全文获取类型
收费全文 | 588篇 |
免费 | 28篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 26篇 |
妇产科学 | 11篇 |
基础医学 | 61篇 |
口腔科学 | 17篇 |
临床医学 | 70篇 |
内科学 | 158篇 |
皮肤病学 | 9篇 |
神经病学 | 66篇 |
特种医学 | 46篇 |
外科学 | 61篇 |
综合类 | 23篇 |
预防医学 | 25篇 |
眼科学 | 4篇 |
药学 | 28篇 |
肿瘤学 | 27篇 |
出版年
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 15篇 |
2014年 | 17篇 |
2013年 | 13篇 |
2012年 | 15篇 |
2011年 | 8篇 |
2010年 | 29篇 |
2009年 | 23篇 |
2008年 | 10篇 |
2007年 | 22篇 |
2006年 | 7篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 16篇 |
1999年 | 13篇 |
1998年 | 29篇 |
1997年 | 20篇 |
1996年 | 26篇 |
1995年 | 12篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 18篇 |
1990年 | 10篇 |
1989年 | 18篇 |
1988年 | 23篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1975年 | 3篇 |
1972年 | 3篇 |
1962年 | 3篇 |
1959年 | 15篇 |
1958年 | 16篇 |
1957年 | 14篇 |
1956年 | 10篇 |
1955年 | 15篇 |
1954年 | 19篇 |
1952年 | 5篇 |
1949年 | 3篇 |
1948年 | 4篇 |
排序方式: 共有635条查询结果,搜索用时 0 毫秒
31.
Emerging patterns of diffusion-weighted MR imaging in Creutzfeldt-Jakob disease: case report and review of the literature 总被引:6,自引:0,他引:6
Mao-Draayer Y Braff SP Nagle KJ Pendlebury W Penar PL Shapiro RE 《AJNR. American journal of neuroradiology》2002,23(4):550-556
We report the use of diffusion-weighted MR imaging in the early diagnosis and monitoring of the progression of a histopathologically proved case of sporadic Creutzfeldt-Jakob disease. Ribbon-like areas of hyperintensity in the cerebral cortex on diffusion-weighted images corresponded to the localization of periodic sharp-wave complexes on the electroencephalogram. 相似文献
32.
The motor cortex shows adaptive functional changes to brain injury from multiple sclerosis 总被引:5,自引:0,他引:5
Lee M Reddy H Johansen-Berg H Pendlebury S Jenkinson M Smith S Palace J Matthews PM 《Annals of neurology》2000,47(5):606-613
Although multiple sclerosis (MS) is an inflammatory demyelinating disease, there can be substantial axonal injury and loss. We therefore hypothesized that adaptive cortical changes may contribute to limiting functional impairment, particularly in the early stages of the disease. To test our hypothesis, we used functional magnetic resonance imaging (MRI) to characterize the localization and volumes of activation in the motor cortex during simple flexion-extension finger movements. There were differences in the patterns of cortical activation with movement between the 12 MS patients and the 12 normal controls. All patients showed greater relative supplementary motor area activation than did the normal controls. The relative hemispheric lateralization of sensorimotor cortex (SMC) activation decreased in direct proportion to the total cerebral T2-weighted MRI hyperintense lesion load. This appeared to be due primarily to increases in ipsilateral SMC activation with increasing lesion load in white matter of the hemisphere contralateral to the limb moved. The center of activation in the contralateral SMC was shifted a mean of 8.8 mm posterior in patients relative to controls, providing additional evidence for cortical adaptive responses to injury. The magnitude of this posterior shift in the SMC activation increased with greater T2 lesion loads. These observations demonstrate that cortical recruitment for simple finger movements can change both quantitatively and qualitatively in the SMCs of MS patients, suggesting that cortical reorganization or "unmasking" of latent pathways can contribute to functional recovery. These adaptive changes are another factor potentially limiting the strength of the relationship between MRI measures of pathology and clinical measures of disability. 相似文献
33.
F Haque ST Fazal SA Ahmad SZ Abbas S Naseem 《Journal of Medical Imaging and Radiation Oncology》2006,50(1):63-65
Primary osteogenic sarcoma of the skull is an exceedingly rare condition. An adult male patient is described, who had a painless swelling in the right forehead that had rapidly enlarged in the previous 6 months. Radiological investigations showed a large destructive mass lesion involving the right side of the frontal bone with extension into the frontal sinus, causing marked extradural compression of brain parenchyma. Histopathological examination confirmed the lesion to be primary osteogenic sarcoma. 相似文献
34.
Expression of differential nitric oxide synthase isoforms in human normal gastric mucosa and gastric cancer tissue 总被引:10,自引:2,他引:10
The present study investigated the expression and distribution of three
isoforms of nitric oxide synthase (NOS) in different anatomical regions of
the human stomach and in gastric neoplastic tissues by immunohistochemistry
using specific antibodies. Intracellular localization of individual
isoenzymes of NOS was detected in normal gastric mucosa. Gastric cancer
tissues had a marked reduction of all three NOS isoforms expression. The
expression of the endothelial NOS, neuronal NOS and inducible NOS in the
tumor tissue was significantly lower than in normal gastric mucosa (P =
0.01, P = 0.02, P < 0.01, respectively). In the tumor tissue the
expression of inducible NOS was significantly lower than the expression of
both constitutive forms of NOS (P < 0.01). There was a tendency to
higher expression of both constitutive forms of NOS in earlier stages T2 of
the tumor compared to advanced T4 tumor. In contrast, the expression of
inducible NOS was higher than in the advanced T4 tumor than in the earlier
stages T2 of the tumor. The mapping of the expression of endothelial NOS,
neuronal NOS and inducible NOS in human stomach showed higher expression of
NOS isoforms in the distal third than in the proximal third of the stomach
(P = 0.03, P = 0.04, P = 0.01, respectively). We conclude that there is
greater expression of NOS in the stomach corpus and in antrum than in the
proximal third of the normal human stomach mirroring the anatomical
predilection of common pathological changes in this part of the human
stomach. Furthermore, there was loss of the expression of individual
isoenzymes in gastric neoplasms.
相似文献
35.
36.
ISAACS J. D.; MANNA V. K.; RAPSON N.; BULPITT K. J.; HAZLEMAN B. L.; MATTESON E. L.; CLAIR E. W. ST.; SCHNITZER T. J.; JOHNSTON J. M. 《Rheumatology (Oxford, England)》1996,35(3):231-240
Forty-one patients with active and refractory rheumatoid arthritis(RA) received a total of 100, 250 or 400 mg of CAMPATH-1H (CAMPATHis a trademark of Glaxo-Wellcome group companies, registeredin the US Patent and Trademark Office) over 5 or 10 days inan open, uncontrolled study. Following therapy, patients weremonitored for adverse effects and disease activity for 6 months.Therapy was associated with prolonged peripheral blood lymphopeniain all dosing cohorts. During the month immediately followingtherapy, lymphopenia was most profound in the 400 mg cohorts.The first dose of monoclonal antibody (Mab) was associated witha flu-like syndrome, more pronounced at higherinitial doses. One patient developed haemolytic-uraemic syndrome.There were a number of dose-related infections during the earlypost-treatment period and one fatal opportunistic infectionwhich followed additional immunosuppressive therapy. Antiglobulinresponses developed in 9 of 31 patients tested. The majorityof patients showed symptomatic improvement following therapyand 20% of patients maintained a 50% Paulus response at 6 months,all of whom were in the 250 or 400 mg cohorts. CAMPATH- 1H appearsto be an effective treatment for RA. Allowing for the smallnumber of patients treated, infections were more common withhigher doses, although this was not true for adverse eventsoverall, and therapeutic responses were more sustained at higherdosing levels. The broad specificity of CAMPATH- 1H may be appropriatefor the immunotherapy of RA and future studies should aim todefine a dose with an optimal therapeutic ratio. KEY WORDS: CAMPATH-1H, Rheumatoid arthritis, Immunotherapy, Monoclonal antibody, Antiglobulin response 相似文献
37.
38.
目的 探讨血管新生指标CD34、CD31、vWF、Ⅳ型胶原纤维及层粘连蛋白在肝细胞肝癌(HCC)中的表达及意义 ,同时比较上述几种血管新生因子与增殖细胞核抗原 (PCNA)、病理指标及预后的相关性 ,以便筛选出有效的临床预后指标。方法 采用免疫组化方法 ,对 5 3例肝细胞肝癌的标本进行CD31、CD34、vWF、Ⅳ型胶原纤维及层粘连蛋白的染色、计数 ,并用检测数据与患者的临床资料进行统计分析。结果 统计染色的血管面积后发现 ,CD34与多种临床病理指标无相关性 ;CD31与肝内门静脉浸润相关 ;vWF与肿瘤的TNM分期及肝内门静脉浸润呈正相关 ;CollⅣ与肝内门静脉浸润呈正相关、与术后生存期呈负相关 ;Lam与肝硬化及术中出血量呈负相关、与术后生存期呈正相关。PCNA与肿瘤TNM分期有关。结论 在HCC中 ,CollⅣ、vWF、及CD31为肝细胞肝癌的有效血管新生及预后指标 ;Lam则与肝硬化及术中出血相关 ;PCNA指数肿瘤分期有关 ;CD34不能用作血管新生或预后指标 相似文献
39.
40.
The initial event in fibrin clot formation is the thrombin-catalyzed cleavage of the A alpha chain of human fibrinogen. Most of the information required for thrombin recognition and cleavage of the A alpha chain lies in the amino terminal 51 residue CNBr fragment. By selective modification of residues in this region, we probed the features that participate in thrombin interactions. We constructed a vector which expressed a tripartite protein (tribrid) consisting of amino acids 1 to 50 of the A alpha chain followed by 60 amino acids of chicken collagen and the beta-galactosidase protein from Escherichia coli. Cell lysates run on NaDodSO4-polyacrylamide gels contained the predicted band of molecular weight (mol wt) 125,000. The tribrid reacted with a monoclonal antibody, Mab-Y18, which recognizes the amino terminus of the A alpha chain. When cell lysates were incubated with thrombin, FPA was released. By including one heterogeneous oligonucleotide in the construction, we generated plasmids that encoded three specific amino acid substitutions. Surprisingly, changing Gly14 to Val did not alter thrombin cleavage, although recognition by Mab-Y18 was lost. Substitution of lie for Arg23 did not alter either thrombin cleavage or monoclonal recognition. Substitution of Leu for Arg 16 altered thrombin cleavage; unexpectedly, recognition by Mab-Y18 was not changed. 相似文献