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   515篇
  免费   34篇
  国内免费   3篇
耳鼻咽喉   3篇
儿科学   4篇
妇产科学   9篇
基础医学   45篇
口腔科学   2篇
临床医学   62篇
内科学   125篇
皮肤病学   5篇
神经病学   28篇
特种医学   24篇
外科学   106篇
综合类   5篇
预防医学   44篇
眼科学   20篇
药学   38篇
中国医学   6篇
肿瘤学   26篇
  2024年   1篇
  2023年   10篇
  2022年   17篇
  2021年   30篇
  2020年   13篇
  2019年   21篇
  2018年   17篇
  2017年   9篇
  2016年   13篇
  2015年   20篇
  2014年   25篇
  2013年   22篇
  2012年   43篇
  2011年   48篇
  2010年   23篇
  2009年   17篇
  2008年   22篇
  2007年   39篇
  2006年   21篇
  2005年   15篇
  2004年   17篇
  2003年   22篇
  2002年   22篇
  2001年   9篇
  2000年   4篇
  1999年   4篇
  1998年   3篇
  1997年   3篇
  1995年   4篇
  1994年   1篇
  1993年   2篇
  1992年   4篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   4篇
  1987年   4篇
  1986年   6篇
  1985年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1977年   1篇
  1974年   1篇
排序方式: 共有552条查询结果,搜索用时 15 毫秒
51.
Peanut lectin (PNA) has been shown to have a high affinity for Thomsen-Friedenreich (T) antigen, which is associated with the membrane of many solid tumour cells. PNA labelled with 131I was used as a tumour-imaging substance in patients with known metastatic cancer. Serial gamma scintiscans were obtained in 17 patients following a single injection of 131I-labelled PNA. Only in 1 patient was this technique able to reveal a known metastasis at analogue imaging. In the remaining patients, no visible uptake of 131I-PNA could be demonstrated at sites of known metastases. PNA is rapidly excreted through the kidneys and localizes in the renal tubules. As a tumour-imaging agent, 131I-PNA appears to be without value, but its renal-excretory characteristics make it a potentially useful agent for the in vivo assessment of renal-tubular disorders.  相似文献   
52.
Decosterd I  Ji RR  Abdi S  Tate S  Woolf CJ 《Pain》2002,96(3):269-277
A spared nerve injury of the sciatic nerve (SNI) or a segmental lesion of the L5 and L6 spinal nerves (SNL) lead to behavioral signs of neuropathic pain in the territory innervated by adjacent uninjured nerve fibers, while a chronic constriction injury (CCI) results in pain sensitivity in the affected area. While alterations in voltage-gated sodium channels (VGSCs) have been shown to contribute to the generation of ectopic activity in the injured neurons, little is known about changes in VGSCs in the neighboring intact dorsal root ganglion (DRG) neurons, even though these cells begin to fire spontaneously. We have now investigated changes in the expression of the TTX-resistant VGSCs, Nav1.8 (SNS/PN3) and Nav1.9 (SNS2/NaN) by immunohistochemistry in rat models of neuropathic pain both with an intermingling of intact and degenerated axons in the nerve stump (SNL and CCI) and with a co-mingling in the same DRG of neurons with injured and uninjured axons (sciatic axotomy and SNI). The expression of Nav1.8 and Nav1.9 protein was abolished in all injured DRG neurons, in all models. In intact DRGs and in neighboring non-injured neurons, the expression and the distribution among the A- and C-fiber neuronal populations of Nav1.8 and Nav1.9 was, however, unchanged. While it is unlikely, therefore, that a change in the expression of TTX-resistant VGSCs in non-injured neurons contributes to neuropathic pain, it is essential that molecular alterations in both injured and non-injured neurons in neuropathic pain models are investigated.  相似文献   
53.

Purpose

The objectives of this study were to evaluate emergency medicine resident-performed ultrasound for diagnosis of effusions, compare the success of a landmark-guided (LM) approach with an ultrasound-guided (US) technique for hip, ankle and wrist arthrocentesis, and compare change in provider confidence with LM and US arthrocentesis.

Methods

After a brief video on LM and US arthrocentesis, residents were asked to identify artificially created effusions in the hip, ankle and wrist in a cadaver model and to perform US and LM arthrocentesis of the effusions. Outcomes included success of joint aspiration, time to aspiration, and number of attempts. Residents were surveyed regarding their confidence in identifying effusions with ultrasound and performing LM and US arthrocentesis.

Results

Eighteen residents completed the study. Sensitivity of ultrasound for detecting joint effusion was 86% and specificity was 90%. Residents were successful with ultrasound in 96% of attempts and with landmark 89% of attempts (p = 0.257). Median number of attempts was 1 with ultrasound and 2 with landmarks (p = 0.12). Median time to success with ultrasound was 38 s and 51 s with landmarks (p = 0.23). After the session, confidence in both US and LM arthrocentesis improved significantly, however the post intervention confidence in US arthrocentesis was higher than LM (4.3 vs. 3.8, p < 0.001).

Conclusions

EM residents were able to successfully identify joint effusions with ultrasound, however we were unable to detect significant differences in actual procedural success between the two modalities. Further studies are needed to define the role of ultrasound for arthrocentesis in the emergency department.  相似文献   
54.

Objective

The use of preparations based on minerals extracts of Calicotome villosa and butter is born from the misuse of drugs without specific microbiological analyzes. Seventeen different preparations were performed. The antibacterial and antifungal activities were determined on five bacteria and two fungi strains respectively.

Material and methods

C.villosa ashes are obtained by incineration of roots plant at 498 °C for 4 hours. They are analyzed to determine the shape of the particles and the mineral constituents by scanning electronic microscopy (SEM) and energy dispersive X-ray spectrometry (EDX) techniques respectively. The effectiveness of preparations or tablets is measured in solid medium. It allows to calculating the diameter of the inhibition zone for the antibacterial activity as well as the diameter of mycelia growth and the critical values (MIC, MFC, IC50 and IC90) for the antifungal activity. Finally, the results are compared to the activity of a commercial positive control aiming to give value of the observed activity.

Results

SEM observations reveal the presence of nanoparticles agglomerated with size of about 50 nm. The EDX analyzes indicate the presence of Fe, Na, Al, Mg, Si, K, Ca, O2 and C. Among all the results, the preparation (Bs + A) or (Bsd + A) can completely inhibit the growth of two fungal pathogens. The activity of the preparation is faced with the activity of the synthetic fungicide nystatin.

Conclusion

The efficacy of the preparation (Bs + A) or (Bsd + A) is larger than that of nystatin against Aspergillus sp. and Fusarium sp. The preparation could serve as natural antifungal for the pharmaceutical industry.  相似文献   
55.
Ten patients with advanced cancer were treated with weekly intravenous escalating doses of human beta-interferon (HuIFN beta) 4 days each week. The starting dose of HuIFN beta was 3.0 X 10(6) units/m2 and the dose was doubled each week until dose-limiting toxicity was observed. Subjective toxicity included mild fevers and chills, malaise and flu-like symptoms. The lowest dose which caused suppression of the platelet and/or white cell count was 64 X 10(6) units daily, and the maximum dose given was 320 X 10(6) units daily. Both subjective and objective toxicity were not dose-related, easily managed and reversible. Serum interferon levels and the duration of measurable interferon activity on natural killer cells was in general dose-dependent. Two patients had an objective partial response, and two others showed stable disease while receiving HuIFN beta.  相似文献   
56.
Liver: an alarm for the heart?   总被引:2,自引:0,他引:2  
BACKGROUND/AIMS: Fatty liver (FL) and coronary artery disease (CAD) have several risk factors in common, which are usually considered to account for their frequent coexistence. The independent association between FL and angiographic CAD was assessed in this case-control study by considering the contribution of their shared risk factors. METHODS: Three hundred and seventeen adult patients who underwent elective coronary angiography (CAG) were recruited immediately after CAG and classified into either of the two groups A (normal or mildly abnormal CAG; n=85) or B (clinically relevant CAD; n=232). A liver sonography was performed on the same day as CAG. RESULTS: The groups were significantly different in terms of gender, fasting blood glucose, low-density lipoproteins, diabetes (DM), hypertension and FL. In binary logistic regression, FL was the strongest independent predictor of CAD [P<0.001, odds ratio (OR)=8.48%, 95% confidence interval (CI)=4.39-16.40], followed by DM (P=0.002, OR=2.94) and male gender (P=0.014, OR=2.31). This pattern of associations did not change after clinically significant variables (waist-to-hip ratio, body mass index, triglycerides and high-density lipoproteins) were added to analysis. CONCLUSION: Fatty liver seems to be a strong independent alarm for the presence of significant CAD.  相似文献   
57.
58.
The prognostic value of pulse pressure has been investigated in heart-failure patients. Low pulse pressure in advanced heart failure and high pulse pressure in mild heart failure have been separately linked to increased mortality rates. We prospectively investigated an association between pulse pressure and 2-year cardiovascular death in an entire heart-failure population.We prospectively enrolled 225 heart-failure patients (New York Heart Association [NYHA] functional class, I–IV; mean age, 56.5 ± 12.3 yr; 188 men). The patients'' blood pressures were measured in accordance with recommended guidelines. Pulse pressures were calculated as the difference between systolic and diastolic blood pressure values. The patients were monitored for a mean period of 670 ± 42 days for the occurrence of cardiovascular death.All patients were divided into quartiles according to their pulse pressures (<35, 35–45, 46–55, and >55 mmHg). Pulse pressure decreased as NYHA class worsened (P <0.001). Patients in the <35-mmHg quartile had the lowest plasma sodium concentrations, left ventricular ejection fractions, and systolic myocardial velocities upon echocardiography; and the highest left ventricular dimensions, early diastolic/late diastolic filling velocity ratios, and peak early/peak late diastolic myocardial velocity ratios. Pulse pressure independently predicted death in the patients with advanced heart failure and in the entire population. Upon receiver operating characteristic analysis, a 30-mmHg cutoff value for pulse pressure predicted death with 83.7% sensitivity and 79.7% specificity.Pulse pressure is easily calculated and enables the prediction of cardiovascular death in patients with mild to advanced heart failure. Pulse pressure can be used reliably as a prognostic marker in clinical practice.Key words: Blood pressure/physiology, cardiovascular diseases/mortality/physiopathology, epidemiologic methods, heart failure/epidemiology/etiology/physiopathology, multivariate analysis, predictive value of tests, prospective studies, pulse/physiology, reference values, risk factorsPulse pressure (PP) is the difference between systolic and diastolic blood pressure (BP) values. Pulse pressure markedly rises after the 5th decade of life, due to arterial stiffening with increasing age.1,2 Several studies have shown a close relationship between high PP and the occurrence of cardiovascular (CV) death.3-5 Furthermore, high PP is a risk factor for the development of coronary heart disease, myocardial infarction, and heart failure in normotensive and hypertensive persons.6-10Data regarding the prognostic value of PP in patients with heart failure are limited and controversial. The importance of PP was investigated in 2 large studies. The SAVE11 (Survival and Ventricular Enlargement) trial revealed a worse prognosis in patients with high PP and symptomatic or asymptomatic left ventricular (LV) systolic dysfunction. The SOLVD12 (Studies of Left Ventricular Dysfunction) trial found that high PP independently predicted total and CV death in mild heart failure. However, in both studies, patients in New York Heart Association (NYHA) functional classes I and II constituted most of the population, and few patients had advanced heart failure (NYHA classes III and IV). In other studies involving patients with advanced heart failure, low PP was associated with high CV mortality rates.13-16 We believed that further study was warranted in order to elucidate the prognostic value of PP in an entire heart-failure population. Accordingly, we investigated the association between PP and 2-year CV death in patients in whom the severity of heart failure ranged from mild to advanced.  相似文献   
59.
Background  We compared tracheal intubation characteristics and arterial oxygenation quality during airway management of morbidly obese patients whose trachea was intubated under video assistance with the LMA CTrach™ (SEBAC, Pantin, France) or the Airtraq™ laryngoscope (VYGON, écouen, France) with that of the conventional Macintosh laryngoscope. Methods  After standardized induction of anesthesia, 318 morbidly obese patients scheduled for elective morbid obesity surgery received tracheal intubation with the LMA CTrach™, the Airtraq™ laryngoscope, or the conventional Macintosh laryngoscope. Duration of apnea, time to tracheal intubation, and oxygenation quality during airway management were compared between the LMA CTrach™ and the laryngoscope groups. Results  Patients’ characteristics were similar in the three groups. The success rate for tracheal intubation was 100% with the LMA CTrach™ and the Airtraq™ laryngoscope. One patient of the Macintosh laryngoscope group received LMA CTrach™ intubation because of early arterial oxygen desaturation associated with unstable facemask ventilation. The duration of apnea was shorter with the LMA CTrach™ than that of the Airtraq™ laryngoscope and the Macintosh laryngoscope. The duration tracheal intubation was shorter with the Airtraq™ laryngoscope than with the Macintosh laryngoscopes and the LMA CTrach™. During airway management, arterial oxygenation was of better quality with the LMA CTrach™ and the Airtraq™ laryngoscope than that of the Macintosh laryngoscope. Conclusion  Because LMA CTrach™ promoted short apnea time and the Airtraq™ laryngoscope allowed early definitive airway, both video-assisted tracheal intubation devices prevented most serious arterial oxygenation desaturation evidenced during tracheal intubation of morbidly obese patients with the conventional Macintosh laryngoscope. Support was provided solely from department sources. LMA and PRODOL Companies promoted material support for the airways.  相似文献   
60.
OBJECTIVE: To evaluate: (i) a correct equivalence ratio of clinical efficacy between low-dose deflazacort (DFZ) and methyl prednisolone (MP); and (ii) bone metabolic effects of low-dose DFZ and MP in the treatment of male RA and PsA. METHODS: A total of 21 male patients with active RA or PsA, naive to steroid treatment were chosen for the study. Group I: 10 patients treated for 6 months with DFZ 7.5 mg, calcium, cholecalciferol and a DMARD; for the following 6 months with MP 4 mg, calcium, cholecalciferol and a DMARD. Group II: 11 patients treated for 6 months with MP 4 mg, calcium, cholecalciferol and a DMARD; for the following 6 months with DFZ 7.5 mg, calcium, cholecalciferol and a DMARD. At day 0, 90, 180, 240 and 360 evaluation of ACR improvement criteria; a blood sample for total and bone-specific ALP, calcium, phosphorus, PTH, SHBG, estradiol, ACTH, osteocalcin, LH, OPG; a sample of urine for calcium, phosphorus, creatinine and DPD. RESULTS: 13/21 patients (6/10 Group I; 7/11 Group II) reached ACR 20 at 6 months; 14/21 (7/10 Group I, 7/10 Group II) at 12 months. Only at the third month we observed in Group II vs Group I a reduction of OPG (24% vs 6%, P = n.s.); ALP (P < 0.001) and osteocalcin (P = 0.006) decreased in both groups from the third month; DPD decreased in both groups only from the sixth month (P = 0.002). CONCLUSIONS: The correct equivalence ratio of DFZ to MP is 1.875:1, and of DFZ to prednisolone 1.5:1. We found a relative prevalence of bone resorption compared to bone formation in the first 6 months of treatment. The trend of OPG requires further investigation.  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