hypothalamus after electrical stimulation of the prefrontal cortex. We compared the efficiencies of using the U-test (Kolmogorov–Mann–Whitney) and Hn estimate for the analysis of the same samples of neuronal responses. The results allow us to conclude that Hn is a significantly more acceptable estimate for detection of stimulation-induced modifications of the IA generated by low-frequency neurons, as compared with the U-test. The direction of shifts in the Hn value makes it possible to estimate the pattern of neuronal response. This value reflects the state of the neuron and correlates with the type of neuronal responses. 相似文献
84.
L I Maleeva V V Sergeev S A Pecherkina V P Kuznetsov 《Antibiotiki i khimioterapii͡a》1988,33(11):820-823
Under the effect of human leukocytic alpha-interferon-II for injections there was observed an increase in sensitivity of bacteria to benzylpenicillin, ristomycin, novobiocin, streptomycin, kanamycin, monomycin and erythromycin. A higher antibacterial effect of the penicillin and erythromycin was recorded only with respect to initially resistant strains of staphylococci. For the antibiotic resistant strains of staphylococci the MICs of the penicillin and erythromycin decreased on the average 17.8 and 208 times (p less than 0.001) respectively. The interferon had no effect on sensitivity of bacteria to chloramphenicol. 相似文献
85.
Using the Perkin Elmer flame photometer sodium and potassium concentrations have been measured in muscle fibers from the m. ileofibularis of Rana temporaria. After 30 minutes preincubation in the Ringer solution, made hypertonic by the addition of 0.22M glycerol, the muscle fibers were incubated in the normal Ringer solution for 30 min. These fibers showed a vacuolation and an increase in total fiber sodium up to 37.2 mmol/l +/- 5.9 S. E., or 45.8 mmol/kg H2O +/- 7.3 S. E. No significant changes in potassium concentration were observed. Then, the fibers were exposed again to the Ringer solution containing 0.22 M glycerol. This procedure caused the disappearance of vacuoles and decrease in fiber sodium concentration down to 17.7 mmol/l +/- 1.6 S. E., or 21.8 mmol/kg H2O +/- 2.0 S. E. The effect of vacuolation was not blocked by ouabain (1.10(-4) M). It is suggested that the vacuoles have a high NaCl concentration. A model for NaCl and water accumulation in T-tubules is presented. 相似文献
86.
87.
Kuznetsova S. A. Vasilyeva N. Yu. Drozd N. N. Mikhailenko M. A. Shakhtshneider T. P. Malyar Yu. N. Kuznetsov B. N. Chesnokov N. V. 《Russian Journal of Bioorganic Chemistry》2020,46(7):1323-1329
Russian Journal of Bioorganic Chemistry - A comparison of IR spectra and molecular weight distribution of arabinogalactan sulfates as sodium and ammonium salts obtained using various sulfating... 相似文献
88.
89.
90.
Zlobin I. E. Kartashov A. V. Kuznetsov Vl. V. 《Russian Journal of Plant Physiology》2019,66(4):591-596
Russian Journal of Plant Physiology - It is well known that excessive zinc accumulation is harmful to plant cells. Though, it is uncertain at which levels of intracellular availability zinc begins... 相似文献