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   6842篇
  免费   216篇
  国内免费   40篇
耳鼻咽喉   241篇
儿科学   136篇
妇产科学   294篇
基础医学   833篇
口腔科学   49篇
临床医学   444篇
内科学   1840篇
皮肤病学   128篇
神经病学   605篇
特种医学   115篇
外科学   739篇
综合类   59篇
一般理论   10篇
预防医学   332篇
眼科学   199篇
药学   675篇
中国医学   4篇
肿瘤学   395篇
  2024年   6篇
  2023年   27篇
  2022年   176篇
  2021年   260篇
  2020年   72篇
  2019年   135篇
  2018年   151篇
  2017年   113篇
  2016年   124篇
  2015年   165篇
  2014年   211篇
  2013年   321篇
  2012年   446篇
  2011年   566篇
  2010年   277篇
  2009年   186篇
  2008年   448篇
  2007年   540篇
  2006年   495篇
  2005年   533篇
  2004年   520篇
  2003年   453篇
  2002年   396篇
  2001年   19篇
  2000年   23篇
  1999年   28篇
  1998年   29篇
  1997年   18篇
  1996年   24篇
  1995年   33篇
  1994年   21篇
  1993年   18篇
  1992年   14篇
  1991年   21篇
  1990年   9篇
  1989年   12篇
  1988年   7篇
  1987年   16篇
  1986年   9篇
  1985年   14篇
  1984年   22篇
  1983年   16篇
  1982年   22篇
  1981年   12篇
  1980年   10篇
  1979年   15篇
  1978年   12篇
  1977年   7篇
  1974年   7篇
  1973年   6篇
排序方式: 共有7098条查询结果,搜索用时 15 毫秒
51.
Spinal stenosis is most common in elderly patients and is defined as narrowing of the spinal canal and (or) lateral nerve root canals. The underlying processes leading to spinal stenosis are degenerative changes in facet joints and intervertebral discs and buckling of the ligamentum flavum. Spinal stenosis can occur in both the cervical and the lumbar spine. Cervical stenosis mayleat to the development of radiculopathy and (or) myelopathy. The majority of patients respond to nonoperative management. Degenerative lumbar spinal stenosis presents with back and (or) leg paints of valuing severity and duration. Nonoperative treatment associated with lumbar spinal stenosis consists of restituting and avoiding those maneuvers that reproduce pain. Surgical treatment of cervical and lumbar stenosis includes decompressive lamine ctomy, often fusion and instrumentation.  相似文献   
52.
The most difficult in proper qualification of the patient with chronic low back pain for an operative treatment is determination of the chance for satisfactory result. The diversity of the pain eliciting structure in the spine influence the decision. In the paper we have analyzed patient where the operative treatment was considered. In 149 patients divided in two groups the (not being previously operated on the spine--group 1 and after spine surgery--group 2) the neuroradiological procedures were performed (sacral epidural block, facet injections, root injections of the lumbar spine). As the result of this procedure in 108 patients (72%) surgical intervention at that time was abandoned. Conclusion. In our opinion the neuroradiological diagnostic procedures should be mandatory in back pain management of the patient were operative treatment is considered. We present the modified algorithm in diagnostic procedure preceding the operation.  相似文献   
53.
A series of 54 patients is presented in which full-thickness soft-tissue defects on 57 digits were reconstructed using homodigital V-Y flaps. This is a modification of the Moberg procedure, which was designed for coverage of injuries of distal thumb. The V-Y flap is pedicled on two digital neurovascular bundles, possible advancement is up to 2 cm, and V-shaped base of the flap allows direct closure of the proximal defect, without skin grafting. This technique was used for the reconstruction both volar and dorsal tissue defects of the fingers. All flaps healed within 2-4 weeks. 14 patients (15 fingers) were evaluated after they recovered. In all affected fingers active range of motion was satisfactory, only with slight defect of extension in 2 cases. However, sensation of the light touch was decreased in 10 fingers, and 2PD discrimination was abnormal in 5 fingers. The versatility of V-Y technique in various clinical occasions and its low risk of complications was emphasized. This method is very useful, easy to learn even for trainees unfamiliar with microsurgery.  相似文献   
54.
The authors present the results of hip arthroplasty of 67 patients treated after failed internal fixation of the osteoporotic, trochanteric fractures of the femur, which were primary stabilised with angular plate AO in 39 patients and with dynamic hip screw (DHS) in 28 patients. In the discussed material 16 persons were male and 51 female, in the age between 51 and 83 years old. According to the Evans classification in 4 cases we diagnosed type I of fracture, in 10--type II, 31--type III and in 22--type IV. Hip arthroplasty was made from the 3rd to the 39th week after primary fixation of the fracture. In 42 patients we made total hip arthroplasty, in 14 cases Austin-Moore hemiarthroplasty, and in 11 patients bipolar arthroplasty. According to the Postel and Merle d'Aubigne classification there were obtained 29 very good, 21 good and 17 satisfactory results.  相似文献   
55.
Health related quality of life (HRQoL) of living kidney donors on average is good, but some donors experience a low HRQoL after donation. This study assessed the prevalence of reduced HRQoL and explored associations with pre‐ and post‐donation variables. 316 donors (response rate 74%) who donated a kidney between 1997 and 2009 filled in a questionnaire. HRQoL was measured using the Short‐Form 36; fatigue using the Multidimensional Fatigue Inventory; societal participation using the Utrecht Scale for Evaluation of Rehabilitation‐Participation. Donors on average had better HRQoL than the general population. However, 12% had a reduced physical (PCS) and 18% a reduced mental (MCS) HRQoL. Donors with reduced HRQoL reported greater fatigue (P < 0.01), lower societal participation (P < 0.01) and showed a trend towards statistical significance in experiencing more donor–recipient relationship changes (P = 0.07). Prior to donation, donors with reduced PCS had a higher BMI (P < 0.05) and more often smoked (P < 0.05). Donors with reduced MCS had higher expectations (P < 0.05). Reduced HRQoL is associated with higher BMI, smoking and higher expectations prior to donation. These results may be used to develop a screening instrument to select donors at high risk for reduced HRQoL.  相似文献   
56.
Background/Aims: Hypoxia-inducible factor (HIF)-1α is responsible for increased expression of genes engaged in angiogenesis. Our previous study indicated capillary rarefaction and atrophy of glycolytic fibers, mainly in locomotor muscles of uremic animals. Perhaps these changes are secondary to disturbances of HIF-1α in skeletal muscles. Methods: Expression of HIF-1α at mRNA and protein levels, as well as mRNA of vascular endothelial growth factor A (VEGF-A), vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS), in gastrocnemius muscle (MG) and longissimus thoracic muscle (ML) were measured by RT-PCR and Western blot. Rats were randomized to subtotal nephrectomy (CKD5/6), uninephrectomy (CKD1/2) or sham operation (controls). Results: For CKD5/6 versus controls, mRNA levels for HIF-1α, VEGF-A, VEGFR-1 and VEGFR-2 were significantly reduced only in MG, while eNOS was significantly decreased and iNOS was significantly increased only in ML. Western blot analysis indicated significantly increased HIF-1α protein levels in MG and ML from CKD1/2 animals versus controls, whereas in the CKD5/6 group, the level of HIF-1α protein decreased significantly in MG and increased significantly in ML versus controls and CKD1/2. Conclusion: The reduced expression of HIF-1α mRNA and protein in locomotor muscle from CKD5/6 animals may be involved in the pathogenesis of uremic myopathy. Increased expression of iNOS in the postural muscles may act as a protective factor through HIF-1α stabilization.  相似文献   
57.
Laparoscopy as a treatment for intraperitoneal bladder injury   总被引:1,自引:0,他引:1  
OBJECTIVE: To present our experience of laparoscopic repair of iatrogenic bladder perforation. MATERIAL AND METHODS: Four cases of intraperitoneal bladder perforation occurred as a complication of transurethral tumor resection. The mean age of the patients was 66 years. Details of the surgical technique are presented. RESULTS: The operation time ranged from 25 to 60 min. There were no intra- or postoperative complications. The average duration of hospitalization was 4 days and the recovery time was < or =12 days. CONCLUSION: Laparoscopic repair of iatrogenic bladder perforation is a valuable alternative to open surgery.  相似文献   
58.
The purpose of this phase III clinical trial was to compare two different extracellular contrast agents, 1.0 M gadobutrol and 0.5 M gadopentate dimeglumine, for magnetic resonance imaging (MRI) in patients with known or suspected focal renal lesions. Using a multicenter, single-blind, interindividual, randomized study design, both contrast agents were compared in a total of 471 patients regarding their diagnostic accuracy, sensitivity, and specificity to correctly classify focal lesions of the kidney. To test for noninferiority the diagnostic accuracy rates for both contrast agents were compared with CT results based on a blinded reading. The average diagnostic accuracy across the three blinded readers (‘average reader’) was 83.7% for gadobutrol and 87.3% for gadopentate dimeglumine. The increase in accuracy from precontrast to combined precontrast and postcontrast MRI was 8.0% for gadobutrol and 6.9% for gadopentate dimeglumine. Sensitivity of the average reader was 85.2% for gadobutrol and 88.7% for gadopentate dimeglumine. Specificity of the average reader was 82.1% for gadobutrol and 86.1% for gadopentate dimeglumine. In conclusion, this study documents evidence for the noninferiority of a single i.v. bolus injection of 1.0 M gadobutrol compared with 0.5 M gadopentate dimeglumine in the diagnostic assessment of renal lesions with CE-MRI.
Bernd TombachEmail:
  相似文献   
59.
OBJECTIVES: To review 26 consecutive patients with sustained monomorphic ventricular tachycardia (VT) of left ventricular origin, who underwent direct VT surgery. METHODS: Economic factors precluded the use of an implantable cardioverter defibrillator (ICD) in the majority of these patients, and the indication for surgery in 81% of patients was for failed medical drug therapy and 27% of patients had frequent or incessant life-threatening VT. The principles of direct VT surgery included intraoperative mapping, extended endocardial resection, cryoablation, left ventricular aneurysm repair by left ventricular remodelling and endoaneurysmorrhaphy, as well as coronary artery bypass grafting. RESULTS: Two patients with non-ischaemic VT were significantly younger (37.7 +/- 19.4 years, P = 0.03), had lower preoperative New York Heart Association class (P = 0.03), and had better left ventricular ejection fractions of 59.5 +/- 2.1% (P = 0.001) than the 24 ischaemic patients. No operative mortality or recurrence of VT occurred in this group. Ischaemic VT patients had an operative mortality of 8.3%; risk factors were concomitant valve surgery (P = 0.02), and perioperative intra-aortic balloon pump (P = 0.02). Surgery improved the left ventricular ejection fraction from 28.4 +/- 9.8% to 43.2 +/- 8.2% (P = 0.0001). Freedom from recurrence or inducibility of VT in operative survivors was 78.8 +/- 9.6% at 10 years; risk factors were arrhythmic focus remote to the left ventricular aneurysm (P = 0.015), and simple cryoablation or endocardial resection alone and not in combination (P = 0.003). Survival was 54.1 +/- 11.6% and 43.3 +/- 13.4% at 5 and 10 years, respectively, and there were no arrhythmic or sudden cardiac deaths. Patients with immediately life-threatening VT unsuitable for ICD implantation requiring urgent or emergent VT surgery had a 10-year survival of 22.2 +/- 13.9% compared to the more elective surgical group with a rate of 73.3 +/- 13.9% (P = 0.08). CONCLUSIONS: Direct VT surgery should remain an objective for symptomatic drug refractory VT of left ventricular origin.  相似文献   
60.

Background

Tri-modality therapy (TMT) is a recognized treatment strategy for selected patients with muscle-invasive bladder cancer (MIBC).

Objective

Report long-term outcomes of patients with MIBC treated by TMT.

Design, setting, and participants

Four hundred and seventy-five patients with cT2–T4a MIBC were enrolled on protocols or treated as per protocol at the Massachusetts General Hospital between 1986 and 2013.

Intervention

Patients underwent transurethral resection of bladder tumor followed by concurrent radiation and chemotherapy. Patients with less than a complete response (CR) to chemoradiation or with an invasive recurrence were recommended to undergo salvage radical cystectomy.

Outcome measurements and statistical analysis

Disease-specific survival (DSS) and overall survival (OS) were calculated using the Kaplan-Meier method.

Results and limitations

Median follow-up for surviving patients was 7.21 yr. Five- and 10-yr DSS rates were 66% and 59%, respectively. Five- and 10-yr OS rates were 57% and 39%, respectively. The risk of salvage cystectomy at 5 yr was 29%. In multivariate analyses, T2 disease (OS hazard ratio [HR]: 0.57, 95% confidence interval [CI]: 0.44–0.75, DSS HR: 0.51, 95% CI: 0.36–0.73), CR to chemoradiation (OS HR: 0.61, 95% CI: 0.46–0.81, DSS HR: 0.49, 95% CI: 0.34–0.71), and presence of tumor-associated carcinoma in situ (OS HR: 1.56, 95% CI: 1.17–2.08, DSS HR: 1.50, 95% CI: 1.03–2.17) were significant predictors for OS and DSS. When evaluating our cohort over treatment eras, rates of CR improved from 66% to 88% and 5-yr DSS improved from 60% to 84% during the eras of 1986–1995 to 2005–2013, while the 5-yr risk of salvage radical cystectomy rate decreased from 42% to 16%.

Conclusions

These data demonstrate high rates of CR and bladder preservation in patients receiving TMT, and confirm DSS rates similar to modern cystectomy series. Contemporary results are particularly encouraging, and therefore TMT should be discussed and offered as a treatment option for selected patients.

Patient summary

Tri-modality therapy is an alternative to radical cystectomy for patients with muscle-invasive bladder cancer, and is associated with comparable long-term survival and high rates of bladder preservation.  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