全文获取类型
收费全文 | 1038篇 |
免费 | 65篇 |
专业分类
1103篇 |
出版年
2023年 | 4篇 |
2022年 | 17篇 |
2021年 | 26篇 |
2020年 | 17篇 |
2019年 | 23篇 |
2018年 | 30篇 |
2017年 | 21篇 |
2016年 | 31篇 |
2015年 | 47篇 |
2014年 | 47篇 |
2013年 | 56篇 |
2012年 | 88篇 |
2011年 | 88篇 |
2010年 | 39篇 |
2009年 | 41篇 |
2008年 | 72篇 |
2007年 | 81篇 |
2006年 | 53篇 |
2005年 | 46篇 |
2004年 | 54篇 |
2003年 | 44篇 |
2002年 | 41篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 13篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 12篇 |
1990年 | 4篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1976年 | 4篇 |
1975年 | 7篇 |
1974年 | 1篇 |
1971年 | 4篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1103条查询结果,搜索用时 0 毫秒
41.
Lou Yuting Kawaue Takumi Yow Ivan Toyama Yusuke Prost Jacques Hiraiwa Tetsuya 《Biomechanics and modeling in mechanobiology》2022,21(5):1511-1530
Biomechanics and Modeling in Mechanobiology - Tissue layers can generally slide at the interface, accompanied by the dissipation due to friction. Nevertheless, it remains elusive how force could... 相似文献
42.
43.
Yuki Takegawa Makoto Nakamura Shin Nakamura Takumi Noguchi Julien Sellés A. William Rutherford Alain Boussac Miwa Sugiura 《BBA》2019,1860(4):297-309
The monomeric chlorophyll, ChlD1, which is located between the PD1PD2 chlorophyll pair and the pheophytin, PheoD1, is the longest wavelength chlorophyll in the heart of Photosystem II and is thought to be the primary electron donor. Its central Mg2+ is liganded to a water molecule that is H-bonded to D1/T179. Here, two site-directed mutants, D1/T179H and D1/T179V, were made in the thermophilic cyanobacterium, Thermosynechococcus elongatus, and characterized by a range of biophysical techniques. The Mn4CaO5 cluster in the water-splitting site is fully active in both mutants. Changes in thermoluminescence indicate that i) radiative recombination occurs via the repopulation of *ChlD1 itself; ii) non-radiative charge recombination reactions appeared to be faster in the T179H-PSII; and iii) the properties of PD1PD2 were unaffected by this mutation, and consequently iv) the immediate precursor state of the radiative excited state is the ChlD1+PheoD1? radical pair. Chlorophyll bleaching due to high intensity illumination correlated with the amount of 1O2 generated. Comparison of the bleaching spectra with the electrochromic shifts attributed to ChlD1 upon QA? formation, indicates that in the T179H-PSII and in the WT*3-PSII, the ChlD1 itself is the chlorophyll that is first damaged by 1O2, whereas in the T179V-PSII a more red chlorophyll is damaged, the identity of which is discussed. Thus, ChlD1 appears to be one of the primary damage site in recombination-mediated photoinhibition. Finally, changes in the absorption of ChlD1 very likely contribute to the well-known electrochromic shifts observed at ~430?nm during the S-state cycle. 相似文献
44.
45.
Yuka Sameshima-Yamashita Takashi Watanabe Takumi Tanaka Shun Tsuboi Tohru Yarimizu Tomotake Morita 《Bioscience, biotechnology, and biochemistry》2019,83(8):1547-1556
ABSTRACTThe basidiomycetous yeast Pseudozyma antarctica GB-4(0) esterase (PaE) is a promising candidate for accelerating degradation of used biodegradable plastics (BPs). To increase safety and reduce costs associated with the use of PaE, we constructed a self-cloning strain with high-PaE productivity. A Lys12 gene (PaLYS12)-deleted lysine auxotroph strain GB4-(0)-L1 was obtained from GB-4(0) by ultraviolet mutagenesis and nystatin enrichment. Subsequently, the PaE gene (PaCLE1) expression cassette consisting of GB-4(0)-derived PaCLE1, under the control of a xylose-inducible xylanase promoter with PaLYS12, was randomly introduced into the GB4-(0)-L1 genome. A PaE high-producing strain, PGB474, was selected from among the transformants by high throughput double-screening based on its ability to degrade emulsified polybutylene succinate-co-adipate. Quantitative PCR revealed that four copies of the PaE gene expression cassette were introduced into the PGB474 genome. PGB474 produced 2.0 g/L of PaE by xylose-fed-batch cultivation using a 3-L jar fermentor for 72 h. 相似文献
46.
Y Inoue H Itoh M Aoki S Ogawa T Yamane T Baba N Tachibana M Kohno Y Oishi K Kobayashi-Hattori 《Bioscience, biotechnology, and biochemistry》2012,76(8):1549-1551
Two weeks of feeding soy peptides containing 2% collagen peptides increased the levels of type I and III tropocollagen and their mRNAs. In contrast, the diet did not increase the mRNA levels of rat hyaluronan synthases, serine palmitoyltransferase (the rate-limiting enzyme of ceramide synthesis), and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (the key enzyme of cholesterol synthesis). These results suggest that feeding of soy peptides with collagen peptides specifically enhanced the tropocollagen level in the skin. 相似文献
47.
Sumie S Kawaguchi T Kuromatsu R Takata A Nakano M Satani M Yamada S Niizeki T Torimura T Sata M 《PloS one》2011,6(11):e26840
Background
Adiponectin is shown to be inversely associated with development and progression of various cancers. We evaluated whether adiponectin level was associated with the prevalence and histological grade of hepatocellular carcinoma (HCC), and liver fibrosis in patients with hepatitis C virus (HCV) infection.Methods
A case-control study was conducted on 97 HCC patients (cases) and 97 patients (controls) matched for sex, Child-Pugh grade and platelet count in patients with HCV infection. The serum total and high molecular weight (HMW) adiponectin levels were measured by enzyme-linked immunosorbent assays and examined in their association with the prevalence of HCC. In addition, the relationship between these adiponectin levels and body mass index (BMI), progression of liver fibrosis, and histological grade of HCC was also evaluated. Liver fibrosis was assessed using the aspartate aminotransferase to platelet ratio index (APRI).Results
There were no significant differences in the serum total and HMW adiponectin levels between cases and controls. Moreover, there were no inverse associations between serum total and HMW adiponectin levels and BMI in both cases and controls. On the other hand, serum total and HMW adiponectin levels are positively correlated with APRI in both cases (r = 0.491, P<0.001 and r = 0.485, P<0.001, respectively) and controls (r = 0.482, P<0.001 and r = 0.476, P<0.001, respectively). Interestingly, lower serum total (OR 11.76, 95% CI: 2.97–46.66 [P<0.001]) and HMW (OR 10.24, CI: 2.80–37.40 [P<0.001] adiponectin levels were independent risk factors of worse histological grade of HCC.Conclusions
Our results suggested that serum total and HMW adiponectin levels were predictors of liver fibrosis, but not prevalence of HCC in patients with HCV infection. Moreover, low these adiponectin levels were significantly associated with worse histological grades. 相似文献48.
Monotherapy with a novel intervenolin derivative,AS‐1934, is an effective treatment for Helicobacter pylori infection 下载免费PDF全文
49.
Hayashi Takahisa; Takeda Takumi; Ogawa Kozo; Mitsuishi Yasushi 《Plant & cell physiology》1994,35(6):893-899
Xyloglucan oligosaccharides were isolated with various degreesof polymerization (DP) and reduced with tritiated sodium borohydride.The 3H-oligosaccharides were tested for their ability to bindto amorphous and microcrystalline celluloses and to cellulosefilter paper. The time course of binding indicated that theradiolabeled oligosaccharides continued to be bound for at least1 h after heating at 120°C. The binding probably requiredthe organization of the oligosaccharides and celluloses by gradualannealing after heating. Although neither pentasaccharide (glucose:xylose, 3 : 2), heptasaccharide (glucose: xylose, 4 : 3) andnonasaccharide (glucose : xylose : galactose : fucose, 4 : 3: 1 : 1) failed to bind to the celluloses, binding occurredwith oligosaccharides with DP equivalent to more than four consecutive1,4-ß-glucosyl residues. The extent of binding tothe celluloses increased gradually from octasaccharide (glucose:xylose, 5 : 3) to hendecosanosaccharide (glucose/xylose, 12: 9), with the increase in the DP of 1,4-ß-glucosylresidues. The binding of reduced cello-dextrins to celluloserequired at least 4 consecutive 1,4-ß-glucosyl residues.The extent of binding of cellopentitol or cellohexitol to cellulosewas similar to that of hendecosanosaccharide, showing lowerbinding for xyloglucan oligosaccharides in spite of longer chainsof 1,4-ß-glucosyl residues. These findings suggestthat the mode of binding to cellulose of xyloglucan oligosaccharidesis different from that of cello-oligosaccharides. (Received February 18, 1994; Accepted June 1, 1994) 相似文献
50.
Plants have evolved various means for controlled and organized cell destruction, known as programmed cell death (PCD). In
plant immune responses against microbial infection, hypersensitive cell death as a form of PCD is a crucial event to prevent
the spread of biotrophic pathogens. Recent live cell imaging techniques have revealed dynamic features and significant roles
of cytoskeletons and the vacuole during defense responses and the PCD. Actin microfilaments (MFs) focus on the infection sites
and function as tracks for the polar transport of antimicrobial materials. To accomplish hypersensitive cell death, further
dynamic changes in cytoskeletons are induced. MFs play a role in the structural and functional regulation of the vacuole,
leading to execution of the PCD. We here overview spatiotemporal dynamic changes in the cytoskeletons and the vacuoles triggered
by signals from pathogens, and propose a hypothetical model for MF-regulated vacuole-mediated PCD in plant immunity. 相似文献