全文获取类型
收费全文 | 1099篇 |
免费 | 96篇 |
国内免费 | 90篇 |
出版年
2023年 | 16篇 |
2022年 | 22篇 |
2021年 | 51篇 |
2020年 | 36篇 |
2019年 | 39篇 |
2018年 | 40篇 |
2017年 | 32篇 |
2016年 | 43篇 |
2015年 | 62篇 |
2014年 | 56篇 |
2013年 | 72篇 |
2012年 | 89篇 |
2011年 | 84篇 |
2010年 | 34篇 |
2009年 | 48篇 |
2008年 | 50篇 |
2007年 | 40篇 |
2006年 | 55篇 |
2005年 | 31篇 |
2004年 | 23篇 |
2003年 | 25篇 |
2002年 | 34篇 |
2001年 | 26篇 |
2000年 | 29篇 |
1999年 | 15篇 |
1998年 | 16篇 |
1997年 | 38篇 |
1996年 | 31篇 |
1995年 | 21篇 |
1994年 | 15篇 |
1993年 | 21篇 |
1992年 | 18篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1946年 | 2篇 |
排序方式: 共有1285条查询结果,搜索用时 15 毫秒
91.
92.
Xiaozhen Wang Guang Lu Li Li Juan Yi Kaowen Yan Yaqing Wang Baili Zhu Jingyu Kuang Ming Lin Sha Zhang Genze Shao 《Biochemical and biophysical research communications》2014
The cellular BRCA1 protein level is essential for its tumor suppression activity and is tightly regulated through multiple mechanisms including ubiquitn–proteasome system. E3 ligases are involved to promote BRCA1 for ubiquitination and degradation. Here, we identified HUWE1/Mule/ARF-BP1 as a novel BRCA1-interacting protein involved in the control of BRCA1 protein level. HUWE1binds BRCA1 through its N-terminus degron domain. Depletion of HUWE1 by siRNA-mediated interference significantly increases BRCA1 protein levels and prolongs the half-life of BRCA1. Moreover, exogenous expression of HUWE1 promotes BRCA1 degradation through the ubiquitin–proteasome pathway, which could explain an inverse correlation between HUWE1 and BRCA1 levels in MCF10F, MCF7 and MDA-MB-231 breast cancer cells. Consistent with a functional role for HUWE1 in regulating BRCA1-mediated cellular response to DNA damage, depletion of HUWE1 by siRNA confers increased resistance to ionizing radiation and mitomycin. These data indicate that HUWE1 is a critical negative regulator of BRCA1 and suggest a new molecular mechanism for breast cancer pathogenesis. 相似文献
93.
Jing Peng Hong Xu Bei Yang Jia Hu Bao-Ping Zhang Lin Zou Hai-Bin Kuang 《Peptides》2010,31(12):2255-2258
The menopause, defined as the permanent cessation of menstruation resulting from ovarian failure, is characterized by elevated levels of serum gonadotropins. Recent studies have demonstrated that the gonadotropin hypersecretion in postmenopausal women is secondary to increase of KiSS-1 mRNA from the hypothalamus neurons, which encoded kisspeptin peptides. The present study was designed to determine whether plasma kisspeptins levels are altered in postmenopausal women. Blood samples were taken from 145 postmenopausal women, 35 young women and 30 pregnant women control in the first trimester. The plasma concentration of kisspeptins, follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E2) was measured using immunoassay kits. Results indicated that plasma kisspeptins levels in postmenopausal women had higher than those in young women (5.25 ± 0.36; 4.48 ± 0.34 pmol/L), but no significant difference was found between the two groups (p = 0.179). Plasma FSH and LH levels were significantly higher in postmenopausal women (124.67 ± 12.78, 57.14 ± 3.57 mIu/mL) than those in young women (9.23 ± 2.78, 7.56 ± 2.71 mIu/mL, p < 0.001). However, Plasma kisspeptins levels were not significantly correlated to FSH and LH in postmenopausal women (r = ?0.23, 0.324; p = 0.927, 0.176, respectively), and also there was no any correlation between plasma kisspeptins and E2 in postmenopausal women (r = ?0.065; p = 0.792). Collectively, there was no significant difference in plasma kisspeptins levels between postmenopausal and young women. Our result suggested that kisspeptins’ role during menopause might mainly act in central rather than peripheral system and it could not be currently used as a clinical marker for menopause. 相似文献
94.
95.
Haibin Kuang Hongying Peng Hong Xu Baoping Zhang Jing Peng Yi Tan 《Journal of molecular histology》2010,41(1):1-7
Uterine Natural Killer (uNK) cells are the most abundant lymphocyte population recruited in the uteri during murine and human
pregnancy. Previous investigation on uNK cells during mouse pregnancy focused more on its accumulation in postimplantation
periods, which were believed to play important roles in regulating trophoblast invasion and angiogenesis towards successful
placentation. However, by using recently developed methods of Dolichos biflorus agglutinin (DBA) lectin, a closer examination
during mouse preimplantation revealed that there were also dynamic regulations of uNK cell, suggesting a major regulation
by steroid hormones. Here we provide a detailed examination of uNK cells distribution during mouse early pregnancy by DBA
lectin reactivity, with emphasis on preimplantation period and its hormonal regulation profiles. Our results showed that uNK
precursor cells or its cell membrane specific components could be recruited in the uterus by estrogen or/and progesterone,
and the effects could be completely abolished by specific antagonists of their nuclear receptors (estrogen and progesterone
receptor). These results suggested that the preimplantation uterus, through concerted hormone regulation, could recruit uNK
precursor cell or its specific cellular component, which might be conducive for uterine receptivity and further uNK construction/function
during postimplantation. 相似文献
96.
Abstract Circadian mating rhythms, mating frequency, mating duration, and the effect of mating duration on fecundity and fertility in the cabbage beetle, Colaphellus bowringi were investigated in the laboratory. Mating occurred throughout the 24-h cycle but the majority of copulations occurred in the photophase with two apparent peaks, one at 8:00 and another at 16:00. Mating frequency observations for 10 consecutive days indicated that pre-mating period of C. bowringi was about 4 days, and pairs mated an average of 5 times per day and an average of 40 times during the first 10 days. There was a negative correlation between mating frequency and mating duration during the consecutive mating. The mean duration of the first copulation (136.24 ± 4.62 min) was significantly longer than those of the second (57.87 ± 2.03 min), third (53.05 ± 2.05 min) and fourth copulation (30.86 ± 2.98 min). Fecundity showed a slight increase with increasing mating duration but no significant difference among treatments. However, fertility was significantly influenced by the mating duration in this species. Mating of 20-min duration did not produce viable eggs. The mean percentage of fertile eggs with completed mating duration (204.43 ± 18.96 min, 56.75% fertile eggs) was significantly higher than those with 60 min (39.55%) and 30 min (17.91%) mating duration, suggesting that the longer mating duration might be associated with transfer of more sperm that are used to increase the fertility of eggs. 相似文献
97.
Background
Androgens bind to the androgen receptor (AR) in prostate cells and are essential survival factors for healthy prostate epithelium. Most untreated prostate cancers retain some dependence upon the AR and respond, at least transiently, to androgen ablation therapy. However, the relationship between endogenous androgen levels and cancer etiology is unclear. High levels of androgens have traditionally been viewed as driving abnormal proliferation leading to cancer, but it has also been suggested that low levels of androgen could induce selective pressure for abnormal cells. We formulate a mathematical model of androgen regulated prostate growth to study the effects of abnormal androgen levels on selection for pre-malignant phenotypes in early prostate cancer development. 相似文献98.
Holterman CE Le Grand F Kuang S Seale P Rudnicki MA 《The Journal of cell biology》2007,179(5):911-922
We identify here the multiple epidermal growth factor repeat transmembrane protein Megf10 as a quiescent satellite cell marker that is also expressed in skeletal myoblasts but not in differentiated myofibers. Retroviral expression of Megf10 in myoblasts results in enhanced proliferation and inhibited differentiation. Infected myoblasts that fail to differentiate undergo cell cycle arrest and can reenter the cell cycle upon serum restimulation. Moreover, experimental modulations of Megf10 alter the expression levels of Pax7 and the myogenic regulatory factors. In contrast, Megf10 silencing in activated satellite cells on individual fibers or in cultured myoblasts results in a dramatic reduction in the cell number, caused by myogenin activation and precocious differentiation as well as a depletion of the self-renewing Pax7+/MyoD− population. Additionally, Megf10 silencing in MyoD−/− myoblasts results in down-regulation of Notch signaling components. We conclude that Megf10 represents a novel transmembrane protein that impinges on Notch signaling to regulate the satellite cell population balance between proliferation and differentiation. 相似文献
99.
Lu Xiaofei Qin Zhangfen Lambers Hans Tang Songbo Kaal Joeri Hou Enqing Kuang Yuanwen 《Plant and Soil》2022,476(1-2):25-29
Plant and Soil - Silicon (Si) is a beneficial element for plants and plays important roles in the biogeochemical cycle of mineral elements. Yet, few studies have focused on the impact of nitrogen... 相似文献
100.
Zhu Qingjun Yang Yanyan Xiao Yanan Han Wenhui Li Xingyue Wang Wenda Kuang Tingyun Shen Jian-Ren Han Guangye 《Photosynthesis research》2022,152(2):193-206
Photosynthesis Research - Photosystem II (PSII) has a number of hydrogen-bonding networks connecting the manganese cluster with the lumenal bulk solution. The structure of PSII from... 相似文献