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   1262篇
  免费   92篇
  国内免费   2篇
耳鼻咽喉   12篇
儿科学   13篇
妇产科学   52篇
基础医学   130篇
口腔科学   49篇
临床医学   114篇
内科学   368篇
皮肤病学   7篇
神经病学   59篇
特种医学   44篇
外科学   190篇
综合类   8篇
一般理论   1篇
预防医学   89篇
眼科学   13篇
药学   86篇
肿瘤学   121篇
  2023年   5篇
  2022年   6篇
  2021年   13篇
  2020年   17篇
  2019年   18篇
  2018年   29篇
  2017年   26篇
  2016年   26篇
  2015年   23篇
  2014年   40篇
  2013年   55篇
  2012年   72篇
  2011年   65篇
  2010年   39篇
  2009年   42篇
  2008年   78篇
  2007年   79篇
  2006年   74篇
  2005年   83篇
  2004年   62篇
  2003年   52篇
  2002年   61篇
  2001年   42篇
  2000年   40篇
  1999年   33篇
  1998年   7篇
  1997年   5篇
  1996年   10篇
  1995年   9篇
  1994年   12篇
  1993年   10篇
  1992年   22篇
  1991年   12篇
  1990年   23篇
  1989年   9篇
  1988年   13篇
  1987年   9篇
  1986年   16篇
  1985年   11篇
  1984年   13篇
  1983年   5篇
  1982年   7篇
  1980年   6篇
  1979年   7篇
  1978年   9篇
  1976年   9篇
  1975年   13篇
  1972年   8篇
  1970年   7篇
  1967年   5篇
排序方式: 共有1356条查询结果,搜索用时 31 毫秒
1.
We report a patient with Sjögren's syndrome and multiple gastrointestinal manifestations who successfully responded to therapy with ursodeoxycholic acid. Our patient had sialoadenitis with dry mouth, dry eyes, arthralgia, chronic pancreatitis, sclerosing cholangitis, and pulmonary inflitrations. The first signs of disease were the symptoms of chronic pancreatitis followed by icterus, caused by extrahepatic bile duct obstruction. Sclerosing cholangitis was diagnosed by liver biopsy and endoscopic retrograde cholangiography. Sialoadenitis, causing dry mouth, was verified by buccal biopsy. Pulmonary infiltrations were seen on standard chest x-ray, and also shown by high-resolution computed tomography examination. Obstructive icterus and even pulmonary infiltration responded successfully to treatment with ursodeoxycholic acid.  相似文献   
2.
Cultivated CD4+ T-helper cells from two patients with cervical adenocarcinoma showed responses to a peptide EKTGILTVTYHSETQRTK derived from an E2 protein of human papillomavirus type 18 (HPV 18), but not to a corresponding HPV 16 peptide (HKSAIVTLTYDSEWQRDQ). Serum antibodies in the HPV 18 peptide were also demonstrated in these patients. The GILT motif resembles a common pattern present in many T-cell epitopes, and is located at the beginning of an 11-amino acid-long A-helix structure close to the carboxyterminal end of HPV 18 E2. We conclude that two epitopes (a T-helper cell epitope and a B-cell epitope) overlap in the HPV 18 E2.  相似文献   
3.
OBJECTIVE--To assess the potential of markers of collagen metabolism to reflect disease processes in rheumatoid arthritis (RA). METHODS--Serum (S) and synovial fluid (SF) from 59 patients with RA, and a knee joint effusion and serum from 90 control subjects were studied with radioimmunoassays for the aminoterminal propeptides of type I and type III procollagens (PINP and PIIINP, respectively). The breakdown of type I collagen was quantified with a radioimmunoassay for the cross linked carboxyterminal telopeptide of type I collagen (ICTP). RESULTS--About 50% of the patients had increased S-ICTP and S-PIIINP values, whereas S-PINP was increased in only 20% of the patients. The mean SF:S ratios of these markers varied between 4 (for ICTP) and 340 (for PIIINP), indicating that markers of collagen metabolism are formed locally and then released into the circulation. SF-PINP and SF-PIIINP correlated with each other (rs = 0.86, p < 0.001) and with SF-ICTP (rs = 0.69, p < 0.001, and rs = 0.65, p < 0.001, respectively). SF-ICTP was clearly related to radiographic findings in the corresponding knee joint, patients with gross bone deformation having the greatest SF-ICTP concentrations. S-ICTP and S-PIIINP also correlated with conventional markers of disease activity, such as C reactive protein and joint swelling score. CONCLUSION--Markers of collagen metabolism both in serum and synovial fluid can be measured to provide an assessment of disease process in patients with RA. ICTP and PIIINP are the most informative.  相似文献   
4.
The aim of this study was to assess the feasibility of a novel respiration-gated spiral synchrotron radiation computed tomography (SRCT) technique for direct quantification of absolute regional lung volumes, using stable xenon (Xe) gas as an inhaled indicator. Spiral SRCT with K-edge subtraction using two monochromatic x-ray beams was used to visualize and directly quantify inhaled Xe concentrations and airspace volumes in three-dimensional (3D) reconstructed lung images. Volume measurements were validated using a hollow Xe-filled phantom. Spiral images spanning 49 mm in lung height were acquired following 60 breaths of an 80% Xe-20% O2 gas mixture, in two anaesthetized and mechanically ventilated rabbits at baseline and after histamine aerosol inhalation. Volumetric images of 20 mm lung sections were obtained at functional residual capacity (FRC) and at end-inspiration. 3D images showed large patchy filling defects in peripheral airways and alveoli following histamine provocation. Local specific lung compliance was calculated based on FRC/end-inspiration images in normal lung. This study demonstrates spiral SRCT as a new technique for direct determination of regional lung volume, offering possibilities for non-invasive investigation of regional lung function and mechanics, with a uniquely high spatial resolution. An example of non-uniform volume distribution in rabbit lung following histamine inhalation is presented.  相似文献   
5.
The aim of the present work was to study interactions between the synthesis of platelet-activating factor (PAF) and leukotriene B4 (LTB4) in human polymorphonuclear leukocytes (PMNs) in vitro. PAF, at nanomolar concentrations, stimulated calcium ionophore A23187-activated PMNs to release LTB4 and 5-hydroxyeicosatetraenoic acid (5-HETE). This seems to be a receptor-mediated process as it was blocked by a PAF receptor antagonist WEB 2086 (IC50 6.6±3.9M). Moreover, LTB4 stimulated the formation of PAF in activated PMNs. WEB 2086 did not, however, alter PMN migration towards either LTB4 or the chemotactic peptide FMLP. This suggests that the enhancement of PAF synthesis in response to LTB4 is a concomitant event rather than a mediating process in LTB4-induced chemotactic movement of PMNs. These effects are implicated in the complex network of interactions between inflammatory mediators that results accumulation and activation of PMNs in the exacerbation of inflammatory processes.  相似文献   
6.
The presence of human papillomavirus (HPV) DNA in cervical and vaginal scrapes was analyzed by the AffiProbe HPV test kit (Orion Corp., Orion Pharmaceutica, Helsinki, Finland), which is a 1-day solution hybridization test for HPV type 6/11, 16, or 18. The AffiProbe test was compared with a commercially available dot blot test (ViraPap and ViraType tests; Life Technologies Inc., Gaithersburg, Md.). The study group consisted of 178 patients seen in a gynecological outpatient clinic. Altogether, 64 specimens (36 cervical and 28 vaginal scrapes) from 49 patients were positive by the AffiProbe test. Concurrently collected cervical scrapes from 174 patients were available for the reference test, which yielded 27 positive results for HPV type 6/11 or 16/18 and 25 positive results for HPV type 31/33/35. Agreement as to the presence of HPV type 6/11, 16, or 18 by the two tests was reached in 85% of the specimens. Eleven cervical specimens were positive by the AffiProbe test only, and nine cervical specimens were positive by the ViraType test only. Independent evidence obtained by the polymerase chain reaction, repeat examination, or the concurrent presence of HPV DNA in vaginal or vulval epithelium supported the AffiProbe and the ViraType test results for 6 of the 11 and 6 of the 9 specimens with discrepant results, respectively. Thus, the DNA tests had similar sensitivities for HPV type 6/11, 16, and 18 DNAs, but the results were obtained within 1 day by the AffiProbe test, whereas results for the ViraPap and ViraType analyses required from 4 days to 2 weeks.  相似文献   
7.
Human vascular adhesion protein-1 (VAP-1) is a homodimeric 170-kDa sialoglycoprotein that is expressed on the surface of endothelial cells and functions as a semicarbazide-sensitive amine oxidase and as an adhesion molecule. Blockade of VAP-1 has been shown to reduce leukocyte adhesion and transmigration in in vivo and in vitro models, suggesting that VAP-1 is a potential target for anti-inflammatory therapy. In this study we have constructed mouse-human chimeric antibodies by genetic engineering in order to circumvent the potential problems involved in using murine antibodies in man. Our chimeric anti-VAP-1 antibodies, which were designed to lack Fc-dependent effector functions, bound specifically to cell surface-expressed recombinant human VAP-1 and recognized VAP-1 in different cell types in tonsil. Furthermore, the chimeric antibodies prevented leukocyte adhesion and transmigration in vitro and in vivo. Hence, these chimeric antibodies have the potential to be used as a new anti-inflammatory therapy.  相似文献   
8.
Rupture of splanchnic artery aneurysms   总被引:1,自引:0,他引:1  
The results of surgical therapy for acute ruptured splanchnic artery aneurysms in 6 patients treated at Helsinki University Central Hospital from 1964 to 1984 were analyzed. There were 3 patients with ruptured splenic, 2 with ruptured hepatic and 1 with ruptured superior mesenteric artery aneurysms. The condition remained undiagnosed in all patients preoperatively, and the diagnosis was obtained only at emergency laparotomy performed for severe shock, abdominal pain, and distension. Five of the 6 patients survived, including a pregnant woman, who gave birth to a living baby by ceserean section. The results indicate that immediate, aggressive surgical approach dictated by the clinical condition of the patient affords good survival in patients suffering from acute rupture of splanchnic artery aneurysms.
Resumen Se analizan los resultados del tratamiento quirúrgico de la ruptura aguda de aneurismas de arterias esplnicas en 6 pacientes manejados en el Hospital Central de la Universidad de Helsinki en el periodo 1964–1984. Se presentaron 3 pacientes con ruptura de aneurismas de la arteria esplénica, 2 de la hepática y 1 de la mesentérica superior. La condición clínica se mantuvo sin diagnóstico durante la fase preoperatoria, y el diagnóstico sólo fue hecho en el curso de la laparotomía, procedimiento que fue realizado por shock severo, dolor abdominal y distensión. Cinco de los 6 pacientes sobrevivieron, incluyendo una mujer embarazada, quien dio a luz un niño vivo mediante sección cesárea. Los resultados indican que el enfoque quirúrgico inicial agresivo indicado por la condición clínica del paciente ofrece una buena oportunidad de supervivencia en pacientes que presentan ruptura de aneurismas de las arterias esplácnicas.

Résumé Les résultats du traitement chirurgical de 6 ruptures d'anévrysmes des artères splanchniques traités à l'Hôpital Central Universitaire d'Helsinki de 1964 à 1984 sont étudiés par les auteurs. Ils concernent la rupture anévrysmale de 3 artères spléniques, de 2 artères hépatiques, de 1 artère mésentérique. Le diagnostic ne fut porté qu'au moment de l'intervention d'urgence pratiquée en présence d'un état de choc sévère s'accompagnant de douleur et de distension abdominales. Cinq des 6 opérés ont survécu, dont une femme enceinte chez qui une césarienne fut pratiquée avec succès. Ces résultats plaident en faveur de l'action chirurgicale d'urgence.
  相似文献   
9.
Objective: The aim of this study was to evaluate and compare the efficacy of punch biopsies and cervical scrapes in the detection of human papillomavirus (HPV) DNA from the cervix and compare the results with the histopathologic diagnosis.Methods: The specimens were collected simultaneously, and HPV DNA was detected using a liquid hybridization test.Results: Biopsies and scrapes were equally efficient, but each detected only two-thirds of all HPV-DNA-positive patients. Thus, the positivity rate increased when both tests were used. Overall, 13% of patients with normal histopathology, 38% of patients with benign atypia, and 66% of patients with squamous intraepithelial lesions (SIL) were HPV-DNA positive. HPV-DNA 16 was found in 54% of HPV-DNA-positive patients with SIL, in 20% of HPV-DNA-positive patients with atypia, and in none of patients with normal histopathology.Conclusions: The liquid hybridization test used in this study detects HPV DNA equally efficiently from both biopsies and scrapes. The test can be performed in 1 working day. However, the sensitivity of the test is low, and it only detects a limited number of HPV types.  相似文献   
10.
A new assay using a multiwell fluorescence scanner was developed for screening cytotoxicity to cells cultured in 96-well microtiter plates. The assay is based on binding of propidium iodide to nuclei of cells whose plasma membranes have become permeable due to cell death. Fluorescence of propidium iodide measured with a multiwell fluorescence scanner increased in proportion to the number of permeabilized cells. After ATP depletion of hepatocytes and neonatal cardiac myocytes with metabolic inhibitors ("chemical hypoxia"), and exposure of Madine Darby canine kidney cells to the toxic chemical, HgCl2, propidium iodide fluorescence progressively increased. Increases of fluorescence were linearly proportional with release of lactate dehydrogenase into the culture medium. Employing this cytotoxicity screening assay, protection by various agents against lethal injury was evaluated in cultured hepatocytes during chemical hypoxia. Inhibitors of cysteine proteases (i.e., antipain, leupeptin, E-64), serine proteases (i.e., PMSF), and aspartic acid proteases (i.e., pepstatin A) did not protect against chemical hypoxia. In contrast, 1,10-phenanthroline, an inhibitor of metalloprotease, markedly protected against the onset of cell death during chemical hypoxia. Half-maximal protection after 60 min occurred at 0.5 microM. Phospholipase inhibitors, chlorpromazine (50 microM) and mepacrine (50 microM), also substantially retarded cell killing. U74006F, an inhibitor of lipid peroxidation, slowed cell killing to a lesser extent during chemical hypoxia and after oxidative stress with t-butyl hydroperoxide. Calciphor, a dimer of prostaglandin B1, did not protect against cell killing during chemical hypoxia or t-butyl hydroperoxide toxicity. In conclusion, this high capacity cytotoxicity assay for cells cultured in 96-well microtiter plates is suitable for rapid screening of potential cytoprotective agents in a variety of cell types.  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