全文获取类型
收费全文 | 15705篇 |
免费 | 1095篇 |
国内免费 | 283篇 |
专业分类
耳鼻咽喉 | 52篇 |
儿科学 | 235篇 |
妇产科学 | 83篇 |
基础医学 | 1602篇 |
口腔科学 | 37篇 |
临床医学 | 1851篇 |
内科学 | 4549篇 |
皮肤病学 | 291篇 |
神经病学 | 89篇 |
特种医学 | 342篇 |
外国民族医学 | 1篇 |
外科学 | 966篇 |
综合类 | 2990篇 |
现状与发展 | 5篇 |
预防医学 | 2321篇 |
眼科学 | 155篇 |
药学 | 1087篇 |
18篇 | |
中国医学 | 263篇 |
肿瘤学 | 146篇 |
出版年
2024年 | 20篇 |
2023年 | 146篇 |
2022年 | 364篇 |
2021年 | 630篇 |
2020年 | 553篇 |
2019年 | 435篇 |
2018年 | 498篇 |
2017年 | 419篇 |
2016年 | 621篇 |
2015年 | 723篇 |
2014年 | 1021篇 |
2013年 | 1179篇 |
2012年 | 1087篇 |
2011年 | 1220篇 |
2010年 | 1015篇 |
2009年 | 845篇 |
2008年 | 844篇 |
2007年 | 936篇 |
2006年 | 861篇 |
2005年 | 709篇 |
2004年 | 568篇 |
2003年 | 413篇 |
2002年 | 315篇 |
2001年 | 260篇 |
2000年 | 235篇 |
1999年 | 181篇 |
1998年 | 146篇 |
1997年 | 114篇 |
1996年 | 138篇 |
1995年 | 103篇 |
1994年 | 97篇 |
1993年 | 54篇 |
1992年 | 60篇 |
1991年 | 41篇 |
1990年 | 41篇 |
1989年 | 33篇 |
1988年 | 38篇 |
1987年 | 17篇 |
1986年 | 16篇 |
1985年 | 16篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
The phenotypic changes of T lymphocytes during the reactivation of latent Mycobacterium tuberculosis infection by activation of the hypothalamic–pituitary–adrenal (HPA) axis was monitored using flow cytometric analysis. Subsets of CD4+ and CD8+ lymphocyte populations from the lung, spleen and draining lymph nodes of infected mice were identified based on their differential expression of the cell surface antigens CD44 and CD45RB. Latent infection was characterized by an accumulation of both naive, activated and memory CD4 and CD8 T lymphocytes in the lung and mediastinal lymph nodes. No changes were observed in the spleen of mice with latent infection when compared with uninfected mice. Immediately following the activation of the HPA axis, a reduction in all CD4+ and CD8+ T cells in the lung and mediastinal lymph nodes was observed. This correlated with the reactivation of mycobacterial growth. The decrease was transient for memory and naive CD4 and CD8 T lymphocyte populations in the lung. However, the number of naive CD4 and CD8 T lymphocyte populations in the mediastinal lymph node following reactivation was less than that found in mice with latent infection. These data provide the first characterization of T lymphocyte populations which may be functionally involved in the immunological response to HPA axis-induced reactivation of M. tuberculosis infection. 相似文献
132.
133.
134.
Röcken C Radun D Glasbrenner B Malfertheiner P Roessner A 《Virchows Archiv : an international journal of pathology》1999,434(1):95-100
We report on a 58-year-old Caucasian woman who went to a general practitioner about recurrent abdominal pain, night sweats
and weight loss of a few weeks’ duration. Once gynaecological disease had been ruled out, the patient was admitted to hospital
with severe abdominal pain and intestinal obstruction and a right-sided hemicolectomy was performed. Following the investigation
of osteolytic lumbar vertebrae, 18 months after visiting the general practitioner the patient was finally found to be suffering
from generalized AA-amyloidosis secondary to gastrointestinal tuberculosis. This had been misinterpreted as Crohn’s disease.
Re-examination of the specimens from the right-sided hemicolectomy demonstrated that scanty deposits of AA-amyloid were present
9 months after the first presentation. AA-amyloid can thus be present in serious inflammatory disease even during the first
9 months after the initial clinical presentation.
Received: 23 June 1998 / Accepted: 19 August 1998 相似文献
135.
Jones DC Gelder CM Ahmad T Campbell IA Barnardo MC Welsh KI Marshall SE Bunce M 《Tissue antigens》2001,58(1):19-23
Mycobacterium malmoense is an opportunistic mycobacterium that occasionally causes disease in non-immunosuppressed individuals. As only a few individuals exposed to these organisms actually develop clinical disease, it is possible there is a genetic component to susceptibility. CD1 molecules are capable of presenting antigens from more virulent mycobacteria to T cells; therefore, we were interested in discovering whether recently described polymorphisms in CD1 molecules modulated susceptibility to M. malmoense pulmonary disease. The CD1 system comprises five genes (CD1A, -B, -C, -D, and -E) located on chromosome 1 (1q22-23). CD1 molecules are structurally and functionally related to major histocompatibility complex (MHC) class I molecules and are expressed on dedicated antigen-presenting cells. The primary function of CD1 molecules is to present lipid and glycolipid antigens to T cells. We have developed an allele-specific polymerase chain reaction-sequence-specific primer (PCR-SSP) method of CD1 genotyping. Using this method, we compared the allele and haplotype frequencies of CD1 in 49 HIV-negative patients with M. malmoense pulmonary disease with those in 342 normal controls. The CD1A and CD1E alleles were nominally identified as CD1A*01, CD1A*02, CD1E*01 and CD1E*02, and the control gene frequencies were found to be 5%, 95%, 67% and 33%, respectively. No significant difference was observed between the patient and control cohorts. Positive linkage disequilibrium values of 0.73 were observed between CD1A*02 and CD1E*01 (P<0.0001; chi2 test), and 0.94 between CD1A*01 and CD1E*02 (P<0.0001; chi2 test). Typing was also performed for two previously described CD1D alleles (CD1D*01 and CD1D*02), although only CD1D*01 was detected. 相似文献
136.
Permissively recognized peptides which can activate lymphocytes from subjects with a variety of class II HLA types are interesting diagnostic and vaccine candidates. In this study we generated T helper clones reactive to the permissively recognized p21–40 and p91–110 peptides of the 16-kD heat shock protein of Mycobacterium tuberculosis. All the clones specific for p91–110 secreted interferon-gamma (IFN-γ) and were of the Th1 phenotype. By contrast, the p21–40 peptide favoured the generation of IL-4-producing clones. Antibody blockade established that the peptide-specific Th clones could either be DR-, DP- or DQ-restricted. Thus, two permissively recognized sequences p21–40 and p91–110 from the same mycobacterial antigen can drive the differentiation of functionally distinct T helper subsets. Attempts to immunize against tuberculosis should bear in mind epitope specificity if a favourable Th subtype response is to be generated. 相似文献
137.
Talreja J Bhatnagar A Jindal SK Ganguly NK 《Clinical and experimental immunology》2003,131(2):292-298
Host defence against tuberculosis infection involves T-lymphocyte mediated cellular immune responses. In this study we assessed T-cell activation by studying the early signal transduction events and production of cytokines by human CD4+ T-cells. The study constituted of five groups of subjects: (a) untreated acid fast bacilli (AFB)+ve TB patients who have not started anti-tuberculosis therapy (ATT) [New]; (b) patients who have taken ATT for two months [2T]; (c) patients who have taken ATT for six months [6T]; (d) mantoux positive healthy controls [T+ve]; (e) mantoux negative healthy controls [T-ve]. We found that mantoux positive healthy controls produced significantly higher levels of IP3, intracellular Ca2+ and presented increased PKC activity when CD4+ T-cells were stimulated with M. tuberculosis H37Rv cell lysate as compared to mantoux negative controls. Furthermore, decreased expression of CD54 (ICAM-1) and reduced [Ca2+]i were seen in TB patients as compared to T+ve healthy controls. TB patients showed significantly lower levels of IL-2 and IFNgamma and higher levels of IL-4 as compared to normal healthy controls, suggesting a diminished Th1 response. Thus, the reciprocal changes in cytokines, reduced [Ca2+]i levels, and CD54 expression in patients imply phenotype shifting of Th precursors to Th2 type in TB patients. 相似文献
138.
F. Gamboa J. M. Manterola J. Lonca L. Matas P. J. Cardona E. Padilla B. Viñado J. Domínguez A. Hernández V. Ausina 《European journal of clinical microbiology & infectious diseases》1998,17(3):151-157
Two commercial systems for the amplification and detection ofMycobacterium tuberculosis directly from respiratory samples were compared. The Roche Cobas Amplicor MTB Test and the Roche manual Amplicor MTB Test (Roche Diagnostic Systems, USA) were applied to 755 decontaminated respiratory specimens collected from 470 patients. Results were compared with those of acid-fast staining and culture. A total of 251 specimens were collected from 156 patients diagnosed with pulmonary tuberculosis, including 28 specimens corresponding to 13 patients that were receiving antituberculous treatment. Given the overall positivity rate of 33.2% (251/755), the sensitivity, specificity, and positive and negative predictive values were 92.4, 100, 100, and 96.5%, respectively, for the Cobas Amplicor MTB Test and 90.8, 100, 100, and 95.8%, respectively, for the Amplicor MTB Test. For 204 (81.3%) smear positive specimens and 47 (19.7%) smear negative specimens, the sensitivity values were 100 and 59.6%, respectively, for the Cobas Amplicor MTB Test and 100 and 51%, respectively, for the Amplicor MTB Test. There were no statistically significant differences in sensitivity or specificity between the two assays and culture (p>0.05). The overall results of both assays were concordant for 99.5% of the samples. It is concluded that although both nucleic acid amplification methods are rapid and specific for the detection ofMycobacterium tuberculosis complex in respiratory specimens, the Cobas Amplicor MTB Test appears to be slightly more sensitive than the Amplicor MTB Test when smear negative specimens are investigated. 相似文献
139.
D. Kirsten U. Rieger K. H. Schröder A. Böhle H. Magnussen 《Journal of molecular medicine (Berlin, Germany)》1993,71(10):787-790
Summary Immunotherapy using bacille Calmette-Guérin (BCG) has gained increasing acceptance in the management of superficial bladder cancer. Systemic reactions after intravesical instillation of BCG are rare. However, when the therapy is complicated, the lung often becomes involved. Since the pathogenesis of lung infiltrates after immunotherapy is unknown, we report on a patient who developed a lung infiltrate after receiving BCG immunotherapy for bladder cancer. The infectious etiology was established by culture confirmation of a BCG strain in the broncheoalveolar lavage fluid.Abbreviation BCG
bacille Calmette-Guérin 相似文献
140.
结核分枝杆菌Ag85B与IL-12基因真核共表达质粒的构建及表达 总被引:3,自引:1,他引:3
目的 :构建结核分枝杆菌Ag85B和鼠IL 12基因的共表达载体pBud85B IL12。方法 :将结核分枝杆菌Ag85B基因和鼠IL 12基因同时克隆入含多启动子的共表达载体pBudCE4 .1中 ,构建真核共表达质粒pBud85B IL12。以pBud85B IL12转染COS 7细胞 ,通过RT PCR及ELISA方法检测目的基因的表达。结果 :在COS 7细胞中同时可检测到Ag85B和IL12的表达。结论 :pBud85B IL12共表达质粒的成功构建 ,为对其免疫原性、免疫反应性及免疫保护作用的进一步研究奠定了基础 相似文献