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   1045篇
  免费   53篇
  国内免费   3篇
儿科学   74篇
妇产科学   17篇
基础医学   95篇
口腔科学   27篇
临床医学   106篇
内科学   272篇
皮肤病学   57篇
神经病学   24篇
特种医学   252篇
外科学   52篇
综合类   9篇
预防医学   34篇
眼科学   4篇
药学   34篇
中国医学   1篇
肿瘤学   43篇
  2023年   7篇
  2022年   2篇
  2021年   9篇
  2020年   3篇
  2019年   4篇
  2018年   16篇
  2017年   11篇
  2016年   16篇
  2015年   15篇
  2014年   21篇
  2013年   20篇
  2012年   23篇
  2011年   21篇
  2010年   37篇
  2009年   46篇
  2008年   30篇
  2007年   22篇
  2006年   26篇
  2005年   18篇
  2004年   18篇
  2003年   24篇
  2002年   10篇
  2001年   12篇
  2000年   6篇
  1999年   19篇
  1998年   51篇
  1997年   65篇
  1996年   49篇
  1995年   41篇
  1994年   52篇
  1993年   52篇
  1992年   10篇
  1991年   14篇
  1990年   11篇
  1989年   39篇
  1988年   45篇
  1987年   30篇
  1986年   28篇
  1985年   26篇
  1984年   12篇
  1983年   22篇
  1982年   17篇
  1981年   20篇
  1980年   21篇
  1979年   5篇
  1978年   8篇
  1977年   12篇
  1976年   10篇
  1975年   17篇
  1939年   2篇
排序方式: 共有1101条查询结果,搜索用时 31 毫秒
1.
2.
JE Kiss  ; D Berman  ; D Van  Thiel 《Transfusion》1998,38(4):327-331
BACKGROUND: Patients who present with fulminant hepatic failure due to Wilson's disease may develop hemolytic anemia and renal insufficiency. In this entity, acute hepatocellular necrosis triggers the release of copper ions into the circulation, which leads to toxic effects on red cell metabolic pathways and hemolysis. STUDY DESIGN AND METHODS: The utility of therapeutic plasma exchange to rapidly remove copper and reduce toxic serum copper levels was studied in two patients with fulminant Wilson's disease. RESULTS: Intensive plasma exchange using fresh-frozen plasma replacement removed substantial amounts of copper from the hypercupremic patients, resulting in a rapid reduction in serum copper levels and decreased hemolysis. The net copper removal was proportional to the serum level, ranging from 7,000 to 11,800 micrograms per procedure in one patient and from 3,700 to 6,800 micrograms in the other. CONCLUSION: Plasma exchange allows a rapid reduction in elevated serum copper levels in patients with fulminant Wilson's disease. This leads to an amelioration of hemolytic anemia and provides clinical stabilization until liver transplantation can be performed.  相似文献   
3.
This multicentre, double-blind, randomized, placebo-controlled, parallel study was designed to evaluate the efficacy of combined oral lysine acetylsalicylate and metoclopramide (LAS-MCP) in the acute treatment of migraine attacks. A total of 266 patients, 18–65 years old, with two to six attacks of migraine with or without aura (IHS criteria) per month were included. The patients had to treat two migraine attacks with LAS-MCP (1620 mg lysine acetylsalicylate-the equivalent of 900 mg aspirin- combined with 10 mg metoclopramide) or placebo. The main outcome measure was headache relief (reduction in headache severity from grade 3 or 2-severe or moderate-to grade 1 or 0-mild or none) 2 h after treatment. LAS-MCP was superior to placebo for headache relief (56% vs 28%) and for the following secondary outcome measures: complete headache relief (18% vs 7%; p < 0.001), nausea (28% vs 44%; p < 0.001), vomiting (3% vs 11%; p = 0.001), use of rescue medication (47% vs 68%; p < 0.001), global efficacy judged as good or excellent (32% vs 14%; p < 0.001). The tolerability was considered as good in 94% of treated attacks in both groups. Combined oral lysine acetylsalicylate and metoclopramide is an effective and well-tolerated acute treatment of migraine attacks.  相似文献   
4.
Formation of metastases in the lungs is the major cause of death in patients suffering from osteosarcoma (OS). Metastases at presentation and poor response to preoperative chemotherapy are strong predictors for poor patient outcome. The elucidation of molecular markers that promote metastasis formation and/or chemoresistance is therefore of importance. CD44 is a plasma membrane glycoprotein that binds to the extracellular matrix component hyaluronan (HA) and has been shown to be involved in metastasis formation in a variety of other tumors. Here we investigated the role of CD44 expression on OS tumor formation and metastasis. High CD44 expression, evaluated with a tissue microarray including samples from 53 OS patients and stained with a pan‐CD44 antibody (Hermes3), showed a tendency (p < 0.08) to shortened overall survival. However, nonresponders and patients with lung metastases and high CD44 expression had significantly poorer prognosis than patients with low CD44 expression. Overexpression of the standard CD44 isoform (CD44s) and its HA‐binding defective mutant R41A in osteoblastic SaOS‐2 cells resulted in HA‐independent higher migration rates and increased chemoresistance, partially dependent on HA. In an orthotopic mouse model of OS, overexpression of CD44s in SaOS‐2 cells resulted in an HA‐dependent increased primary tumor formation and increased numbers of micrometastases and macrometastases in the lungs. In conclusion, although CD44 failed to be an independent predictor for patient outcome in this limited cohort of OS patients, increased CD44 expression was associated with even worse survival in patients with chemoresistance and with lung metastases. CD44‐associated chemoresistance was also observed in vitro, and increased formation of lung metastases was found in vivo in SCID mice. © 2013 American Society for Bone and Mineral Research.  相似文献   
5.
目的:观察碱性成纤维细胞生长因子对大鼠脑出血后出血灶周围脑组织和出血侧海马bax、bcl-2基因表达的影响,探讨神经营养因子对神经细胞调亡的调控。方法:实验于2006-01/10在广西医科大学医学科学实验中心完成。①取成年清洁级Wistar大鼠72只,雌雄各半,体质量250g左右。②采用脑内囊注射胶原酶建立大鼠脑出血模型,动物于苏醒后按Bederson法进行神经病学评分,评分>3分后入选本实验,入选72只大鼠随机抽签法分为3组,每组24只。碱性成纤维细胞生长因子组按8μg/kg剂量肌肉注射,1次/d;生理盐水组肌肉注射等剂量的生理盐水,1次/d;模型组不作任何干预。③每组分别于干预后1,3,7d随机抽取8只大鼠,麻醉状态下取出血灶周围脑组织和出血侧海马,采用半定量反转录-聚合酶链反应检测调亡调控基因bax mRNA,bcl-2mRNA的表达。结果:在建立脑出血模型中共5只大鼠死亡,随后对死亡动物进行解剖,发现脑内血肿量过大,致脑疝形成而导致死亡,后随机补充动物。72只大鼠进入结果分析。①血肿周围脑组织bax mRNA表达:干预后3d,7d,碱性成纤维细胞生长因子组血肿周围脑组织bax mRNA表达比生理盐水组明显减少(3d:0.54±0.19,0.76±0.23,P<0.05;7d:0.45±0.19,0.71±0.16,P<0.01)。②血肿周围脑组织bcl-2mRNA表达:干预后3d,7d,碱性成纤维细胞生长因子组的血肿周围脑组织bcl-2mRNA表达比生理盐水组明显增高(3d:0.68±0.25,0.39±0.19,P<0.05;7d:0.80±0.21,0.48±0.18,P<0.01)。③出血侧海马bax mRNA表达:干预后3d和7d,碱性成纤维细胞生长因子组的出血侧海马bax mRNA表达比生理盐水组均明显减少(3d:0.54±0.18,0.70±0.11;7d:0.43±0.24,0.69±0.18,P均<0.05)。④出血侧海马bcl-2mRNA表达:干预后3d和7d,碱性成纤维细胞生长因子组的出血侧海马bcl-2mRNA表达比生理盐水组均明显增多(3d:0.66±0.11,0.50±0.15;7d:0.72±0.12,0.52±0.22,P均<0.05)。结论:碱性成纤维细胞生长因子能调节凋亡相关基因,提高大鼠脑出血后大脑脑组织和海马bcl-2mRNA的表达,降低bax mRNA的表达。  相似文献   
6.

OBJECTIVE

Diabetic nephropathy and cardiovascular disease are strongly related in adults with type 1 diabetes, yet little is known about this relationship in adolescents prior to the onset of detectable clinical disease. We hypothesized that cardiopulmonary fitness would be directly associated with albumin-to-creatinine ratio (ACR) and inversely related to estimated glomerular filtration rate (eGFR) in adolescents with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Sixty-nine adolescents with type 1 diabetes and 13 nondiabetic control subjects of similar pubertal stage and BMI had insulin sensitivity (glucose infusion rate [GIR]), measured by hyperinsulinemic-euglycemic clamp, and lean body mass, measured by DEXA. Cardiopulmonary fitness was measured by cycle ergometry to obtain peak volume of oxygen (VO2peak), and renal function was measured by eGFR using the Bouvet equation (measuring creatinine and cystatin C levels) and ACR.

RESULTS

Adolescents (15.5 ± 2.2 years of age) with type 1 diabetes (6.3 ± 3.8 years diabetes duration) had reduced VO2peak (31.5 ± 6.3 vs. 36.2 ± 7.9 mL/kg ⋅ min, P = 0.046) and VO2peak/lean kg (43.7 ± 7.0 vs. 51.0 ± 8.6 mL/lean kg ⋅ min, P = 0.007) compared with nondiabetic control subjects. eGFR was inversely associated with VO2peak and VO2peak/lean kg after adjusting for sex, Tanner stage, GIR, HbA1c level, systolic blood pressure, and LDL cholesterol level (β ± SE, VO2peak: −0.19 ± 0.07, P = 0.02; VO2peak/lean kg: −0.19 ± 0.09, P = 0.048). Moreover, participants in the highest tertile for eGFR had significantly lower sex- and Tanner-adjusted VO2peak and VO2peak/lean kg compared with participants in the lowest tertile.

CONCLUSIONS

Adolescents with type 1 diabetes had reduced exercise capacity, which was strongly associated with renal health, independent of insulin sensitivity. Future studies should examine the underlying interrelated pathophysiology in order to identify probable targets for treatment to reduce cardiovascular and renal complications.  相似文献   
7.
Tighe  JE; Daga  A; Calabi  F 《Blood》1993,81(3):592-596
The t(8;21)(q22;q22) is consistently associated with acute myeloid leukemia (AML) M2. Recent data have suggested that breakpoints on chromosome 21 are clustered within a single intron of a novel gene, AML1, just downstream of a region of homology to the runt gene of D melanogaster. In this report, we confirm rearrangement at the same location in at least 12 of 18 patients with t(8;21). Furthermore, we have isolated recombinant clones spanning the breakpoint regions on both the der(8) and the der(21) from one patient. By using a chromosome 8 probe derived from these clones, we show that t(8;21) breakpoints are also clustered on chromosome 8.  相似文献   
8.
9.
Aim: To describe gut colonization in preterm infants using standard culture and 16S gene rRNA profiling, exploring differences in healthy infants and those who developed NEC/late onset sepsis (LOS). Methods: Ninety‐nine stools from 38 infants of median 27‐week gestation were cultured; 44 stools from 27 infants had their microbial profiles determined by 16S. Ordination analyses explored effects of patient variables on gut communities. Results: Standard microbiological culture identified a mean of two organisms (range 0–7), DGGE 12 (range 3–18) per patient. Enterococcus faecalis and coagulase negative staphylococci (CONS) were most common by culture (40% and 39% of specimens). Meconium was not sterile. No fungi were cultured. Bacterial community structures in infants with NEC and LOS differed from healthy infants. Infants who developed NEC carried more CONS (45% vs 30%) and less Enterococcus faecalis (31% vs 57%). 16S identified Enterobacter and Staphylococcus presence associated with NEC/LOS, respectively. Conclusions: Important differences were found in the gut microbiota of preterm infants who develop NEC/LOS. The relationship of these changes to current practices in neonatal intensive care requires further exploration.  相似文献   
10.
Roxadustat is an oral hypoxia‐inducible factor prolyl hydroxylase inhibitor developed to treat anemia in chronic kidney disease (CKD) patients. This Phase 3, randomized, open‐label, 24‐week study investigated the efficacy and safety of roxadustat in Japanese CKD patients with anemia on peritoneal dialysis (PD) who were previously treated or not treated with erythropoiesis stimulating agents (ESAs). Patients not previously receiving ESA (ESA‐Naïve group) were randomized to roxadustat at a starting dose of 50 or 70 mg three times weekly; patients previously receiving ESA (ESA‐Converted group) switched from ESA to roxadustat 70 or 100 mg three times weekly depending on the prior ESA dose. Outcomes included maintenance rate of average hemoglobin (Hb) level within 10–12 g/dL at weeks 18–24, cumulative response rate at end of treatment (Hb thresholds, 10.0 g/dL or 10.5 g/dL; Hb increase, ≥1.0 g/dL), and average Hb levels at weeks 18–24. Safety was assessed by occurrence of treatment‐emergent adverse events (TEAEs). Fifty‐six patients were enrolled (ESA‐Naïve, n = 13; ESA‐Converted, n = 43). Maintenance rates (weeks 18–24) were 92.3% (95% CI: 64.0–99.8; ESA‐Naïve) and 74.4% (95% CI: 58.8–86.5; ESA‐Converted). Cumulative response rate was 100.0% in the ESA‐Naïve group. Average Hb levels (weeks 18–24) were 11.05 g/dL (95% CI: 10.67–11.42; ESA‐Naïve) and 10.93 g/dL (95% CI: 10.73–11.13; ESA‐Converted). Common TEAEs included nasopharyngitis and back pain. Roxadustat was well tolerated and effective in maintaining target Hb levels in CKD patients on PD who were previously treated or not treated with ESA.  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