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   882篇
  免费   46篇
  国内免费   1篇
耳鼻咽喉   5篇
儿科学   37篇
妇产科学   7篇
基础医学   146篇
口腔科学   8篇
临床医学   93篇
内科学   193篇
皮肤病学   18篇
神经病学   45篇
特种医学   32篇
外科学   139篇
综合类   16篇
预防医学   65篇
眼科学   12篇
药学   81篇
中国医学   5篇
肿瘤学   27篇
  2023年   5篇
  2022年   24篇
  2021年   38篇
  2020年   30篇
  2019年   27篇
  2018年   38篇
  2017年   25篇
  2016年   31篇
  2015年   35篇
  2014年   37篇
  2013年   52篇
  2012年   70篇
  2011年   67篇
  2010年   54篇
  2009年   23篇
  2008年   55篇
  2007年   56篇
  2006年   47篇
  2005年   39篇
  2004年   39篇
  2003年   28篇
  2002年   22篇
  2001年   15篇
  2000年   9篇
  1999年   6篇
  1998年   3篇
  1996年   2篇
  1995年   2篇
  1992年   3篇
  1991年   2篇
  1990年   2篇
  1989年   4篇
  1988年   1篇
  1987年   4篇
  1986年   5篇
  1985年   3篇
  1984年   4篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1971年   4篇
  1970年   1篇
  1967年   1篇
  1942年   1篇
排序方式: 共有929条查询结果,搜索用时 15 毫秒
101.

Background

Single nucleotide polymorphisms (SNP) in the promoter region of the interleukin (IL)-10 genes have a role in determining hepatitis B virus (HBV) outcome.

Objectives

This study evaluates the correlation between HBV infection and SNP in IL-10 gene promoter.

Patients and Methods

Ninety-six HBV-infected patients (32 chronic hepatitis B infection patients, 34 healthy carriers, 30 spontaneously recovered cases) and 31 healthy controls were enrolled. Three biallelic (-819,-592,-1082) regions in the IL-10 gene promoter were sequenced for all patients.

Results

Genotypes and haplotypes of IL-10 gene promoter region at position -1082, -819 and -592 were not significantly different among controls, HBV recovered cases, carriers and chronic HBV patients. Nevertheless, A/A genotype at position -592 and T/T genotype at position -819 were more frequently seen in the HBV clearance group, while frequency of G/G genotype at position -1082 was more prevalent in the persistence group. GCC/GCC and GCC/ACC haplotypes were significantly observed in anti-HBe positive individuals.

Conclusions

Our findings showed that IL-10 promoter polymorphisms were not correlated with HBV infection prognosis. Nevertheless, individuals carrying high and intermediate producer of IL-10 haplotypes had a better ability to develop anti-HBe than low producer carriers.  相似文献   
102.
103.

Background  

It has been suggested that lithium increases choline concentrations, although previous human studies examining this possibility using 1H magnetic resonance spectroscopy (1H MRS) have had mixed results: some found increases while most found no differences.  相似文献   
104.
105.
C3bBbP complex formation was studied by an enzyme linked immunosorbent assay (ELISA). Microtitre plates were coated with anti-P to trap the complexes and peroxidase labelled anti-C3 was used to detect them with the help of substrates of peroxidase. Incubation of normal serum pool (NSP) at 37 degrees C in the presence of high concentrations (greater than or equal to 0.5 mmol/l) of Mg2+, usually used in alternative pathway (AP) assay systems, caused the generation of C3bBbP complexes. This generation was not observed when NSP was incubated in the presence of low Mg2+ concentration (less than or equal to 0.2 mmol/l) or EDTA. The concentration of Mg2+ required for maximum complex formation was 2.0 mmol/l under the experimental conditions. Complexes could not be generated in B-depleted serum. Incubation of NSP with endotoxin or CoVF in the presence of 0.2 mmol/l Mg2+ caused the generation of the complexes. The generation was influenced by ionic strength in the incubation mixture. Endotoxin and Mg2+-dependent generation of complexes could not be detected when peroxidase-labelled anti-B was used instead of peroxidase-labelled anti-C3. Serum incubated with 0.2 mmol/l Mg2+ or EDTA apparently detected in vivo formed complexes whereas that incubated with 0.2 mmol/l Mg2+ and endotoxin reflected the complex forming capacity of the serum. The serum of a patient with Raynaud's phenomenon having 45% of normal AP activity did not show increased amounts of preformed complexes but had the ability to generate the complexes to a level of about 45% of that attainable by NSP. These observations suggest that the ELISA used here has the potential of detecting activation as well as the integrity of the AP under carefully controlled conditions.  相似文献   
106.
107.
Different codes are used for Monte Carlo (MC) calculations in radiation therapy. In this research, MCNP4C and GEANT3 codes have been compared in calculations of dosimetric characteristics of Varian Clinac 2300C/D. The parameters of influence in the differences seen in dosimetric features were discussed. This study emphasizes that both MCNP4C and GEANT3 MC can be used in radiation therapy computations and their differences in photon spectra calculations have a negligible effect on percentage depth dose computations in radiation therapy.  相似文献   
108.
109.
This paper describes Monte Carlo simulation of intrinsic count rate performance of a scintillation gamma camera. MCNP Monte Carlo code was employed to calculate pulse height spectrum and detector efficiency. A custom code written in Fortran language was then developed to simulate, by Monte Carlo method, the distortion in pulse height spectrum due to the pile-up effect for paralyzable and nonparalyzable systems. The results of the simulations, compared with the experimental measurement of count rate performance, showed a good agreement between the two different approaches.  相似文献   
110.
Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency characterized by reduced levels of all major immunoglobuline classes and recurrent c infections. The risk of non-Hodgkin's lymphoma (NHL) among patients with CVID was found to be increased in different studies. Mucosa-associated lymphoid tissue (MALT) lymphomas are a recently recognized sub-set of low-grade B-cell NHL composed of marginal zone-related cells. MALT lymphomas appear in the lymphoid tissues as a result of chronic inflammatory or autoimmune stimulation. This study briefly reviews previously published cases and reports a patient suffering from CVID with a history of chronic diarrhea and recurrent sinopulmonary infections. Despite treatment with intravenous immunoglobulin, chronic cough and wheezing progressed. Open lung biopsy showed a MALT lymphoma. Although a rare complication, pulmonary low grade B-cell lymphoma is a diagnosis that must be kept in mind in CVID patients with chronic pulmonary symptoms unresponsive to conventional therapies.  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