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   9780篇
  免费   525篇
  国内免费   78篇
耳鼻咽喉   94篇
儿科学   179篇
妇产科学   91篇
基础医学   1227篇
口腔科学   219篇
临床医学   635篇
内科学   2686篇
皮肤病学   239篇
神经病学   547篇
特种医学   363篇
外科学   1783篇
综合类   41篇
预防医学   204篇
眼科学   193篇
药学   634篇
中国医学   20篇
肿瘤学   1228篇
  2024年   11篇
  2023年   144篇
  2022年   267篇
  2021年   421篇
  2020年   222篇
  2019年   318篇
  2018年   374篇
  2017年   273篇
  2016年   298篇
  2015年   287篇
  2014年   380篇
  2013年   413篇
  2012年   723篇
  2011年   669篇
  2010年   396篇
  2009年   327篇
  2008年   553篇
  2007年   645篇
  2006年   579篇
  2005年   587篇
  2004年   563篇
  2003年   509篇
  2002年   491篇
  2001年   82篇
  2000年   67篇
  1999年   92篇
  1998年   97篇
  1997年   76篇
  1996年   76篇
  1995年   61篇
  1994年   48篇
  1993年   42篇
  1992年   34篇
  1991年   33篇
  1990年   26篇
  1989年   19篇
  1988年   25篇
  1987年   17篇
  1986年   15篇
  1985年   15篇
  1984年   20篇
  1983年   13篇
  1982年   24篇
  1981年   11篇
  1980年   8篇
  1979年   8篇
  1978年   5篇
  1977年   6篇
  1974年   2篇
  1927年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Difficulty in diagnosing autoimmune pancreatitis by imaging findings   总被引:5,自引:0,他引:5  
BACKGROUND: Autoimmune pancreatitis (AIP) presents as diffuse enlargement of the pancreas and as diffuse irregular narrowing of the main pancreatic duct. However, some AIP cases are difficult to diagnose because of atypical imaging findings. OBJECTIVE: To clarify a variety of imaging findings of AIP and the reason for its misdiagnosis. DESIGN: We examined the imaging findings of 37 AIP cases and also examined misdiagnosed cases of AIP to determine their reasons for misdiagnosis. PATIENTS: A total of 37 patients with AIP who reported to our hospital or its affiliate over a 17-year period (1989 to May 2005). RESULTS: Patients in 15 AIP cases showed segmental narrowing of the main pancreatic duct. There were 6 patients with focal enlargement of the pancreas, whereas 3 patients showed no enlargement. There were 3 cases of calcification of the pancreas. Pancreatic cysts were detected in 2 patients. Abdominal US showed multiple low-echoic masses in 1 case and a single mass in 3 cases. Sixteen patients had stenosis of the bile duct at the hilar hepatic lesion and/or the intrahepatic duct. Only 7 patients had typical AIP findings. Six patients were misdiagnosed with pancreatic cancer and 2 with bile-duct cancer. Seven cases were surgically treated. Five cases were misdiagnosed because of the nonexistence of, or the unfamiliarity with, the concept of AIP and sclerosing cholangitis with AIP. Another 3 cases were diagnosed with pancreatic cancer because of segmental stenosis of the main pancreatic duct and no or focal enlargement of the pancreas. CONCLUSIONS: The results of this study suggest that AIP presents a variety of imaging findings. The most important diagnostic factor is clinician awareness of the concept of AIP and the diverse nature of imaging findings.  相似文献   
992.
Rare neoplastic diseases including sarcomas can occur in the middle mediastinum. Obtaining a histological specimen is crucial for diagnosis and for establishing a treatment plan. Our research group has recently reported a minimal invasive method of tissue sampling of the mediastinum using direct real-time endobronchial ultrasound-guided transbronchial needle aspiration. By the use of this new modality, histological cores can be obtained for pathological diagnosis that can be used for immunohistochemistry as well as genetic analysis. A very rare case of spinal chondrosarcoma due to hereditary multiple exostoses successfully diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration and by immunohistochemistry with genetic analysis is reported.  相似文献   
993.
BACKGROUND AND AIMS: The authors have previously shown that a third member of the CD28 family, inducible costimulator (ICOS), was increased in the inflamed intestinal mucosa of murine experimental colitis, and that the blockade of ICOS ameliorated the development of colitis. However, the role of ICOS in rat intestinal inflammation and its expression profile remains unclear. In the present study, the authors investigated the involvement of ICOS in the development of rat dextran sulfate sodium (DSS)-induced colitis, and the therapeutic potential of anti-ICOS monoclonal antibody (mAb) in colitis. METHODS: The authors first examined expression of ICOS protein in normal rat by immunohistochemistry and flow cytometry. Sprague-Dawley rats were fed 3.0% DSS. The expression of ICOS on infiltrating lamina propria mononuclear cells and splenocytes were examined. The DSS-fed rats were then administered anti-ICOS mAb to test its effect on the development of colitis. RESULTS: Unlike mice and human, ICOS was expressed on a part of CD4+ T-cells from the thymus, spleen, mesenteric lymph nodes and lamina propria. Levels of ICOS on CD4+ T-cells from the spleen and colonic lamina propria were significantly upregulated after Concanavalin A (Con A) stimulation. In addition, ICOS was also upregulated on CD4+ T-cells from DSS-fed rats compared with those from non DSS-fed rats. However, anti-ICOS mAb did not ameliorate the development of both acute and chronic DSS colitis. CONCLUSION: These results suggest that the different expression of ICOS in rats plays a distinct role in rat intestinal inflammation.  相似文献   
994.
Background We have reported that percutaneous radiofrequency ablation (RFA) with balloon occlusion of the hepatic artery (balloon-occluded RFA), using an expandable electrode, increases the coagulation area. In this study, we investigated the efficacy of balloon-occluded RFA and balloon-microcatheter-occluded RFA, using a cool RF single electrode.Methods We studies 41 patients with 47 hepatocellular carcinoma (HCC) lesions. We treated 28 patients (32 nodules) with balloon-occluded RFA, 5 patients (6 nodules) with balloon-microcatheter-occluded RFA, and 8 patients (9 nodules) with standard RFA. Initial therapeutic efficacy was evaluated with dynamic computed tomography performed 1 week after one session of treatment.Results One session of treatment was done for 20 nodules (62.5%) in the balloon-occluded RFA group and for 4 nodules (66.7%) in the balloon-microcatheter-occluded RFA group. We compared the coagulation diameter for balloon-occluded RFA (7 nodules), balloon-microcatheter-occluded RFA (6 nodules), and standard RFA (9 nodules) after one application cycle (12min). The greatest dimension of the area coagulated by balloon-occluded RFA was significantly larger (greatest long-axis dimension, 47.6 ± 7.8mm; greatest short-axis dimension, 33.4 ± 7.5mm) than that coagulated by standard RFA (greatest long-axis dimension, 35.3 ± 4.7mm; greatest short-axis dimension, 25.9 ± 3.7mm; P = 0.002 for greatest long-axis dimension; P = 0.041 for greatest short-axis dimension). However, there was significant difference only in the greatest short-axis dimension of the area coagulated comparing balloon-microcatheter-occluded RFA and standard RFA.Conclusions We consider balloon-occluded RFA using a cool RF electrode to be superior to standard RFA for the treatment of HCC, especially when larger coagulation volumes are required.  相似文献   
995.
Blastic natural killer (NK) cell lymphoma corresponding to CD4+CD56+ malignancies is a novel disease entity, according to the results of clinical, morphologic, and immunologic studies. It is especially noteworthy that this disease likely arises from plasmacytoid dendritic cells (pDCs), described previously as plasmacytoid T-cells, which have an important role in innate and adaptive immunity. However, the exact relationship between the tumor cells and pDCs remains to be elucidated. We encountered a patient with typical blastic NK cell lymphoma, which later converted to leukemic manifestations, and tried to establish a cell line using the leukemic cells. We succeeded in establishment of a novel cell line, CAL-1, which originated from the primary malignant cells. The genetic and phenotypic features of CAL-1 cells bear a similarity to those of pDCs, namely, plasmacytoid morphology at light and electron microscopy; negative results for CD11c and lineage-associated markers of CD3, CD14, CD19, and CD16; positive results for HLA-DR, CD4, CD56, CD45RA, and CD123; and negative results for TCR and IgH gene rearrangements. An interesting finding was that CAL-1 cells change morphologically into the mature DC appearance with many long dendrites after short-term culture in the presence of granulocyte-macrophage colony-stimulating factor and interleukin 3. CAL-1 cells can secrete tumor necrosis factor alpha but not interferon alpha. Thus although they do not share in part phenotypic and functional features with their normal counterparts, CAL-1 cells mostly exhibit a striking pDC phenotype. We describe the first novel pDC cell line of CAL-1. This cell line should open the opportunity for study not only of CD4+CD56+ tumor cells but also of pDCs in vitro.  相似文献   
996.
997.
Intercellular adhesion molecule-1 (ICAM-1) is involved in inflammation and development of atherosclerotic change of vascular endothelium. The aim of the present study is to investigate whether K469E polymorphism of the ICAM-1 gene is associated with various clinical factors including plasma fibrinogen in patients with type 2 diabetes. ICAM-1 gene polymorphism was examined using polymerase chain reaction and restriction enzyme analysis in 360 type 2 diabetic patients. Plasma fibrinogen levels and other clinical variables were measured as well as circulating soluble ICAM-1 (sICAM-1) levels by enzyme-linked immunosorbent assay. The distribution of ICAM-1 genotypes, EE, EK, and KK, was not significantly different between type 2 diabetes and 152 healthy control subjects. Among 3 groups according to ICAM-1 genotypes in type 2 diabetes, no difference was found in adiposity, glycemic control, lipid profile, insulin sensitivity evaluated by homeostasis model assessment, or sICAM-1. Regarding fibrinogen, the patients with E allele showed significantly lower plasma fibrinogen levels in a dose-dependent manner (P = .033). Spearman rank correlation analyses revealed that ICAM-1 genotype showed significant correlation with plasma fibrinogen level (P < .001). In multiple regression analysis, ICAM-1 genotype was independent contribution factor of plasma fibrinogen level as well as high-density lipoprotein-cholesterol and urinary albumin excretion (R2 = 0.148, P < .001). In conclusion, K469E polymorphism of the ICAM-1 gene had impact on plasma fibrinogen level independently of other clinical factors in 360 type 2 diabetic patients, suggesting that fibrinogen is a candidate which links the ICAM-1 gene polymorphism to atherosclerosis.  相似文献   
998.
In order to bail out the slow-flow phenomenon (slow flow) created by a massive thrombus in an ectasic right coronary artery, a thrombus was mechanically extracted with a 6 Fr right Judkins (JR) catheter, which proved to be more useful than a usual thrombectomy using a Rescue PT system catheter (Rescue). In case 1, the Rescue was used in combination with thrombolysis but failed to alleviate the slow flow that was implicated in a large infarction. On the other hand, in case 2, aggressive thrombectomy with a 6 Fr JR catheter with an 8 Fr Amplatz guiding catheter successfully extracted the massive intracoronary thrombus, restoring good coronary flow. Therefore, mechanical extraction with a 6 Fr JR catheter is safe and useful in cases of massive thrombus when diffuse coronary artery ectasia complicates an acute myocardial infarction. In addition, this method should be applicable to cases of acute coronary syndrome with massive thrombus.  相似文献   
999.
Prognostic factors, including clinical, biological, and histological parameters, were assessed for 94 patients with follicular lymphomas at our institute. Follicular lymphomas constituted 7.7% (94/1208) of malignant lymphomas in this study. Eighteen patients were diagnosed with stage I follicular lymphoma, 20 with stage II, 23 with stage III, and 33 with stage IV. The cases of follicular lymphoma were subclassified as: follicular small cleaved cell lymphoma (FSC) in 20 cases, follicular mixed cell lymphoma (FMX) in 59 cases, and follicular large cell lymphoma (FLC) in 15 cases. The patients comprised 49 men and 45 women with a median age of 54 years (range, 25-84 years). The complete response rate was 76.5%, and the median survival time was 13 years. The expected 10-year overall survival and event-free survival rates were 61.9% and 38.2%, respectively. Univariate analysis identified the factors associated with poor survival as elevated serum lactate dehydrogenase (LDH) level (P < .0001), age of >60 (P < .0001), Ann Arbor stage III/IV (P < .01), and Eastern Cooperative Oncology Group performance status (PS) of 2 to 4 (P = .048). Multivariate analysis showed that LDH, age, and PS were independent predictors. After application of the International Prognostic Index (IPI), the 10-year survival rates for the low-risk, low-intermediate risk, high-intermediate risk and high-risk groups were 80.4%, 48.7%, 21.9%, and 0.0%, respectively. The differences among these groups were significant at P < .01. The IPI for aggressive non-Hodgkin's lymphoma was found to be applicable to survival prediction for Japanese follicular lymphoma patients.  相似文献   
1000.
The plasma renin activity (PRA) is affected by a number of environmental factors. However, significant heritability has been shown for the activity. A hypothesis that a candidate regulatory single-nucleotide polymorphism, C-5312T, of human renin gene should have a significant effect on PRA was elucidated and updating of independent determinants of PRA was attempted.Cross sectional study.Outpatient study.We enrolled consecutive 810 subjects who had consulted our hospitals for lifestyle-related diseases.Genotypes were assayed with genomic DNA for C-5312T. Among the genetic variants, the difference of PRA was evaluated. Monovariate linear regression analysis was performed to test the correlation between PRA and clinical variables. Finally, stepwise multiple regression analysis was performed to evaluate the independent determinants.On comparing 2 genotype groups, CC/CT and T allele homozygote, the geometric means of PRA were 0.778 and 0.941 ng/ml/h, respectively (F = 5.992, P = 0.015). Monovariate linear regression analysis revealed that a number of variables have a significant correlation with the activity, including urinary salt excretion. A stepwise multivariate regression analysis revealed that renin C-5312T variant (TT) is one of the independent determinants of PRA.Thus, for the first time, a human renin gene variant was associated with a significant increase in PRA as a genetic factor and the independent determinants for the activity were updated including genetic factor.  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