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   4870篇
  免费   388篇
  国内免费   20篇
耳鼻咽喉   28篇
儿科学   101篇
妇产科学   118篇
基础医学   574篇
口腔科学   78篇
临床医学   552篇
内科学   1097篇
皮肤病学   52篇
神经病学   313篇
特种医学   148篇
外国民族医学   1篇
外科学   1028篇
综合类   88篇
一般理论   2篇
预防医学   302篇
眼科学   137篇
药学   291篇
中国医学   13篇
肿瘤学   355篇
  2023年   44篇
  2022年   109篇
  2021年   195篇
  2020年   97篇
  2019年   160篇
  2018年   177篇
  2017年   150篇
  2016年   142篇
  2015年   164篇
  2014年   229篇
  2013年   251篇
  2012年   426篇
  2011年   401篇
  2010年   210篇
  2009年   177篇
  2008年   264篇
  2007年   258篇
  2006年   269篇
  2005年   255篇
  2004年   208篇
  2003年   224篇
  2002年   187篇
  2001年   66篇
  2000年   56篇
  1999年   48篇
  1998年   36篇
  1997年   23篇
  1996年   20篇
  1995年   19篇
  1994年   12篇
  1993年   12篇
  1992年   31篇
  1991年   29篇
  1990年   24篇
  1989年   22篇
  1988年   16篇
  1987年   14篇
  1986年   15篇
  1985年   13篇
  1984年   16篇
  1983年   15篇
  1982年   13篇
  1977年   11篇
  1976年   14篇
  1975年   10篇
  1974年   10篇
  1973年   13篇
  1972年   22篇
  1971年   21篇
  1970年   10篇
排序方式: 共有5278条查询结果,搜索用时 15 毫秒
41.
OBJECTIVES: To prospectively compare in a contemporary and contemporaneous series the positive surgical margin (PSM) rate between laparoscopic (LRP) and retropubic (RRP) radical prostatectomy at the same institution. METHODS: Between 1 January 2003 and 30 June 2005, 1177 consecutive men with clinically localized adenocarcinoma of the prostate underwent radical prostatectomy at the same institution: 485 laparoscopically and 692 through a retropubic approach. Partin table probability of organ-confined (OC) disease was used as an index of disease aggressiveness: The PSM rate between the two approaches was compared, with adjustment for the OC probability. RESULTS: Overall both surgical approaches had a comparable PSM rate of 11.3% after LRP and 11% after RRP. In a logistic regression analysis adjusting for OC probability, there was no statistically significant difference between LRP and RRP (odds ratio [OR]: 1.156; 95% confidence interval [%95 CI], 0.792, 1.686; p=0.5). There was a statistically significant decrease over time in the rate of PSM for LRP (OR: 0.71 per 100 patients treated; %95 CI, 0.57, 0.89; p=0.003), while that of RRP was unchanged (OR: 1.06 per 100 patients treated; %95 CI, 0.94, 1.21; p=0.3; p=0.002 for interaction between change over time and procedure). CONCLUSIONS: In our institution, laparoscopic and retropubic radical prostatectomy provide comparable PSM rates for patients with clinically localized prostate cancer. The PSM rate over the study period remained unchanged in the RRP experience, indicating a mature and well-established operative technique, while that of LRP underwent a significant decrease, demonstrating that the procedure and therefore the results continued to evolve during the study.  相似文献   
42.

Background

Recently, we identified a gene signature of intrahepatic cholangiocarcinoma (ICC) stroma and demonstrated its clinical relevance for prognosis. The most upregulated genes included epithelial cell adhesion molecule (EpCAM), a biomarker of cancer stem cells (CSC). We hypothesized that CSC biomarkers could predict recurrence of resected ICC.

Methods

Both functional analysis of the stroma signature previously obtained and immunohistochemistry of 40 resected ICC were performed. The relationships between the expression of CSC markers and clinicopathologic factors including survival were assessed by univariate and multivariable analyzes.

Results

Gene expression profile of the stroma of ICC highlighted embryonic stem cells signature. Immunohistochemistry on tissue microarray showed at a protein level the increased expression of CSC biomarkers in the stroma of ICC compared with nontumor fibrous liver tissue. The overexpression of EpCAM in the stroma of ICC is an independent risk factor for overall (hazard ratio = 2.6; 95% confidence interval, 1.3–5.1; P = 0.005) and disease-free survival (hazard ratio = 2.2; 95% confidence interval, 1.2–4.2; P = 0.012). In addition, the overexpression of EpCAM in nontumor fibrous liver tissue is closely correlated with a worst disease-free survival (P = 0.035).

Conclusions

Our findings provide new arguments for a potential role of CSC on ICC progression supporting the idea that targeting CSC biomarkers might represent a promise personalized treatment.  相似文献   
43.
ObjectivesTo analyze to what extent partial nephrectomy (PN) is superior to radical nephrectomy (RN) in preserving renal function outcome in relation to tumor size indication.Methods and materialsClinical data from 973 patients operated at 9 academic institutions were retrospectively analyzed. Glomerular filtration rate (GFR) before and after surgery was calculated with the abbreviated Modification of the Diet in Renal Disease equation. For a fair comparison between the 2 techniques, all imperative indications for PN were excluded. A shift to a less favorable GFR group following surgery was considered clinically significant.ResultsMedian age at diagnosis was 60 years (19–91). Tumor size was smaller than 4 cm in 665 (68.3%) cases and larger than 4 cm in 308 (31.7%) cases. PN and RN were performed in 663 (68.1%) and 310 (31.9%) patients, respectively. In univariate analysis, patients undergoing PN had a smaller risk for developing significant GFR change following surgery than those undergoing RN did. This was true for tumors≤4 cm (P = 0.0001) and for tumors>4 cm (P = 0.0001). In multivariate analysis, the following criteria were independent predictive factors for developing significant postoperative GFR loss: the use of RN (P = 0.0001), preoperative GFR<60 ml/min (P = 0.0001), tumor size≥4 cm (P = 0.0001), and older age at diagnosis (P = 0.0001).ConclusionsThe renal function benefit carried out by elective PN over RN persists even when expanding nephron-sparing surgery indications beyond the traditional 4-cm cutoff.  相似文献   
44.

Context

The European Association of Urology Renal Cell Carcinoma (RCC) Guideline Panel has prepared evidence-based guidelines and recommendations for the management of RCC.

Objective

To provide an updated RCC guideline based on standardised methodology including systematic reviews, which is robust, transparent, reproducible, and reliable.

Evidence acquisition

For the 2019 update, evidence synthesis was undertaken based on a comprehensive and structured literature assessment for new and relevant data. Where necessary, formal systematic reviews adhering to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were undertaken. Relevant databases (Medline, Cochrane Libraries, trial registries, conference proceedings) were searched until June 2018, including randomised controlled trials (RCTs) and retrospective or controlled studies with a comparator arm, systematic reviews, and meta-analyses. Where relevant, risk of bias (RoB) assessment, and qualitative and quantitative syntheses of the evidence were performed. The remaining sections of the document were updated following a structured literature assessment. Clinical practice recommendations were developed and issued based on the modified GRADE framework.

Evidence synthesis

All chapters of the RCC guidelines were updated based on a structured literature assessment, for prioritised topics based on the availability of robust data. For RCTs, RoB was low across studies. For most non-RCTs, clinical and methodological heterogeneity prevented pooling of data. The majority of included studies were retrospective with matched or unmatched cohorts, based on single- or multi-institutional data or national registries. The exception was for the treatment of metastatic RCC, for which there were several large RCTs, resulting in recommendations based on higher levels of evidence.

Conclusions

The 2019 RCC guidelines have been updated by the multidisciplinary panel using the highest methodological standards. These guidelines provide the most reliable contemporary evidence base for the management of RCC in 2019.

Patient summary

The European Association of Urology Renal Cell Carcinoma Guideline Panel has thoroughly evaluated the available research data on kidney cancer to establish international standards for the care of kidney cancer patients.  相似文献   
45.
Abstract

We evaluated transcranial magnetic stimulation producing motor evoked potentials (TMS MEP) as a method to detect spinal cord ischemia during surgery for thoracoabdominal aneurysms. Four groups of swine were subjected to different types of surgically-induced ischemia. TMS MEP and neurological function were assessed at baseline, immediately after the ischemic insult and after four hours of reperfusion/post-ligation. Cross-clamping of the aorta in groups A & B resulted in the disappearance and subsequent reappearance of TMS MEP with significantly prolonged latencies in most animals and variable neurological function. Ligation of intercostal arteries produced no changes in TMS MEP or neurological function (group C). However, after ligation of intercostal and lumbar arteries, group D demonstrated no reappearance of TMS MEP and severe neurological deficits. TMS MEP can provide rapid detection of global spinal cord ischemia and can also predict local devascularization injury. (J Spinal Cord Med 1997; 20:395-401)  相似文献   
46.
47.

Purpose

To describe the natural history and identify predictors of cancer-specific survival in patients who experience disease recurrence after radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC).

Methods

Of 2,494 UTUC patients treated with RNU without neoadjuvant chemotherapy, 597 patients experienced disease recurrence. A total of 148 patients (25?%) received adjuvant chemotherapy before disease recurrence. Multivariable Cox regression model addressed time to cancer-specific mortality after disease recurrence.

Results

The median time from RNU to disease recurrence was 12?months (interquartile range 5?C22). A total of 491 (82?%) of 597 patients died from UTUC, and 8 patients (1.3?%) died from other causes. The median time from disease recurrence to death of UTUC was 10?months. Actuarial cancer-specific survival estimate at 12?months after disease recurrence was 35?%. On multivariable analysis that adjusted for the effects of standard clinicopathologic characteristics, higher tumor stages [hazard ratio (HR) pT3 vs. pT0?CT1: 1.66, p?=?0.001; HR pT4 vs. pT0?CT1: 1.90, p?=?0.002], absence of lymph node dissection (HR 1.28, p?=?0.041), ureteral tumor location (HR 1.44, p?<?0.0005) and a shorter interval from surgery to disease recurrence (p?<?0.0005) were significantly associated with cancer-specific mortality. The adjusted 6-, 12- and 24-month postrecurrence cancer-specific mortality was 73, 60 and 57?%, respectively.

Conclusions

Approximately 80?% of patients who experience disease recurrence after RNU die within 2?years after recurrence. Patients with non-organ-confined stage, absence of lymph node dissection, ureteral tumor location and/or shorter time to disease recurrence died of their tumor more quickly than their counterparts. These factors should be considered in patient counseling and risk stratification for salvage treatment decision making.  相似文献   
48.
49.
ObjectiveCarcinoma in situ (CIS) is associated with increased risk of progression when found with high-grade non-muscle-invasive bladder cancer, yet its impact is less clear in the upper urinary tract. In the current study, we evaluated the impact of concomitant CIS on recurrence-free survival and cancer-specific survival following radical nephroureterectomy for upper tract urothelial carcinoma (UTUC).Materials and methodsA multi-institutional retrospective cohort of 1,387 patients undergoing radical nephroureterectomy was identified. Concomitant CIS was defined as the presence of CIS in association with another pathologic stage; patients with CIS alone were excluded from the analysis. The presence of concomitant CIS served as the exposure variable with disease recurrence and cancer-specific mortality as the outcomes. Organ-confined disease was defined as AJCC/UICC stage II or lower.ResultsConcomitant CIS was identified in 371 of 1,387 (26.7%) patients and was significantly more common in patients with a previous bladder cancer history, high grade, and high stage tumors. In a multivariable analysis, concomitant CIS was a predictor of disease recurrence (HR = 1.25, P = 0.04) and cancer specific mortality (HR = 1.34, P = 0.05) for patients with organ-confined UTUC, but not in the entire cohort. Other prognostic variables, such as grade, stage, lymphovascular invasion, and lymph node status, were associated with poorer overall and recurrence-free survival for all patients.ConclusionThe presence of concomitant CIS in patients with organ-confined UTUC is associated with a higher risk of recurrent disease and cancer-specific mortality. This information may be useful in refining surveillance protocols and in more appropriate selection of patients for adjuvant chemotherapy.  相似文献   
50.
Study Type – Decision analysis (cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Very little is known about prostate cancer decision‐making. Hence, marital status is often assumed a proxy for the amount of social support. While marital status is often used as a proxy for social support, we found that the quality of support may impact treatment type more than the extent of the social matrix.

OBJECTIVES

  • ? To determine whether martial status and social support impact treatment choice.
  • ? The decision to pursue radical prostatectomy for prostate cancer is often influenced by factors outside the realm of tumour risk, such as a man's support system at home.

PATIENTS AND METHODS

  • ? We performed a retrospective cohort study of 418 low‐income men who were diagnosed with non‐metastatic prostate cancer and underwent definitive treatment with either radical prostatectomy or radiotherapy.
  • ? We performed univariate and multivariate mixed‐effects logistic regression analysis, with the dependent variable being treatment type.
  • ? Confidence intervals (CIs) for the predicted probabilities and relative risks were derived using bias‐corrected bootstrapping with 1000 repetitions.

RESULTS

  • ? Men with two or more members in their support system were more likely to be older, Hispanic, have less than a high school education, earn more than US $1500 monthly, have high‐risk disease and be in a significant relationship.
  • ? In multivariate analysis, partnered men with fewer than two social support members (relative risk, RR, 1.23; 95% CI, 1.02–1.63) were more likely to undergo surgery, whereas men who were morbidly obese (RR, 0.46; 95% CI, 0.09–0.88), high school graduates (RR, 0.80; 95% CI, 0.64–0.99) or had high‐risk disease (RR, 0.58; 95% CI, 0.44–0.85) were less likely to undergo surgery than their respective referent groups.
  • ? Partnered men with two or more social support members were no more likely to undergo surgery than unpartnered men who lacked any social support.

CONCLUSIONS

  • ? In the present study cohort, married men with fewer than two members in their social network were more likely to have undergone surgery.
  • ? Although marital status is often used as a proxy for social support, we find that the quality of support and partner may impact treatment type more than the extent of the social matrix.
  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