首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   447篇
  免费   30篇
  2023年   9篇
  2022年   8篇
  2021年   24篇
  2020年   24篇
  2019年   21篇
  2018年   27篇
  2017年   22篇
  2016年   27篇
  2015年   15篇
  2014年   21篇
  2013年   39篇
  2012年   23篇
  2011年   31篇
  2010年   23篇
  2009年   21篇
  2008年   21篇
  2007年   15篇
  2006年   8篇
  2005年   3篇
  2004年   8篇
  2003年   6篇
  2002年   6篇
  2001年   4篇
  2000年   1篇
  1999年   2篇
  1998年   3篇
  1997年   4篇
  1995年   2篇
  1993年   3篇
  1992年   5篇
  1991年   5篇
  1990年   3篇
  1989年   7篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   5篇
  1984年   3篇
  1982年   2篇
  1980年   4篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1975年   1篇
  1974年   4篇
  1972年   2篇
  1971年   3篇
  1970年   2篇
  1966年   1篇
排序方式: 共有477条查询结果,搜索用时 15 毫秒
1.
Background: Schizophrenia, schizoaffective disorder, and bipolar illness are common psychological disorders with high heritability and variable phenotypes. The disrupted in schizophrenia 1 ( DISC1) gene, on chromosome 1q42, has an essential role in neurite outgrowth and cell signaling. The purpose of this study was to investigate the association of three single-nucleotide polymorphisms (SNPs; rs6675281, rs2255340, and rs2738864) with schizophrenia disorder. These three SNPs were chosen as they had been used in most of the previous studies. Methods: In a case-control study of Iranian population for the first time 778 blood samples were collected including, 402 schizophrenic patients and 376 healthy controls. Genomic DNA was extracted from peripheral blood using DNA extraction kit (BioFlux Co). The genotypes of rs6675281, rs2255340, and rs2738864 were detected by nested allele-specific multiplex polymersae chain reaction (PCR). Results: Our data revealed that the three SNPs are significantly associated with schizophrenia (rs2255349 C>T: confidence interval (CI), 2.115 to 3.268; P = 0.0000 OR: 2.629; rs2738864 C>T: CI, 1.538 to 2.339; P = 0.0000 OR: 1.897; rs6675281 C>T: CI, 2.788 to 4.662; P = 0.0009241 OR: 3.605). Through applying the expectation-maximization (EM) algorithm, we calculated the haplotype frequency, and finally performed haplotype analysis with Bonferroni correction and data preprocessing methods and the results showed rs66875281 to have the highest association. Discussion: Our findings primarily showed that DISC1 gene polymorphisms contribute to schizophrenia risk and have a significant association with this disorder among Iranian population. The strategy was found to be easy, rapid, specific, and consistent for the co-occurring detection of the DISC1 polymorphisms. We could finally confirm that the polymorphisms are related to schizophrenia studied in Iranian population.  相似文献   
2.
The characteristics of yeast eukaryotic initiation factor 2 (eIF-2) and Co-eIF-2A have been studied and compared with those of the corresponding factors from rabbit reticulocytes. 1) Unlike eIF-2r, purified eIF-2y did not contain bound GDP. 2) Purified eIF-2y preparation contained GTPase activity and dephosphorylated GTP to GDP. 3) An anti-eIF-2r preparation which predominantly precipitated the gamma-subunit (Mr 54,000) of eIF-2r also precipitated the larger subunit (Mr 54,000) of eIF-2y. 4) Unlike eIF-2r, ternary complex formation by eIF-2y was not inhibited by Mg2+. 5) Both Co-eIF-2A20y and Co-eIF-2r significantly enhanced Met-tRNAf binding to eIF-2y and, again, Mg2+ did not have any effect on this stimulated Met-tRNAf binding to eIF-2y. 6) Both Co-eIF-2A20y and Co-eIF-2r were similarly effective in stimulating Met-tRNAf binding to eIF-2r in the absence of Mg2+. However, in the presence of Mg2+, Co-eIF-2A20y was significantly less effective than Co-eIF-2r as Co-eIF-2A20y did not promote displacement of GDP from eIF-2r X GDP. 7) eIF-2y bound [3H]GDP and this binding was significantly enhanced in the presence of Mg2+. Also, [3H]GDP in the preformed eIF-2y X [3H]GDP complex was rapidly exchanged with exogenously added unlabeled GDP in the presence of Mg2+. Co-eIF-2A20y had no effect on GDP binding to eIF-2y nor on GDP exchange reactions. 8) Reticulocyte heme-regulated protein synthesis inhibitor, which phosphorylated almost completely (in excess of 80%) the alpha-subunit (Mr 38,000) of eIF-2r, also phosphorylated similarly the smaller subunit (Mr 36,000) of eIF-2y. However, such phosphorylation had no significant effect on ternary complex formation, GDP binding, and GDP exchange reactions.  相似文献   
3.
4.
Cancer is one of the main challenges of the health system around the world. This disease is increasing in developing countries and imposes heavy costs on patients and governments. On the other hand, despite various drugs, the death rate among cancer patients is still high and the current treatments have many harmful effects. In the traditional medicine of different countries, there are many medicinal plants that can be effective in the treatment of cancer. Ferula plants are traditionally used as spices and food or for medicinal purposes. Ferula assa-foetida is one of the famous plants of this genus, which has been used for the treatment of various diseases since ancient times. Among the main compounds of this plant, we can mention monoterpenes, sulfide compounds and polyphenols, which can show different therapeutic effects. This article has been compiled with the aim of collecting evidence and articles related to the anti-cancer effects of extracts, derived compounds, essential oils and nanoparticles containing Ferula assa-foetida. This review article was prepared by searching the terms Ferula assa-foetida and cancer, and relevant information was collected through searching electronic databases such as ISI Web of Knowledge, PubMed, and Google Scholar. Fortunately, the results of this review showed that relatively comprehensive studies have been conducted in this field and shown that Ferula assa-foetida can be very promising in the treatment of cancer.  相似文献   
5.
Localization of retinoic acid-binding protein in nuclei   总被引:5,自引:0,他引:5  
Retinoic acid-binding component has been detected in the nuclei of chick embryo skin. The physicochemical properties of this macromolecule are in agreement with the properties of the retinoic acid-binding protein isolated from tissue cytosol. Although no binding protein could be detected in normal colon or lung tissue, nuclei isolated from a transplantable colon tumor and Lewis lung carcinoma contained this protein.  相似文献   
6.
Microsurgical transposition of fallopian tube and ovary has the potential of being an efficient therapeutic treatment in patients with tubal sterility. The Authors present their experience of microsurgical adnexal transplantation in rabbit by two different techniques: the first procedure by microvascular anastomosis of the ovarian vessels, the second one without vascular pedicle. Function is evaluated at various time after grafting by: exploratory laparotomy on day 30 to establish whether circulation to the grafts was still maintained; macroscopic and microscopic examination of ovaries and fallopian tubes. The microvascular techniques prove highly reliable in terms of immediate vascular patency rate but it is disappointing that 50% of the autografts has failed with blocked vessels by day 30. Perhaps this is due to the difficult techniques in anastomosing the ovarian vessels of small caliber. In spite of these outcomes the vascularized autografts were viable and functional after transplantation in contrast with the non-vascularized tubo-ovarian grafts which all failed. This experience encourages to believe that the microsurgical technique could be employed for homograft transplantation in woman with extensive ovarian and tubal damages.  相似文献   
7.
In this study we compared two different conservative surgery techniques performed on 12 ovaries of female rabbits: microsurgery and CO2 Laser surgery. After the surgical procedure all the animals were investigated by a Laparotomy to evaluate the post-operative adhesion formation. Histological examinations were performed on 6 ovaries, to evaluate the possible damage to the ovarian parenchyma. We did not find significant differences between the two methods employed, particularly for the adherence formation and the parenchymal thermic damages: no post-operative adhesions were detected respectively in 3 ovaries operated on by microsurgery and 5 by laser surgery; slight adhesions were present in 2 ovaries treated with microsurgery and in 3 with laser surgery; 3 ovaries treated with microsurgery and 2 with laser surgery showed moderate adhesions. Only 2 ovaries treated with microsurgery presented severe adhesions.  相似文献   
8.
A highly potent beta-adrenergic antagonist based on the structure of alprenolol has been prepared by replacement of the isopropylamine residue of alprenolol by 1, 8-diamino-p-menthane (AlpM). The resulting mixture of isomers (AlpM) competes for occupancy of beta-adrenergic receptors in frog erythrocycte membranes with an apparent KD of 210 pM. The bromoacetylated derivative of AlpM (BrAlpM) leads to an irreversible inactivation of the [3H]dihydroalprenolol ([3H]DHA) binding sites. Various adrenergic agonists and antagonists afford specific and stereoselective protection of the receptor against inactivation by BrAlpM. Tritiation of AlpM followed by bromoacetylation and chromatographic separation yielded two isomers, Br-1-AlpM and Br-8-AlpM of high specific radioactivity (~ 40 Ci/mmol). Both radiolabelled isomers interacted specifically and with high affinity with the beta-adrenergic receptor, but only a small amount of the ligands could be covalently incorporated into the receptor subunit. This agent provides a powerful new probe for studies of beta-adrenergic receptors in analogy with bungarotoxin for the nicotinic cholinergic receptor.  相似文献   
9.
Coal is one of the most abundant nonrenewable fossil fuels, in Pakistan. However, in general, the quality of coal is too low to offset the practical, economic, and regulatory barriers to its utilization. High sulfur content comes up as one of the bottlenecks in productive usage of indigenous coal. Biotechnology can emerge as a panacea for upgrading the huge reserves of high sulfur coal. In current study, the sulfur removal potential of Rhodococcus spp. (Eu-32) was investigated using coal from Dukki, Baluchistan, Pakistan. Biodesulfurization process was optimized for various parameters and maximum decrease of 40% and 60% in total and organic sulfur contents, respectively were achieved in 15 days. The Langmuir and Brunauer–Emmett–Teller (BET) surface areas of the biotreated coal were increased by 20 and 16 times, respectively. Scanning electron microscope showed higher tendency of attachment of bacterial cells to the coal particles. Our results revealed that Eu-32 could remove significant amounts of organic sulfur from coal and could be used in the pre-combustion operations with appropriate arrangements.  相似文献   
10.
Dye removal from industrial waste water has become an important issue. The highvisibility, undesirability and recalcitrance are the significant environmental problemfor the dyes. In the present work,β‐cyclodextrin functionalized KCC‐1 (KCC‐1‐NH‐β‐CD)was synthesized and utilized to the removal of hazardous malachite green. In order to study the morphology of the synthesized nano adsorbent, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were obtained from the surface of the sample. Additionally, the functionalization of KCC‐1 with β‐cyclodextrin was confirmed with Furrier Transform Infrared spectroscopy (FTIR). The textural property of KCC‐1 was verified using nitrogen adsorption/ desorption analysis (BET equation). UV‐Vis spectroscopy utilized for the investigation of malachite green by KCC‐1‐NH‐β‐CD. Specific surface area of the adsorbent was calculated to be 140 m2/g and it can be stated that the synthesized nano adsorbent has high removal efficiency. It should be noted that the adsorption capacity of the employed nano adsorbent was more than 95%, which could be attributed to high porosity of β‐cyclodextrin functionalized KCC‐1.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号