全文获取类型
收费全文 | 2672篇 |
免费 | 221篇 |
国内免费 | 1篇 |
专业分类
2894篇 |
出版年
2022年 | 18篇 |
2021年 | 23篇 |
2018年 | 28篇 |
2017年 | 16篇 |
2016年 | 42篇 |
2015年 | 59篇 |
2014年 | 75篇 |
2013年 | 156篇 |
2012年 | 122篇 |
2011年 | 127篇 |
2010年 | 86篇 |
2009年 | 77篇 |
2008年 | 142篇 |
2007年 | 128篇 |
2006年 | 119篇 |
2005年 | 143篇 |
2004年 | 125篇 |
2003年 | 101篇 |
2002年 | 99篇 |
2001年 | 91篇 |
2000年 | 76篇 |
1999年 | 90篇 |
1998年 | 46篇 |
1997年 | 35篇 |
1996年 | 30篇 |
1995年 | 25篇 |
1994年 | 27篇 |
1993年 | 28篇 |
1992年 | 66篇 |
1991年 | 64篇 |
1990年 | 67篇 |
1989年 | 47篇 |
1988年 | 34篇 |
1987年 | 33篇 |
1986年 | 48篇 |
1985年 | 26篇 |
1984年 | 31篇 |
1983年 | 26篇 |
1982年 | 19篇 |
1981年 | 23篇 |
1980年 | 15篇 |
1979年 | 28篇 |
1978年 | 22篇 |
1977年 | 15篇 |
1976年 | 16篇 |
1975年 | 18篇 |
1971年 | 17篇 |
1970年 | 17篇 |
1969年 | 20篇 |
1967年 | 14篇 |
排序方式: 共有2894条查询结果,搜索用时 0 毫秒
1.
Immune deficiency in the X-linked lymphoproliferative syndrome. I. Epstein-Barr virus-specific defects 总被引:8,自引:0,他引:8
S Harada K Sakamoto J K Seeley T Lindsten T Bechtold J Yetz G Rogers G Pearson D T Purtilo 《Journal of immunology (Baltimore, Md. : 1950)》1982,129(6):2532-2535
Eleven males with XLP were evaluated for EBV-specific antibodies during periods of 2 to 7 yr. Variable responses to EBV-specific antigens were found. All 11 patients had subnormal anti-EBNA titers, which probably reflected a T cell deficiency. The patients showed four different patterns in their anti-VCA response: 1) two boys who had experienced malignant lymphoma mounted no antibodies at all; 2) two patients showed intermittent anti-VCA titers; 3) four males had persistently elevated anti-VCA titers; and 4) three patients showed normal anti-VCA titers. ADCC against EBV-infected cells was abnormally low in six patients and was elevated in two patients given gamma-globulin. ADCC titers did not correlate with anti-VCA titers. However, most patients with XLP failed to effect regression of autologous EBV-infected lymphoblastoid cell lines, indicating a deficiency in long-lived T cell-mediated immunity to EBV. 相似文献
2.
We examined whether actin filaments are involved in the cAMP-dependent activation of a high affinity sodium/glucose cotransporter (SGLT1) using epithelial expression systems. The expression of enhanced green fluorescent protein-tagged SGLT1 (EGFP-SGLT1) in Madin-Darby canine kidney (MDCK) cells was revealed by Western blotting and confocal laser microscopy. 8-Br-cAMP, a membrane permeable cAMP analog, enhanced [14C]-α-methyl glucopyranoside ([14C]-AMG) uptake. Both basal and 8-Br-cAMP-elicited [14C]-AMG uptakes were inhibited by N-(2{[3-(4-bromophenyl)-2-propenyl]-amino}-ethyl)-5-isoquinolinesulfonamide (H-89), a protein kinase A inhibitor, and cytochalasin D, an actin filament formation inhibitor. Furthermore, cytochalasin D inhibited the distribution of EGFP-SGLT1 at the apical surface. These results suggest that the EGFP-SGLT1 protein is functionally expressed in the apical membrane of MDCK cells, and is up-regulated by a cAMP-dependent pathway requiring intact actin filaments. 相似文献
3.
Masayo Suzuki Hiroyuki Ishida Yukimasa Shiotsu Taisuke Nakata Shiro Akinaga Shigemitsu Takashima Toshiaki Utsumi Toshiaki Saeki Nobuhiro Harada 《The Journal of steroid biochemistry and molecular biology》2009,113(3-5):195-201
In order to evaluate the importance of estrogen production in tumor and surrounding tissues, we measured mRNA expression levels of 5 enzymes participating to estrogen synthesis in situ and 4 breast cancer-related proteins in 27 pairs of tumor and non-malignant tissues. Steroid sulfatase (STS) mRNA was more frequently detected in tumor tissues rather than in their non-malignant counterparts. Estrogen sulfotransferase (EST) was constantly expressed with high level not only in tumor tissues but also in their surrounding non-malignant counterparts. In contrast, mRNA expression levels of aromatase, and 17β-hydroxysteroid dehydrogenase type I and II were relatively low and detected only in small proportion of the patients. We also measured the mRNA expression levels of the same nine genes in tumor tissues of 197 breast cancer patients, and analyzed relationship between the mRNA expression level and the clinicopathological parameters. The mRNA expression levels of STS, aromatase and erbB2 in tumor tissues increased as breast cancer progressed. The tumoral mRNA expression levels of STS, estrogen receptor β, and erbB2 in patients with recurrence were higher than those in patients without recurrence. Upregulation of STS expression plays an important role in tumor progression of human breast cancer and is considered to be responsible for estrogen production in tumor and surrounding tissues. 相似文献
4.
5.
6.
7.
Nucleotide sequence of the PR-1 gene of Nicotiana tabacum 总被引:7,自引:0,他引:7
M Ohshima M Matsuoka N Yamamoto Y Tanaka Y Kano-Murakami Y Ozeki A Kato N Harada Y Ohashi 《FEBS letters》1987,225(1-2):243-246
A gene encoding one of the pathogenesis-related proteins, PR1a, and two related pseudogenes were isolated from Nicotiana tabacum. The cloned PR1a gene (pPR-gamma) and one of the pseudogenes (pPR-alpha) were sequenced and found to have similar structures. The sequence of pPR-gamma was quite similar to that of the cDNA clone of PR1a. The plasmid pPR-gamma did not contain an intron and had a typical promoter sequence in the 5'-flanking region. 相似文献
8.
9.
Complete deficiency of 20 KDa homologous restriction factor (HRF20) and restoration with purified HRF20 总被引:4,自引:0,他引:4
N Okada R Harada R Taguchi H Okada 《Biochemical and biophysical research communications》1989,164(1):468-473
20 KDa homologous restriction factor (HRF20) is a membrane glycoprotein which inhibits formation of membrane attack complexes of homologous complement. Erythrocytes from a patient who is completely deficient in HRF20 were readily hemolyzed by homologous complement activated by sucrose or by acidification as in paroxysmal nocturnal hemoglobinuria (PNH). After incubating PNH erythrocytes (PNH-E) with purified HRF20, the cells were analyzed by flow cytometry using a monoclonal antibody to HRF20 and shown to have the antigen absorbed. These PNH-E acquired resistance to hemolysis by homologous complement suggesting that HRF20 may be successfully used for treatment of these patients. 相似文献
10.
Ishikawa Keiko; Kamada Hiroshi; Yamaguchi Isomaro; Takahashi Nobutaka; Harada Hiroshi 《Plant & cell physiology》1988,29(3):461-466
Carrot and tobacco plants were transformed with Agrobacteriumtumefaciens harboring wild-type, aux or cyt Tiplasmids. In tobacco, these wild and mutant Ti plasmids inducedthe formation of non-morphogenic galls, galls with shoots, andgalls with roots, respectively. In carrot, however, transformationwith any of these plasmids resulted in only the formation ofamorphous tumors. Determination of IAA and cytokinin contentsshowed that in tobacco, significantly high amounts of cytokininsor IAA are present in the cells transformed with Ti plasmidspossessing cytokinin or IAA biosynthetic genes, respectively.In carrot, cytokinin contents were also high in the cells transformedwith Ti plasmids having cytokinin biosynthetic genes, whereasIAA contents of the cells were similar regardless of the plasmidsused for transformation. These results suggest that the mechanism regulating IAA metabolismmay be different in tobacco and carrot. (Received June 25, 1987; Accepted February 1, 1988) 相似文献