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   3291篇
  免费   149篇
  国内免费   30篇
耳鼻咽喉   48篇
儿科学   41篇
妇产科学   96篇
基础医学   342篇
口腔科学   110篇
临床医学   202篇
内科学   693篇
皮肤病学   12篇
神经病学   328篇
特种医学   143篇
外科学   661篇
综合类   12篇
一般理论   1篇
预防医学   297篇
眼科学   30篇
药学   204篇
中国医学   2篇
肿瘤学   248篇
  2024年   3篇
  2023年   18篇
  2022年   69篇
  2021年   102篇
  2020年   51篇
  2019年   73篇
  2018年   81篇
  2017年   68篇
  2016年   111篇
  2015年   105篇
  2014年   132篇
  2013年   195篇
  2012年   296篇
  2011年   287篇
  2010年   151篇
  2009年   151篇
  2008年   251篇
  2007年   206篇
  2006年   211篇
  2005年   193篇
  2004年   183篇
  2003年   133篇
  2002年   138篇
  2001年   14篇
  2000年   19篇
  1999年   16篇
  1998年   14篇
  1997年   16篇
  1996年   18篇
  1995年   26篇
  1994年   16篇
  1993年   13篇
  1992年   11篇
  1991年   13篇
  1990年   21篇
  1989年   12篇
  1988年   9篇
  1987年   8篇
  1986年   6篇
  1985年   6篇
  1984年   2篇
  1982年   3篇
  1980年   2篇
  1977年   2篇
  1957年   2篇
  1955年   2篇
  1954年   2篇
  1951年   1篇
  1942年   1篇
  1940年   1篇
排序方式: 共有3470条查询结果,搜索用时 15 毫秒
21.
INTRODUCTION: Highly active antiretroviral therapy (HAART) has been able to improve the immune system function and survival of HIV patients with a consequent increase in the number of HIV patients affected by end-stage liver disease (ESLD). Between June 2003 and October 2006, 10 HIV-positive patients underwent liver transplantations in our center. METHODS: All patients were treated with HAART before transplantation; treatment was interrupted on transplantation day and was restarted once the patients' conditions stabilized. Five patients were hepatitis C virus (HCV)-positive, 3 were hepatitis B virus (HBV)-positive, and 2 were HBV-HCV coinfected. HIV viral load before transplantation was <50 copies/mL in all cases. CD4+ cell count before transplantation ranged between 144 and 530 c/microL. Immunosuppression was based on Cyclosporine (CyA) and steroid weaning for 8 patients, and on Tacrolimus and steroid weaning for 2 patients. RESULTS: Five patients were cytomegalovirus (CMV)-positive pp65 antigenemia posttransplantation, and 1 patient was EBV-positive; 2 patients had a coinfection with HHV6. Four patients suffered from a cholestatic HCV recurrent hepatitis treated with antiviral therapy (peginterferon and Ribavirin). Three patients died after transplantation. DISCUSSION: The outcome of liver transplantation in HIV patients was influenced by infections (HCV, CMV, and EBV) and Kaposi's Sarcoma. HCV recurrence was more aggressive, showing a faster progression in this patient population. Drug interaction between HAART and immunosuppressants occurs; longer follow-up and better experience may improve the management of these drug interactions.  相似文献   
22.
Alendronate improves screw fixation in osteoporotic bone   总被引:3,自引:0,他引:3  
BACKGROUND: Animal studies have demonstrated the efficacy of the use of bisphosphonates to enhance screw fixation in bone. In this prospective, randomized study of pertrochanteric fractures treated with external fixation, we tested whether systemic administration of bisphosphonates would improve the fixation of hydroxyapatite-coated screws implanted in osteoporotic bone. METHODS: Sixteen consecutive patients with a pertrochanteric fracture were selected. Inclusion criteria were female gender, an age of at least sixty-five years, and a bone mineral density T-score of less than -2.5 standard deviations. Exclusion criteria included bisphosphonate treatment during the two-year period prior to the fracture. Fractures were fixed with a pertrochanteric fixator and four hydroxyapatite-coated pins. Two pins were implanted in the femoral head (pin positions 1 and 2), and two were placed in the femoral diaphysis (pin positions 3 and 4). The patients were randomized either to therapy with alendronate for a three-month postoperative period (Group A) or to no therapy (Group B). The Group-A patients received an oral dose of 70 mg of alendronate per week. The fixators were removed after three months. RESULTS: All of the fractures healed, and no loss of reduction, nonunion, or delayed union was observed. The combined mean extraction torque (and standard deviation) of the pins implanted at positions 1 and 2 (cancellous bone) was 2558 +/- 1103 N/mm in Group A and 1171 +/- 480 N/mm in Group B (p < 0.0005). The combined mean extraction torque of the pins implanted at positions 3 and 4 (cortical bone) was 4327 +/- 1720 N/mm in Group A and 4075 +/- 1022 N/mm in Group B. CONCLUSIONS: These data show that weekly systemic administration of alendronate improves pin fixation in cancellous bone in elderly female patients with osteoporosis. We observed a twofold increase in extraction torque with the pins implanted in cancellous bone. These results support the use of alendronate in the treatment of osteoporotic pertrochanteric fractures to improve screw fixation in the femoral head.  相似文献   
23.
Background contextAlthough the incidence of pyogenic spinal infections is increasing, the ideal treatment of spondylodiscitis is still a controversially discussed issue. Furthermore, the proportion of multiresistant bacteria in spondylodiscitis is increasing, and treatment recommendations or reported results are missing for this especially difficult subset of patients.PurposeThe aim of this study is to evaluate the surgical outcome and the postoperative antibacterial treatment regime.Study designRetrospective case series.Patient samplePatients treated for a spondylodiscitis from multiresistant bacteria at our department between 2006 and 2011.MethodsData were gathered through review of patients' case notes, relevant imaging, and electronic records. Magnetic resonance imaging of the whole spine including gadolinium (Gd)-enhanced T1 sequences and computed tomography scans of the affected regions were obtained in all cases.Outcome measuresC-reactive protein (CRP) and complete blood cell count were analyzed in all cases using routine laboratory techniques. Neurologic deficits were classified according to the American Spinal Injury Association (ASIA) impairment scale.ResultsTwenty-five patients were identified (15 gram-positive and 10 gram-negative drug-multiresistant bacteria). The mean age at presentation was 66 years, and 14 patients were male (56%). All patients presented with pain, and a neurologic deficit was present in 11 (44%) cases. An epidural abscess was found in 11 (44%) cases. At admission, CRP was elevated in all cases with a mean of 13±9.2 mg/dL. The main source of infection was previous spine surgery (36%). All patients in this series underwent surgical debridement of the infection and instrumentation of the spine. Postoperative intravenous antibiotics were administered for 19±8.6 days followed by 3±0.3 months of oral antibiotic therapy. Eradication of the infection was achieved ultimately in all surviving patients. Out of 11 patients with neurologic deficits, 4 had a full recovery, 4 improved incompletely, and 3 remained unchanged after surgery.ConclusionsStaged surgical immobilization and instrumentation and optimal debridement at the interdiscal space and spinal canal is a reliable approach to achieve complete healing of spinal infection with multiresistant bacteria. A period of intravenous antibiotic therapy of 2 to 3 weeks followed by a 3-month oral antibiotic therapy seems appropriate for most cases.  相似文献   
24.

Background Context

The concept of dynamic stabilization (DS) of the lumbar spine for treatment of degenerative instability has been introduced almost two decades ago. Dynamic stabilization follows the principle of controlling movement in the coronal plane by providing load transfer of the spinal segment without fusion and, at the same time, reducing side effects such as adjacent segment disease (ASD). So far, only little is known about revision rates after DS due to ASD and screw loosening (SL).

Purpose

The present study aimed to evaluate the longitudinal revision rates following dynamic pedicle screw stabilization in the lumbar spine and to determine specific risk factors predictive for ASD, SL, and overall reoperation in a large cohort with considerable follow-up.

Design

We carried out a post hoc analysis of a prospectively collected database in a level I spine center.

Patients Example

The patient sample comprised 283 (151 female/132 male) consecutive patients suffering from painful degenerative lumbar segmental instability with or without spinal stenosis who underwent DS of the lumbar spine (Ulrich Cosmic, Ulrich Medical, Ulm, Germany) between January 2008 and December 2011.

Outcome Measures

Longitudinal reoperation rate and risk factors predictive for revision surgery were evaluated.

Methods

We analyzed the longitudinal reoperation rate due to ASD and SL and overall reoperation. Risk factors such as age, gender, body mass index, lumbar lordosis (LL), number of segments, and number of previous surgeries were taken into account. Regular and mixed model logistic regressions were performed to determine risk factors for revision surgery on a patient and on a screw level.

Results

The mean age was 65.7±10.2 years (range 31–88). One hundred thirty-two patients were stabilized in 1 segment, 134 in 2 segments, 15 in 3 segments, and 2 patients in 4 segments. Reoperation rate for ASD and SL after 1 year was 7.4 %, after 2 years was 15.0%, and after a mean follow-up of 51.4±15 months was 22.6%. Reasons for revision were SL in 19 cases (6.6%), ASD in 39 cases (13.7%), SL and ASD in 6 cases, hematoma in 2 cases (0.7%), cerebrospinal fluid fistulae in 3 cases (1.1%), infection in 6 cases (2.1%), and implant failure in 1 case (0.4%). The patients' age, the number of stabilized segments, and the number of previous surgeries and postoperative LL had a significant influence on the probability for revision surgery.

Conclusions

Reoperation rates after DS of the lumbar spine are comparable with rigid fixations. The younger the patient and the more segments are involved, the lower the LL and the more previous surgeries were found, the higher was the risk of revision. Risk of revision was almost twice as high in men compared with women. We therefore conclude that for clear clinical indication and careful evaluation of preoperative imaging data, DS using the Cosmic system seems to be a possible option. The presented data will help to further tailor indication and patient selection.  相似文献   
25.

Purpose

Several bony and soft tissue procedures have been described for the treatment of hallux valgus, and currently mini-invasive surgical techniques are preferred in order to reduce surgical trauma, complications, time of surgery and to allow an earlier recovery. The aim of this study is to analyse a series of 1,000 consecutive cases of hallux valgus, surgically treated by the minimally invasive SERI technique, reporting results at mid-term follow-up.

Methods

We prospectively studied 641 patients (1,000 feet) with symptomatic hallux valgus surgically treated by SERI osteotomy. Inclusion criteria were: age between 20 and 65 years, reducible mild or moderate hallux valgus, HVA ≤ 40°, IMA ≤ 20°, and arthritis of the first metatarsophalangeal joint up to grade 2 according to the Regnauld classification.

Results

The American Orthopaedic Foot and Ankle Society (AOFAS) score rose from 46.8 ± 16.7 preoperatively to 89 ± 10.3 at last follow-up. Radiographic control at follow-up showed a complete healing of the osteotomy and remodelling of the metatarsal bone. Low rate of complication has been reported.

Conclusions

This study demonstrated that the SERI technique is effective in treating mild to moderate hallux valgus in terms of relief from symptoms and functional improvement. This technique allowed correction of the main parameters of the deformity, with durable clinical and radiographic results at a mid-term follow-up.

Electronic supplementary material

The online version of this article (doi:10.1007/s00264-013-1980-8) contains supplementary material, which is available to authorized users.  相似文献   
26.

Background

The aims of this study were to evaluate the associated injuries occurring with acute perilunate instability and to assess the clinical and radiographic outcomes of perilunate dislocations and fracture–dislocations treated with a combined dorsal and volar approach.

Methods

A total of 45 patients (46 wrist injuries) with perilunate dislocations and fracture–dislocations were prospectively evaluated. The size of the mid-carpal ligament tear, the location of the scapholunate ligament tear, and the presence of osteochondral fragments and of the dorsal radiocarpal ligament avulsions were recorded at injury. Final clinical and radiographic outcomes were evaluated in 25 cases (25 wrists) with a minimum of 6 months of follow-up.

Results

Intraoperative examination of the 46 cases with operative treatment showed the volar carpal ligament tear to be present 100 % of the time and to be an average length of 3.4 cm. Complete avulsion of the dorsal extrinsic radiocarpal ligaments was found in 65.2 % of cases. The scapholunate ligament was torn in 35 cases. Osteochondral fragments were found either volarly or dorsally in 74 % of the cases. The average flexion–extension arc was 82°, forearm rotation was 155°, and grip strength averaged 59 % of the uninjured hand. The average final scapholunate angle was 55° and the scapholunate gap was 2.2 mm.

Conclusion

Treatment of perilunate fracture–dislocations with a combined volar and dorsal approach results in reasonable and functional clinical results. The incidence of associated injuries with these carpal dislocations is high. Although the perilunate fracture–dislocations have a slightly better radiologic alignment than the dislocation group, the clinical outcome is similar.  相似文献   
27.
Early glottic carcinoma: Treatment according patient's preference?   总被引:1,自引:0,他引:1  
BACKGROUND: To analyze the results in early (stage I and II) glottic carcinoma of a single institution with a patient-oriented concept. METHODS: After diagnostic workup and multidisciplinary counseling, either radiotherapy or CO(2) laser surgery was chosen with respect to the patient's preference. RESULTS: Sixty-five patients underwent laser surgery and 75 had radiotherapy. For T1 tumors, the 5-year overall survival, disease-specific survival, and initial local control rate after laser surgery and radiotherapy were comparable (OS, 85% vs 88%; DSS, 96% vs 93%; LCR, 86% vs 85%). In contrast, initial local control for T2 tumors was significantly more favorable after surgery (OS, 83% vs 78%; DSS, 83% vs 88%; LCR, 89% vs 67%). Larynx preservation was significantly higher after surgery in T1 tumors (96% vs 82%) and in T2 tumors (89% vs 77%). CONCLUSIONS: Selection of the treatment modality according to patient's preference results in a comparable control of disease for T1 tumors. The initial local control for T2 tumors is significantly better after surgery. In both stages laser surgery warrants a better larynx preservation rate.  相似文献   
28.
29.

Background

To compare selected outcomes (30-day reoperation and total length of hospital stay) following emergency appendectomy between populations from New York State and England.

Methods

This retrospective cohort study used demographic and in-hospital outcome data from Hospital Episode Statistics (HES) and the New York Statewide Planning and Research Cooperative System (SPARCS) administrative databases for all patients aged 18+ years undergoing appendectomy between April 2009 and March 2014. Univariate and adjusted multivariable logistic regression were used to test significant factors. A one-to-one propensity score matched dataset was created to compare odd ratios (OR) of reoperations between the two populations.

Results

A total of 188,418 patient records, 121,428 (64.4%) from England and 66,990 (35.6%) from NYS, were extracted. Appendectomy was completed laparoscopically in 77.7% of patients in New York State compared to 53.6% in England (P < 0.001). The median lengths of hospital stay for patients undergoing appendectomy were 3 (interquartile range, IQR 2–4) days versus 2 (IQR 1–3) days (P < 0.001) in England and New York State, respectively. All 30-day reoperation rates were higher in England compared to New York State (1.2 vs. 0.6%, P < 0.001), representing nearly a twofold higher risk of 30-day reoperation (OR 1.88, 95% CI 1.64–2.14, P < 0.001). As the proportion of appendectomy completed laparoscopically increased, there was a reduction in the reoperation rate in England (correlation coefficient ?0.170, P = 0.036).

Conclusions

Reoperations and total length of hospital stay is significantly higher following appendectomy in England compared to New York State. Increasing the numbers of appendectomy completed laparoscopically may decrease length of stay and reoperations.
  相似文献   
30.
Israel has faced ongoing terrorism since the beginning of the Al Aqsa Intifada in September 2000. The authors examined risk and resiliency factors associated with posttraumatic stress disorder (PTSD) among 1,117 Jews and 394 Arab adult citizens of Israel during August and September 2004 through telephone interviews. Probable PTSD was found among 6.6% of Jews and 18.0% of Arabs. Predictors of probable PTSD in a multivariate model for Jews were refusal to report income, being traditionally religious, economic and psychosocial resource loss, greater traumatic growth, and lower social support. For Arabs, predictors were low education and economic resource loss among those exposed to terrorism. Findings for only those directly exposed to terrorism were similar to those for the overall national sample.  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