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   6880篇
  免费   435篇
  国内免费   63篇
耳鼻咽喉   42篇
儿科学   156篇
妇产科学   227篇
基础医学   1047篇
口腔科学   59篇
临床医学   554篇
内科学   1774篇
皮肤病学   275篇
神经病学   591篇
特种医学   240篇
外科学   577篇
综合类   15篇
预防医学   412篇
眼科学   75篇
药学   562篇
中国医学   14篇
肿瘤学   758篇
  2023年   54篇
  2022年   55篇
  2021年   210篇
  2020年   142篇
  2019年   187篇
  2018年   180篇
  2017年   162篇
  2016年   208篇
  2015年   263篇
  2014年   289篇
  2013年   360篇
  2012年   596篇
  2011年   620篇
  2010年   299篇
  2009年   288篇
  2008年   484篇
  2007年   456篇
  2006年   472篇
  2005年   489篇
  2004年   428篇
  2003年   376篇
  2002年   303篇
  2001年   44篇
  2000年   33篇
  1999年   39篇
  1998年   49篇
  1997年   39篇
  1996年   37篇
  1995年   33篇
  1994年   27篇
  1993年   26篇
  1992年   12篇
  1991年   10篇
  1990年   14篇
  1989年   9篇
  1988年   9篇
  1987年   8篇
  1986年   4篇
  1985年   8篇
  1984年   3篇
  1983年   5篇
  1982年   3篇
  1981年   4篇
  1979年   6篇
  1978年   4篇
  1977年   3篇
  1975年   5篇
  1970年   3篇
  1969年   4篇
  1966年   3篇
排序方式: 共有7378条查询结果,搜索用时 15 毫秒
1.
An increased number of patients is at risk of Candida spp. bloodstream infection (CBSI) in modern medicine. Moreover, the rising of antifungal resistance (AR) was recently reported. All consecutive CBSI occurred in our Hospital (consisting of 1,370 beds) between 2015 and 2018, were reviewed. For each case, Candida species, AR pattern, ward involved and demographic data of patients were recorded. Overall, 304 episodes of CBSI occurred, with a median (q1:first-,q3:third quartile) of 77 (71-82) CBSI/year. Over the years, a significant increase of CBSI due to C. albicans compared to non-albicans strains was recorded in medical wards (from 65% to 71%, p=0.030), while this ratio remained stable in others. An increase of resistant strains to multiple antifungals such as C. guillermondii was noticed in recent years (from 0% to 9.8%, p=0.008). Additionally, from 2015 to 2018 an increase in fluconazole-resistance was recorded in our Hospital (from 7.4% to 17.4%, p=0.025) and a slight increase in voriconazole-resistance (from 0% to 7% in 2018, p=0.161) was observed, while resistance to echinocandin and amphotericin B remained firmly below 2%.This study suggests a rapid spread of antifungal resistance in our Hospital; therefore, an appropriate antifungal stewardship programs is urgently warranted.  相似文献   
2.
3.
Systemic inflammation is associated with reduced bone mineral density and may be influenced by pro-inflammatory diets. We undertook an observational analysis of associations between late pregnancy energy-adjusted dietary inflammatory index (E-DII) scores and offspring bone outcomes in childhood. E-DII scores (higher scores indicating pro-inflammatory diets) were derived from food frequency questionnaires in late pregnancy in two prospective mother-offspring cohorts: the Southampton Women's Survey (SWS) and the Avon Longitudinal Study of Parents and Children (ALSPAC). The mean (SD) offspring age at dual-energy X-ray absorptiometry (DXA) scanning was 9.2 (0.2) years. Linear regression was used to assess associations between E-DII and bone outcomes, adjusting for offspring sex and age at DXA and maternal age at childbirth, educational level, pre-pregnancy body mass index (BMI), parity, physical activity level, and smoking in pregnancy. Associations were synthesized using fixed-effect meta-analysis. Beta coefficients represent the association per unit E-DII increment. In fully adjusted models (total n = 5910) late pregnancy E-DII was negatively associated with offspring whole body minus head bone area (BA: β = −3.68 [95% confidence interval −6.09, −1.27] cm2/unit), bone mineral content (BMC: β = −4.16 [95% CI −6.70, −1.62] g/unit), and areal bone mineral density (aBMD: β = −0.0012 [95% CI −0.0020, −0.0004] g.cm−2/unit), but there was only a weak association with BMC adjusted for BA (β = −0.48 [95% CI −1.11, 0.15] g/unit) at 9 years. Adjustment for child height partly or, for weight, fully attenuated the associations. Higher late pregnancy E-DII scores (representing a more pro-inflammatory diet) are negatively associated with offspring bone measures, supporting the importance of maternal and childhood diet on longitudinal offspring bone health. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).  相似文献   
4.
5.
Although the rate of patients reporting satisfaction is generally high after joint replacement surgery, up to 23% after total hip replacement and 34% after total knee arthroplasty of treated subjects report discomfort or pain 1 year after surgery. Moreover, chronic or subacute inflammation is reported in some cases even a long time after surgery. Another open and debated issue in prosthetic surgery is implant survivorship, especially when related to good prosthesis bone ingrowth. Pulsed Electro Magnetic Fields(PEMFs) treatment, although initially recommended after total joint replacement to promote bone ingrowth and to reduce inflammation and pain, is not currently part of usual clinical practice. The purpose of this review was to analyze existing literature on PEMFs effects in joint replacement surgery and to report results of clinical studies and current indications. We selected all currently available prospective studies or RCT on the use of PEMFs in total joint replacement with the purpose of investigating effects of PEMFs on recovery, pain relief and patients' satisfaction following hip, knee or shoulder arthroplasty. All the studies analyzed reported no adverse effects, and good patient compliance to the treatment. The available literature shows that early control of joint inflammation process in the first days after surgery through the use of PEMFs should be considered an effective completion of the surgical procedure to improve the patient's functional recovery.  相似文献   
6.
7.
Nephroenteric fistulas can be secondary to different etiologies, the most common of which are pyelocolic fistulas. The absence of pathognomonic symptoms and the heterogeneity of presentation can sometimes result in a delay in diagnosis. We report on three cases: a pyelo-duodenal fistula secondary to kidney stones and subsequent pyonephrosis, a pyelocolic fistula due to inveterate ureteral stones with hydropyonephrosis, and a rare case of posttraumatic pyelocolic fistula. All patients were treated with radical nephrectomy and resection of the involved intestinal tract. Fistulas of the kidney with the gastrointestinal tract are complex not only for the surgical treatment, which is mandatory in the majority of cases, but also for clinical and instrumental diagnosis. Severe infection is a major concern due to the admixture of the enteric bacterial flora with the urinary tract. Nephroenteric fistulas require skilled surgical procedures, close control of the septic risk, management of patient''s overall medical condition, and balance between invasive and conservative approach.  相似文献   
8.
Intravascular large B cell lymphoma (IVLBCL) is a rare, aggressive, extranodal large B cell lymphoma characterised by growth of tumour cells within the lumen of vessels, particularly capillaries. Programmed cell death ligand 1 (PD‐L1) is a cell surface glycoprotein that interacts with programmed death 1 (PD‐1) on the T cell surface, leading to modulation of the immune response. PD‐L1 is a targetable immune check‐point molecule that is expressed on neoplastic cells in various cancers, including a subset of lymphomas. We correlated the expression of PD‐L1 with clinical and pathological findings in this rare disease. Eleven cases of IVLBCL were identified in the archives of Laboratory of Pathology at the National Cancer Institute, NIH. A panel of immunostains (CD20, CD3, CD5, PD‐L1) was performed. The cases were classified as the classic form or the variant associated with haemophagocytic syndrome (HPS) based on published 2017 WHO criteria. Three cases (27.3%) were HPS variant and eight cases (72.7%) were the classic form. Five (45.5%) of 11 cases were CD5‐positive; two of three (66%) were HPS variants and three of eight (37.5%) were classic form. Overall, four of nine evaluable cases (44.4%) were positive for PD‐L1, three of which were classic. Only one CD5‐positive case was PD‐L1‐positive, a classic variant. In summary, a subset of IVLBCL express PD‐L1. Although limited, these data suggest that PD‐L1 is expressed in both the so‐called classic form as well as the HPS variant. PD‐L1 is expressed irrespective of CD5 expression. Finally, detection of PD‐L1 expression in a subset of IVLBCL lymphoma cases may identify patients who might benefit from targeted immunotherapy.  相似文献   
9.

Background

Available models for predicting lymph node invasion (LNI) in prostate cancer (PCa) patients undergoing radical prostatectomy (RP) might not be applicable to men diagnosed via magnetic resonance imaging (MRI)-targeted biopsies.

Objective

To assess the accuracy of available tools to predict LNI and to develop a novel model for men diagnosed via MRI-targeted biopsies.

Design, setting, and participants

A total of 497 patients diagnosed via MRI-targeted biopsies and treated with RP and extended pelvic lymph node dissection (ePLND) at five institutions were retrospectively identified.

Outcome measurements and statistical analyses

Three available models predicting LNI were evaluated using the area under the receiver operating characteristic curve (AUC), calibration plots, and decision curve analyses. A nomogram predicting LNI was developed and internally validated.

Results and limitations

Overall, 62 patients (12.5%) had LNI. The median number of nodes removed was 15. The AUC for the Briganti 2012, Briganti 2017, and MSKCC nomograms was 82%, 82%, and 81%, respectively, and their calibration characteristics were suboptimal. A model including PSA, clinical stage and maximum diameter of the index lesion on multiparametric MRI (mpMRI), grade group on targeted biopsy, and the presence of clinically significant PCa on concomitant systematic biopsy had an AUC of 86% and represented the basis for a coefficient-based nomogram. This tool exhibited a higher AUC and higher net benefit compared to available models developed using standard biopsies. Using a cutoff of 7%, 244 ePLNDs (57%) would be spared and a lower number of LNIs would be missed compared to available nomograms (1.6% vs 4.6% vs 4.5% vs 4.2% for the new nomogram vs Briganti 2012 vs Briganti 2017 vs MSKCC).

Conclusions

Available models predicting LNI are characterized by suboptimal accuracy and clinical net benefit for patients diagnosed via MRI-targeted biopsies. A novel nomogram including mpMRI and MRI-targeted biopsy data should be used to identify candidates for ePLND in this setting.

Patient summary

We developed the first nomogram to predict lymph node invasion (LNI) in prostate cancer patients diagnosed via magnetic resonance imaging-targeted biopsy undergoing radical prostatectomy. Adoption of this model to identify candidates for extended pelvic lymph node dissection could avoid up to 60% of these procedures at the cost of missing only 1.6% patients with LNI.  相似文献   
10.
Melanomas and nevi displaying regression features can be difficult to differentiate. To describe reflectance confocal microscopy features in benign and malignant pigmented skin lesions characterized by regression features in dermoscopy. Observational retrospective study. Inclusion criteria were presence of dermoscopic features of regression; availability of clinical, dermoscopic and RCM imaging; definite histopathologic diagnosis. The study sample comprised 217 lesions; 108 (49.8%) melanomas and 109 were benign lesions, of which 102 (47.0%) nevi and 7 (3.2%) lichen planus‐like keratosis (lplk). Patients with melanoma were significantly older than those with benign lesions (61.9 ± 15.4 vs 46.1 ± 14.8; P < 0.001) and a higher proportion of melanomas displayed dermoscopic regression structures in more than 50% of lesion surface (n = 83/108; 76.9%; P < 0.001). On RCM examination, pagetoid cells were significantly more reported in melanoma group, than in benign lesions (86.1% vs 59.6%; P < 0.001) and were more frequently widespread distributed (65.6% vs 20.0%; P < 0.001) and both dendritic and roundish (36.6% vs 15.4%; P < 0.001) in shape. Aspecific architecture at the dermo‐epidermal junction (DEJ) was more commonly seen among melanomas than benign lesions (23.1% vs 11.9%; P = 0.002) with higher presence of dendritic and both dendritic and roundish atypical cells at the DEJ (28.7% vs 18.3% and 19.4% vs 3.7%; P < 0.001, respectively). Focal pagetoid infiltration and ringed or clod patterns were more commonly seen in benign lesion. In conclusion, the correct interpretation of regressing lesions remains a challenge, assessing carefully the extent and characteristics of architectural and cytologic atypia on RCM is an additional piece of the complex puzzle of melanoma diagnosis.  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