全文获取类型
收费全文 | 3211篇 |
免费 | 209篇 |
国内免费 | 2篇 |
专业分类
3422篇 |
出版年
2022年 | 17篇 |
2021年 | 39篇 |
2020年 | 13篇 |
2019年 | 22篇 |
2018年 | 37篇 |
2017年 | 13篇 |
2016年 | 48篇 |
2015年 | 76篇 |
2014年 | 82篇 |
2013年 | 176篇 |
2012年 | 118篇 |
2011年 | 156篇 |
2010年 | 94篇 |
2009年 | 85篇 |
2008年 | 145篇 |
2007年 | 138篇 |
2006年 | 123篇 |
2005年 | 135篇 |
2004年 | 160篇 |
2003年 | 138篇 |
2002年 | 143篇 |
2001年 | 145篇 |
2000年 | 149篇 |
1999年 | 124篇 |
1998年 | 43篇 |
1997年 | 45篇 |
1996年 | 36篇 |
1995年 | 26篇 |
1994年 | 30篇 |
1993年 | 40篇 |
1992年 | 76篇 |
1991年 | 71篇 |
1990年 | 65篇 |
1989年 | 73篇 |
1988年 | 68篇 |
1987年 | 50篇 |
1986年 | 48篇 |
1985年 | 47篇 |
1984年 | 39篇 |
1983年 | 34篇 |
1982年 | 22篇 |
1981年 | 27篇 |
1980年 | 18篇 |
1979年 | 25篇 |
1978年 | 24篇 |
1977年 | 17篇 |
1976年 | 28篇 |
1975年 | 14篇 |
1973年 | 16篇 |
1971年 | 12篇 |
排序方式: 共有3422条查询结果,搜索用时 15 毫秒
991.
Y Takeuchi K Nishimura N Aoki T Adachi C Sato K Kitajima T Matsuda 《European journal of biochemistry》1999,260(3):736-742
992.
Two cytosolic cyclophilin genes of Arabidopsis thaliana differently regulated in temporal- and organ-specific expression. 总被引:2,自引:0,他引:2
T Saito K Tadakuma N Takahashi H Ashida K Tanaka M Kawamukai H Matsuda T Nakagawa 《Bioscience, biotechnology, and biochemistry》1999,63(4):632-637
We have previously isolated two closely related genes (ATCYP1 and ATCYP2) each encoding a cytosolic cyclophilin of Arabidopsis thaliana. Here we tested expression patterns of these two genes by Northern analysis and by histochemical analysis with transgenic plants carrying the promoter: beta-glucuronidase (GUS) fusion. The results showed that ATCYP1 is predominantly transcribed in vascular tissue and flowers, but ATCYP2 is at higher levels in younger leaves. The different expression patterns seemed to be conferred by the quite different promoter structures carrying various cis elements. Our finding suggests that the two cyclophilins have different roles in Arabidopsis thaliana cells. 相似文献
993.
Abstract The promoting effects on cell proliferation of the 105K glycoprotein (105Kgp), purified from sera of chickens to which a Marek's disease (MD) lymphoblastoid cell line, MDCC-MSB1-41C (MSB1-41C), had been transplanted, were examined using culture cells from various sources. The MSB1-41C line as well as the other chicken lymphoblastoid cell lines examined were sensitive to the 105Kgp. The growth-promoting effects of 105Kgp showed a biphasic pattern depending upon the amount of 105Kgp added into the culture medium.
These findings indicate that the 105Kgp may be a promoting factor for chicken growing cells, especially lymphoblastoid cell lines. 相似文献
These findings indicate that the 105Kgp may be a promoting factor for chicken growing cells, especially lymphoblastoid cell lines. 相似文献
994.
T Matsuda H Tonomura A Baba H Iwata 《The International journal of biochemistry》1991,23(10):1111-1114
1. Thiamine triphosphatase activity in particulate fraction, but not in soluble, of rat skeletal muscle was stimulated by several anions. 2. The stimulative effect of anions was dependent on pH of reaction medium and was reversible. 3. The activities of ATPase in rat muscle particulate preparation and thiamine triphosphatase in the brain were inhibited by the anions. 相似文献
995.
996.
Takuya Tsumita Ryo Takeda Nako Maishi Yasuhiro Hida Michihito Sasaki Yasuko Orba Akihiko Sato Shinsuke Toba Wataru Ito Takahito Teshirogi Yuya Sakurai Tomohiro Iba Hisamichi Naito Hitoshi Ando Haruhisa Watanabe Amane Mizuno Toshiki Nakanishi Aya Matsuda Ren Zixiao Ji-Won Lee Tadahiro Iimura Hirofumi Sawa Kyoko Hida 《Aging cell》2024,23(2):e14050
997.
Yuuya Kasahara Shunsuke Kitadume Kunihiko Morihiro Masayasu Kuwahara Hiroaki Ozaki Hiroaki Sawai Takeshi Imanishi Satoshi Obika 《Bioorganic & medicinal chemistry letters》2010,20(5):1626-1629
The capping of the 3′-ends of thrombin binding aptamers (TBAs) with bridged nucleotides increased the nuclease resistances and the stabilities in human serum. The binding abilities of the aptamers were not affected by the capping. The capping could be simply executed via a one step enzymatic process using 2′,4′-bridged nucleoside 5′-triphosphate and terminal deoxynucleotidyl transferase. 相似文献
998.
Yuka Miyoshi Yoshichika Yoshioka Kinuko Suzuki Taisuke Miyazaki Minako Koura Kazumasa Saigoh Naoko Kajimura Yoko Monobe Susumu Kusunoki Junichiro Matsuda Masahiko Watanabe Naoto Hayasaka 《PloS one》2014,9(9)
Spinocerebellar degenerations (SCDs) are a large class of sporadic or hereditary neurodegenerative disorders characterized by progressive motion defects and degenerative changes in the cerebellum and other parts of the CNS. Here we report the identification and establishment from a C57BL/6J mouse colony of a novel mouse line developing spontaneous progressive ataxia, which we refer to as ts3. Frequency of the phenotypic expression was consistent with an autosomal recessive Mendelian trait of inheritance, suggesting that a single gene mutation is responsible for the ataxic phenotype of this line. The onset of ataxia was observed at about three weeks of age, which slowly progressed until the hind limbs became entirely paralyzed in many cases. Micro-MRI study revealed significant cerebellar atrophy in all the ataxic mice, although individual variations were observed. Detailed histological analyses demonstrated significant atrophy of the anterior folia with reduced granule cells (GC) and abnormal morphology of cerebellar Purkinje cells (PC). Study by ultra-high voltage electron microscopy (UHVEM) further indicated aberrant morphology of PC dendrites and their spines, suggesting both morphological and functional abnormalities of the PC in the mutants. Immunohistochemical studies also revealed defects in parallel fiber (PF)–PC synapse formation and abnormal distal extension of climbing fibers (CF). Based on the phenotypic similarities of the ts3 mutant with other known ataxic mutants, we performed immunohistological analyses and found that expression levels of two genes and their products, glutamate receptor delta2 (grid2) and its ligand, cerebellin1 (Cbln1), are significantly reduced or undetectable. Finally, we sequenced the candidate genes and detected a large deletion in the coding region of the grid2 gene. Our present study suggests that ts3 is a new allele of the grid2 gene, which causes similar but different phenotypes as compared to other grid2 mutants. 相似文献
999.
Matsuda N Hattori Y Takahashi Y Nishihira J Jesmin S Kobayashi M Gando S 《American journal of physiology. Lung cellular and molecular physiology》2004,287(6):L1248-L1255
Nuclear factor-kappaB (NF-kappaB) plays a key role in regulating expression of several genes involved in the pathophysiology of endotoxic shock. We investigated whether in vivo introduction of synthetic double-stranded DNA with high affinity for the NF-kappaB binding site could block expression of genes mediating pulmonary vascular permeation and thereby provide effective therapy for septic lung failure. Endotoxic shock was induced by an intravenous injection of 10 mg/kg Escherichia coli endotoxin in mice. We introduced NF-kappaB decoy oligodeoxynucleotide (ODN) in vivo 1 h after endotoxic shock by using a gene transfer kit. At 10 h, blood samples were collected for measurement of histamine and for blood-gas analysis. Gene and protein expression levels of target molecules were determined by means of Northern and Western blot analyses, respectively. The transpulmonary flux of (125)I-labeled albumin was used as an index of lung vascular permeability. Administration of endotoxin caused marked increases in plasma histamine and gene and protein expressions of histidine decarboxylase, histamine H(1) receptors, and inducible nitric oxide synthase in lung tissues. Elevated lung vascular permeability was also found. Blood-gas analysis showed concurrent decreases in arterial Po(2), Pco(2), and pH. All of these events induced by endotoxin were significantly inhibited by transfection of NF-kappaB decoy ODN but not by its mutated (scrambled) form (used as a control). Our results indicate for the first time the potential usefulness of NF-kappaB decoy ODN for gene therapy of endotoxic shock. 相似文献
1000.
Ishizaka A Matsuda T Albertine KH Koh H Tasaka S Hasegawa N Kohno N Kotani T Morisaki H Takeda J Nakamura M Fang X Martin TR Matthay MA Hashimoto S 《American journal of physiology. Lung cellular and molecular physiology》2004,286(6):L1088-L1094
KL-6 is a pulmonary epithelial mucin more prominently expressed on the surface membrane of alveolar type II cells when these cells are proliferating, stimulated, and/or injured. We hypothesized that high levels of KL-6 in epithelial lining fluid and plasma would reflect the severity of lung injury in patients with acute lung injury (ALI). Epithelial lining fluid was obtained at onset (day 0) and day 1 of acute respiratory distress syndrome (ARDS)/ALI by bronchoscopic microsampling procedure in 35 patients. On day 0, KL-6 and albumin concentrations in epithelial lining fluid were significantly higher than in normal controls (P < 0.001), and the concentrations of KL-6 in epithelial lining fluid (P < 0.002) and in plasma (P < 0.0001) were higher in nonsurvivors than in survivors of ALI/ARDS. These observations were corroborated by the immunohistochemical localization of KL-6 protein expression in the lungs of nonsurvivors with ALI and KL-6 secretion from cultured human alveolar type II cells stimulated by proinflammatory cytokines. Because injury to distal lung epithelial cells, including alveolar type II cells, is important in the pathogenesis of ALI, the elevation of KL-6 concentrations in plasma and epithelial lining fluid could be valuable indicators for poor prognosis in clinical ALI. 相似文献