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   3191篇
  免费   143篇
  国内免费   4篇
耳鼻咽喉   74篇
儿科学   155篇
妇产科学   39篇
基础医学   283篇
口腔科学   139篇
临床医学   228篇
内科学   557篇
皮肤病学   24篇
神经病学   229篇
特种医学   178篇
外科学   555篇
综合类   103篇
预防医学   153篇
眼科学   245篇
药学   194篇
中国医学   12篇
肿瘤学   170篇
  2023年   20篇
  2022年   66篇
  2021年   122篇
  2020年   46篇
  2019年   68篇
  2018年   101篇
  2017年   79篇
  2016年   88篇
  2015年   84篇
  2014年   118篇
  2013年   161篇
  2012年   241篇
  2011年   250篇
  2010年   153篇
  2009年   137篇
  2008年   191篇
  2007年   185篇
  2006年   151篇
  2005年   166篇
  2004年   139篇
  2003年   109篇
  2002年   118篇
  2001年   62篇
  2000年   48篇
  1999年   44篇
  1998年   19篇
  1997年   17篇
  1996年   14篇
  1993年   14篇
  1992年   20篇
  1991年   26篇
  1990年   26篇
  1989年   37篇
  1988年   23篇
  1987年   24篇
  1986年   14篇
  1985年   10篇
  1984年   8篇
  1983年   11篇
  1981年   19篇
  1980年   6篇
  1979年   6篇
  1977年   6篇
  1976年   9篇
  1975年   8篇
  1974年   6篇
  1973年   10篇
  1972年   6篇
  1971年   7篇
  1969年   6篇
排序方式: 共有3338条查询结果,搜索用时 15 毫秒
71.

Background/Aim:

Hypersplenism due to splenic congestion is observed in portal hypertensive patients. This study was done to know the change in platelets count following early ligation of splenic artery during splenectomy in patients with thrombocytopenia due to portal hypertension with a hypothesis that splenic decongestion results in increased platelets count; thereby platelet transfusion can be avoided.

Materials and Methods:

Patients with platelets count <100,000 per mm3 due to portal hypertension were involved and we followed a protocol of ligating splenic artery first, followed by 30 minutes waiting period for splenic decongestion. Blood sample was collected at 5 and 30 minutes for the estimation of platelets count.

Results:

Significant rise in platelets was observed after 5 and 30 minutes of early ligation of splenic artery with mean rise being 23735 ± 15417 and 35085 ± 20458 per mm3, respectively. The rise in platelets at 30 minutes was significant when compared with 5 minutes rise with mean platelets count being 91661 and 103070 per mm3 at 5 and 30 minutes, respectively. The platelets rise was equal to 4 and 6 units of platelets concentrates, respectively.

Conclusion:

Early ligation of splenic artery during splenectomy for portal hypertension results in significant rise in platelets after 5 and 30 minutes. This method conserves platelets and avoids platelets transfusion and its complications.  相似文献   
72.
PurposeTo study the association between gut microbial abundance and sight-threatening diabetic retinopathy among patients with a history of type 2 diabetes mellitus.MethodsAn observational case-control study was performed using a sample population of diabetics referred to a tertiary eye institute. Sample subjects were identified as cases if they were diagnosed with sight-threatening diabetic retinopathy and controls if they were not but had at least a 10-year history of diabetes. Fecal swabs for all patients were collected for enumeration and identification of sequenced gut microbes. Statistical analyses were performed to associate the clinically relevant Bacteroidetes to Firmicutes relative abundance ratio (B/F ratio) with sight-threatening diabetic retinopathy and an optimal cutoff value for the ratio was identified using Youden''s J statistics.ResultsA sample size of 58 diabetic patients was selected (37 cases, 21 controls). No statistically significant difference in the relative abundance among the predominant phyla between the groups were found. In our univariate analysis, the B/F ratio was elevated in cases compared to controls (cases, 1.45; controls, 0.94; P = 0.049). However, this statistically significant difference was not seen in our multivariate regression model. Optimal cutoff value of 1.05 for the B/F ratio was identified, and significant clustering of cases above this value was noted in beta diversity plotting.ConclusionsNo difference in gut microbial abundance for any particular phylum was noted between the control and diseased population. Increased gut microbial B/F ratio can be a potential biomarker for the development of sight-threatening diabetic retinopathy among type 2 diabetic patients.  相似文献   
73.
Malnutrition is prevalent among cirrhotic patients and is an important prognostic factor. Etiologic factors include hypermetabolism, malabsorption, altered nutrient metabolism, and anorexia. It is a challenge to manage nutrition in cirrhotic patients because of alterations to metabolic and storage functions of the liver; use of traditional assessment tools, such as anthropometric and biometric measures, is difficult because of complications such as ascites and inflammation. In addition to meeting macro- and micronutrient requirements, the composition and timing of supplements have been proposed to affect efficacy of nutrition support. Studies have indicated that branched chain aromatic acid can be given as therapeutic nutrients, and that probiotics and nocturnal feeding improve patient outcomes.  相似文献   
74.
75.
The low-pressure spark plasma sintering (SPS) technique is adopted to fabricate hydroxyapatite–bioglass (HA–BG) scaffolds while maintaining the physical properties of both components, including their bulk and relative density and hardness. However, prior to their orthopaedic and dental applications, these scaffolds must be validated via pre-clinical assessments. In the present study, scaffolds with different ratios of HA : BG, namely, 100 : 0 (HB 0 S), 90 : 10 (HB 10 S), 80 : 20 (HB 20 S) and 70 : 30 (HB 30 S) were fabricated. These scaffolds were characterized by investigating their physicochemical properties (X-ray diffraction (XRD) and surface wettability), bioactivity in a simulated body fluid (SBF) (field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR) and calcium dissolution), antimicrobial properties, biocompatibility and osteoinduction of human bone marrow-derived mesenchymal stromal cells (hBMSCs) and human monocyte immune cell response. The XRD and surface wettability results confirmed no formation of undesirable phases and the enhanced surface hydrophilicity of the scaffolds, respectively. The bioactivity in SBF indicated the formation of bone-like apatite on the surface of the scaffolds, corresponding to an increase in BG%, which was confirmed through FTIR spectra and the increasing trend of calcium release in SBF. The scaffolds showed inhibition properties against Staphylococcus aureus and Staphylococcus epidermidis. The scanning electron microscopy (SEM) micrographs and Alamar Blue proliferation assay indicated the good attachment and significant proliferation, respectively, of hBMSCs on the scaffolds. Alizarin Red S staining confirmed that the scaffolds supported the mineralisation of hBMSCs. The osteogenic protein secretion (bone morphogenetic protein-2 (BMP2), type-I collagen (COL1) and osterix (OSX)) was significant on the HB 30 S-seeded hBMSCs when compared with that of HB 0 S. The monocyte migration was significantly halted in response to HA–BG-conditioned media when compared with the positive control (monocyte chemoattractant protein-1: MCP-1). In conclusion, the HB 30 S composite scaffold has a greater potential to substitute bone grafts in orthopaedic and dental applications.

HB 30 S composite scaffold inhibits Staphylococcus spp., supports the biocompatibility and osteogenic differentiation of hBMSCs and resists monocyte migration.  相似文献   
76.
77.
Periprosthetic infections of hip and knee joints are now treated by two-stage revision arthroplasty with an infection control rate of 91%. The present systematic review studied the reported incidence of acute kidney injury (AKI) and infection recurrence from January 1989 to June 2012 to assess the risk–benefit ratio of antibiotic spacer use. Ten observational studies (n = 544 patients) with clinical outcomes showed an average incidence of AKI of 4.8%. The average reported persistence or recurrence rate of infection was 11% during a follow-up period that ranged from 13 to 108 months. The risk–benefit ratio presently favors treatment although there appears to be higher complication rates and incidence of AKI than previously reported. Marked heterogeneity in practice and lack of detail in reporting precluded more robust quantitative synthesis. Clinicians need to be aware of the potential risk of AKI, particularly in high-risk patients; practice patterns for the use of antibiotic spacers need to be standardized.  相似文献   
78.

Background

The optimal surgical management of small nonfunctional pancreatic neuroendocrine tumors (NF-PNETs) remains controversial. We sought to identify (1) clinicopathologic factors associated with survival in NF-PNETs and (2) preoperative tumor characteristics that can be used to determine which lesions require resection and lymph node (LN) harvest.

Methods

The records of all 116 patients who underwent resection for NF-PNETs between 1989 and 2012 were reviewed retrospectively. Preoperative factors, operative data, pathology, surgical morbidity, and survival were analyzed.

Results

The overall 5- and 10-year survival rates were 83.9 and 72.8 %, respectively. Negative LNs (p?=?0.005), G1 or G2 histology (p?=?0.033), and age <60 years (p?=?0.002) correlated with better survival on multivariate analysis. The 10-year survival rate was 86.6 % for LN-negative patients (n?=?73) and 34.1 % for LN-positive patients (n?=?32). Tumor size ≥2 cm on preoperative imaging predicted nodal positivity with a sensitivity of 93.8 %. Positive LNs were found in 38.5 % of tumors ≥2 cm compared to only 7.4 % of tumors <2 cm.

Conclusions

LN status, a marker of systemic disease, was a highly significant predictor of survival in this series. Tumor size on preoperative imaging was predictive of nodal disease. Thus, it is reasonable to consider parenchyma-sparing resection or even close observation for NF-PNETs <2 cm.  相似文献   
79.
This study reports a case of a 34 year old man who sustained an Achilles tendon rupture which was surgically repaired using a non-absorbable suture that was complicated by a deep sinus and chronic infection. Despite antibiotics, surgical debridement and skin grafting, his condition did not resolve. Further imaging revealed a sinus leading to the core suture knot that was eccentrically placed but not buried within the healed tendon repair, and the offending suture was subsequently removed.This case highlights the importance of meticulous surgical technique when performing Achilles tendon repair and a high index of suspicion for early imaging when patients present with chronic wound infection post-operatively.The authors urge surgeons to use routinely use an absorbable non-braided suture, which remains buried within the core when performing Achilles tendon repair.  相似文献   
80.
It is widely accepted that tabagism is a predisposing factor to oral candidosis and cumulate data suggest that cigarette compounds may increase candidal virulence. To verify if enhanced virulence occurs in Candida albicans from chronic smokers, a cohort of 42 non-smokers and other of 58 smokers (all with excellent oral conditions and without signs of candidosis) were swabbed on tong dorsum and jugal mucosa. Results showed that oral candidal loads do not differ between smoker and non-smokers. Activities of secreted aspartyl-protease (Sap), phospholipase, chondroitinase, esterase-lipase, and haemolysin secretions were screened for thirty-two C. albicans isolates. There were detected significant increments in phospholipasic and chondroitinasic activities in isolates from non-smokers. For other virulence factors, no differences between both cohorts were achieved.  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