全文获取类型
收费全文 | 8111篇 |
免费 | 588篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 175篇 |
妇产科学 | 165篇 |
基础医学 | 1370篇 |
口腔科学 | 191篇 |
临床医学 | 803篇 |
内科学 | 1811篇 |
皮肤病学 | 235篇 |
神经病学 | 937篇 |
特种医学 | 214篇 |
外科学 | 834篇 |
综合类 | 25篇 |
一般理论 | 5篇 |
预防医学 | 527篇 |
眼科学 | 113篇 |
药学 | 616篇 |
中国医学 | 10篇 |
肿瘤学 | 688篇 |
出版年
2024年 | 18篇 |
2023年 | 130篇 |
2022年 | 238篇 |
2021年 | 394篇 |
2020年 | 246篇 |
2019年 | 297篇 |
2018年 | 294篇 |
2017年 | 248篇 |
2016年 | 268篇 |
2015年 | 265篇 |
2014年 | 379篇 |
2013年 | 433篇 |
2012年 | 678篇 |
2011年 | 609篇 |
2010年 | 357篇 |
2009年 | 345篇 |
2008年 | 526篇 |
2007年 | 477篇 |
2006年 | 484篇 |
2005年 | 465篇 |
2004年 | 395篇 |
2003年 | 364篇 |
2002年 | 323篇 |
2001年 | 68篇 |
2000年 | 44篇 |
1999年 | 58篇 |
1998年 | 65篇 |
1997年 | 52篇 |
1996年 | 35篇 |
1995年 | 38篇 |
1994年 | 23篇 |
1993年 | 17篇 |
1992年 | 25篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1977年 | 4篇 |
1942年 | 1篇 |
1907年 | 2篇 |
1906年 | 3篇 |
1905年 | 3篇 |
1904年 | 2篇 |
1903年 | 4篇 |
排序方式: 共有8754条查询结果,搜索用时 15 毫秒
61.
Patient-controlled epidural analgesia reduces analgesic requirements compared to continuous epidural infusion after major abdominal surgery 总被引:12,自引:0,他引:12
Thomas Standl Marc-Alexander Burmeister Henning Ohnesorge Stephan Wilhelm Martina Striepke André Gottschalk Ernst-Peter Horn Jochen Schulte 《Journal canadien d'anesthésie》2003,50(3):258-264
PURPOSE: To compare the quality of pain relief and incidence of side effects between 24-hr postoperative continuous epidural infusion (CEI) and subsequent patient-controlled epidural analgesia (PCEA) with different analgesics after major abdominal surgery. METHODS: Twenty-eight women undergoing extended gynecological tumour surgery received postoperative CEI with 0.15 mL x kg(-1) x hr(-1) 0.2% ropivacaine (R: n = 14) or 0.125% bupivacaine plus 0.5 micro g x mL(-1) sufentanil (BS: n = 14) during 24 postoperative hours. Twenty-four hours later, postoperative pain management was switched to PCEA without background infusion and 5 mL single bolus application of R or BS every 20 min at most. Visual analogue scales (VAS; 1-100 mm) were assessed by patients at rest and on coughing after 24 hr of CEI and PCEA. Side effects, doses of local anesthetics and opioids were recorded and plasma concentrations of total and unbound ropivacaine and bupivacaine were measured. RESULTS: Patients required lower doses of each respective analgesic medication with PCEA (R: 108 +/- 30 mL; BS: 110 +/- 28 mL) than with CEI (R: 234 +/- 40; BS: 260 +/- 45; P < 0.01). Ropivacaine plasma concentrations were lower 24 hr after PCEA when compared with CEI (P < 0.01). No patient after PCEA but two after CEI (n = 4; NS) presented motor block. PCEA with R provided better postoperative pain relief than CEI (37 +/- 32 vs 59+/-27, P < 0.05). No difference in parenteral opioid rescue medication between CEI and PCEA was seen. CONCLUSION: PCEA in comparison to preceding CEI provides equivalent analgesia with lower local anesthetic doses and plasma levels, and without motor blocking side effects, irrespective of the applied drug regimen. 相似文献
62.
Sester M Sester U Gärtner BC Girndt M Meyerhans A Köhler H 《Journal of the American Society of Nephrology : JASN》2002,13(10):2577-2584
Cellular immune responses are of high importance in initiating and maintaining immunity against virus infections. Whereas the cellular immune response during persistent cytomegalovirus (CMV) infection is well assessable, the individual contribution of CD4 and CD8 T cell responses during primary infection has not been described. A novel whole-blood assay, which relies on the flow-cytometric detection of antigen-induced cytokine expression, was used to characterize CMV-specific CD4 and CD8 T cell responses during primary infection of CMV seronegative recipients of a renal allograft from a CMV seropositive donor. These T cell responses were compared with long-term CMV-positive patients with known history of transplantation-related seroconversion. Results were further correlated to CMV load and serum IgG and IgM. The long-term seroconverted patients consistently showed a dominant CMV-specific CD4 T cell response (median frequencies: CD4, 1.12% [range, 0.35 to 8.10%] versus CD8 0.13% [range, <0.05 to 0.55%]). In contrast, during primary infection, the cellular immune response is strongly dominated by CMV-specific CD8 T cells (median peak frequencies: CD4, 1.24% [range, 0.21 to 1.60%] versus CD8, 2.47% [range, 1.34 to 6.67%]). Upon receipt of ganciclovir, viral load as well as CMV-specific CD8 responses decreased. The frequency of the respective CD4 T cells fluctuated during decrease of CMV load and became dominant over CMV-specific CD8 T cell responses. These results are consistent with the view of an effective direct antiviral activity of CD8 T cells, which is most critical during periods of high viremia. Later on during persistent infection, CD4 T cells dominate the immune response to support the state of antiviral immunity. 相似文献
63.
Deferrari G Ravera M Deferrari L Vettoretti S Ratto E Parodi D 《Journal of the American Society of Nephrology : JASN》2002,13(Z3):S224-S229
Aggressive treatment of hypertension is effective in reducing both microvascular and macrovascular complications in type 2 diabetes, and target BP less than 130/85 or 130/80 mmHg are now recommended. Inhibition of renin angiotensin aldosterone system (RAAS) plays an essential role in the treatment of hypertension and diabetes-related complications. Studies focusing on renal end-points suggest that angiotensin-converting enzyme inhibitors (ACE-I) are more effective than other traditional agents in reducing the onset of clinical proteinuria in both type 1 and type 2 diabetic patients with incipient nephropathy, mainly in normotensive ones (secondary prevention). However, several small trials in type 2 diabetic patients with overt nephropathy (tertiary prevention) failed to demonstrate a specific renoprotective role for ACE-I, at variance with type 1 diabetes. Three recent large trials address the question of whether angiotensin II receptor blockers (ARB) prevent the development of clinical proteinuria or delay the progression of nephropathy in type 2 diabetes. The IRMA study showed that irbesartan is more effective than conventional therapy in preventing the development of clinical proteinuria and in favoring the regression to normoalbuminuria for comparable BP control in patients with incipient nephropathy. The IDNT and RENAAL trials showed that ARB are more effective than traditional antihypertensive therapies in reducing progression toward end-stage renal failure (ESRF) in type 2 diabetic patients with overt nephropathy independently of changes in BP. Moreover, a reduction in hospitalizations for heart failure was demonstrated for ARB-treated patients compared with placebo. Furthermore, the LIFE study showed that losartan is more effective than conventional therapy in reducing cardiovascular morbidity and mortality in a cohort of diabetic patients with hypertension and left ventricular hypertrophy. In conclusion, ARB seem to be effective in both preventing renal damage and reducing progression toward ESRF in type 2 diabetic patients. Thus, the guidelines for the prevention and treatment of diabetic nephropathy are now changed. In type 1 diabetes ACE-I are the first-choice drug; in type 2 diabetes, ARB are considered first-choice drugs in secondary prevention as well as ACE-I and have been now elected the unique first-choice drug in tertiary prevention of ESRF. Finally, ARB should be considered as the first-choice drug in cardiovascular prevention too, as well as ACE-I. 相似文献
64.
Haese A de la Taille A van Poppel H Marberger M Stenzl A Mulders PF Huland H Abbou CC Remzi M Tinzl M Feyerabend S Stillebroer AB van Gils MP Schalken JA 《European urology》2008,54(5):1081-1088
Background
The Prostate CAncer gene 3 (PCA3) assay has shown promise as an aid in prostate cancer (pCA) diagnosis in identifying men with a high probability of a positive (repeat) biopsy.Objective
This study evaluated the clinical utility of the PROGENSA PCA3 assay.Design, setting, and participants
This European prospective, multicentre study enrolled men with one or two negative biopsies scheduled for repeat biopsy.Measurements
After digital rectal examination (DRE), first-catch urine was collected to measure PCA3 mRNA concentration and to calculate the PCA3 score. The PCA3 score was compared to biopsy outcome. The diagnostic accuracy of the PCA3 assay was compared to percent of free prostate-specific antigen (%fPSA).Results and limitations
In 463 men, the positive repeat biopsy rate was 28%. The higher the PCA3 score, the greater the probability of a positive repeat biopsy. The PCA3 score (cut-off of 35) had a greater diagnostic accuracy than %fPSA (cut-off of 25%). The PCA3 score was independent of the number of previous biopsies, age, prostate volume, and total prostate-specific antigen (PSA) level. Moreover, the PCA3 score was significantly higher in men with high-grade prostate intraepithelial neoplasia (HGPIN) versus those without HGPIN, clinical stage T2 versus T1, Gleason score ≥7 versus <7, and “significant” versus “indolent” (clinical stage T1c, PSA density [PSAD] <0.15 ng/ml, Gleason score in biopsy ≤6, and percent positive cores ≤33%) pCA.Conclusions
The probability of a positive repeat biopsy increases with rising PCA3 scores. The PCA3 score was superior to %fPSA for predicting repeat prostate biopsy outcome and may be indicative of clinical stage and significance of pCa. 相似文献65.
Evzen Machytka Ram Chuttani Martina Bojkova Tomas Kupka Marek Buzga Kathryn Stecco Samuel Levy Shantanu Gaur 《Obesity surgery》2016,26(3):512-516
Background
Endoscopic gastric balloons have been used effectively as weight loss devices for decades, but the requirement for endoscopy and sedation poses several limitations. The goal of this pilot study was to evaluate the safety and performance of a prototype version of Elipse?, a procedureless gastric balloon.Methods
Eight patients (mean BMI?=?31.0 kg/m2) participated in this study. Each patient swallowed one Elipse? balloon intended to remain in the stomach for 6 weeks, self-empty, and then pass. Each balloon was filled with 450 mL of filling fluid. Patients returned every 2 weeks for abdominal ultrasound. No specific diet or exercise plan was prescribed.Results
All eight patients successfully swallowed the device. The most common adverse events were nausea and vomiting. There were no serious adverse events, and all balloons were excreted safely. Despite not being prescribed a diet or exercise plan, all eight patients lost weight. In 6/8 patients, the balloon remained full through 6 weeks, self-emptied, and passed. In one patient, the balloon appeared partially collapsed on ultrasound after 11 days and was endoscopically punctured. One asymptomatic patient elected to have the balloon endoscopically punctured after 19 days. Both balloons passed in the stool after 4 days. In both cases, endoscopic examination of the upper GI tract showed no abnormalities.Conclusions
This pilot study demonstrates the safety and performance of Elipse?, a procedureless gastric balloon for weight loss. Future studies will test a commercial design filled to 550 mL intended to last in the stomach for at least 12 weeks.66.
Christian Rizzetto Giovanni Zaninotto Mario Costantini Raffaele Bottin Elena Finotti Lisa Zanatta Emanuela Guirroli Martina Ceolin Loredana Nicoletti Alberto Ruol Ermanno Ancona 《Journal of gastrointestinal surgery》2008,12(12):2057-2065
Background Zenker’s diverticula (ZD) can be treated by transoral diverticulostomy or open surgery (upper esophageal sphincter myotomy
and diverticulectomy or diverticulopexy). The aim of this study was to compare the effectiveness of a minimally invasive (group
A) versus a traditional open surgical approach (group B) in the treatment of ZD.
Material and Methods Between 1993 and September 2007, 128 ZD patients underwent transoral diverticulostomy (n = 51) or cricopharyngeal myotomy and diverticulectomy or diverticulopexy (n = 77). All patients were evaluated for symptoms using a detailed questionnaire. Manometry recorded upper esophageal sphincter
(UES) pressure, relaxations, and intrabolus pharyngeal pressure. The size of the pouch was measured on the barium swallow.
The choice of treatment was based on the size of the diverticulum and the patients’ preference. Long-term follow-up data were
available for 121/128 (94.5%) patients with a median follow-up of 40 months (interquartile range, 17–83).
Results Mortality was nil. Three patients in group A (5.8%) and ten in group B (13%) had postoperative complications (p = n.s.). Hospital stays were markedly shorter for patients after diverticulostomy (p < 0.01). Postoperative manometry showed a reduction in UES pressure, improved UES relaxation, and lower intrabolus pressure
in both groups (p < 0.05). Four patients in the open surgery group (5.2%) complained of severe dysphagia after surgery (three of them required
endoscopic dilations). In the transoral diverticulostomy group, 11 patients (21.5%) required additional septal reduction (n = 8) or a surgical myotomy (n = 3) for persistent symptoms (p < 0.01); nine of these 11 patients had a ZD ≤ 3 cm in size. After primary and complementary treatments, symptoms disappeared
or improved significantly at long-term follow-up in 93.5% of patients in group A and 96% of those in group B.
Conclusion Diverticulostomy is safe, quick, and effective for most patients with medium-sized ZD, but open surgery offers better long-term
results as a primary treatment and should be recommended for younger, healthy patients, especially those with small diverticula.
Small ZD may represent a formal contraindication to the transoral approach because an excessively short septum prevents a
complete division of the sphincter fibers. 相似文献
67.
Urban Sester Barbara C. Gärtner Heinrike Wilkens Bernhard Schwaab Rolf Wössner Ingrid Kindermann Matthias Girndt reas Meyerhans Nikolaus Mueller-Lantzsch Hans-Joachim Schäfers Gerhard W. Sybrecht Hans Köhler Martina Sester 《American journal of transplantation》2005,5(6):1483-1489
Patients after kidney, heart and lung transplantation differ in their immunosuppressive drug regimens and in susceptibility to infectious complications with cytomegalovirus (CMV). In this study, CMV-specific T-cell responses were characterized in long-term transplant recipients and associated with the frequency of infectious complications. CMV-reactive CD4 T cells from 50 healthy controls, 68 renal, 14 heart and 24 lung transplant recipients were flow cytometrically quantified by the induction of cytokines after specific stimulation. Moreover, the immunosuppressive effect of calcineurin inhibitors on specific T-cell reactivity was quantified in vitro and compared with responses in vivo. Median CMV-specific T-cell frequencies in long-term renal (1.48%; range 0.06-17.26%) and heart transplant recipients (0.90%; 0.13-12.49%) did not differ from controls (1.82%; 0.26-21.00%). In contrast, CMV-specific T-cell levels were significantly lower in lung transplant recipients (0.50%; <0.05-4.98%) and showed a significant correlation with the frequency of infectious episodes (r =-0.57, p = 0.005). The differences within the groups were associated with increasing dosages of immunosuppressive drugs, as exemplified for calcineurin inhibitors that dose dependently reduced specific T-cell reactivity in vitro. In conclusion, monitoring CMV-specific CD4 T cells may serve as a measure for long-term disease susceptibility and may contribute to an improved management of CMV complications after lung transplantation. 相似文献
68.
Berger AP Deibl M Leonhartsberger N Bektic J Horninger W Fritsche G Steiner H Pelzer AE Bartsch G Frauscher F 《BJU international》2005,96(7):1073-1078
OBJECTIVE: To assess benign prostatic hyperplasia (BPH) and erectile dysfunction (ED), both considered to be associated with urogenital ageing, in ageing men in a cross-sectional population study, comparing them with healthy controls by using symptom scores and contrast-enhanced colour Doppler ultrasonography (CDUS). PATIENTS, SUBJECTS AND METHODS: Transrectal CDUS and quantitative measurement of colour pixel intensity (CPI) are excellent minimally invasive techniques for assessing normal and pathological blood flow. CDUS was performed using the microbubble-based ultrasound enhancer for evaluating prostate, bladder neck and corpus cavernosum vascularity in young healthy men, men with BPH, and men with severe vascular damage (diabetes mellitus type 2). Resistive index measurements and computer-assisted quantification of CPI were used to objectively evaluate perfusion. The International Prostate Symptom Score (IPSS) and the International Index of Erectile Function (IIEF) were applied to quantify the symptoms. RESULTS: In patients with BPH, perfusion of the transition zone (TZ) of the prostate was significantly lower and the resistive index of the TZ significantly higher (both P < 0.001) than in healthy controls. The perfusion patterns of men with BPH and those who also had severe vascular damage (diabetes mellitus type 2) showed that vascularity in the latter group was lower in the prostatic TZ and the corpora cavernosa. In patients with BPH the IPSS, quality-of-life and IIEF scores were significantly worse than in the control group. Men with concomitant atherosclerosis had even worse symptom scores. CONCLUSION: These results strongly support the hypothesis that age-related impairment of blood supply to the lower urinary tract is important in the development of BPH and ED. Vascular damage may cause chronic ischaemia and thus be a contributing factor in the pathogenesis of BPH and ED. 相似文献
69.
Zangrillo A Crescenzi G Landoni G Benussi S Crivellari M Pappalardo F Dorigo E Pappone C Alfieri O 《Anesthesia and analgesia》2005,101(1):24-9, table of contents
All patients undergoing heart surgery experience a certain amount of nonspecific myocardial injury documented by the release of cardiac biomarkers and associated with poor outcome. We investigated the role of unipolar radiofrequency ablation of atrial fibrillation on the release of cardiac biomarkers in 71 patients undergoing mitral valve surgery and concomitant left atrial ablation case-matched with 71 patients undergoing isolated mitral surgery. The study was powered to detect a 3 ng/mL difference. There was no difference between the 2 groups in terms of cardiac troponin I (10 +/- 5.3 versus 12 + 10.4 ng/mL; P = 0.7) or creatine kinase-MB (50 +/- 21.8 versus 57 +/- 62.0 ng/mL; P = 0.5) release. Postoperative peak cardiac troponin I levels had univariate associations with the duration of cardiopulmonary bypass (P = 0.002) and aortic cross-clamping (P = 0.001) and with the surgical technique (15 +/- 12 ng/mL for mitral valve replacement versus 9 +/- 4.8 for mitral valve repair; P = 0.0007) at univariate analysis. Mitral valve replacement was the only independent predictor of postoperative peak release of cardiac troponin I identified with multivariate analysis (P = 0.005). Radiofrequency ablation of atrial fibrillation does not significantly increase cardiac biomarker release compared with isolated mitral surgery; mitral valve repair is associated with less release of cardiac biomarkers compared with mitral valve replacement. 相似文献
70.
Subsequent displacement of initially nondisplaced and minimally displaced fractures of the lateral humeral condyle in children 总被引:1,自引:0,他引:1
BACKGROUND: Although conservative treatment is a well-established method for treating nondisplaced and minimally displaced (< or =2 mm) fractures of the lateral humeral condyle in children, there is still great uncertainty concerning the rate and time course of subsequent displacement. Therefore, the appropriate frequency of radiographic follow-up remains unclear. The aim of the study was to determine the rate of subsequent displacement after conservative treatment of nondisplaced and minimally displaced fractures of the lateral humeral condyle in children. METHODS: A retrospective analysis of 51 consecutive patients with nondisplaced and minimally displaced fractures of the lateral humeral condyle was performed. RESULTS: Five fractures (9.8%) displaced within 5 days while immobilized and were safely detected by a follow-up radiograph within 1 week after trauma. Additional follow-up radiographs between the first and third weeks did not show relevant alterations in the fracture gap. Mean time of cast immobilization was 22 days, with a range of 17 to 34 days. No pseudarthrosis occurred. CONCLUSION: Fractures with less than or equal to 2 mm of displacement can probably be primarily treated safely by cast immobilization. Anteroposterior and lateral radiographs out of plaster between the fourth and sixth days are necessary to diagnose subsequent displacement of unstable fractures, whereas further "late" displacement did not occur. 相似文献