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   1009篇
  免费   63篇
  国内免费   9篇
耳鼻咽喉   5篇
儿科学   53篇
妇产科学   7篇
基础医学   116篇
口腔科学   45篇
临床医学   84篇
内科学   221篇
皮肤病学   40篇
神经病学   27篇
特种医学   151篇
外国民族医学   1篇
外科学   67篇
综合类   49篇
预防医学   77篇
眼科学   5篇
药学   101篇
中国医学   1篇
肿瘤学   31篇
  2019年   7篇
  2018年   9篇
  2017年   13篇
  2016年   15篇
  2015年   25篇
  2014年   14篇
  2013年   29篇
  2012年   22篇
  2011年   26篇
  2010年   30篇
  2009年   45篇
  2008年   25篇
  2007年   22篇
  2006年   20篇
  2005年   15篇
  2004年   40篇
  2003年   21篇
  2002年   14篇
  2001年   18篇
  2000年   21篇
  1999年   26篇
  1998年   56篇
  1997年   63篇
  1996年   57篇
  1995年   44篇
  1994年   40篇
  1993年   39篇
  1992年   19篇
  1991年   15篇
  1990年   18篇
  1989年   16篇
  1988年   26篇
  1987年   29篇
  1986年   27篇
  1985年   11篇
  1984年   6篇
  1983年   9篇
  1982年   20篇
  1980年   10篇
  1979年   6篇
  1978年   6篇
  1977年   6篇
  1976年   6篇
  1972年   6篇
  1971年   8篇
  1970年   5篇
  1969年   11篇
  1968年   9篇
  1967年   12篇
  1966年   7篇
排序方式: 共有1081条查询结果,搜索用时 15 毫秒
61.
Fixed-dose combination antihypertensive therapy has received interest since the publication of the JNC-VI report. Relatively few head-to-head comparative studies between fixed-dose combinations and first-line monotherapies for hypertension have been published. The objective of this study was to conduct a meta-analysis of various first-line monotherapies and the fixed-dose combination of amlodipine/benazepril. The results of the meta-analysis were used to compare the efficacy and safety of the first-line monotherapies with amlodipine/benazepril. The meta-analysis included 82 studies that included 110 treatment groups (cohorts). The study compared nine different monotherapies and one combination therapy (amlodipine/benazepril). Of the 82 studies, 22 were placebo-controlled and 60 were active treatment controlled. The mean absolute decrease in supine diastolic blood pressure (BP) ranged from 9.7 to 13.3 mm Hg with verapamil showing the greatest effect and captopril the least (13.3 +/- 3.0 mm Hg; 9.7 +/- 2.9 mm Hg, respectively). When studies were weighted by sample size, atenolol, verapamil, lisinopril and amlodipine/benazepril showed the greatest BP effect. When studies were weighted by variance, amlodipine/benazepril and atenolol showed the greatest BP effect. The percentage of patients controlled on therapy ranged from 54% to 79%. Lisinopril and amlodipine/benazepril showed the greatest percent controlled. The overall incidence of adverse effects ranged from 12.1% to 41.8% with lisinopril having the lowest and nifedipine having the highest incidence. The overall incidence of adverse effects resulting in drug discontinuance ranged from 1.3% to 10.7%, with amlodipine/benazepril having the lowest and nifedipine having the highest incidence. The results of the meta-analysis indicate that amlodipine/benazepril produces above average reductions in BP with a lower than average incidence of overall side effects and the lowest incidence of adverse effects resulting in drug discontinuance. The fixed-dose combination of amlodipine/benazepril achieves its goal of effective BP lowering with a minimum of significant side effects.  相似文献   
62.
This single-blind, placebo-controlled study evaluated long-term therapy with cibenzoline in 19 patients with chronic ventricular arrhythmias. Antiarrhythmic efficacy, defined as greater than or equal to 75% reduction in single premature ventricular complexes (PVCs), greater than or equal to 90% reduction in paired PVCs, and total abolition of ventricular tachycardia (VT), was established after dose titration in 14 of 19 (74%) patients. Mean frequency of single PVCs was reduced by 65%, mean paired PVC frequency was reduced by 68%, and mean VT event frequency was reduced by 82%. Antiarrhythmic efficacy was maintained during long-term therapy in five of the 14 (36%) short-term responders. Of the nine patients who discontinued cibenzoline during long-term follow-up, five had a loss of arrhythmia control, three failed to redevelop arrhythmias during placebo reintroduction, and one developed an adverse reaction. Three patients (16%) experienced a proarrhythmic effect. Echocardiographic evaluation did not reveal any deleterious effect of cibenzoline on left ventricular function in the group as a whole. In six patients with preexisting left ventricular dysfunction, left ventricular ejection fraction and fractional shortening improved significantly (P less than .05) during cibenzoline therapy. Adverse effects occurred in seven patients (37%) but necessitated drug discontinuation in only one patient (5%). Cibenzoline provides effective short-term therapy for patients with chronic ventricular arrhythmias. Long-term therapy must be assessed periodically to ensure continued efficacy. Drug-related adverse effects occur infrequently. Cibenzoline can be used safely in patients with compensated left ventricular dysfunction.  相似文献   
63.
Anti-Sc1 was detected in a gravida-2 patient at 12 weeks' gestation. At 29 weeks, the antibody was found to be of the IgG3 subclass with a titer of 16, score 36, by the indirect antiglobulin test, and it produced 7 percent lysis by antibody-dependent cellular cytotoxicity (ADCC) assay, a finding that suggested an unaffected fetus. The titer remained constant throughout the pregnancy, as did the IgG subclass and activity in the ADCC assay. At delivery of the full-term infant, the cord hemoglobin was 13.5 g per dL and the direct antiglobulin test was positive (3+) with anti-IgG. The infant did not require transfusion. A sample taken 9 weeks after delivery showed 44 percent lysis in the ADCC assay. The anti-Sc1 titer was 32, score 65.  相似文献   
64.
Background  Pemphigus foliaceus is an autoimmune blistering skin disease characterized by the production of pathogenic IgG autoantibodies directed against desmoglein 1.
Aim  To determine the prevalence of anti-desmoglein 1 antibodies in healthy subjects and their distribution in the different regions of Tunisia and to better identify endemic areas of pemphigus foliaceus.
Methods  We tested, by enzyme-linked immunoserbent assay, sera of 270 normal subjects recruited from different Tunisian areas and 203 related healthy relatives to 90 Tunisian pemphigus foliaceus patients.
Results  Seventy-six patients (84.4%), 20 healthy controls (7.4%), and 32 relatives (15.76%) had anti-desmoglein 1 antibodies. In southern regions where pemphigus foliaceus is associated with a significant sex ratio imbalance (9 female : 1 male in the south vs. 2.3 : 1 in the north) and a lower mean age of disease onset (33.5 in the south vs. 45 years in the north), a higher prevalence of anti-desmoglein 1 antibodies in healthy controls was observed (9.23% vs. 5.71% in the north). Interestingly, the highest prevalence of anti-desmoglein 1 antibodies in healthy relatives (up to 22%) was observed in the most rural southern localities. More than half anti-desmoglein 1–positive healthy controls were living in rural conditions with farming as occupation, which suggests that this activity may expose the subjects to particular environmental conditions.
Conclusion  These results show that the endemic features of Tunisian pemphigus foliaceus are focused in these southern areas more than in other areas and that both environmental and genetic factors contribute to the disease.

Conflicts of interest


None declared.  相似文献   
65.
As the current antipsoriatic medications are commonly associated with deleterious side-effects, a determined search for safer agents, which could be used alone or in combination with current antipsoriatic drugs, would be very imperative. Psoriasis is believed to be characterized by a type 1 cytokine pattern; interferon-gamma, interleukin (IL)-2 and tumour necrosis factor (TNF)-alpha are predominantly expressed in this disorder. Nitric oxide, reactive oxygen species, histamine, leukotriene B4, and decreased [corrected] keratinocyte cyclic adenosine monophosphate/cyclic guanosine monophosphate (cAMP/cGMP) ratio are supposed to play roles in the pathogenesis of this disorder. Based on the immunopathogenesis of psoriasis, this paper introduces three novel, potential treatments for this clinical conundrum: (i) cannabinoids, which exert inhibitory effects on antigen processing and macrophage/T-cell interaction and also on the release of IL-2, TNF-alpha and nitric oxide from immune cells; (ii) loratadine, which is an antihistamine capable of increasing [corrected] the cAMP/cGMP ratio and the production of leukotriene B4; and (iii) allopurinol, which scavenges free radicals, inhibits the production of TNF-alpha, and downregulates the expression of intercellular adhesion molecule-1 and P2X7 receptors on monocytes/macrophages, which are involved in antigen presentation and production of the inflammatory response, respectively. Importantly, allopurinol, especially in combination with cyclosporin, has been shown to be effective against experimental autoimmune uveitis, which, like psoriasis, is a cell-mediated autoimmune disorder.  相似文献   
66.
MR Wren  ; PD Issitt 《Transfusion》1988,28(2):113-118
Studies on 24 Wr(a+b+) and 23 Wr(a-b+) blood samples, using anti-Wrb in the enzyme-linked antiglobulin test (ELAT), have shown that Wr(a+b+) red cells bind, on average, a little over half the amount of anti-Wrb bound by Wr(a-b+) red cells. Similarly, ELAT studies using six different anti-Wra and 10 Wr(a+b+) samples, as well as red cells from the original Wr(a+b-) proposita, have shown that Wr(a+b+) red cells bind about half the amount of anti-Wra bound by Wr(a+b-) red cells. Various pitfalls that can arise when the ELAT is used to measure antigen ratios on red cells have been avoided but are described. This conclusive evidence that Wra and Wrb have an antithetical relationship is discussed in light of the knowledge that a ficin-resistant portion of MN sialoglycoprotein (SGP), when carried in liposomes, can inhibit anti-Wrb. It is possible that Wra, Wrb, or both may encode a post-translational change in MN SGP, or production of transferases that glycosylate membrane lipids that affect in situ orientation of MN SGP, or production of protein band 3 that then forms a complex with MN SGP at the red cell membrane surface.  相似文献   
67.
大鼠脂肪间充质干细胞的成骨分化   总被引:2,自引:2,他引:2  
目的:观察大鼠脂肪间充质干细胞经成骨诱导向成骨细胞分化的生物学特性,探讨其作为骨组织工程种子细胞的可行性。方法:实验于2004-07/2006-03在中南大学湘雅医院中心实验室完成主要工作。①取健康SD大鼠双侧腹股沟区脂肪垫,消化法分离出脂肪间充质干细胞,接种入含有体积分数为0.1的新生牛血清的低糖DMEM培养基进行原代培养。②取第3代的脂肪间充质干细胞,用含有体积分数为0.1的新生牛血清、0.1μmol/L地塞米松、50μmol/L抗坏血酸、10mmol/Lβ-甘油磷酸钠的高糖DMEM培养基诱导其向成骨细胞分化。③于3,5,7,10,12,14,21d分别采用倒置显微镜观察细胞形态及增殖情况、Gomori改良钙钴法碱性磷酸酶染色、茜素红S钙结节染色和Ⅰ型胶原免疫细胞化学染色检测脂肪间充质干细胞成骨分化的情况。结果:①脂肪间充质干细胞原代细胞呈成纤维细胞样长梭形外观,传代稳定,细胞形态均一。②经成骨诱导,脂肪间充质干细胞体积增大,呈多角形;成骨诱导14d,Gomori改良钙钴法碱性磷酸酶染色,细胞胞浆内可见浅棕色至棕黑色的颗粒,平均染色阳性率为80%;碱性磷酸酶活性随时间的延长而逐渐增高[3,5,7,10,12,14d依次为(2.43±0.09),(3.60±0.08),(5.01±0.09),(7.75±0.07),(9.59±0.09),(10.94±0.10)μkat/L];成骨诱导21d,钙结节形成明显,茜素红S染色,呈红色结节;成骨诱导7d,Ⅰ型胶原免疫细胞化学染色,细胞胞浆呈棕黄色,胞核经苏木精复染为蓝色。结论:大鼠脂肪间充质干细胞经成骨诱导具有成骨细胞的生物学特性,可作为骨组织工程的种子细胞。  相似文献   
68.
69.
70.
Trichinella infection and clinical disease   总被引:1,自引:0,他引:1  
Trichinellosis is caused by ingestion of insufficiently cooked meat contaminated with infective larvae of <it>Trichinella</it> species. The clinical course is highly variable, ranging from no apparent infection to severe and even fatal disease. We report two illustrative cases of trichinellosis. Returning to Denmark a few days after having eaten roasted pork in the Republic of Serbia, a female patient suffered from severe vomiting, epigastric pain, diarrhoea, and later myalgia, generalized oedema, and prostration. A biopsy showed heavy infestation with <it>Trichinella spiralis</it>, 2000 larvae/g of muscle. Life-threatening cardiopulmonary, renal and central nervous system complications developed. The patient recovered after several months. Her husband, who also ate the pork, did not have clinical symptoms, but an increased eosinophil count and a single larva in a muscle biopsy confirmed infection. The epidemiology, clinical manifestations, diagnosis, treatment and prevention of trichinellosis are reviewed.   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