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   1522篇
  免费   101篇
  国内免费   5篇
耳鼻咽喉   25篇
儿科学   69篇
妇产科学   80篇
基础医学   182篇
口腔科学   41篇
临床医学   110篇
内科学   345篇
皮肤病学   29篇
神经病学   151篇
特种医学   106篇
外科学   160篇
综合类   16篇
现状与发展   1篇
预防医学   107篇
眼科学   6篇
药学   97篇
中国医学   3篇
肿瘤学   100篇
  2023年   12篇
  2022年   26篇
  2021年   54篇
  2020年   31篇
  2019年   46篇
  2018年   71篇
  2017年   39篇
  2016年   38篇
  2015年   46篇
  2014年   41篇
  2013年   56篇
  2012年   107篇
  2011年   104篇
  2010年   62篇
  2009年   43篇
  2008年   62篇
  2007年   59篇
  2006年   69篇
  2005年   62篇
  2004年   46篇
  2003年   41篇
  2002年   51篇
  2001年   39篇
  2000年   35篇
  1999年   25篇
  1998年   8篇
  1997年   11篇
  1996年   10篇
  1995年   9篇
  1994年   6篇
  1992年   21篇
  1991年   22篇
  1990年   18篇
  1989年   25篇
  1988年   19篇
  1987年   14篇
  1986年   22篇
  1985年   18篇
  1984年   18篇
  1983年   16篇
  1982年   7篇
  1981年   6篇
  1979年   10篇
  1978年   9篇
  1977年   10篇
  1976年   8篇
  1975年   8篇
  1974年   13篇
  1970年   10篇
  1968年   8篇
排序方式: 共有1628条查询结果,搜索用时 109 毫秒
51.

Background

Liver transplant is a potential cure for liver failure and hepatic malignancy but there are many techniques which have been described for vascular reconstruction. This study was to compare the prevalence of non-anastomotic biliary stricture and other surgical complications based on Clavien-Dindo scoring system, in initial portal reperfusion (sequential) versus simultaneous or initial artery reperfusion.

Data sources

Meta-analysis of published studies comparing the outcomes of both techniques was carried out. Data search was conducted across the major databases and studies were selected under the guidance of the Cochrane guidelines for systematic reviews and meta-analysis.

Results

Seven studies were included to address the primary and the secondary outcomes. No statistical difference was found in the incidence of non-anastomotic biliary strictures (OR?=?0.40; P?=?0.14), regardless of reperfusion technique. The pooled estimate of the Clavien-Dindo grading of complications was not significantly different between the techniques, though Clavien-Dindo II complications were higher in the simultaneous or initial artery reperfusion group than the initial portal reperfusion group (OR?=?2.73; P?=?0.01). Similarly, there was no difference in the operative time, hospital stay and other outcomes addressed in this report.

Conclusions

The available evidence suggests that there is no significant difference demonstrated in the rate of non-anastomotic biliary strictures or other complications, between the two techniques, except for Clavien-Dindo II complications.  相似文献   
52.
Monocytoid B-cell lymphoma (MBCL) is a newly recognized B-cell neoplasm of uncertain histogenesis. The cytologic features of the neoplastic monocytoid B lymphocytes are virtually identical to those of hairy cell leukemia (HCL). As with HCL, progression of MBCL to a higher histologic grade is very unusual. However, whereas circulating leukemic cells are a characteristic feature of HCL, peripheral blood involvement has not been reported in MBCL. We recently studied a patient with MBCL of the spleen and axillary lymph nodes who developed peripheral blood involvement by MBCL cells. Unlike the cells of HCL, the circulating MBCL cells exhibited strong acid phosphatase activity that was tartrate sensitive. The leukemic cells had the antigenic phenotype IgM lambda, CD20+, CD11c+, CD5-, CD25(TAC)-, and PCA-1-. Immunogenetic studies of both lymph node and peripheral blood cells revealed identical immunoglobulin heavy-chain gene rearrangements. When compared with a series of HCL, the immunophenotype was similar except for the absence of PCA-1 and TAC. Progression of the MBCL to a large cell lymphoma, also expressing IgM lambda, was documented in an abdominal lymph node of this patient. Therefore, although rare, peripheral blood involvement by lymphoma cells may occur during the course of MBCL and should be distinguished from HCL with cytochemical and immunophenotypic studies. In addition, comparison of the clinical, pathologic, and immunologic features of MBCL with those of other low-grade B-cell neoplasms suggests that a close lineage relationship exists between MBCL and HCL.  相似文献   
53.
The ability of technetium (Tc)-99m sestamibi myocardial perfusion imaging at rest to evaluate myocardial infarction and first-pass ejection fraction was studied in a trial involving 18 institutions. Protocol I compared regional perfusion with occurrence of infarction by Q wave or by gated blood pool scan wall motion abnormality in 146 patients. Protocol II assessed first-pass right and left ventricular ejection fraction in 85 patients. In protocol I, Tc-99m sestamibi images were abnormal in 104 of 111 patients (94%) with both a Q wave and a gated scan wall motion abnormality and was normal in 23 of 25 patients (92%) in whom both were normal. Therefore, concordance existed in 105 (94%) patients. Of 115 patients with a Q wave, 107 (93%) had an abnormal Tc-99m sestamibi study. Of 115 patients with a gated scan wall motion abnormality, 108 (94%) had an abnormal Tc-99m sestamibi study. Tc-99m sestamibi imaging showed corresponding perfusion abnormalities in 81% of 69 anterior Q-wave infarcts, 73% of 55 inferior Q-wave infarcts and 88% of 8 posterior infarcts. Specificity in normal regions on electrocardiography and wall motion was 91, 100 and 100%, respectively, for anterior, inferior and posterior regions, respectively, between wall motion and perfusion. Of 17 myocardial segments per patient, there was concordance in 74% of patients. First pass Tc-99m sestamibi imaging of ejection fraction agreed well with conventional first-pass imaging for the right and left ventricle. It is concluded that Tc-99m sestamibi myocardial imaging at rest reliably diagnoses and localizes infarction and assesses ejection fraction by first-pass imaging.  相似文献   
54.
BACKGROUND: Timely diagnosis and treatment of spontaneous bacterial peritonitis (SBP) are essential to survival. The purpose of the present paper was to evaluate leukocyte esterase reagent strips (Nephur-Test and MultistixSG10) in the bedside diagnosis of SBP. METHODS: Patients with cirrhotic ascites were prospectively included in France (center 1) and in the USA (center 2). Paracenteses were performed on admission and repeated as indicated. Bedside reagent strip testing was performed on the ascitic fluid and compared to manual cell count with differential and ascitic fluid culture. In center 1, the Nephur-Test was tested in all cases, with dual testing with MultistixSG10 in a subgroup. In center 2, all cases had dual testing. Spontaneous bacterial peritonitis was defined as a polymorphonuclear ascites count > or =250/microL. RESULTS: A total of 184 samples was obtained in 76 patients. Center 1 included 151 samples from 53 patients. Seven samples had SBP, obtained in six patients. Center 2 included 33 samples from 23 patients. Six samples had SBP, obtained in five patients. The sensitivity, specificity, positive and negative predictive value of the reagent strips were as follows. Center 1/Nephur-Test: 86%, 100%, 100%, 99%; center 1/MultistixSG10: 100%, 100%, 100%, 100%; center 2/Nephur-Test: 100%, 92.5%, 75%, 100%; center 2/MultistixSG10: 83%, 96%, 83%, 96%. CONCLUSION: Leukocyte esterase reagent strips may provide a rapid bedside diagnosis of SBP.  相似文献   
55.
Smith  D. K.  Rawlings  M. K.  Glick  N.  Mena  L.  Coleman  M.  Houlberg  M.  McCallister  S.  Wiener  J. 《AIDS and behavior》2022,26(2):350-360
AIDS and Behavior - The prevention effectiveness of oral preexposure prophylaxis (PrEP) is highly dependent on medication adherence but no validated longer term PrEP adherence measures are readily...  相似文献   
56.
Colonic motility and transit in health and ulcerative colitis   总被引:13,自引:0,他引:13  
Preprandial and postprandial colonic motility and transit (scintigraphy), with respect to the splenic flexure, were studied in 10 patients with ulcerative colitis and in 9 healthy subjects. The healthy subjects had a postprandial increase in intraluminal pressure that was significantly (P less than 0.03) greater in the descending colon than in other regions of the colon. In ulcerative colitis, the pressure was decreased in all regions compared with healthy subjects, with no significant pressure gradient among different regions. In normal subjects, transit was quiescent during fasting; eating stimulated both antegrade and retrograde transit. In ulcerative colitis, transit was variable before as well as after the meal. Both healthy subjects and patients with ulcerative colitis had more rapid emptying from the splenic flexure into the sigmoid than into the transverse colon. More frequent, low-amplitude, postprandial propagating contractions occurred in ulcerative colitis (P less than 0.05) than in healthy subjects. Propagating contractions were always antegrade and caused a rapid movement of the tracer into the sigmoid. In conclusion, ulcerative colitis is characterized by (a) decreased contractility, (b) increased low-amplitude propagating contractions, and (c) variable transit. These disturbances may accentuate the diarrhea in ulcerative colitis.  相似文献   
57.
The nuclear factor-B (NF-B) path-way has been implicated in tumor B-cell survival, growth, and resistance to therapy. Because tumor cells overcome single-agent antitumor activity, we hypothesized that combination of agents that target differentially NF-B pathway will induce significant cytotoxicity. Therapeutic agents that target proteasome and Akt pathways should induce significant activity in B-cell malignancies as both pathways impact NF-B activity. We demonstrated that perifosine and bortezomib both targeted NF-B through its recruitment to the promoter of its target gene IB using chromatin immunoprecipitation assay. This combination led to synergistic cytotoxicity in Waldenstrom macroglobulinemia (WM) cells that was mediated through a combined reduction of the PI3K/Akt and ERK signaling pathways, found to be critical for survival of WM cells. Moreover, a combination of these drugs with the CD20 monoclonal antibody rituximab further increased their cytotoxic activity. Thus, effective WM therapy may require combination regimens targeting the NF-B pathway.   相似文献   
58.
Recent observations have shown that in lactating rats previously deprived of suckling, either suckling stimulus or ip injection of norepinephrine was capable of increasing mammary deiodinase type 1 (M-D1) mRNA content and enzyme activity. In the present work, we show that intact efferent sympathetic mammary innervation is required to restore both mammary D1 mRNA content and enzyme activity, whereas suckling-induced secretion of catecholamines from the adrenal glands does not seem to participate in M-D1 enzyme regulation. The data also indicate that the sympathetic reflex activation in response to suckling involves two complementary autonomic components: (1) activation, presumably through mammary segmental arrangement affecting neighboring mammary glands; and (2) an individual reflex regulatory mechanism capable of maintaining M-D1 activity within each mammary gland. In addition to these findings, we show that the suckling-induced sympathetic activation of M-D1 activity could be blocked by prior activation of ductal mechanoreceptors. This set of regulatory and counterregulatory mechanisms seems to ensure the optimal control of mammary energetic expenditure according to litter size.  相似文献   
59.
60.
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