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   1172篇
  免费   91篇
  国内免费   8篇
耳鼻咽喉   15篇
儿科学   29篇
妇产科学   30篇
基础医学   183篇
口腔科学   5篇
临床医学   109篇
内科学   279篇
皮肤病学   13篇
神经病学   97篇
特种医学   34篇
外科学   144篇
综合类   10篇
预防医学   122篇
眼科学   17篇
药学   93篇
中国医学   6篇
肿瘤学   85篇
  2023年   23篇
  2022年   31篇
  2021年   59篇
  2020年   27篇
  2019年   35篇
  2018年   34篇
  2017年   18篇
  2016年   40篇
  2015年   44篇
  2014年   59篇
  2013年   58篇
  2012年   90篇
  2011年   84篇
  2010年   43篇
  2009年   30篇
  2008年   75篇
  2007年   80篇
  2006年   68篇
  2005年   66篇
  2004年   53篇
  2003年   42篇
  2002年   64篇
  2001年   9篇
  2000年   14篇
  1999年   13篇
  1998年   7篇
  1997年   14篇
  1996年   9篇
  1995年   7篇
  1994年   7篇
  1993年   4篇
  1992年   9篇
  1991年   4篇
  1990年   2篇
  1989年   3篇
  1988年   6篇
  1987年   3篇
  1986年   2篇
  1985年   4篇
  1984年   5篇
  1983年   3篇
  1981年   3篇
  1980年   3篇
  1979年   4篇
  1978年   5篇
  1976年   1篇
  1975年   1篇
  1974年   2篇
  1972年   1篇
  1966年   1篇
排序方式: 共有1271条查询结果,搜索用时 31 毫秒
1.
Clinical Rheumatology - Since December 2019, the pandemic caused by coronavirus disease 2019 (COVID-19) raises a real public health problem. COVID-19 appeared in Wuhan (Hubei province) in China....  相似文献   
2.
T B?ttger  S St?rkel  M St?ckle  W Wahl  A Heintz  M Jugenheimer  O Effenberger-Kim  T Vinh  T Junginger 《Der Chirurg》1991,62(6):467-72; discussion 472-3
Esophagus cancer is a heterogeneous disease with considerable differences in malignant behaviour. Some relevant factors for prognosis are known. In this study we analyzed DNA-ploidy as a potential prognostic parameter in esophagus carcinoma. Paraffin embedded histological material from 50 patients with an esophagus cancer, obtained by resection, were selected for analysis. Tumor areas within the paraffin material were identified by HE-stained reference sections. One 50 microns section was dewaxed, rehydrated and mechanically and enzymatically treated to a suspension of 10,000 cells/ml. 1 ml of the suspension, containing bare nuclei with small rests of cytoplasma was centrifuged on glass slides. The fixed nuclei were air-dried and stained by Feulgen-SITS technique, which allows quantitative measurement of DNA. The DNA analysis was carried out with a computer-controlled single cell cytophotometry (Leytas 2, Leitz, Wetzlar). In contrast to the flow cytometry with image cytometry only tumors cells were measured. Overlapping nuclei, dirt and other artefacts as well as inflammatory cells were efficiently eliminated. With the DNA image cytometry we could differentiate between diploid and hypotriploid, hypertriploid aneuploid tumors. Best prognosis had diploid and hypotriploid tumors, the worst hypertriploid carcinomas. In the multivariate analysis the DNA-content of the tumor cells in esophagus cancer was the only prognostic parameter. DNA-content of tumor cells may become considerably clinical relevant in esophagus cancer for the decision to perform a resection or palliative treatment. In patients with hypertriploid tumors an adjuvant oncological therapy may increase the prognosis.  相似文献   
3.
BACKGROUND: Vibrio vulnificus can cause a necrotizing soft tissue infection or primary septicemia; these infections are collectively known as vibriosis. This bacterium is commonly found within molluscan shellfish. Primary septicemia is often fatal, principally affecting persons with chronic liver disease. CASE PRESENTATION: A fatal case of V vulnificus sepsis that developed in a patient with chronic hepatitis B and chronic renal failure is reported. Diagnosis was made by isolation of the pathogen by blood culture. Upon further questioning, the patient's family recounted that the patient had handled and ingested Tilapia species fish in the hours preceding the patient's presentation. Despite treatment with doxycycline and cefotaxime, in conjunction with supportive care in the intensive care unit, the patient died on day 7 from multiple organ dysfunction. CONCLUSION: The present case highlights the need to consider V vulnificus in the microbiological differential diagnosis when a person presents with sepsis and bullous cutaneous lesions. The importance of educating patients with liver disease (and certain other chronic diseases) about the need to be cautious when handling or consuming seafood is underscored.  相似文献   
4.
5.
This study reviews the demographic, radiologic, and histologic characteristics of 13 cases of an important primary skeletal neoplasm, giant cell tumor of bone, occurring in an uncommon location, the scapula. that eight of 13 patients presented prior to 20 years of age contrasts significantly with the typical age distribution (between 20–40 years) encountered in giant cell tumors arising in long bones. As it does elsewhere in the skeleton, giant cell tumor of the scapula frequently demonstrates cystic and/or telangiectatic components on histologic examination. The radiologic appearances of giant cell tumor in the scapula and in more typical locations are similar and include: (1) well-defined (geographic) margins, occasionally with a delicate sclerotic rim, (2) prominent trabeculations, (3) expanded bone contour, (4) frequent extension to the subchondral plate, and (5) absence of internal mineralization. Tumor sites within the scapula included: coracoid process, acromion, and body (three cases each); glenoid (two cases); and superior and inferior angles (one case each).The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army, the Department of Defense, or the Uniformed Services University of the Health Sciences.  相似文献   
6.
OBJECTIVE: Comparative genomic hybridization (CGH) has been established as an informative technique in genetic analysis. However, differences in the ratio of hybridization intensities were reported for particular chromosomes, which may affect CGH results. The aim of this study was to define these differences in more detail. For this purpose, CGH results of 70 samples of bone marrow cells (BMC) with normal karyotype in conventional cytogenetics (CC) were evaluated using seven different reference DNAs and two different DNA labeling systems. METHODS AND RESULTS: CGH using fluorochrome-conjugated nucleotides for DNA labeling indicated signal deviations in 21/70 BMC samples. Deviations affected chromosomes 1 (n = 21), 2 (n = 11), 4 (n = 11), 5 (n = 9), 6 (n = 7), 7 (n = 2), 8 (n = 2), 12 (n = 5), 13 (n = 15), 14 (n = 1), 16 (n = 17), 17 (n = 11), 19 (n = 21), 20 (n = 12), and/or 22 (n = 17). None of the imbalances were confirmed by fluorescence in situ hybridization (FISH). Using digoxigenin and biotin-conjugated nucleotides in exemplary cases (n = 5) led to the disappearance of the signal deviations. Repeated CGH experiments using seven different reference DNAs showed remarkable variations in the signal deviations. CONCLUSION: Hybridization differences depend not only on the hapten or fluorochrome-labeled nucleotides used for DNA labeling, but also on the reference DNA chosen. Therefore, close control of CGH experiments is mandatory, and additional techniques such as FISH should be performed to confirm the results obtained by CGH.  相似文献   
7.
Multidrug-resistant Salmonella enterica serotype Typhi isolates from four outbreaks of typhoid fever in southern Vietnam between 1993 and 1997 were compared. Pulsed-field gel electrophoresis, bacteriophage and plasmid typing, and antibiotic susceptibilities showed that independent outbreaks of multidrug-resistant typhoid fever in southern Vietnam are caused by single bacterial strains. However, different outbreaks do not derive from the clonal expansion of a single multidrug-resistant serotype Typhi strain.  相似文献   
8.
We have investigated the density of peptides required to elicit different biological responses in cytotoxic T lymphocytes (CTL), including trogocytosis (i.e., the phenomenon whereby the lymphocytes actively capture fragments of plasma membrane from those cells with which they establish an immune synapse). We have used two separate mouse models of CTL recognising defined peptides presented by MHC class I molecules. In both systems, triggering of cytotoxicity and capture of membrane components reached saturation with low densities of ligand. On the other hand, down-modulation of cell-surface levels of TCR, induction of IFN-gamma production and detection of peptide captured required much higher ligand densities. Interestingly, fratricide (i.e., killing between CTL sharing the same specificity), a mechanism proposed to account for CTL exhaustion, was detected only at antigen concentrations still well above that second threshold leading to full blown activation. Taken together, our results show that the different thresholds that govern the elicitation of different CTL functions correlate with different proportions of antigen among the target cell components being captured via trogocytosis.  相似文献   
9.
Introduction: Fungal diseases are a threat to human health. Therapies targeting the fungus continue to lead to disappointing results. Strategies targeting the host response represent unexplored opportunities for innovative treatments. To do so rationally requires the identification and neat delineation of critical mechanistic pathways that underpin human antifungal immunity. The study of humans with single-gene defects of the immune system, i.e. inborn errors of immunity (IEIs), provides a foundation for these paradigms.

Areas covered: A systematic literature search in PubMed, Scopus, and abstracts of international congresses was performed to review the history of genetic resistance/susceptibility to fungi and identify IEIs associated with fungal diseases. Immunologic mechanisms from relevant IEIs were integrated with current definitions and understandings of mycoses to establish a framework to map out critical immunobiological pathways of human antifungal immunity.

Expert opinion: Specific immune responses non-redundantly govern susceptibility to their corresponding mycoses. Defining these molecular pathways will guide the development of host-directed immunotherapies that precisely target distinct fungal diseases. These findings will pave the way for novel strategies in the treatment of these devastating infections.  相似文献   

10.
In southern Vietnam, a four-year-old boy presented with severe diarrhea, followed by seizures, coma, and death. The cerebrospinal fluid contained 1 white cell per cubic millimeter, normal glucose levels, and increased levels of protein (0.81 g per liter). The diagnosis of avian influenza A (H5N1) was established by isolation of the virus from cerebrospinal fluid, fecal, throat, and serum specimens. The patient's nine-year-old sister had died from a similar syndrome two weeks earlier. In both siblings, the clinical diagnosis was acute encephalitis. Neither patient had respiratory symptoms at presentation. These cases suggest that the spectrum of influenza H5N1 is wider than previously thought.  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