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   16246篇
  免费   931篇
  国内免费   170篇
耳鼻咽喉   176篇
儿科学   439篇
妇产科学   350篇
基础医学   1719篇
口腔科学   513篇
临床医学   1288篇
内科学   4274篇
皮肤病学   306篇
神经病学   1663篇
特种医学   777篇
外科学   2739篇
综合类   45篇
一般理论   4篇
预防医学   538篇
眼科学   221篇
药学   866篇
  3篇
中国医学   18篇
肿瘤学   1408篇
  2024年   61篇
  2023年   231篇
  2022年   408篇
  2021年   756篇
  2020年   453篇
  2019年   537篇
  2018年   639篇
  2017年   506篇
  2016年   517篇
  2015年   602篇
  2014年   708篇
  2013年   868篇
  2012年   1310篇
  2011年   1291篇
  2010年   710篇
  2009年   674篇
  2008年   1038篇
  2007年   949篇
  2006年   858篇
  2005年   824篇
  2004年   739篇
  2003年   610篇
  2002年   571篇
  2001年   164篇
  2000年   154篇
  1999年   140篇
  1998年   103篇
  1997年   79篇
  1996年   78篇
  1995年   74篇
  1994年   49篇
  1993年   51篇
  1992年   68篇
  1991年   54篇
  1990年   59篇
  1989年   40篇
  1988年   38篇
  1987年   44篇
  1986年   29篇
  1985年   33篇
  1984年   25篇
  1983年   11篇
  1979年   27篇
  1978年   11篇
  1977年   15篇
  1976年   17篇
  1975年   18篇
  1974年   11篇
  1971年   9篇
  1968年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
This study aimed to examine the physical and mental Quality of Life (QoL) trajectories in prostate cancer (PCa) patients participating in the Pros-IT CNR study. QoL was assessed using the Physical (PCS) and Mental Component Score (MCS) of Short-Form Health Survey upon diagnosis and two years later. Growth mixture models were applied on 1158 patients and 3 trajectories over time were identified for MCS: 75% of patients had constantly high scores, 13% had permanently low scores and 12% starting with low scores had a recovery; the predictors that differentiated the trajectories were age, comorbidities, a family history of PCa, and the bowel, urinary and sexual functional scores at diagnosis. In the physical domain, 2 trajectories were defined: 85% of patients had constantly high scores, while 15% started with low scores and had a further slight decrease. Two years after diagnosis, the psychological and physical status was moderately compromised in more than 10% of PCa patients. For mental health, the trajectory analysis suggested that following the compromised patients at diagnosis until treatment could allow identification of those more vulnerable, for which a level 2 intervention with support from a non-oncology team supervised by a clinical psychologist could be of help.  相似文献   
122.
Bariatric surgery (BS) is the most effective treatment in reducing weight and the burden of comorbidities in patients with severe obesity. Despite the overall low mortality rate, intra- and post-operative complications remains quite common. Weight loss before BS reduces surgical risk, but studies are inconclusive regarding which is the best approach to apply. In this review, we summarize the current evidence on the effect of a ketogenic diet (KD) before BS. All studies agree that KD leads to considerable weight loss and important improvements in terms of surgical risk, but populations, interventions and outcomes are very heterogeneous. KD appears to be a safe and effective approach to induce weight loss before BS. However, randomized controlled trials with better-defined dietary protocols and homogeneous outcomes are necessary in order to draw firm conclusions.  相似文献   
123.
Background Intraductal papillary neoplasms (IPN) and biliary epithelial neoplasia (BilIN) are well‐defined precursor lesions of biliary tract carcinoma (BTC). The aim of this study was to provide a comprehensive characterisation of the inflammatory microenvironment in BTC precursor lesions.Methods Immunohistochemistry was employed to assess tumour-infiltrating immune cells in tissue samples from patients, for whom precursor lesions were identified alongside invasive BTC. The spatiotemporal evolution of the immune microenvironment during IPN-associated carcinogenesis was comprehensively analysed using triplet sample sets of non-neoplastic epithelium, precursor lesion and invasive BTC. Immune-cell dynamics during IPN- and BilIN-associated carcinogenesis were subsequently compared.Results Stromal CD3+ (P = 0.002), CD4+ (P = 0.007) and CD8+ (P < 0.001) T cells, CD20+ B cells (P = 0.008), MUM1+ plasma cells (P = 0.012) and CD163+ M2-like macrophages (P = 0.008) significantly decreased in IPN compared to non-tumorous biliary epithelium. Upon transition from IPN to invasive BTC, stromal CD68+ (P = 0.001) and CD163+ (P < 0.001) macrophages significantly increased. In contrast, BilIN-driven carcinogenesis was characterised by significant reduction of intraepithelial CD8+ T-lymphocytic infiltration from non-tumorous epithelium via BilIN (P = 0.008) to BTC (P = 0.004).Conclusion IPN and BilIN are immunologically distinct entities that undergo different immune-cell variations during biliary carcinogenesis. Intraepithelial CD8+ T-lymphocytic infiltration of biliary tissue decreased already at the IPN-precursor stage, whereas BilIN-associated carcinogenesis showed a slowly progressing reduction towards invasive carcinoma.Subject terms: Cancer microenvironment, Immunoediting, Biliary tract cancer  相似文献   
124.
BackgroundThe itAlian pRospective Study on CANGrELOr (ARCANGELO) was aimed to assess the safety of using cangrelor during percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS) in the daily practice.HypothesisThe safety of cangrelor after the transition to oral P2Y12 inhibitors was evaluated as the incidence of bleeding outcomes in the 30 days following PCI according to postauthorization safety study guidelines.MethodsAdults with ACS who were treated with cangrelor in one of the 28 centers involved in the study. Patients who consented to participate were followed in the 30 days following their PCI. Bleedings (Bleeding Academic Research Consortium [BARC] classification), major adverse cardiac events (MACEs), and adverse events were recorded. The interim results at two‐thirds of the enrollment period are presented.ResultsA total of 17 bleedings were observed in the 320 patients who completed the study at this stage. All bleedings were classified as BARC Type 1–2, except for one case of Type 3a (vessel puncture site hematoma). Four patients experienced MACEs (2 acute myocardial infarctions, 1 sudden cardiac death, 1 noncardiovascular death due to respiratory distress, and multiorgan failure). None of the bleedings was rated as related to cangrelor.ConclusionsThe interim results of the ARCANGELO study provide a preliminary confirmation that the use of cangrelor on patients with ACS undergoing PCI is not associated with severe bleedings.  相似文献   
125.
BackgroundDue to the COVID-19 pandemic, a national lockdown was applied in Spain from March to May 2020. It is uncertain when SARS-CoV-2 started to circulate in Catalonia, and only a few cases were diagnosed in this period. We assessed the SARS-CoV-2 seroprevalence in blood donors before and after the first wave and compared it with public health service (PHS) data.Materials and methodsRetrospective archive or prospective fresh blood samples were obtained from blood donors aged 18 to 70 and anonymized after demographic data had been recorded (gender, age, place of residence, blood collection date). Two CE-marked enzyme-linked immunosorbent assays were used to test for anti-SARS-CoV-2. A SARS-CoV-2 IgM test was additionally performed in positive samples. Individuals aged 18 to 70 from among the general population diagnosed as having SARS-CoV-2 by the PHS were included for comparison with blood donor results.ResultsA total of 10,170 blood donations were included in the first period, between 24 February and 9 March 2020, and 6,829 in the second period, between 16 May and 17 June 2020. The observed SARS-CoV-2 seroprevalence among blood donors rose from 0.27% (95% CI: 0.18–0.39) before the first wave to 5.55% (95% CI: 5.03–6.12) after it, and was even higher (6.90% [95% CI: 5.64–8.41]) among blood donors aged 18 to 29. The seroprevalence among blood donors was higher in more populated areas (Barcelona: 7.69%). A comparison of blood donor data with officially diagnosed cases showed a global 87.44% underestimation of SARS-CoV-2 in June 2020.DiscussionWe analyzed the explosive 3-month increase in blood donor SARS-CoV-2 seroprevalence (from 0.27% to 5.55%) and show that more than 87% of cases went undiagnosed, despite the unprecedented deployment of testing measures. SARS-CoV-2 IgM results suggest that the virus was circulating among blood donors in February 2020. Blood donors are definitively proven to be a valuable resource for emerging disease surveillance studies.  相似文献   
126.
BackgroundThe reconstructive tracheal options for extensive lesions still remain limited and although a valid substitute is required unfortunately, the biomechanical tracheal characteristics do not allow an easy replacement. In this study we reviewed the described options and investigated, in human cadaver model, whether thigh fascia can be used, as an alternative to forearm fascia, as recipient site for trachea graft heterotopical allotransplantation.Anatomical studyIn three fresh cadavers, 3 tracheal graft, 6 radial forearm (RF) fascial flaps and 6 antero-lateral thigh (ALT) fascial flaps were harvested. For each flap we simulated the heteretopical transplantation of the trachea in each fascial flap, and the harvesting of the composite graft as a free flap. The composite graft was finally decomposed at bench and the pedicle was injected to confirm fascial vascularization. The main measured outcomes were: flap fascia vascularization after pedicle injection, average time of flap harvesting, number of perforators included in ALT fascial flap and diameter of the vessels for anastomosis. Difficulties were noted, in order to compare RF flap and ALT flap.ResultsFascia vascularization was confirmed in all cases by pedicle injection. The main difficulty with radial flap was to harvest the fascial layer due to its thinness and its strong adherence to palmaris longus tendon, while the main difficulty with ALT flap was to prevent any traction on the perforators. The average time of flap harvesting and graft inset (by a junior plastic surgeon) was 1 h and 30 min for radial forearm flap and 2 h and 10 min for ALT flap.ConclusionDespite many different techniques proposed in the literature, tracheal heterotopical allotransplantation still seemed the most promising, and ALT flap promised be a feasible alternative for heterotopical transplantation of trachea.  相似文献   
127.
ObjectiveThe aim of the study is to evaluate clinical features and outcomes after different therapeutic strategies for ductal prostate adenocarcinoma (DPC), a rare but aggressive subtype of invasive prostate cancer (PCa) accounting for, in the pure and mixed form, 1% or less and 5% or less, respectively, of all the newly diagnosed PCa.Materials and methodsPatients with a proven diagnosis of DPC undergoing surgery, radiotherapy, and androgen deprivation therapy, alone or in combination, were considered for this multicenter, retrospective study. The study assessed overall survival (OS), disease-free survival (DFS), and age-related disease-specific survival.ResultsEighty-one patients met the study inclusion criteria. Pure DPC was found in 29 patients (36%) and mixed ductal-acinar-PCa in 52 patients (64%). After a median follow-up of 63 months (range, 3–206 months), 3- and 5-year OS rates were 84% and 67%, respectively, and 3- and 5-year DFS rates were 54% and 34%, respectively. There were no significant differences in OS or DFS between the pure and mixed DPC groups. Pure DPC was associated with a higher rate of metastatic disease at onset. Patients 74 years or younger had better disease-specific survival (p=0.0019). A subgroup analysis favored radiotherapy as the primary treatment for nonmetastatic, organ-confined DPC (3- and 5-year DFS of 80% and 50%, respectively, compared with 5-year DFS of 35% for surgical patients; p = 0.023).ConclusionsOur study found DPC to be rarer, more aggressive, more likely to metastasize, and have a worse prognosis than the common acinar variant, especially in its pure form. Multicenter series are encouraged to obtain large data sets, or propensity score matching analyses with patients with conventional PCa are desirable to understand the best therapeutic approach and improve outcomes.  相似文献   
128.
129.
130.
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