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   903篇
  免费   49篇
  2023年   7篇
  2022年   14篇
  2021年   18篇
  2020年   17篇
  2019年   17篇
  2018年   22篇
  2017年   24篇
  2016年   28篇
  2015年   50篇
  2014年   42篇
  2013年   64篇
  2012年   90篇
  2011年   76篇
  2010年   39篇
  2009年   35篇
  2008年   38篇
  2007年   37篇
  2006年   30篇
  2005年   22篇
  2004年   17篇
  2003年   17篇
  2002年   22篇
  2001年   19篇
  2000年   7篇
  1999年   11篇
  1998年   5篇
  1996年   5篇
  1993年   6篇
  1992年   7篇
  1991年   9篇
  1990年   6篇
  1989年   8篇
  1987年   4篇
  1986年   4篇
  1985年   5篇
  1984年   6篇
  1983年   6篇
  1982年   10篇
  1981年   5篇
  1980年   6篇
  1979年   11篇
  1978年   5篇
  1977年   8篇
  1976年   7篇
  1975年   5篇
  1974年   8篇
  1973年   5篇
  1972年   12篇
  1971年   7篇
  1969年   6篇
排序方式: 共有952条查询结果,搜索用时 93 毫秒
81.
Effect of methyl carbonate pesticide, carbonyl, was studied on macrophage functions, lymphocyte proliferation and delayed type hypersensitivity response. Sixteen adult chicken, vaccinated against Newcaslte disease, were procured and randomly divided in two experimental groups. Chicken of group I served as control, while group II birds were given carbaryl at 20 ppm (No observable effect level, NOEL) in feed for 3 months. To measure the functional activity of phagocytic cells, nitroblue tetrazolium (NBT) reduction test was performed on peripheral blood leucocytes. Concanvalin A (Con-A) and lipopolysaccharide stimulated proliferation of T and B lymphocytes was assessed using MTT dye method. At the end of experiment, the phagocytic capacities of macrophages were significantly reduced in carbaryl treated group. Lymphocyte proliferation responses to Con-A and LPS were (23 and 28%, respectively lower) in chicken fed with carbaryl. Delayed hypersensitivity reaction to tuberculin was reduced to 77% of control values indicating inhibition of cell mediated immune response. The present study suggested of immunosuppressive effect of (NOEL dose carbaryl) in chicken.  相似文献   
82.
The Bioinformatics Resource Manager (BRM) is a software environment that provides the user with data management, retrieval and integration capabilities. Designed in collaboration with biologists, BRM simplifies mundane analysis tasks of merging microarray and proteomic data across platforms, facilitates integration of users' data with functional annotation and interaction data from public sources and provides connectivity to visual analytic tools through reformatting of the data for easy import or dynamic launching capability. BRM is developed using Java and other open-source technologies for free distribution. AVAILABILITY: BRM, sample data sets and a user manual can be downloaded from http://www.sysbio.org/dataresources/brm.stm.  相似文献   
83.

Background  

Down's syndrome (DS), or trisomy 21, is a complex developmental disorder that exhibits many clinical signs that vary in occurrence and severity among patients. The molecular mechanisms responsible for DS have thus far remained elusive. We argue here that normal variation in gene expression in the population contributes to the heterogeneous clinical picture of DS, and we estimated the amplitude of this variation in 50 mouse orthologs of chromosome 21 genes in brain regions of Ts65Dn (a mouse model of DS). We analyzed the RNAs of eight Ts65Dn and eight euploid mice by real-time polymerase chain reaction.  相似文献   
84.
A multiple-unit-type oral floating dosage form (FDF) of 5-fluorouracil (5-FU) was developed to prolong gastric residence time, target stomach cancer, and increase drug bioavailability. The floating bead formulations were prepared by dispersing 5-FU together with calcium carbonate into a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as alginate undergoes ionotropic gelation by calcium ions and carbon dioxide develops from the reaction of carbonate salts with acid. The evolving gas permeated through the alginate matrix, leaving gas bubbles or pores, which provided the beads buoyancy. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, image, surface topography, buoyancy, and in vitro release. The formulations were optimized for different weight ratios of gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated instantaneous, complete, and excellent floating ability over a period of 24 hours. The optimized formulation was subjected to in vivo antitumor studies to check the therapeutic efficacy of the floating dosage forms containing 5-FU against benzo(a)pyrene-induced stomach tumors in albino female mice (Balb/C strain). The multiple-bead FDF was found to reduce the tumor incidence in mice by 74%, while the conventional tablet dosage form reduced this incidence by only 25%. Results indicate that FDF performed significantly better than the simple tablet dosage form. Published: June 22, 2007  相似文献   
85.
Mycopathologia - Literature on COVID-19-associated pulmonary mucormycosis (CAPM) is sparse. Pulmonary artery pseudoaneurysm (PAP) is an uncommon complication of pulmonary mucormycosis (PM), and...  相似文献   
86.
87.
88.
Eleven germplasms of faba bean seeds from four agroclimatic regions of Bihar, India, have been investigated to estimate their nutritional (soluble protein, free amino acids, starch, reducing and non reducing sugar, total soluble sugar) and antinutritional (total extractable phenol and condensed tannin/proanthocyanidin) parameters. These parameters were found in varying concentration in all genotypes studied. The highest concentration of total extractable phenol and proanthocyanidin (condensed tannin) (2.56 and 1.59 % leucocyanidin equivalents respectively on dry matter basis) were found in Samastipur while the lowest from Patna (0.95 and 0.426 % leucocyanidin equivalent on dry matter basis). The different nutritional parameters were also found to be in variable concentration among different germplasms viz. total soluble protein ≈ 20–32 %, free amino acids ≈ 188–348 mg/100 g, starch ≈ 27–33 %, reducing sugars ≈ 85–188 mg/100 g, non reducing sugars ≈ 0.7–1.7 % and total soluble sugars ≈ 0.8–1.9 %.  相似文献   
89.
During DNA damage response (DDR), histone ubiquitination by RNF168 is a critical event, which orchestrates the recruitment of downstream DDR factors, e.g. BRCA1 and 53BP1. Here, we report USP7 deubiquitinase regulates the stability of RNF168. We showed that USP7 disruption impairs H2A and ultraviolet radiation (UVR)-induced γH2AX monoubiquitination, and decreases the levels of pBmi1, Bmi1, RNF168 and BRCA1. The effect of USP7 disruption was recapitulated by siRNA-mediated USP7 depletion. The USP7 disruption also compromises the formation of UVR-induced foci (UVRIF) and ionizing radiation-induced foci (IRIF) of monoubiquitinated H2A (uH2A) and polyubiquitinated H2AX/A, and subsequently affects UVRIF and IRIF of BRCA1 as well as the IRIF of 53BP1. USP7 was shown to physically bind RNF168 in vitro and in vivo. Overexpression of wild-type USP7, but not its interaction-defective mutant, prevents UVR-induced RNF168 degradation. The USP7 mutant is unable to cleave Ub-conjugates of RNF168 in vivo. Importantly, ectopic expression of RNF168, or both RNF8 and RNF168 together in USP7-disrupted cells, significantly rescue the formation of UVRIF and IRIF of polyubiquitinated H2A and BRCA1. Taken together, these findings reveal an important role of USP7 in regulating ubiquitin-dependent signaling via stabilization of RNF168.  相似文献   
90.
Over two billion people, depending largely on staple foods, suffer from deficiencies in protein and some micronutrients such as iron and zinc. Among various approaches to overcome protein and micronutrient deficiencies, biofortification through a combination of conventional and molecular breeding methods is the most feasible, cheapest, and sustainable approach. An interspecific cross was made between the wheat cultivar 'Chinese Spring' and Aegilops kotschyi Boiss. accession 396, which has a threefold higher grain iron and zinc concentrations and about 33% higher protein concentration than wheat cultivars. Recurrent backcrossing and selection for the micronutrient content was performed at each generation. Thirteen derivatives with high grain iron and zinc concentrations and contents, ash and ash micronutrients, and protein were analyzed for alien introgression. Morphological markers, high molecular weight glutenin subunit profiles, anchored wheat microsatellite markers, and GISH showed that addition and substitution of homoeologous groups 1, 2, and 7 chromosomes of Ae. kotschyi possess gene(s) for high grain micronutrients. The addition of 1U/1S had high molecular weight glutenin subunits with higher molecular weight than those of wheat, and the addition of 2S in most of the derivatives also enhanced grain protein content by over 20%. Low grain protein content in a derivative with a 2S-wheat translocation, waxy leaves, and absence of the gdm148 marker strongly suggests that the gene for higher grain protein content on chromosome 2S is orthologous to the grain protein QTL on the short arm of group 2 chromosomes.  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