全文获取类型
收费全文 | 1713篇 |
免费 | 99篇 |
国内免费 | 45篇 |
出版年
2024年 | 4篇 |
2023年 | 25篇 |
2022年 | 22篇 |
2021年 | 40篇 |
2020年 | 39篇 |
2019年 | 68篇 |
2018年 | 51篇 |
2017年 | 40篇 |
2016年 | 44篇 |
2015年 | 41篇 |
2014年 | 148篇 |
2013年 | 235篇 |
2012年 | 133篇 |
2011年 | 128篇 |
2010年 | 104篇 |
2009年 | 68篇 |
2008年 | 85篇 |
2007年 | 109篇 |
2006年 | 91篇 |
2005年 | 88篇 |
2004年 | 69篇 |
2003年 | 55篇 |
2002年 | 38篇 |
2001年 | 22篇 |
2000年 | 20篇 |
1999年 | 21篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1857条查询结果,搜索用时 97 毫秒
11.
Under the protection of ascorbic acid a 2-hydroxyestrone bovine serum albumin conjugate was prepared containing intact 2-hydroxyestrone as determined by gas chromatographymass spectrometry. Using this antigen highly specific antibodies were raised in rabbits. Cross-reactivity for 2-hydroxyestradiol and 2-hydroxyestriol was 26 and 4.5%, respectively. An assay procedure of 2-hydroxyestrone in human plasma is described. Using special precautions the assay allows the determination of 2-hydroxyestrone in plasma samples of women (50–95 pg/ml), pregnant women (105–220 pg/ml), men (45–65 pg/ml) and children (20–40 pg/ml). 相似文献
12.
S. B. Greenberg G. L. Grove V. J. Cristofalo 《In vitro cellular & developmental biology. Plant》1977,13(5):297-300
Summary Changes in the size of the area covered by individual cultured WI-38 cells as the cultures age have been studied by using
a new microphotographic paper cutout technique. This method is nondestructive and nonintrusive and avoids a number of artifacts
which can occur in the measurement of suspended cells. The measurements reveal that the decreased cell yield of late passage
cultures-reflects not only the appearance of a subpopulation of larger cells but also the failure of the cells to utilize
all the growth surface available to them.
This work was supported in part by USPHS research grant AG-00378 and by a fellowship, AG-05019, from the National Institute
on Aging. 相似文献
13.
Critical adjustment of cysteine and glutamine concentrations for improved clonal growth of WI-38 cells 总被引:2,自引:0,他引:2
Dr. Richard G. Ham Susan L. Hammond Linda L. Miller 《In vitro cellular & developmental biology. Plant》1977,13(1):1-10
Summary Clonal growth of WI-38 cells with a plating efficiency of 45% has been achieved in a synthetic nutrient mixture (MCDB 102)
supplemented with either whole or dialyzed fetal bovine serum. For optimum growth, the concentration of cysteine in the medium
must be adjusted precisely. Deviation by a factor of three in either direction from the optimum concentration (9.0×10−5M) eliminates essentially all clonal growth. A high concentration of glutamine (2.5×10−3M) is also needed for, optimum clonal growth.
Presented in preliminary form at the 26th Annual Meeting of the Tissue Culture Association, June 4, 1975.
This work was supported by Grant No. HD-08181 from the National Institute of Child Health and Human Developement, Grant No.
AG-00310 from the National Institute on Aging, and by Contract No. 223-74-1156 from the Bureau of Biologics, Food and Drug
Administration. 相似文献
14.
Dry lettuce (Lactuca sativa L.) seeds (achenes) contain -galactosidase (EC 3.2.122) at a level which is maintained in the imbibed dormant state in darkness. Both red light (R) and gibberellic acid promote an increase in enzyme activity several hours prior to the completion of germination. Germination and enzyme activity are not essentially linked, however, for the latter can increase while the former is inhibited. -Galactosidase activity increases within the cotyledons and the endosperm following R stimulation, but the axis is essential to perceive the stimulus and to promote and maintain the increase in enzyme activity. A diffusible factor (or factors) is produced by and-or released from irradiated axes, and it migrates to the cotyledons (and possibly endosperm) to promote the increase in -galactosidase activity. Gibberellic acid, particularly in the presence of benzyladenine, can replace the requirement for irradiated axes.Abbreviations GA3
gibberellic acid
- R
red light 相似文献
15.
STEVEN T. KALINOWSKI 《Molecular ecology resources》2006,6(4):974-979
Deviations from Hardy–Weinberg expectations are frequently a sign of genotyping error. hw‐quickcheck is an easy‐to‐use computer program for detecting departures from Hardy–Weinberg equilibrium. hw‐quickcheck uses exact tests for all of its calculations. These tests include a global test for heterozygote excess/deficiency and genotype‐specific tests. 相似文献
16.
17.
Zhuona Xi Yahong Qiao Jifang Wang Hongjian Su Zhen Bao Hongyan Li Xiaoming Liao Xiaolan Zhong 《Journal of cellular and molecular medicine》2020,24(2):1451-1459
The beneficial function of gastrodin towards many inflammatory diseases has been identified. This study designed to see the influence of gastrodin in a cell model of chronic obstructive pulmonary disease (COPD). MRC‐5 cells were treated by LPS, before which gastrodin was administrated. The effects of gastrodin were evaluated by conducting CCK‐8, FITC‐PI double staining, Western blot, qRT‐PCR and ELISA. Besides this, the downstream effector and signalling were studied to decode how gastrodin exerted its function. And dual‐luciferase assay was used to detect the targeting link between miR‐103 and lipoprotein receptor‐related protein 1 (LRP1). LPS induced apoptosis and the release of MCP‐1, IL‐6 and TNF‐α in MRC‐5 cells. Pre‐treating MRC‐5 cells with gastrodin attenuated LPS‐induced cell damage. Meanwhile, p38/JNK and NF‐κB pathways induced by LPS were repressed by gastrodin. miR‐103 expression was elevated by gastrodin. Further, the protective functions of gastrodin were attenuated by miR‐103 silencing. And LRP1 was a target of miR‐103 and negatively regulated by miR‐103. The in vitro data illustrated the protective function of gastrodin in LPS‐injured MRC‐5 cells. Gastrodin exerted its function possibly by up‐regulating miR‐103 and modulating p38/JNK and NF‐κB pathways. 相似文献
18.
Jianli Liu Siqi Tian Mingyang Fu Yin He Hui Yu Xiangyu Cao Yiyang Cao Hanyuan Xu 《化学与生物多样性》2020,17(2)
Anthocyanins (AC) from Coreopsis tinctoria possesses strong antioxidant properties, while the effects of AC on cells damage induced by reactive oxygen species (ROS) in diabetes mellitus diseases progression have not been reported. The present study was carried out to evaluate the protective property of AC against cellular oxidative stress with an experimental model, H2O2‐exposed MIN6 cells. AC could reverse the decrease of cell viability induced by H2O2 and efficiently suppressed cellular ROS production and cell apoptosis. In addition, Real‐time PCR and Western blot analyses indicated that AC could protect MIN6 cells against oxidative injury through increasing the translocation of Nrf2 into nuclear, decreasing the phosphorylation level of p38 and up‐regulating the protein expression of antioxidant enzyme (SOD1, SOD2 and CAT). Thus, this study provides evidence to support the beneficial effect of AC in inhibiting MIN6 cells from H2O2‐induced oxidative injury. 相似文献
19.
Yun Ge Man Huang Yao Wu Ning Dong Yong‐Ming Yao 《Journal of cellular and molecular medicine》2020,24(2):2027-2039
Naturally occurring CD4+CD25+ regulatory T cells (Tregs) are required to limit immune‐induced pathology and to maintain homeostasis during the early‐phase of sepsis. This study aimed to investigate the role of interleukin (IL)‐38, a newly described member of the IL‐1 cytokine family, in mediated immune response of CD4+CD25+ Tregs in sepsis. Here, we provide evidence that expressions of IL‐38 and its receptor were detected in murine CD4+CD25+ Tregs. Stimulation of CD4+CD25+ Tregs with LPS markedly up‐regulated the expression of IL‐38. Treatment with rmIL‐38 dramatically enhanced the immunosuppressive activity of CD4+CD25+ Tregs after LPS stimulation and in septic mice induced by CLP, resulting in amplification of helper T cell (Th) 2 response and reduction in the proliferation of effector T cells. These effects were robustly abrogated when anti–IL‐38 antibody was administered. Administration of rmIL‐38 improved the survival rate of CLP mice. In addition, CD4+CD25+ Tregs depletion before the onset of sepsis obviously abolished IL‐38–mediated protective response. These findings suggest that IL‐38 enhances the immunosuppressive activity of CD4+CD25+ Tregs, which might contribute to the improvement of host immune function and prognosis in the setting of sepsis. 相似文献
20.
Juan Wang Min Han Su‐xia Han Cuiju Zhi Suli Gao Yao Li 《Journal of cellular and molecular medicine》2020,24(2):1795-1803
Atrial fibrosis is an important factor in the initiation and maintenance of atrial fibrillation (AF); therefore, understanding the pathogenesis of atrial fibrosis may reveal promising therapeutic targets for AF. In this study, we successfully established a rapid atrial pacing canine model and found that the inducibility and duration of AF were significantly reduced by the overexpression of c‐Ski, suggesting that this approach may have therapeutic effects. c‐Ski was found to be down‐regulated in the atrial tissues of the rapid atrial pacing canine model. We artificially up‐regulated c‐Ski expression with a c‐Ski–overexpressing adenovirus. Haematoxylin and eosin, Masson's trichrome and picrosirius red staining showed that c‐Ski overexpression alleviated atrial fibrosis. Furthermore, we found that the expression levels of collagen III and α‐SMA were higher in the groups of dogs subjected to right‐atrial pacing, and this increase was attenuated by c‐Ski overexpression. In addition, c‐Ski overexpression decreased the phosphorylation of smad2, smad3 and p38 MAPK (p38α and p38β) as well as the expression of TGF‐β1 in atrial tissues, as shown by a comparison of the right‐atrial pacing + c‐Ski‐overexpression group to the control group with right‐atrial pacing only. These results suggest that c‐Ski overexpression improves atrial remodelling in a rapid atrial pacing canine model by suppressing TGF‐β1–Smad signalling and p38 MAPK activation. 相似文献