全文获取类型
收费全文 | 1790篇 |
免费 | 111篇 |
出版年
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 16篇 |
2019年 | 17篇 |
2018年 | 25篇 |
2017年 | 27篇 |
2016年 | 30篇 |
2015年 | 40篇 |
2014年 | 55篇 |
2013年 | 99篇 |
2012年 | 101篇 |
2011年 | 74篇 |
2010年 | 46篇 |
2009年 | 48篇 |
2008年 | 91篇 |
2007年 | 106篇 |
2006年 | 97篇 |
2005年 | 104篇 |
2004年 | 83篇 |
2003年 | 82篇 |
2002年 | 87篇 |
2001年 | 67篇 |
2000年 | 53篇 |
1999年 | 43篇 |
1998年 | 29篇 |
1997年 | 17篇 |
1996年 | 19篇 |
1995年 | 21篇 |
1994年 | 21篇 |
1993年 | 22篇 |
1992年 | 37篇 |
1991年 | 32篇 |
1990年 | 24篇 |
1989年 | 28篇 |
1988年 | 26篇 |
1987年 | 29篇 |
1986年 | 18篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1981年 | 10篇 |
1980年 | 13篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1976年 | 14篇 |
1975年 | 7篇 |
1973年 | 11篇 |
1967年 | 7篇 |
1965年 | 5篇 |
排序方式: 共有1901条查询结果,搜索用时 15 毫秒
991.
Mami Asano Tatsuro Yamamoto Takeshi Tsuruta Naomichi Nishimura Kei Sonoyama 《Development, growth & differentiation》2015,57(1):68-73
Small intestinal epithelium is a self‐renewing system in which the entire sequence of cell proliferation, differentiation, and removal is coupled to cell migration along the crypt‐villus axis. We examined whether dual labeling with different thymidine analogues, 5‐bromo‐2'‐deoxyuridine (BrdU) and 5‐ethynyl‐2'‐deoxyuridine (EdU), can be used to estimate cell migration rates on the villi of small intestines in rats. Rats received a single intraperitoneal injection of BrdU and EdU within a time interval, and signals in tissue sections were examined by immunohistochemistry and the “click” reaction, respectively. We successfully observed BrdU‐ and EdU‐positive cells on the epithelium with no cross‐reaction. In addition, we observed an almost complete overlapping of BrdU‐ and EdU‐positive cells in rats administered simultaneously with BrdU and EdU. By calculating the cell migration rate by dividing the distance between the median cell positions of the distribution of BrdU‐ and EdU‐positive cells by the time between the injection of BrdU and EdU, we estimated approximately 9 and 5 μm/h for the cell migration rates on the villi in the jejunum and ileum, respectively. We propose that dual labeling with BrdU and EdU within a time interval, followed by detecting with immunohistochemistry and the click reaction, respectively, is useful to estimate accurately the cell migration rate in the intestinal epithelium in a single animal. 相似文献
992.
993.
994.
M Kondo K Tashiro G Fujii M Asano R Miyoshi R Yamada M Muramatsu K Shiokawa 《Biochemical and biophysical research communications》1991,181(2):684-690
Activin is a member of the transforming growth factor beta (TGF-beta) and possesses various activities in cellular control phenomena. During Xenopus embryonic development, activin is thought to act as a natural mesoderm-inducing factor. We isolated here the Xenopus activin receptor cDNA from Xenopus tadpole cDNA library and examined the expression of the Xenopus activin receptor gene during the course of early embryonic development. The Xenopus activin receptor has an 87% homology at the level of deduced amino acid sequence with the mouse activin receptor, and using the cDNA obtained, three bands of mRNA with different lengths were detected in Xenopus embryos throughout early embryogenesis. We synthesized activin receptor mRNA in vitro and tested the effect of the injection of the mRNA into Xenopus fertilized eggs on subsequent development. When the synthetic mRNA was injected into uncleaved fertilized eggs, embryos with reduced trunk structure were formed. However, when the mRNA was injected into the ventral blastomeres at the 16-cell stage, embryos with a secondary body axis were formed. These results indicate the importance of the function of activin receptor in the regulatory mechanism for body axis formation. 相似文献
995.
Hiroki Yasuga Ryuji Kawano Masahiro Takinoue Yutaro Tsuji Toshihisa Osaki Koki Kamiya Norihisa Miki Shoji Takeuchi 《PloS one》2016,11(2)
Logical operations using biological molecules, such as DNA computing or programmable diagnosis using DNA, have recently received attention. Challenges remain with respect to the development of such systems, including label-free output detection and the rapidity of operation. Here, we propose integration of biological nanopores with DNA molecules for development of a logical operating system. We configured outputs “1” and “0” as single-stranded DNA (ssDNA) that is or is not translocated through a nanopore; unlabeled DNA was detected electrically. A negative-AND (NAND) operation was successfully conducted within approximately 10 min, which is rapid compared with previous studies using unlabeled DNA. In addition, this operation was executed in a four-droplet network. DNA molecules and associated information were transferred among droplets via biological nanopores. This system would facilitate linking of molecules and electronic interfaces. Thus, it could be applied to molecular robotics, genetic engineering, and even medical diagnosis and treatment. 相似文献
996.
997.
998.
Ryuji Matsumura Jotaro Hirakawa Kaori Sato Toshiaki Ikeda Motoe Nagai Minoru Fukuda Yasuyuki Imai Hiroto Kawashima 《The Journal of biological chemistry》2015,290(24):15313-15326
Sialyl Lewis X (sLex) antigen functions as a common carbohydrate determinant recognized by all three members of the selectin family. However, its expression and function in mice remain undefined due to the poor reactivity of conventional anti-sLex monoclonal antibodies (mAbs) with mouse tissues. Here, we developed novel anti-sLex mAbs, termed F1 and F2, which react well with both human and mouse sLex, by immunizing fucosyltransferase (FucT)-IV and FucT-VII doubly deficient mice with 6-sulfo-sLex-expressing cells transiently transfected with an expression vector encoding CMP-N-acetylneuraminic acid hydroxylase. F1 and F2 specifically bound both the N-acetyl and the N-glycolyl forms of sLex as well as 6-sulfo-sLex, a major ligand for L-selectin expressed in high endothelial venules, and efficiently blocked physiological lymphocyte homing to lymph nodes in mice. Importantly, both of the mAbs inhibited contact hypersensitivity responses not only when administered in the L-selectin-dependent sensitization phase but also when administered in the elicitation phase in mice. When administered in the latter phase, F1 and F2 efficiently blocked rolling of mouse leukocytes along blood vessels expressing P- and E-selectin in the auricular skin in vivo. Consistent with these findings, the mAbs blocked P- and E-selectin-dependent leukocyte rolling in a flow chamber assay. Taken together, these results indicate that novel anti-sLex mAbs reactive with both human and mouse tissues, with the blocking ability against leukocyte trafficking mediated by all three selectins, have been established. These mAbs should be useful in determining the role of sLex antigen under physiological and pathological conditions. 相似文献
999.
1000.
Toshiharu Matsumura Ryuji Konishi Yoshitaka Nagai 《In vitro cellular & developmental biology. Plant》1982,18(6):510-514
Summary When L-929 mouse fibroblasts grown in Eagle’s medium (MEM) supplemented with 10% fetal bovine serum (FBS) were stored in a
monodisperse suspension at 4° C, the viability decreased rapidly from the beginning of storage. The viability in this study
was determined by counting electronically the number of cells with the capacity to attach to glass substrate and with the
membrane boundary resistant to a proteolytic digestion. When, however, the dissociated cells were preincubated briefly at
37° C, and subsequently stored at 4° C as they were attaching on a glass substrate, the rapid loss of viability could be reduced
effectively. A biphasic survival profile consisting of an initial phase of slowly decreasing viability and the subsequent
phase of rapidly decreasing viability were then observed. The rapid viability loss occurred not only when the cell suspension
was prepared by mechanical dislodging but also after trypsinization or dispase treatment. Such viability loss was also observed
when the dissociated cells were not stored at 4° C directly but preincubated in a monodisperse suspension at 37° C in a siliconized
plate and then stored at 4° C. The above results show that the rapid loss of viability is associated closely with the fact
that the cells were not attached to the substrate but in suspension.
This work was supported in part by grants-in-aids from the Institute of Physical and Chemical Research and from the Mitsubishi
Foundation. 相似文献