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   1272篇
  免费   45篇
  国内免费   14篇
耳鼻咽喉   4篇
儿科学   40篇
妇产科学   12篇
基础医学   198篇
口腔科学   34篇
临床医学   98篇
内科学   202篇
皮肤病学   10篇
神经病学   93篇
特种医学   169篇
外科学   185篇
综合类   13篇
一般理论   1篇
预防医学   68篇
眼科学   11篇
药学   108篇
中国医学   5篇
肿瘤学   80篇
  2024年   1篇
  2023年   7篇
  2022年   31篇
  2021年   33篇
  2020年   14篇
  2019年   20篇
  2018年   20篇
  2017年   20篇
  2016年   23篇
  2015年   29篇
  2014年   40篇
  2013年   65篇
  2012年   124篇
  2011年   152篇
  2010年   50篇
  2009年   38篇
  2008年   89篇
  2007年   121篇
  2006年   84篇
  2005年   76篇
  2004年   69篇
  2003年   64篇
  2002年   42篇
  2001年   13篇
  2000年   8篇
  1999年   10篇
  1998年   16篇
  1997年   7篇
  1996年   5篇
  1995年   7篇
  1994年   7篇
  1993年   7篇
  1992年   5篇
  1991年   4篇
  1990年   5篇
  1987年   2篇
  1986年   3篇
  1985年   3篇
  1983年   1篇
  1982年   1篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   3篇
  1973年   3篇
  1971年   2篇
  1969年   2篇
  1968年   1篇
排序方式: 共有1331条查询结果,搜索用时 15 毫秒
61.
62.
HSPs (heat-shock proteins) are molecular chaperones synthesized under stress conditions, and are involved in renal cell survival and matrix remodelling in acute and chronic renal diseases. In the present study, we investigated whether the HSP70 gene polymorphisms affect susceptibility to DN (diabetic nephropathy) in patients with T2DM (Type 2 diabetes mellitus). The study group consisted of 452 patients with nephropathy. Two control subgroups involved 340 healthy individuals and 132 patients with T2DM lasting > or =10 years who were free of nephropathy. Subjects were genotyped for the HSP70-1 +190 G/C and -110 A/C, HSP70-2 +1267 A/G and HSP70-hom +2437 T/C polymorphisms by PCR, followed by digestion with restriction endonucleases. There were no statistically significant differences in genotype distribution between patients with T2DM with DN and controls for the HSP70-hom polymorphism. Significant differences were observed for HSP70-1 and HSP70-2 polymorphisms. CC homozygotes of the -110 and +190 HSP70-1 polymorphisms were more frequent in patients with T2DM with DN compared with healthy controls (22 compared with 6% and 15 compared with 6.5% respectively; P<0.01). The OR (odds ratio) for the risk allele was 2.17 [95% CI (confidence interval), 1.73-2.72] for the -110 A/C and 1.74 (95% CI, 1.40-2.15) for +190 G/C polymorphisms. A strong association with DN was found for the +1267 HSP70-2 polymorphism. The GG genotype and the G allele were associated with DN, with the OR for the G allele being 4.77 (95% CI, 3.81-5.96). All GG homozygotes in the patient group had higher LDL (low-density lipoprotein)-cholesterol levels than AA homozygotes (P<0.01), suggesting that the observed effect might be associated with this cardiovascular risk factor. These patients progressed faster to end-stage renal failure than those with other genotypes. In conclusion, our results indicate that the HSP70-1 and HSP70-2 polymorphisms are associated with renal complications in T2DM and may be useful in identifying patients with increased risk of DN.  相似文献   
63.
The complex-formation reactions of the platinum(II) complexes, [Pt(dien)H2O]2+, [PtCl(dien)]+ and [PtBr(dien)]+ (dien is diethylenetriamine) with some biologically relevant ligands such as inosine (INO), inosine-5'-monophosphate (5'-IMP), guanosine-5'-monophosphate (5'-GMP), glutathione (GSH) and L-methionine (S-meth), were studied by UV-Vis (UV-Visible) spectrophotometry and 1H NMR spectroscopy. Reactions of the [PtCl(dien)]+ with L-methionine were studied in the presence and absence of 5'-GMP. The rate constants clearly showed a kinetic preference toward L-methionine. However, competitive reactions of [PtCl(dien)]+ with L-methionine and 5'-GMP demonstrated initially rapid formation of [Pt(dien)(S-meth)]2+ followed by displacement of L-methionine by 5'-GMP. In the later stages the concentration of [Pt(dien)(N7-GMP )]2+ is predominant. The results are analyzed in reference to the anti-tumour activity of Pt(II) complexes.  相似文献   
64.
BACKGROUND: The role of AT2R in regulation of blood pressure (BP) was mainly investigated in animal models. It is proposed to be a negative regulator of BP. X-linked AT2R -1332 A/G polymorphism has been denoted as functional. This polymorphism was associated with certain cardiovascular phenotypes in hypertensive patients, but it was poorly investigated in essential hypertension. The aim of our study was to evaluate possible association of -1332 A/G gene polymorphism with essential hypertension in males from Serbian population. METHODS: The study group included 304 men of Caucasian origin, 190 normotensive (NT) and 114 hypertensive (HT), free of cardiovascular disorders. Genotyping was done by PCR RFLP method. RESULTS: G/- genotype was in association with HT (OR 1.6, CI=1.0-2.6, p=0.04). Stratification by age (<40 years, mean 31.65+/-5.29 and >40 years, mean 51.36+/-8.32) pronounced significance only in older males (OR 2.4, CI=1.2-5.0, p=0.02). After adjustment for confounding factors the OR for hypertension remained unchanged and significant (adjusted OR 2.3, CI=1.0-5.4, p=0.04). Conclusion: Hemizygosity for the G allele was found to be susceptibility factor for hypertension in males. Still, clarifying the role of AT2R in development of human hypertension requires further replication studies in larger and different populations.  相似文献   
65.

Objective

Matrix metalloproteinases (MMPs) are involved in the remodeling of the extracellular matrix in the arterial wall. Collagen I is associated with vascular smooth muscle cell (VSMC) migration and monocyte differentiation. MMP-8 is expressed in atherosclerotic plaque and preferentially cleaves collagen type I. The aim of this study was to investigate the associations of two MMP-8 promoter polymorphisms, rs11225395 (−799 C/T) and rs1320632 (−381 A/G), with carotid plaque occurrence, and the influence of these polymorphisms on MMP-8 mRNA expression in plaque tissue.

Methods

The study included a total of 766 participants: 277 controls and 489 patients with carotid atherosclerosis undergoing endarterectomy. The two investigated polymorphisms were genotyped by PCR-RFLP. The gene expression analysis was performed by real-time PCR.

Results

In females only, a significantly higher frequency of the −381G allele was found in patients with carotid atherosclerosis compared to controls (OR, 1.7; 95% CI 1.1–2.9; p = 0.001). Significant up-regulation of MMP-8 gene expression was observed in patients carrying the −381G allele compared to those with the AA genotype (mean factor, 3.54; S.E. range, 0.643–19.551; p = 0.007). Carotid plaque tissue of the haplotype G−381T−799 showed a significantly higher mRNA level compared with the reference A−381C−799 haplotype (p = 0.003).

Conclusion

Our preliminary results indicate that MMP-8 −381A/G and −799 C/T gene polymorphisms could be risk factors for carotid atherosclerosis. Further validation and functional studies are needed to establish the potential regulatory role of these polymorphisms and their impact on susceptibility to carotid atherosclerosis.  相似文献   
66.
BACKGROUND: We have successfully performed heart transplantation despite the most unfavourable risk factors for graft and patient survival: the presence of a high level of antibodies (Abs) against the donor's human leukocyte antigens (HLA) class I/II and blood group A1 antigens. The present study concerns post-transplant follow-up and characterization of donor reactive antibodies (DRA). METHODS: Pre-transplant treatment consisted of mycophenolate mofetil (MMF), prednisolone, tacrolimus, intravenous immunoglobulin (IVIG), rituximab, protein-A immunoadsorption (PAIA) and per-operative plasma exchange. A standard triple-drug immunosuppressive protocol was used post-operatively. Abs were analyzed by the complement dependent cytotoxicity (CDC) test against donor and panel B/T cells and by flow cytometry (FlowPRA tests detecting isolated HLA class I/II antigens). Abs against the donor's erythrocytes were analyzed using a standard direct agglutination test for immunoglobulin M (IgM) Abs and a Bio-Rad AHG gel card test detecting IgG Abs and C3d. RESULTS: Pre-transplant treatment reduced Ab titers against the donor's lymphocytes from 128 to 16 and against the donor's blood group A1 antigen from 256 to 0. The patient was emergently transplanted with a heart from a blood group incompatible donor (A1 secretor to O). No hyperacute rejection was seen. DRA were present against all mismatched HLA class I and class II antigens at the time of transplantation; two of these DRA Abs disappeared within the first year post-transplant (anti-B62 and anti-DR4), one showed weakened reactivity (anti-A24) and one is still strongly reactive (anti-DQ3). The donor-specific CDC cross-match is still positive (titers 2 to 8). The level of panel reactive antibodies (PRA) remained unchanged from 6 months on post-transplant. Rising anti-A1 blood group Abs preceded the second rejection and were adsorbed by two blood group specific immunoadsorptions (Glycosorb)-ABO) and remained at a low level. IgM anti-A1 blood group Abs disappeared at 1 yr post-transplant and IgG Abs are still reactive with blood group A1 erythrocytes but at low titers (1 to 2). CONCLUSIONS: The patient is clinically well 2 years after heart transplantation despite the constant persistence of donor reactive IgG Abs against blood group A1 and HLA-DQ antigens. The reactivity of DRA against other mismatched HLA antigens disappeared or weakened during the follow-up period.  相似文献   
67.
Patients who have survived myocardial infarction (MI), compared to the general population, have an increased risk of reinfarction, myocardial revascularization, and death. In this study we investigated the prognostic significance of the predictors of the risk for adverse coronary events in 118 patients, both male and female, with a confirmed diagnosis of MI in the last 3 years. The predictors of reinfarction, revascularization and death in patients who survived MI were: poor adherence to hypolipemics (hazard ratio [HR] 3.06, p=0.006), physical inactivity (HR 2.22, p=0.056), the number of variable risk factors (HR 1.29, p=0.025), and age (HR 1.06, p=0.007). After the inclusion of the invariable risk factors in the model of multivariant analysis, the following factors were singled out as significant predictors of the risk: gender (HR 3.86, p=0.0015), physical inactivity (HR 2.38, p=0.007), change in the level of triglycerides (HR 1.49, p=0.040), change in the number of variable risk factors (HR 1.41, p=0.0007), and age (HR 1.05, p=0.009). A 3-year follow-up of the patients who survived the first MI and who were enrolled in this study of secondary prevention demonstrated that physical inactivity, the number of variable risk factors and age significantly contributed to an increased risk of reinfarction, revascularization, and death.  相似文献   
68.
The authors reviewed the clinical results of leg lengthening by distraction osteogenesis, where two different osteotomy techniques were used: classical corticotomy according to Ilizarov or osteoclasis. Evaluation of results of 64 patients were bases on orthopedic examination and detailed X-ray analysis which included criteria assessing osseous regeneration rate. In those cases where osteoclasis was performed bone formation in the distraction gap was faster than in after osteotomy. An accelerated rate of regenerate formation, as well as a more active regenerate remodelling was observed. This allowed to shorten the time of external fixator application and an earlier rehabilitation.  相似文献   
69.
Sympathetic reflex dystrophy of the upper extremity is among the most serious complications of trauma injuries. The aim of this paper was to assess the effectiveness of mobilization treatment, augmented by cryogenic temperatures of post trauma SRD of the upper extremity. The material comprised 113 patients treated at the Orthopedic Outpatient Clinic of the J. Babiński Hospital in Breslau during the years 1987-1995. All patients underwent conservative treatment because of post trauma SRD. The effectiveness of cryo-therapy was based on pre- and post-therapy ROM examination. These results were compared to the ROM of the healthy extremity and the degree of ROM limitation was hence calculated. Limitation of ROM was found in all joints of the upper extremity regardless to the stage of the disease. The greatest limitations were found in the joints directly adjacent to the area were the disease was most pronounced. The applied therapy in these cases was found to increase ROM in all patients, with the greatest increase of ROM during stage I and II of the disease.  相似文献   
70.
BACKGROUND: The aim of this study was to examine prothrombogenic factors and antioxidative defense in obese children and adolescents with pre-metabolic and metabolic syndrome, and to analyze insulin secretion and resistance, early glycoregulation disorders and lipid status. METHODS: Insulin sensitivity was determined using the homeostasis model assessment for insulin resistance (HOMA-IR), while insulin secretion was determined using the homeostasis model assessment beta (HOMA-beta). Prothrombogenic factors analyzed were plasma plasminogen activator inhibitor-1 (PAI-1) and fibrinogen. Superoxide dismutase and glutathione peroxidase were measured as markers of antioxidative defense. RESULTS: Patients with metabolic syndrome were characterized with increased body mass index (BMI), waist circumference, and HOMA-IR and HOMA-beta levels, and all had increased blood pressure and triglyceride levels, low high-density lipoprotein cholesterol levels, increased PAI-1 levels and reduced antioxidative defense levels. Patients with pre-metabolic syndrome had higher levels of basal and mean insulinemia during an oral glucose tolerance test, higher levels of HOMA-beta and lower levels of antioxidative defense compared to patients with metabolic syndrome. CONCLUSIONS: Negative correlations between antioxidative defense parameters and BMI, abdominal obesity, insulin secretion, systolic blood pressure and atherogenic lipid factors, as well as correlations between PAI-1 and insulin resistance and basal glycemia in the metabolic syndrome group contribute to accelerated atherosclerosis. Positive correlations between PAI-1 and waist circumference and BMI, and negative correlations between BMI and antioxidative defense in the pre-metabolic syndrome patients show that this early stage preceding the metabolic syndrome is also characterized by atherosclerotic complication risks and evident hyperinsulinism and insulin resistance.  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