全文获取类型
收费全文 | 3668篇 |
免费 | 252篇 |
国内免费 | 5篇 |
出版年
2023年 | 10篇 |
2022年 | 22篇 |
2021年 | 54篇 |
2020年 | 21篇 |
2019年 | 47篇 |
2018年 | 50篇 |
2017年 | 56篇 |
2016年 | 87篇 |
2015年 | 126篇 |
2014年 | 150篇 |
2013年 | 253篇 |
2012年 | 243篇 |
2011年 | 267篇 |
2010年 | 129篇 |
2009年 | 135篇 |
2008年 | 261篇 |
2007年 | 234篇 |
2006年 | 248篇 |
2005年 | 255篇 |
2004年 | 253篇 |
2003年 | 217篇 |
2002年 | 189篇 |
2001年 | 31篇 |
2000年 | 19篇 |
1999年 | 40篇 |
1998年 | 53篇 |
1997年 | 36篇 |
1996年 | 38篇 |
1995年 | 35篇 |
1994年 | 41篇 |
1993年 | 35篇 |
1992年 | 21篇 |
1991年 | 17篇 |
1990年 | 21篇 |
1989年 | 27篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 31篇 |
1984年 | 23篇 |
1983年 | 17篇 |
1982年 | 16篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1978年 | 11篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1967年 | 3篇 |
排序方式: 共有3925条查询结果,搜索用时 31 毫秒
961.
Shinjirou Kawazoe Nobuhito Ikeda Kengo Miki Masayuki Shibuya Kumi Morikawa Seiji Nakano Mitsuo Oshimura Ichiro Hisatome Yasuaki Shirayoshi 《Development, growth & differentiation》2009,51(2):81-93
Embryonic carcinoma (EC) cells, which are malignant stem cells of teratocarcinoma, have numerous morphological and biochemical properties in common with pluripotent stem cells such as embryonic stem (ES) cells. However, three EC cell lines (F9, P19 and PCC3) show different developmental potential and self‐renewal capacity from those of ES cells. All three EC cell lines maintain self‐renewal capacity in serum containing medium without Leukemia Inhibitory factor (LIF) or feeder layer, and show limited differentiation capacity into restricted lineage and cell types. To reveal the underlying mechanism of these characteristics, we took the approach of characterizing extrinsic factors derived from EC cells on the self‐renewal capacity and pluripotency of mouse ES cells. Here we demonstrate that EC cell lines F9 and P19 produce factor(s) maintaining the undifferentiated state of mouse ES cells via an unidentified signal pathway, while P19 and PCC3 cells produce self‐renewal factors of ES cells other than LIF that were able to activate the STAT3 signal; however, inhibition of STAT3 activation with Janus kinase inhibitor shows only partial impairment on the maintenance of the undifferentiated state of ES cells. Thus, these factors present in EC cells‐derived conditioned medium may be responsible for the self‐renewal capacity of EC and ES cells independently of LIF signaling. 相似文献
962.
Kiyotaka Nakano Junichi Nezu Iwao Ohizumi Koh Furugaki Takahiro Ishiguro Tatsuhiko Kodama Hisafumi Yamada-Okabe Masayuki Tsuchiya 《Biochemical and biophysical research communications》2009,378(2):279-284
Glypican 3 (GPC3), a GPI-anchored heparan sulfate proteoglycan, is expressed in the majority of hepatocellular carcinoma (HCC) tissues. Using MRL/lpr mice, we successfully generated a series of anti-GPC3 monoclonal antibodies (mAbs). GPC3 was partially cleaved between Arg358 and Ser359, generating a C-terminal 30-kDa fragment and an N-terminal 40-kDa fragment. All mAbs that induced antibody-dependent cellular cytotoxicity (ADCC) and/or complement-dependent cytotoxicity (CDC) against cells expressing GPC3 recognized the 30-kDa fragment, indicating that the C-terminal region of GPC3 serves as an epitope for mAb with ADCC and/or CDC inducing activities. Chimeric mAbs with Fc replaced by human IgG1 were created from GC33, one of the mAbs that reacted with the C-terminal 30-kDa fragment. Chimeric GC33 induced not only ADCC against GPC3-positive human HCC cells but also was efficacious against the Huh-7 human HCC xenograft. Thus, mAbs against the C-terminal 30-kDa fragment such as GC33 are useful in therapy targeting HCC. 相似文献
963.
Hidenori Tani Nobuyoshi Akimitsu Yasuyoshi Matsuda Ryo Miyata Masayuki Igarashi Naohiro Noda 《Biochemical and biophysical research communications》2009,379(4):1054-1059
We have developed a novel high-throughput screening assay of hepatitis C virus (HCV) nonstructural protein 3 (NS3) helicase inhibitors using the fluorescence-quenching phenomenon via photoinduced electron transfer between fluorescent dyes and guanine bases. We prepared double-stranded DNA (dsDNA) with a 5′-fluorescent-dye (BODIPY FL)-labeled strand hybridized with a complementary strand, the 3′-end of which has guanine bases. When dsDNA is unwound by helicase, the dye emits fluorescence owing to its release from the guanine bases. Our results demonstrate that this assay is suitable for quantitative assay of HCV NS3 helicase activity and useful for high-throughput screening for inhibitors. Furthermore, we applied this assay to the screening for NS3 helicase inhibitors from cell extracts of microorganisms, and found several cell extracts containing potential inhibitors. 相似文献
964.
Ryohei Iwasaki Masaki Ihara Masayuki Kawakami 《Biochemical and biophysical research communications》2009,384(3):316-321
To cultivate the use of trans-splicing as a novel means to rapidly express various antibody fusion proteins, we tried to express antibody-reporter enzyme fusions in a COS-1 co-transfection model. When a vector designed to induce trans-splicing with IgH pre-mRNA was co-transfected with a vector encoding the mouse IgM locus, the expression of VH-secreted human placental alkaline phosphatase (SEAP) as well as Fab-SEAP were successfully expressed both in mRNA and protein levels. Especially, the vectors encoding complementary sequence to Sμ as a binding domain was accurate and efficient, producing trans-spliced mRNA of up to 2% of cis-spliced one. Since Sμ sequence should exist in every IgH pre-mRNA, our finding will lead to the rapid production and analysis of various antibody-enzyme fusions suitable for enzyme-linked immunosorbent assay (ELISA) or antibody-dependent enzyme prodrug therapy (ADEPT). 相似文献
965.
966.
967.
Masayuki Kubo Tao‐Sheng Li Takahiro Kamota Mako Ohshima Shu‐Lan Qin Kimikazu Hamano 《Journal of cellular physiology》2009,220(2):508-514
Cell‐based angiogenesis is a promising method for the treatment of ischemic diseases, but the poor retention of implanted cells in targeted tissues is a major drawback. We tested whether hypoxic preconditioning increased retention and angiogenic potency of implanted cells in ischemic tissue. Hypoxic preconditioning of mouse peripheral blood mononuclear cells (PBMNCs) was done with 24 h of culture under 2% O2. Normoxia‐cultured PBMNCs were used as a control. Hypoxic preconditioning increased the adhesion capacity of the PBMNCs. Moreover, the expression of integrin αM and CXCR4 was significantly higher in the hypoxia‐preconditioned PBMNCs than in the normoxia‐cultured PBMNCs. Interestingly, the expression of intercellular adhesion molecule‐1 (ICAM‐1), a ligand of integrin αM, and stromal cell‐derived factor‐1 (SDF‐1), a chemokine for CXCR4, were remarkably increased in the ischemic hindlimbs. The retention of the hypoxia‐preconditioned PBMNCs was significantly higher than that of the normoxia‐cultured PBMNCs, 3 days after their intramuscular implantation into ischemic hindlimbs. We also noted better blood flow in the ischemic hindlimbs implanted with the hypoxia‐preconditioned PBMNCs than in those implanted with the normoxia‐cultured PBMNCs, 14 days after treatment. Furthermore, antibody neutralization of integrin αM and CXCR4 abolished completely the increased cell retention and angiogenic potency of the hypoxia‐preconditioned PBMNCs after implantation into the ischemic hindlimbs. These results indicate that hypoxic preconditioning of implanted cells is a feasible method of enhancing therapeutic angiogenesis by increasing their retention. J. Cell. Physiol. 220: 508–514, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
968.
Erdembileg Anuurad Masayuki Yamasaki Neil Shachter Thomas A. Pearson Lars Berglund 《Journal of lipid research》2009,50(7):1472-1478
Apolipoproteins (apo) E and C-I are components of triglyceride (TG)-rich lipoproteins and impact their metabolism. Functional polymorphisms have been established in apoE but not in apoC-I. We studied the relationship between apoE and apoC-I gene polymorphisms and plasma lipoproteins and coronary artery disease (CAD) in 211 African Americans and 306 Caucasians. In African Americans but not in Caucasians, apoC-I H2-carriers had significantly lower total and LDL cholesterol and apoB levels, and higher glucose, insulin, and HOMA-IR levels compared with H1 homozygotes. Differences across CAD phenotypes were seen for the apoC-I polymorphism. African-American H2-carriers without CAD had significantly lower total cholesterol (P < 0.001), LDL cholesterol (P < 0.001), and apoB (P < 0.001) levels compared with H1 homozygotes, whereas no differences were found across apoC-I genotypes for African Americans with CAD. Among African-American apoC-I H1 homozygotes, subjects with CAD had a profile similar to the metabolic syndrome (i.e., higher triglyceride, glucose, and insulin) compared with subjects without CAD. For African-American H2-carriers, subjects with CAD had a pro-atherogenic lipid pattern (i.e., higher LDL cholesterol and apoB levels), compared with subjects without CAD. ApoC-I genotypes showed an ethnically distinct phenotype relationship with regard to CAD and CAD risk factors. 相似文献
969.
Masayuki Takada Yoshio Mishima Shosuke Natsume 《Landscape and Ecological Engineering》2009,5(1):45-58
By examining the area of the Sarobetsu Mire in northern Japan using ALOS/PALSAR data, we have clarified the backscattering
behavior and characteristics of the L-band microwaves when used in the study of peatlands. We classified the vegetation into
six categories and noted the differences in scattering intensity and incident-angle dependencies among these. The scattering
intensity for HH and HV polarizations was greatest with sasa (dwarf bamboo) and reeds, and least with sphagnum. The incident-angle
dependency with the HH polarization was higher for sasa and reed than for other vegetation types. Analysis of the polarization
revealed that such differences among vegetation classes were reflected most clearly in the volume scattering characteristic.
Applying simple and multiple regression analysis for the environmental factors of soil, hydrology, vegetation, and roughness
against the backscatter coefficient, we also found stronger interrelations with soil factors such as bulk density, nitrogen
and carbon content, and C/N ratio, and against the backscatter coefficient, than with either the roughness or vegetation.
Based on such results, we clarified the unique scattering characteristics of peatlands in which scattering from the surface
soil is more marked than that from other elements. We consequently estimated the spatial distribution of surface soil characteristics
in peatland using the combined data available from L-band satellite SAR, aircraft laser (airborne LiDAR), and optical sensors. 相似文献
970.
Masayuki Ikeda Moritoshi Hirono Takashi Sugiyama Takahiro Moriya Masami Ikeda-Sagara Naomi Eguchi Yoshihiro Urade Tohru Yoshioka 《PloS one》2009,4(11)