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   2901篇
  免费   177篇
  国内免费   6篇
耳鼻咽喉   64篇
儿科学   148篇
妇产科学   53篇
基础医学   283篇
口腔科学   47篇
临床医学   196篇
内科学   683篇
皮肤病学   47篇
神经病学   149篇
特种医学   212篇
外国民族医学   1篇
外科学   445篇
综合类   75篇
预防医学   123篇
眼科学   117篇
药学   149篇
中国医学   6篇
肿瘤学   286篇
  2023年   18篇
  2022年   35篇
  2021年   111篇
  2020年   51篇
  2019年   90篇
  2018年   112篇
  2017年   61篇
  2016年   75篇
  2015年   80篇
  2014年   128篇
  2013年   154篇
  2012年   204篇
  2011年   180篇
  2010年   123篇
  2009年   129篇
  2008年   171篇
  2007年   146篇
  2006年   114篇
  2005年   105篇
  2004年   85篇
  2003年   66篇
  2002年   53篇
  2001年   43篇
  2000年   42篇
  1999年   49篇
  1998年   43篇
  1997年   40篇
  1996年   46篇
  1995年   44篇
  1994年   34篇
  1993年   26篇
  1992年   35篇
  1991年   28篇
  1990年   28篇
  1989年   37篇
  1988年   41篇
  1987年   32篇
  1986年   24篇
  1985年   23篇
  1984年   18篇
  1983年   19篇
  1982年   14篇
  1981年   13篇
  1980年   15篇
  1979年   8篇
  1978年   13篇
  1976年   13篇
  1972年   6篇
  1970年   7篇
  1968年   6篇
排序方式: 共有3084条查询结果,搜索用时 171 毫秒
71.
72.
Inflammation has an integral role in the pathophysiology of AKI. We investigated the associations of two biomarkers of inflammation, plasma IL-6 and IL-10, with AKI and mortality in adults undergoing cardiac surgery. Patients were enrolled at six academic centers (n=960). AKI was defined as a ≥50% or ≥0.3-mg/dl increase in serum creatinine from baseline. Pre- and postoperative IL-6 and IL-10 concentrations were categorized into tertiles and evaluated for associations with outcomes of in-hospital AKI or postdischarge all-cause mortality at a median of 3 years after surgery. Preoperative concentrations of IL-6 and IL-10 were not significantly associated with AKI or mortality. Elevated first postoperative IL-6 concentration was significantly associated with higher risk of AKI, and the risk increased in a dose-dependent manner (second tertile adjusted odds ratio [OR], 1.61 [95% confidence interval (95% CI), 1.10 to 2.36]; third tertile adjusted OR, 2.13 [95% CI, 1.45 to 3.13]). First postoperative IL-6 concentration was not associated with risk of mortality; however, the second tertile of peak IL-6 concentration was significantly associated with lower risk of mortality (adjusted hazard ratio, 0.75 [95% CI, 0.57 to 0.99]). Elevated first postoperative IL-10 concentration was significantly associated with higher risk of AKI (adjusted OR, 1.57 [95% CI, 1.04 to 2.38]) and lower risk of mortality (adjusted HR, 0.72 [95% CI, 0.56 to 0.93]). There was a significant interaction between the concentration of neutrophil gelatinase-associated lipocalin, an established AKI biomarker, and the association of IL-10 concentration with mortality (P=0.01). These findings suggest plasma IL-6 and IL-10 may serve as biomarkers for perioperative outcomes.  相似文献   
73.

Purpose

The purpose of our study was to determine the long-term functional outcomes of pin tract infection after percutaneous pinning of displaced supracondylar humeral fractures in children, and to evaluate the potential for intracapsular pin placement based on pin configuration in cadaveric elbows.

Methods

We conducted a retrospective review of all patients requiring percutaneous pinning in a single institution over a 19-year period. The functional outcome assessment consisted of a telephone interview using the Disabilities of the Arm, Shoulder and Hand (DASH)] Outcome Measure and the Patient-Rated Elbow Evaluation (PREE) questionnaires. The risk of intracapsular pin placement was studied in cadaveric elbows for the three most common pin configurations: divergent lateral, parallel lateral, and medial and lateral crossed pins.

Results

Of 490 children, 21 (4.3 %) developed pin tract infection. There were 15 (3.1 %) superficial and six (1.2 %) deep infections (osteomyelitis and septic arthritis). Both DASH and PREE scores were excellent at a mean of 18 years post-surgery. The risk of intracapsular pin placement using parallel lateral pins was found to be greater (p < 0.05) than either crossed or divergent lateral pinning configurations.

Conclusions

Most infections after pinning of supracondylar humerus fractures are superficial and can be managed with pin removal, oral antibiotics, and local wound care. Septic arthritis and osteomyelitis are rare complications; when they do occur, they seem to be associated with parallel lateral pin configuration, though a causal relationship could not be established from the current study. Satisfactory long-term outcomes of these deep infections can be expected when treated aggressively with surgical debridement and intravenous antibiotics.  相似文献   
74.
75.
76.
77.

Background and objectives

The influence of deceased-donor AKI on post-transplant outcomes is poorly understood. The few published studies about deceased-donor preimplant biopsy have reported conflicting results regarding associations between AKI and recipient outcomes.

Design, setting, participants, & measurements

This multicenter study aimed to evaluate associations between deceased-donor biopsy reports of acute tubular necrosis (ATN) and delayed graft function (DGF), and secondarily for death-censored graft failure, first adjusting for the kidney donor risk index and then stratifying by donation after cardiac death (DCD) status.

Results

Between March 2010 and April 2012, 651 kidneys (369 donors, 4 organ procurement organizations) were biopsied and subsequently transplanted, with ATN reported in 110 (17%). There were 262 recipients (40%) who experienced DGF and 38 (6%) who experienced graft failure. DGF occurred in 45% of kidneys with reported ATN compared with 39% without ATN (P=0.31) resulting in a relative risk (RR) of 1.13 (95% confidence interval [95% CI], 0.9 to 1.43) and a kidney donor risk index–adjusted RR of 1.11 (95% CI, 0.88 to 1.41). There was no significant difference in graft failure for kidneys with versus without ATN (8% versus 5%). In stratified analyses, the adjusted RR for DGF with ATN was 0.97 (95% CI, 0.7 to 1.34) for non-DCD kidneys and 1.59 (95% CI, 1.23 to 2.06) for DCD kidneys (P=0.02 for the interaction between ATN and DCD on the development of DGF).

Conclusions

Despite a modest association with DGF for DCD kidneys, this study reveals no significant associations overall between preimplant biopsy-reported ATN and the outcomes of DGF or graft failure. The potential benefit of more rigorous ATN reporting is unclear, but these findings provide little evidence to suggest that current ATN reports are useful for predicting graft outcomes or deciding to accept or reject allograft offers.  相似文献   
78.
MRSI permits the non‐invasive mapping of brain temperature in vivo, but information regarding its reliability is lacking. We obtained MRSI data from 31 healthy male volunteers [age range, 22–40 years; mean ± standard deviation (SD), 30.5 ± 5.0 years]. Eleven subjects (age range, 23–40 years; mean ± SD, 30.5 ± 5.2 years) were invited to receive four point‐resolved spectroscopy MRSI scans on each of 3 days in both 1.5‐T (TR/TE = 1000/144 ms) and 3‐T (TR/TE = 1700/144 ms) clinical scanners; a further 20 subjects (age range, 22–40 years; mean ± SD, 30.5 ± 4.9 years) were scanned on a single occasion at 3 T. Data were fitted in the time domain to determine the water–N‐acetylaspartate chemical shift difference, from which the temperature was estimated. Temperature data were analysed using a linear mixed effects model to determine variance components and systematic temperature changes during the scanning sessions. To characterise the effects of instrumental drift on apparent MRSI brain temperature, a temperature‐controlled phantom was constructed and scanned on multiple occasions. Components of apparent in vivo temperature variability at 1.5 T/3 T caused by inter‐subject (0.18/0.17 °C), inter‐session (0.18/0.15 °C) and within‐session (0.36/0.14 °C) effects, as well as voxel‐to‐voxel variation (0.59/0.54 °C), were determined. There was a brain cooling effect during in vivo MRSI of 0.10 °C [95% confidence interval (CI): –0.110, –0.094 °C; p < 0.001] and 0.051 °C (95% CI: –0.054, –0.048 °C; p < 0.001) per scan at 1.5 T and 3 T, respectively, whereas phantom measurements revealed minimal drift in apparent MRSI temperature relative to fibre‐optic temperature measurements. The mean brain temperature at 3 T was weakly associated with aural (R = 0.55, p = 0.002) and oral (R = 0.62, p < 0.001) measurements of head temperature. In conclusion, the variability associated with MRSI brain temperature mapping was quantified. Repeatability was somewhat higher at 3 T than at 1.5 T, although subtle spatial and temporal variations in apparent temperature were demonstrated at both field strengths. Such data should assist in the efficient design of future clinical studies. © 2013 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd.  相似文献   
79.
The ATR‐CHEK1 pathway is upregulated and overactivated in Ataxia Telangiectasia (AT) cells, which lack functional ATM protein. Loss of ATM in AT confers radiosensitivity, although ATR‐CHEK1 pathway overactivation compensates, leads to prolonged G2 arrest after treatment with ionizing radiation (IR), and partially reverses the radiosensitivity. We observed similar upregulation of the ATR–CHEK1 pathway in a subset of oral squamous cell carcinoma (OSCC) cell lines with ATM loss. In the present study, we report copy number gain, amplification, or translocation of the ATR gene in 8 of 20 OSCC cell lines by FISH; whereas the CHEK1 gene showed copy number loss in 12 of 20 cell lines by FISH. Quantitative PCR showed overexpression of both ATR and CHEK1 in 7 of 11 representative OSCC cell lines. Inhibition of ATR or CHEK1 with their respective siRNAs resulted in increased sensitivity of OSCC cell lines to IR by the colony survival assay. siRNA‐mediated ATR or CHEK1 knockdown led to loss of G2 cell cycle accumulation and an increased sub‐G0 apoptotic cell population by flow cytometric analysis. In conclusion, the ATR‐CHEK1 pathway is upregulated in a subset of OSCC with distal 11q loss and loss of the G1 phase cell cycle checkpoint. The upregulated ATR‐CHEK1 pathway appears to protect OSCC cells from mitotic catastrophe by enhancing the G2 checkpoint. Knockdown of ATR and/or CHEK1 increases the sensitivity of OSCC cells to IR. These findings suggest that inhibition of the upregulated ATR–CHEK1 pathway may enhance the efficacy of ionizing radiation treatment of OSCC. © 2013 Wiley Periodicals, Inc.  相似文献   
80.
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