全文获取类型
收费全文 | 1560篇 |
免费 | 125篇 |
出版年
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 7篇 |
2018年 | 11篇 |
2017年 | 18篇 |
2016年 | 23篇 |
2015年 | 24篇 |
2014年 | 30篇 |
2013年 | 70篇 |
2012年 | 85篇 |
2011年 | 82篇 |
2010年 | 43篇 |
2009年 | 45篇 |
2008年 | 46篇 |
2007年 | 60篇 |
2006年 | 56篇 |
2005年 | 60篇 |
2004年 | 83篇 |
2003年 | 67篇 |
2002年 | 80篇 |
2001年 | 49篇 |
2000年 | 79篇 |
1999年 | 55篇 |
1998年 | 27篇 |
1997年 | 24篇 |
1996年 | 24篇 |
1995年 | 32篇 |
1994年 | 29篇 |
1993年 | 21篇 |
1992年 | 47篇 |
1991年 | 33篇 |
1990年 | 28篇 |
1989年 | 46篇 |
1988年 | 34篇 |
1987年 | 34篇 |
1986年 | 28篇 |
1985年 | 24篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1980年 | 7篇 |
1979年 | 19篇 |
1978年 | 16篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1974年 | 10篇 |
1971年 | 6篇 |
1970年 | 7篇 |
1969年 | 6篇 |
排序方式: 共有1685条查询结果,搜索用时 15 毫秒
41.
Kazuyoshi Masuda Shunji Nagata Koichiro Hirano Yasushi Takagishi Hidematsu Hirai 《Microbiology and immunology》1993,37(2):165-167
This paper describes an attempt to effectively induce antibody-dependent cell-mediated cytotoxicity (ADCC) in nude mice. A monoclonal antibody against α-fetoprotein, 80G, coadministered with spleen cells from other nude mice bearing HuH-7N (xenograft of human hepatoma cell line, HuH-7) significantly suppressed the growth of HuH-7N as compared to treatment with 80G alone. 80G with spleen cells from normal nude mice also had some suppressive effect. In contrast, no effect was observed with each spleen cells alone as well as 80G alone. These results suggest that further supply of effector cells could enhance ADCC activity in nude mice. 相似文献
42.
43.
Yoshihiro Izumi Kanji Ono Masayuki Takamiya Kiichi Fukui 《Journal of plant research》1993,106(4):319-325
Using cultured cells of the hornwortAnthoceros punctatus, the change in the relative chloroplast DNA content in each stage of chloroplast division was investigated to clarify the
relationship between the division cycle of a chloroplast and a cell nucleus. Samples of cultured cells were stained with 4′,6-diamidino-2-phenylindole
(DAPI) and then observed with an epifluorescence microscope and a chromosome image analyzing system (CHIAS). A chloropiast
in cultured cells duplicated DNA with an increase in size. When a chloroplast began to divide, it was constricted in the middle,
taking a dumbbell shape, and then divided into two daughter chloroplasts. In cultured cells of this species, the pattern of
quantitative change of chloroplast DNA, that is, the DNA replication pattern of chloroplasts, corresponded to that of cell
nuclear DNA in mitosis. 相似文献
44.
Kanji Hori Yoshiharu Shimada Chihiro Oiwa Keisuke Miyazawa Keiji Ito 《Journal of applied phycology》1993,5(2):219-223
Nine species of marine algae have been assessed for the presence of novel hemagglutinins not extractable with buffer, unless
the algal tissue was pretreated with Pronase. All species examined contained hemagglutinins, indicating the existence of a
novel group of hemagglutinins which differed from those reported previously in marine algae. 相似文献
45.
Kazuyoshi Masuda Shunji Nagata Koichiro Hirano Yasushi Takagishi Hidematsu Hirai 《生物化学与生物物理学报:疾病的分子基础》1993,1182(2):128-132
This study was carried out to clarify the reason for elevation of serum α-fetoprotein (AFP) level of nude mice bearing hepatoma cells after treatment with monoclonal antibodies (MoAbs) to AFP. MoAbs to AFP showed no effect on the cumulative amounts of AFP secreted from human hepatoma cell line, HuH-7, in vitro. However, the treatment of nude mice bearing HuH-7N cells (HuH-7 xenograft) with MoAbs to AFP led to elevation of the serum AFP level in spite of the fact that the growth curve of HuH-7N cells was similar to that for PBS treatment. This apparent elevation of the serum AFP level is thought to be due to the slow elimination of AFP-MoAb immune complexes with little lattice structure from circulation, but not the enhancement of AFP secretion of HuH-7N cells. Thus, when using a MoAb alone or MoAb-drug conjugate, the serum AFP level should only be cautiously used as a tumor marker for evaluating the targeting immunotherapy. 相似文献
46.
Transforming growth factor beta (TGF beta) regulates the growth of human umbilical vein endothelial cells (HUVEC) differently depending on the isoform of TGF beta and the culture conditions. The cells are resistant to growth inhibition by TGF beta when the cells are cultured on substratum coated with gelatin. However, the proliferation of HUVEC cultured on substratum without a gelatin coating is inhibited by TGF beta, depending on the isoform and concentration of TGF beta. Binding assays with 125I-TGF beta 1 reveal that HUVEC contain a single class of high-affinity (Kd = 4.4 pM) TGF beta 1 binding sites with 8500 sites per cell. Affinity cross-linking studies demonstrate that HUVEC express 180 and 80 kDa TGF beta 1 binding sites that do not bind TGF beta 2. The reduction and the removal of glycosaminoglycans does not affect the electrophoretic mobility of the 180-kDa binding protein cross-linked with 125I-TGF beta 1. Therefore, the 180-kDa TGF beta 1 binding protein is not related to the type III TGF beta receptor, but might be a novel TGF beta 1-specific receptor/binding protein expressed on vascular endothelial cells. The expression of TGF beta 1 binding sites is not affected by the presence or absence of the gelatin coating on the culture substratum. The data suggest that a gelatin coating does not regulate the susceptibility of HUVEC to TGF beta 1 at the level of the receptor/binding proteins, and that growth inhibition of HUVEC by TGF beta 1 is linked to the regulation of extracellular matrices required for the interaction between the cells and the substratum. 相似文献
47.
Motohiro Matsuura Shinji Saito Yoshikazu Hirai Haruki Okamura 《European journal of biochemistry》2003,270(19):4016-4025
Production of nitric oxide (NO) in response to bacterial lipopolysaccharide (LPS) was investigated using cultures of mouse peritoneal exudate cells (PEC) and the macrophage cell line RAW264.7. In the presence of anti-(interferon-gamma) (IFN-gamma), NO production was markedly suppressed in the PEC culture but not in the RAW264.7 culture. In the PEC culture, LPS induced both IFN-gamma production and activation of IFN response factor-1, which leads to the gene expression of inducible NO synthase, but neither was induced in the culture of RAW264.7 cells. In addition to anti-(IFN-gamma), antibodies against interleukin (IL)-12 and IL-18 showed a suppressive effect on LPS-induced NO production in the PEC culture, and these antibodies in synergy showed strong suppression. Stimulation of the PEC culture with IL-12 or IL-18 induced production of IFN-gamma and NO, and these cytokines, in combination, exhibited marked synergism. Stimulation of the culture with IFN-gamma induced production of NO, but not IL-12. The macrophage population in the PEC, prepared as adherent cells, responded well to LPS for IL-12 production, but weakly for production of IFN-gamma and NO. The macrophages also responded well to IFN-gamma for NO production. For production of IFN-gamma by stimulation with LPS or IL-12 + IL-18, nonadherent cells were required in the PEC culture. Considering these results overall, the indirect pathway, through the production of intermediates (such as IFN-gamma-inducing cytokines and IFN-gamma) by the cooperation of macrophages with nonadherent cells, was revealed to play the main role in the LPS-induced NO production pathway, as opposed to the direct pathway requiring only a macrophage population. 相似文献
48.
Kohei Irifune Kanji Ono Misa Takahashi Hideko Murakami Hiromichi Morikawa 《Transgenic research》1996,5(5):337-341
Suspension-cultured cells (A-18 line) of the liverwortMarchanta polymorpha were bombarded by a pneumatic particle gun with plasmid pCH harbouring the hygromycin phosphotransferase (HPT) gene (hpt) under the control of the cauliflower mosaic virus (CaMV) 35 S promoter and the nopaline synthase polyadenylation region. Nine weeks after bombardments, 128 hygromycin-resistant calluses were obtained from an approximate total of 7×106 cells. Ten cell lines chosen randomly were analysed further. Southern blot analysis showed that all of the ten lines contain thehpt gene in the genome, demonstrating that these lines are transformants. An HPT enzyme activity assay confirmed the expression of the gene in all of the transformant lines. 相似文献
49.
Chromosomes from several species of ants from the genus Myrmecia were hybridized with deoxyoligomer probes of either (T2AG2)7, the putative insect telomere repeat sequence, or (T2AG3)7, the vertebrate telomere repeat sequence. While both sequence hibridized over a range of stringency conditions, (T2AG2)n was clearly the predominant sequence at the termini of the Myrmecia chromosomes. No interstitial sites of either sequence were detected. The genus Myrmecia has a wide range of karyotypes, with chromosome numbers ranging from 2n=2–84. It has been hypothesized that the ancestral karyotype was 2n=4 and karyotype evolution proceeded with an increase in chromosome number. In the absence of detectable interstitial sites of telomere sequence, it is interesting to speculate on the origin of the new telomeres as the chromosome numbers increased. 相似文献
50.
Alternative splicing and genomic structure of the AML1 gene involved in acute myeloid leukemia. 总被引:17,自引:0,他引:17
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
H Miyoshi M Ohira K Shimizu K Mitani H Hirai T Imai K Yokoyama E Soeda M Ohki 《Nucleic acids research》1995,23(14):2762-2769