全文获取类型
收费全文 | 1370篇 |
免费 | 91篇 |
国内免费 | 4篇 |
出版年
2024年 | 4篇 |
2023年 | 27篇 |
2022年 | 60篇 |
2021年 | 97篇 |
2020年 | 91篇 |
2019年 | 166篇 |
2018年 | 98篇 |
2017年 | 78篇 |
2016年 | 82篇 |
2015年 | 72篇 |
2014年 | 87篇 |
2013年 | 123篇 |
2012年 | 108篇 |
2011年 | 88篇 |
2010年 | 57篇 |
2009年 | 50篇 |
2008年 | 45篇 |
2007年 | 18篇 |
2006年 | 26篇 |
2005年 | 20篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 16篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1988年 | 2篇 |
1985年 | 1篇 |
排序方式: 共有1465条查询结果,搜索用时 15 毫秒
991.
Haghi Ashtiani MT Rabbani A Mostafavi F Monajemzadeh M Ranjbar Kermani F Soltaninia J 《Biochemical genetics》2008,46(11-12):712-719
Congenital adrenal hyperplasia (CAH) is a group of potentially life-threatening disorders, most often caused by deficiency of steroid 21-hydroxylase. Children with ambiguous genitalia, hermaphroditism, or signs and symptoms of CAH admitted to Children's Medical Center were enrolled in the survey, and 101 patients were found. Karyotyping, clinical examination, and paraclinical tests were done. HLA typing was done in patients with proven classical CAH and their parents. HLA antigens were typed in children with CAH-type 21-hydroxylase deficiency. The antigen frequencies were compared with those of the control population. The studies revealed that two HLA antigens, HLA-B18 and HLA-B21, showed a significant increase in frequency. The calculated relative risk value was high, distinguishing the population of patients and their parents. The relative risk among patients was 11.82 for HLA-B18 and 1.75 for HLA-B21 antigens. There was no relationship between HLA-DR antigens and CAH. Studies on the correlation between HLA and CAH indicate an association with HLA-B18 and HLA-B21 antigens, and they can be used as genetic markers of the disorder in the Iranian population, if they are restricted to Iranian patients. 相似文献
992.
Induction of trophinin in human endometrial surface epithelia by CGbeta and IL-1beta 总被引:1,自引:0,他引:1
Sugihara K Kabir-Salmani M Byrne J Wolf DP Lessey B Iwashita M Aoki D Nakayama J Fukuda MN 《FEBS letters》2008,582(2):197-202
During embryo implantation, trophinin mediates cell adhesion by homophilic binding at the apical surfaces of trophectoderm and endometrium. Trophinin is expressed on the human endometrial epithelia in rare occasions. We developed hCG-coated agarose beads that mimic the physical and physiological features of an implantation-stage human blastocyst. When hCG-coated beads were applied to human endometrial epithelial cells in the presence of IL-1beta, endometrial cells acquired strong trophinin expression and the ability for apical cell adhesion with trophinin-expressing human trophoblastic cells. These results provide a mechanism for trophinin-mediated adhesion of human blastocyst to endometrium by a spatially and temporally restricted paracrine effect of hCG derived from the blastocyst. 相似文献
993.
The role of vitamin E in the pathogenesis of diabetes mellitus is unknown. The purpose of this study was to examine the effect of oral administration of vitamin E on some of the metabolic parameters of experimental diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin (60 mg/kg body weight at 12 weeks of age). Vitamin E (0.2, 0.4, 0.8 mg/kg body weight) was administered orally for a period of 3 weeks to normal and diabetic Wistar rats. In some experiments, Vitamin E was given either before or after the induction of diabetes mellitus. Blood glucose level and weight were recorded for each rat in different groups on a weekly basis. Oral glucose tolerance test (OGTT) was performed on fasted normal, diabetic and vitamin E treated rats at the end of the experiment. Vitamin E significantly (p < 0.01) reduced blood glucose levels in experimental diabetes mellitus at all doses as compared to untreated rats. Vitamin E induced weight loss in normal as well as in diabetic rats. The beneficial effect of vitamin E on the hyperglycaemia of diabetic rats was dose-dependent. Moreover, vitamin E also improved OGTT in diabetic rats compared to untreated diabetics. In conclusion, vitamin E may play a role in glucose metabolism and thus be a useful adjuvant therapy in type I diabetes. (Mol Cell Biochem 261: 35–42, 2004) 相似文献
994.
Kabir-Salmani M Fukuda MN Kanai-Azuma M Ahmed N Shiokawa S Akimoto Y Sakai K Nagamori S Kanai Y Sugihara K Iwashita M 《Molecular endocrinology (Baltimore, Md.)》2008,22(3):707-715
CD98 heavy chain (CD98hc) is expressed highly in developing human placental trophoblast. CD98hc is an amino acid transporter and is thought to function in cell fusion, adhesion, and invasion by interacting with integrins. In invasive extravillous trophoblast, alpha(v)beta(3) integrin is expressed in a temporally and spatially specific manner, which prompted us to investigate the potential role of CD98hc in signal transduction of alpha(v)beta(3) integrin. Immunocytochemistry of extravillous trophoblast derived from human placenta revealed that CD98hc colocalized with alpha(v)beta(3) integrin and with alpha(v)beta(3)-associated cytoplasmic proteins including paxillin, vinculin, and focal adhesion kinase. Coimmunoprecipitation of CD98hc and its mutants revealed that the transmembrane domain of CD98hc is necessary for the association of CD98hc with alpha(v)beta(3) integrin. When CD98hc negative liver cells (FLC4) were stably transfected with CD98hc and the extracellular domain of CD98hc was cross-linked by anti-CD98 antibody, FLC4 cells binding affinity to fibronectin and cell motility increased. The anti-CD98 antibody cross-linking promoted actin stress fiber formation and activation of signal transduction downstream of RhoA GTPase, and elevated the phosphorylation of focal adhesion kinase, paxillin, and protein kinase B. Pretreatment of transfected FLC4 cells with specific inhibitors for alpha(v)beta(3)integrin, phosphatidylinositol 3-kinase, and RhoA diminished these effects caused by anti-CD98 antibody cross-linking. These results suggest that notoriously invasive activity of extravillous trophoblast is mediated by CD98hc, which promotes alpha(v)beta(3) integrin-dependent signals. 相似文献
995.
Ablolreza Mirmohseni Maryam Shojaei Maryam Farbodi 《Biotechnology and Bioprocess Engineering》2008,13(5):592-597
A quartz crystal nanobalance (QCN) biosensor was developed for the selective determination of phenylalanine (Phe) in aqueous
solutions. A Phe imprinted copolymer was synthesized using polyacrylonitrile and acrylic acid [poly(AN-co-AA)]. The copolymer
was then coated on quartz crystal electrode to form complementary structures for the template recognition of Phe. The composite
electrode was then used to determine Phe levels in solution. Determinations were based on frequency shifts of molecularly
imprinted polymer (MIP) modified quartz crystal electrode caused by Phe adsorption. The frequency shifts were linearly dependent
on Phe concentration over the range 50∼500 mgL−1. The results obtained show that the imprinted poly(AN-co-AA) modified biosensor had higher sensitivity (0.5839 Hz/mgL−1) than a non-molecularly imprinted copolymer (0.2724 Hz/mgL−1). Furthermore, good reproducibility, R.S.D. = 1.84% (n = 7) was observed, and the detection limit was 45 mgL−1. The selectivity of the imprinted poly(AN-co-AA) modified biosensor was examined using a number of analytes similar to Phe,
i.e., dopamine (DA), ascorbic acid (AscA), vanillylmandelic acid (VMA), uric acid (UA), tryptophan (Trp), and tyrosine (Tyr),
and the results obtained showed a size dependent selective effect. 相似文献
996.
Raffalli-Mathieu F Orre C Stridsberg M Hansson Edalat M Mannervik B 《The Biochemical journal》2008,414(1):103-109
hGSTA3-3 (human Alpha-class glutathione transferase 3-3) efficiently catalyses steroid Delta(5)-Delta(4) double-bond isomerization in vitro, using glutathione as a cofactor. This chemical transformation is an obligatory reaction in the biosynthesis of steroid hormones and follows the oxidation of 3beta-hydroxysteroids catalysed by 3beta-HSD (3beta-hydroxysteroid dehydrogenase). The isomerization has commonly been ascribed to a supplementary function of 3beta-HSD. The present study is the first to provide evidence that hGSTA3-3 contributes to this step in steroid hormone biosynthesis in complex cellular systems. First, we find glutathione-dependent Delta(5)-Delta(4) isomerase activity in whole-cell extracts prepared from human steroidogenic cells. Secondly, effective inhibitors of hGSTA3-3 dramatically decrease the conversion of Delta(5)-androstene-3,17-dione into Delta(4)-androstene-3,17-dione in cell lysates. Thirdly, we show that RNAi (RNA interference) targeting hGSTA3-3 expression decreases by 30% the forskolin-stimulated production of the steroid hormone progesterone in a human placental cell line. This effect is achieved at low concentrations of two small interfering RNAs directed against distinct regions of hGSTA3-3 mRNA, and is weaker in unstimulated cells, in which hGSTA3-3 expression is low. The results concordantly show that hGSTA3-3 makes a significant contribution to the double-bond isomerization necessary for steroid hormone biosynthesis and thereby complements the indispensable 3beta-hydroxysteroid oxidoreductase activity of 3beta-HSD. The results indicate that the lower isomerase activity of 3beta-HSD is insufficient for maximal rate of cellular sex hormone production and identify hGSTA3-3 as a possible target for pharmaceutical intervention in steroid hormone-dependent diseases. 相似文献
997.
998.
Avian embryos and related cell lines: A convenient platform for recombinant proteins and vaccine production
下载免费PDF全文
![点击此处可从《Biotechnology journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Maryam Farzaneh Seyedeh‐Nafiseh Hassani Paul Mozdziak Hossein Baharvand 《Biotechnology journal》2017,12(5)
Chick embryos are a significant historical research model in basic and applied sciences. The embryonated eggs have been used for virus inoculation in order to vaccine production for nearly a century. Recently, avian eggs and cell lines derived from embryonated eggs have found wide application in biotechnology. This review will discuss about the unique characteristics of avian eggs in terms of safety, large scale and economical production of recombinant proteins. This system also provides the human‐like glycosylation on target proteins and therefore can be considered as a suitable host for biomanufacturing of humanized monoclonal antibodies and therapeutic proteins. Avian derived cell lines are an alternative for rapid vaccine manufacturing during a pandemic. Based on the latest knowledge in cell and animal transgenesis, the currently available germ cell‐mediated gene transfer system provides a more efficient strategy in gene targeting and creation of transgenic birds that lead to advancements in industrial, biotechnology, and biological research applications. This review covers the recent development of avian fertilized eggs and related cell lines in a variety of human biopharmaceuticals and viral vaccine manufacturing. 相似文献
999.
Ahmad Nejati Mohammad Farahmand Hamideh Tabatabaie Maryam Yousefi Yaghoob Mollaei-Kandelous Shohreh Shahmahmoodi 《中国病毒学》2017,32(3):249-252
<正>Dear Editor,Acute flaccid paralysis(AFP)is a complex syndrome often caused by polioviruses.While most countries have eradicated wild polioviruses by vaccination,AFP still remains a health problem in these countries.Most studies have highlighted non-polio enteroviruses(NPEVs)as 相似文献
1000.
Fine‐tuning sortase‐mediated immobilization of protein layers on surfaces using sequential deprotection and coupling
下载免费PDF全文
![点击此处可从《Biotechnology progress》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Maryam Raeeszadeh‐Sarmazdeh Ranganath Parthasarathy Eric T. Boder 《Biotechnology progress》2017,33(3):824-831
Increasing interest in protein immobilization on surfaces has heightened the need for techniques enabling layer‐by‐layer protein attachment. Here, we report a technique for controlling enzyme‐mediated immobilization of layers of protein on the surface using a genetically encoded protecting group. An enterokinase‐cleavable peptide sequence was inserted at the N‐terminus of bifunctional fluorescent proteins containing Sortase A substrate recognition tags at both ends to control Sortase A‐mediated protein immobilization on the surface layer‐by‐layer. Efficient, sequential immobilization of a second layer of protein using Sortase A required removal of the N‐terminal protecting group, suggesting the method enables multilayer synthesis using cyclic deprotection and coupling steps. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:824–831, 2017 相似文献