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   2667411篇
  免费   198029篇
  国内免费   13271篇
耳鼻咽喉   35155篇
儿科学   86554篇
妇产科学   72471篇
基础医学   370597篇
口腔科学   71356篇
临床医学   245734篇
内科学   523447篇
皮肤病学   63950篇
神经病学   216092篇
特种医学   103738篇
外国民族医学   762篇
外科学   393748篇
综合类   71461篇
现状与发展   28篇
一般理论   974篇
预防医学   203722篇
眼科学   58731篇
药学   198524篇
  87篇
中国医学   11325篇
肿瘤学   150255篇
  2021年   20885篇
  2019年   22796篇
  2018年   31586篇
  2017年   25119篇
  2016年   28782篇
  2015年   33571篇
  2014年   45823篇
  2013年   66305篇
  2012年   88757篇
  2011年   93554篇
  2010年   58204篇
  2009年   55399篇
  2008年   86190篇
  2007年   90985篇
  2006年   92195篇
  2005年   87624篇
  2004年   83340篇
  2003年   80624篇
  2002年   76888篇
  2001年   131056篇
  2000年   133179篇
  1999年   111235篇
  1998年   30420篇
  1997年   27069篇
  1996年   27003篇
  1995年   27747篇
  1994年   25370篇
  1993年   23577篇
  1992年   85343篇
  1991年   81779篇
  1990年   78941篇
  1989年   76177篇
  1988年   69544篇
  1987年   68071篇
  1986年   63587篇
  1985年   60541篇
  1984年   44929篇
  1983年   37885篇
  1982年   22398篇
  1981年   19929篇
  1979年   38909篇
  1978年   27394篇
  1977年   23173篇
  1976年   21434篇
  1975年   22768篇
  1974年   26746篇
  1973年   25350篇
  1972年   23738篇
  1971年   21946篇
  1970年   20174篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.

Background

Limited data exist on the clinical behavior of pediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) with distant metastases at onset, and a clear standard of care has not yet been defined.

Methods

This cohort study reports on pediatric adult-type metastatic NRSTS enrolled in two concurrent prospective European studies, i.e., the randomized BERNIE study and the single-arm MTS 2008 study developed by the European paediatric Soft tissue sarcoma Study Group. Treatment programs were originally designed for patients with metastatic rhabdomyosarcoma, i.e., nine courses of multidrug chemotherapy (with or without bevacizumab in the BERNIE study), followed by 12 cycles of maintenance therapy, whereas radiotherapy and/or surgery (on primary tumor and/or metastases) were delayed until after seven courses of chemotherapy had been administered.

Results

The study included 61 patients <21 years old treated from July 2008 to December 2016. The lung was the site of metastases in 75% of the cases. All patients received multi-agent chemotherapy, 44% had local therapy to primary tumor, and 18% had treatment of metastases. Median time to progression/relapse was 6 months. A high rate of tumor progression was observed during the initial part of the chemotherapy program. With a median follow-up of 41.5 months (range, 2–111 months), 3-year event-free survival and overall survival were 15.4% (95% confidence interval [CI], 7.6–25.7) and 34.9% (95% CI, 22.7–47.5), respectively. There were no statistically significant differences in outcome depending on the type of treatment administered.

Conclusions

The study confirmed the overall poor outcome for patients with metastatic NRSTS, whose treatment remains a challenge.

Plain Language Summary

  • Pediatric non-rhabdomyosarcoma soft tissue sarcomas form a heterogeneous group of rare tumors.
  • Although recent international studies have defined the standard of care for patients with localized disease, limited data are available on the clinical behavior of patients with distant metastases.
  • This study on 61 metastatic cases treated on two prospective European protocols confirms that the chances of survival of such patients are often dismal and a standard treatment is still lacking.
  相似文献   
102.
103.
International recommendations encourage liberal administration of oxygen to patients having surgery under general anaesthesia, ostensibly to reduce surgical site infection. However, the optimal oxygen regimen to minimise postoperative complications and enhance recovery from surgery remains uncertain. The hospital operating theatre randomised oxygen (HOT-ROX) trial is a multicentre, patient- and assessor-blinded, parallel-group, randomised clinical trial designed to assess the effect of a restricted, standard care, or liberal peri-operative oxygen therapy regimen on days alive and at home after surgery in adults undergoing prolonged non-cardiac surgery under general anaesthesia. Here, we report the findings of the internal vanguard feasibility phase of the trial undertaken in four large metropolitan hospitals in Australia and New Zealand that included the first 210 patients of a planned overall 2640 trial sample, with eight pre-specified endpoints evaluating protocol implementation and safety. We screened a total of 956 participants between 1 September 2019 and 26 January 2021, with data from 210 participants included in the analysis. Median (IQR [range]) time-weighted average intra-operative FiO2 was 0.30 (0.26–0.35 [0.20–0.59]) and 0.47 (0.44–0.51 [0.37–0.68]) for restricted and standard care, respectively (mean difference (95%CI) 0.17 (0.14–0.20), p < 0.001). Median time-weighted average intra-operative FiO2 was 0.83 (0.80–0.85 [0.70–0.91]) for liberal oxygen therapy (mean difference (95%CI) compared with standard care 0.36 (0.33–0.39), p < 0.001). All feasibility endpoints were met. There were no significant patient adverse events. These data support the feasibility of proceeding with the HOT-ROX trial without major protocol modifications.  相似文献   
104.
Detailed contemporary knowledge of the characteristics of the surgical population, national anaesthetic workload, anaesthetic techniques and behaviours are essential to monitor productivity, inform policy and direct research themes. Every 3–4 years, the Royal College of Anaesthetists, as part of its National Audit Projects (NAP), performs a snapshot activity survey in all UK hospitals delivering anaesthesia, collecting patient-level encounter data from all cases under the care of an anaesthetist. During November 2021, as part of NAP7, anaesthetists recorded details of all cases undertaken over 4 days at their site through an online survey capturing anonymous patient characteristics and anaesthetic details. Of 416 hospital sites invited to participate, 352 (85%) completed the activity survey. From these, 24,177 reports were returned, of which 24,172 (99%) were included in the final dataset. The work patterns by day of the week, time of day and surgical specialty were similar to previous NAP activity surveys. However, in non-obstetric patients, between NAP5 (2013) and NAP7 (2021) activity surveys, the estimated median age of patients increased by 2.3 years from median (IQR) of 50.5 (28.4–69.1) to 52.8 (32.1–69.2) years. The median (IQR) BMI increased from 24.9 (21.5–29.5) to 26.7 (22.3–31.7) kg.m–2. The proportion of patients who scored as ASA physical status 1 decreased from 37% in NAP5 to 24% in NAP7. The use of total intravenous anaesthesia increased from 8% of general anaesthesia cases to 26% between NAP5 and NAP7. Some changes may reflect the impact of the COVID-19 pandemic on the anaesthetic population, though patients with confirmed COVID-19 accounted for only 149 (1%) cases. These data show a rising burden of age, obesity and comorbidity in patients requiring anaesthesia care, likely to impact UK peri-operative services significantly.  相似文献   
105.
Journal of Thrombosis and Thrombolysis - Bleeding gastrointestinal angiodysplasia may occur in patients with vasculitis and can be challenging to treat. We describe the novel use of bevacizumab...  相似文献   
106.
Postbariatric loss of muscle tissue could negatively affect long-term health due to its role in various bodily processes, such as metabolism and functional capacity. This meta-analysis aimed to unravel time-dependent changes in the magnitude and progress of lean body mass (LBM), fat-free mass (FFM), and skeletal muscle mass (SMM) loss following bariatric surgery. A systematic literature search was conducted in Pubmed, Embase, and Web of Science. Fifty-nine studies assessed LBM (n = 37), FFM (n = 20), or SMM (n = 3) preoperatively and ≥1 time points postsurgery. Random-effects meta-analyses were performed to determine pooled loss per outcome parameter and follow-up time point. At 12-month postsurgery, pooled LBM loss was ?8.13 kg [95%CI ?9.01; ?7.26]. FFM loss and SMM loss were ?8.23 kg [95%CI ?10.74; ?5.73] and ?3.18 kg [95%CI ?5.64; ?0.71], respectively. About 55% of 12-month LBM loss occurred within 3-month postsurgery, followed by a more gradual decrease up to 12 months. Similar patterns were seen for FFM and SMM. In conclusion, >8 kg of LBM and FFM loss was observed within 1-year postsurgery. LBM, FFM, and SMM were predominantly lost within 3-month postsurgery, highlighting that interventions to mitigate such losses should be implemented perioperatively.  相似文献   
107.
Background: Considering the poor prognosis of non-small cell lung cancer (NSCLC), the objective of this study was to examine the potential of plasma-derived vesicles as a source of lung cancer-specific proteins. Extracellular vesicle (EV) cargos are specific to the source cells, hence they have the potential of being a source of cancer-specific proteins.  Methods: The proteins differently expressed in cancer were determined and derived from EVs isolated from the plasma of NSCLC patients at the National Lung Hospital. To this end, purification was done using gel filtration chromatography and ultracentrifugation. In addition, nano liquid chromatography mass spectrometry (LC–MS/MS) was used for analyzing. Results: Fifty-seven EV-derived proteins related to NSCLC were highlighted in this research. Some of them have not been addressed before, such as EEF1A1 (elongation factor 1-α1), KPNB1 (Importin subunit beta 1), SRC (proto-oncogene tyrosine-protein kinase) and ACTC1 (actin, alpha cardiac muscle 1). This list was further confirmed through a comparison with ExoCarta and Vesiclepedia. Conclusion: This study is the first work to show the involvement of several novel proteins of small EV (EEF1A1, KPNB1, SRC, and ACTC1) in the progression of NSCLC. The results suggested that they could serve as novel biomarkers for non-small cell lung cancer in the future.  相似文献   
108.
International Journal of Clinical Oncology - A recently reported phase III randomized trial comparing open and minimally invasive hysterectomy showed significantly higher rates of local recurrence...  相似文献   
109.
110.

Background

Health-related quality of life (HRQoL) is frequently assessed in randomised clinical trials (RCTs) in the intensive care unit (ICU), but data are limited regarding the proportions of patients without responses or not surviving to HRQoL follow-up and the handling of this. We aimed to describe the extent and pattern of missing HRQoL data in intensive care trials and describe how these data and deaths were handled statistically.

Methods

We conducted a systematic review and meta-analysis following a published protocol. We searched PubMed, EMBASE, CINAHL and Cochrane Library for RCTs involving adult ICU patients reporting HRQoL as an outcome and excluded RCTs unobtainable in full text. We performed risk of bias assessment independently and in duplicate.

Results

We included 196 outcomes from 88 RCTs published in the years 2002–2022; the numbers of patients alive and eligible to respond HRQoL were reported in 76% of trials. At follow-up, median 27% (interquartile range 14%–39%) of patients had died, and median 20% (9%–38%) of survivors did not respond across outcomes. Analyses of 80% of outcomes were restricted to complete cases only. The handling of non-survivors in analyses were reported for 46% of outcomes, with 26% of all outcomes reported as including non-survivors (using the value zero or the worst possible score).

Conclusion

For HRQoL outcomes in ICU trials, we found that mortality at time of follow-up was high and non-response among survivors frequent. The reporting and statistical handling of these issues were insufficient, which may have biased results.  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