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   14125篇
  免费   848篇
  国内免费   317篇
耳鼻咽喉   46篇
儿科学   150篇
妇产科学   108篇
基础医学   888篇
口腔科学   37篇
临床医学   1017篇
内科学   6829篇
皮肤病学   41篇
神经病学   379篇
特种医学   220篇
外国民族医学   1篇
外科学   2182篇
综合类   372篇
现状与发展   1篇
一般理论   1篇
预防医学   526篇
眼科学   27篇
药学   589篇
  3篇
中国医学   114篇
肿瘤学   1759篇
  2023年   843篇
  2022年   1079篇
  2021年   1154篇
  2020年   1035篇
  2019年   714篇
  2018年   625篇
  2017年   631篇
  2016年   625篇
  2015年   655篇
  2014年   1329篇
  2013年   924篇
  2012年   667篇
  2011年   608篇
  2010年   739篇
  2009年   778篇
  2008年   391篇
  2007年   440篇
  2006年   337篇
  2005年   285篇
  2004年   200篇
  2003年   158篇
  2002年   177篇
  2001年   127篇
  2000年   130篇
  1999年   117篇
  1998年   92篇
  1997年   78篇
  1996年   80篇
  1995年   40篇
  1994年   27篇
  1993年   21篇
  1992年   13篇
  1991年   16篇
  1990年   8篇
  1989年   15篇
  1988年   6篇
  1987年   8篇
  1986年   7篇
  1985年   8篇
  1984年   12篇
  1983年   8篇
  1982年   11篇
  1981年   13篇
  1980年   11篇
  1979年   6篇
  1978年   11篇
  1977年   10篇
  1974年   5篇
  1971年   4篇
  1970年   4篇
排序方式: 共有10000条查询结果,搜索用时 578 毫秒
1.
2.
BackgroundThis study compares morbidity and mortality associated with retroperitoneal and transperitoneal para-aortic lymphadenectomy (PAAL) for pretherapeutic nodal staging of locally advanced cervical cancers (FIGO IB3–IVA).MethodsPre-, per- and postoperative data of patients treated for locally advanced stage cervical cancer between 1999 and 2018 in 12 French referral centers (FRANCOGYN Study Group) were retrospectively collected.ResultsThe study was conducted using a sample of 448 patients, of whom 223 (49,8%) underwent retroperitoneal (group 1) and 225 (50,2%) had transperitoneal PAAL (group 2). No differences were noted concerning clinical and histological characteristics between the two groups. Among these 448 patients, 23 (5,1%) had an intraoperative complication (9 (2,0%) in group 1 and 14 (3,1%) in group 2, p = 0.28) and 47 (10,5%) had a postoperative complication (22 (4,9%) in group 1 and 25 (5,6%) in group 2, p = 0.44), only one of which required revision surgery but the patient died. The length of hospital stay was significantly shorter in group 1 than in group 2 (3.97 versus 4.88 days, p < 0.001). There was no significant difference in mortality between the two groups; 34 of 223 patients in group 1 (15.3%) and 40 of 225 patients in group 2 (15.6%) died (HR = 0.968, 95% CI [0.591–1.585]). There was no significant difference in recurrence-free or overall survival between the two groups.ConclusionRetroperitoneal PAAL appears as a valuable and safety surgical route for nodal staging in locally advanced cervical cancer compared with standard transperitoneal PAAL.  相似文献   
3.
BackgroundThe clinical importance of postoperative hyperamylasemia (POHA) grade is unknown. Our objectives were to evaluate the association of POHA grade with clinically relevant postoperative pancreatic fistula (CR-POPF) and compare its prognostic utility against postoperative day 1 drain fluid amylase (DFA-1).MethodsPatients who underwent pancreatectomy from January 2019 through March 2020 were identified in the ACS NSQIP pancreatectomy-targeted dataset. POHA grade was assigned using post-operative serum amylase and clinical sequelae. The primary outcome was CR-POPF within 30 days. The association of POHA grade with CR-POPF was assessed using multivariable logistic regression, and c-statistics were used to compare POHA grade versus DFA-1.ResultsPOHA occurred in 520 patients at 98 hospitals, including 261 (50.2%) with grade A, 234 (45.0%) with grade B, and 25 (4.8%) with grade C POHA. CR-POPFs were increased among patients with grade B (66.2%, OR 9.28 [5.84–14.73]) and C (68.0%, OR 10.50 [3.77–29.26]) versus grade A POHA (19.2%). POHA-inclusive models better predicted CR-POPF than those with DFA-1 alone (p < 0.002) and models with both predictors outperformed POHA alone (p = 0.039).ConclusionPOHA grade represents a measure of post-pancreatectomy outcomes that predicts CR-POPF and outperforms DFA-1 but must be aligned with new international definitions.  相似文献   
4.
5.
Background and aimsWe intended to investigate the predictors for bowel resection in infants with necrotizing enterocolitis (NEC). We further developed a scoring system for better predicting bowel resection.MethodsA total of 207 infants who underwent surgical management at Children's Hospital, Chongqing Medical University between April 2008 and December 2020 were identified for the following investigation. Bowel resection was reviewed among the infants who underwent the procedure. Potential parameters related to bowel resection were explored using a multiple logistic regression method, and then a scoring system was developed.ResultsAmong the 207 patients who underwent operative intervention that were reviewed, 109 infants underwent bowel resection. Multivariate logistic regression analysis showed that birth weight, hypotension, neutropenia, pneumoperitoneum, acidosis, and intestinal wall thickness were predictors related to the occurrence of bowel resection. A 6-point scoring system was further developed based on the obtained total coefficient, and the infants could be divided into low-, moderate- and high-risk groups according to cut values of 7 and 13.ConclusionThe results of this study demonstrated that severe NEC features and low birth weight were associated with bowel resection. The risk scoring system could accurately separate infants that were suspected to have bowel loss during surgery.  相似文献   
6.
BackgroundCholangiocarcinomas (CCA) are rare tumours originating from bile duct. Due to their asymptomatic nature they are usually diagnosed when the disease is advanced. Little data exists with respect to their incidence and treatment outcomes in low and middle income countries.MethodA retrospective analysis of a prospectively maintained database of all patients with perihilar (pCCA) and intrahepatic (iCCA) CCA registered between January 2012 and December 2018 was performed.ResultsA total of 760 patients, 427 (56.2%) diagnosed with pCCA and 333 (43.8%) of iCCA were included. Patients with localised, locally advanced and metastatic disease in pCCA were 45.5%, 25.9%, 8.5% and that in iCCA were 22.1%, 10.1% and 67.7% respectively. Only 141 (43.9%, 57 - iCCA, 84 -pCCA) of the total 321 patients started on some definitive cancer directed therapy could complete the intended treatment. The overall curative resection rate for all patients of iCCA was 14.5% whereas for patients of pCCA it was only 10.5%.ConclusionMore than half of CCA patients are not able to complete their intended treatment, being worse for pCCA as compared to iCCA. Early referral and centralisation of treatment for this complex disease might be the way forward to achieve optimal outcomes.  相似文献   
7.
BackgroundPancreatic ductal adenocarcinoma (PDAC) has poor survival. Current treatments offer little likelihood of cure or long-term survival. This systematic review evaluates prognostic models predicting overall survival in patients diagnosed with PDAC.MethodsWe conducted a comprehensive search of eight electronic databases from their date of inception through to December 2019. Studies that published models predicting survival in patients with PDAC were identified.Results3297 studies were identified; 187 full-text articles were retrieved and 54 studies of 49 unique prognostic models were included. Of these, 28 (57.1%) were conducted in patients with advanced disease, 17 (34.7%) with resectable disease, and four (8.2%) in all patients. 34 (69.4%) models were validated, and 35 (71.4%) reported model discrimination, with only five models reporting values >0.70 in both derivation and validation cohorts. Many (n = 27) had a moderate to high risk of bias and most (n = 33) were developed using retrospective data. No variables were unanimously found to be predictive of survival when included in more than one study.ConclusionMost prognostic models were developed using retrospective data and performed poorly. Future research should validate instruments performing well locally in international cohorts and investigate other potential predictors of survival.  相似文献   
8.
9.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  相似文献   
10.
The study aimed to evaluate the impact of the updated 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines on Human Epidermal Growth Factor Receptor 2 (HER2) testing in invasive breast cancer compared with previous 2013 guidelines. Between Jan 2014 and May 2020, 3364 consecutive invasive breast carcinomas with concurrent HER2 immunohistochemistry (IHC) and fluorescence in-situ hybridization (FISH) results were retrospectively reviewed for HER2 status. Both 2013 and 2018 testing criteria were applied to establish the HER2 status. The testing algorithms involved testing of invasive breast carcinomas by IHC, with equivocal results being reflexed to FISH assays. Concordance rate improved from 92.7% to 94.1% in the non-equivocal IHC cases with the 2018 guidelines. Comparing 2013 versus 2018 criteria, HER2 non-amplified cases increased significantly from 73.7% (n = 2478) to 76.8% (n = 2585), HER2 amplified cases remained similar from 23.4% (n = 789) to 23.2% (n = 779) while equivocal cases decreased from 2.9% (n = 97) to 0% with the new guidelines. Thus, 107 cases (3.2%) were reclassified from HER2 equivocal (n = 97) and amplified (n = 10) to non-amplified with the updated 2018 guidelines. Under the 2018 criteria, a total of 259 cases (7.7%) belonged to the uncommon categories (groups 2 to 4), with group 3 being the most frequent (4.6%), followed by group 4 (2.9%) and group 2 (0.2%). Implementation of 2018 guidelines resulted in a significant increase in HER2 non-amplified cases, mainly due to the abolishment of the equivocal FISH group. This has helped resolve the clinical practice dilemma by providing a more definitive HER2 gene status.  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