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   187599篇
  免费   1458篇
  国内免费   111篇
耳鼻咽喉   1209篇
儿科学   6874篇
妇产科学   3381篇
基础医学   17984篇
口腔科学   1868篇
临床医学   13146篇
内科学   34304篇
皮肤病学   886篇
神经病学   17614篇
特种医学   9388篇
外科学   30603篇
综合类   2339篇
一般理论   1篇
预防医学   18445篇
眼科学   2868篇
药学   10069篇
中国医学   644篇
肿瘤学   17545篇
  2023年   85篇
  2022年   103篇
  2021年   338篇
  2020年   211篇
  2019年   306篇
  2018年   22217篇
  2017年   17585篇
  2016年   19741篇
  2015年   1236篇
  2014年   1307篇
  2013年   1410篇
  2012年   7827篇
  2011年   21854篇
  2010年   19352篇
  2009年   12007篇
  2008年   20338篇
  2007年   22543篇
  2006年   1356篇
  2005年   3032篇
  2004年   4146篇
  2003年   5037篇
  2002年   3109篇
  2001年   347篇
  2000年   482篇
  1999年   249篇
  1998年   318篇
  1997年   293篇
  1996年   189篇
  1995年   182篇
  1994年   190篇
  1993年   134篇
  1992年   105篇
  1991年   142篇
  1990年   174篇
  1989年   118篇
  1988年   82篇
  1987年   59篇
  1986年   58篇
  1985年   60篇
  1984年   48篇
  1983年   42篇
  1982年   57篇
  1981年   33篇
  1980年   71篇
  1974年   29篇
  1938年   60篇
  1937年   25篇
  1934年   31篇
  1932年   57篇
  1930年   51篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
An increased number of patients is at risk of Candida spp. bloodstream infection (CBSI) in modern medicine. Moreover, the rising of antifungal resistance (AR) was recently reported. All consecutive CBSI occurred in our Hospital (consisting of 1,370 beds) between 2015 and 2018, were reviewed. For each case, Candida species, AR pattern, ward involved and demographic data of patients were recorded. Overall, 304 episodes of CBSI occurred, with a median (q1:first-,q3:third quartile) of 77 (71-82) CBSI/year. Over the years, a significant increase of CBSI due to C. albicans compared to non-albicans strains was recorded in medical wards (from 65% to 71%, p=0.030), while this ratio remained stable in others. An increase of resistant strains to multiple antifungals such as C. guillermondii was noticed in recent years (from 0% to 9.8%, p=0.008). Additionally, from 2015 to 2018 an increase in fluconazole-resistance was recorded in our Hospital (from 7.4% to 17.4%, p=0.025) and a slight increase in voriconazole-resistance (from 0% to 7% in 2018, p=0.161) was observed, while resistance to echinocandin and amphotericin B remained firmly below 2%.This study suggests a rapid spread of antifungal resistance in our Hospital; therefore, an appropriate antifungal stewardship programs is urgently warranted.  相似文献   
2.
3.
Colorectal cancer (CRC) screening programs help diagnose cancer precursors and early cancers and help reduce CRC mortality. However, currently recommended tests, the fecal immunochemical test (FIT) and colonoscopy, have low uptake. There is therefore a pressing need for screening strategies that are minimally invasive and consequently more acceptable to patients, most likely blood based, to increase early CRC identification. MicroRNAs (miRNAs) released from cancer cells are detectable in plasma in a remarkably stable form, making them ideal cancer biomarkers. Using plasma samples from FIT-positive (FIT+) subjects in an Italian CRC screening program, we aimed to identify plasma circulating miRNAs that detect early CRC. miRNAs were initially investigated by quantitative real-time PCR in plasma from 60 FIT+ subjects undergoing colonoscopy at Fondazione IRCCS Istituto Nazionale dei Tumori, then tested on an internal validation cohort (IVC, 201 cases) and finally in a large multicenter prospective series (external validation cohort [EVC], 1121 cases). For each endoscopic lesion (low-grade adenoma [LgA], high-grade adenoma [HgA], cancer lesion [CL]), specific signatures were identified in the IVC and confirmed on the EVC. A two-miRNA-based signature for CL and six-miRNA signatures for LgA and HgA were selected. In a multivariate analysis including sex and age at blood collection, the areas under the receiver operating characteristic curve (95% confidence interval) of the signatures were 0.644 (0.607–0.682), 0.670 (0.626–0.714) and 0.682 (0.580–0.785) for LgA, HgA and CL, respectively. A miRNA-based test could be introduced into the FIT+ workflow of CRC screening programs so as to schedule colonoscopies only for subjects likely to benefit most.  相似文献   
4.
BackgroundVascular complications are the main cause of early graft loss in renal transplant (RT). A graft with multiple vessels represents the most validated risk factor. The aim of the present study was to identify potential predictive factors for acute vascular complications causing graft loss when graft vascular anomalies are excluded.MethodsThis is a retrospective case-control (1:3 ratio) study extrapolated from the RT series of the Renal Transplant Unit - Udine University Hospital, during the period 1993-2017. Grafts with multiple vessels and retransplant cases were excluded.ResultsThe overall prevalence of graft loss due to acute vascular complications was 2.6% (25/961). Seventeen complicated recipients had grafts without vascular anomalies (case group). The median time between RT and complication was 6 days (interquartile range, 4-23 days). The following types of vascular complications were recorded: 5 isolated renal artery thromboses (0.5%), 4 isolated renal vein thromboses (0.4%), 4 combined renal artery and vein thromboses (0.3%), 3 renal artery ruptures due to mycotic arteritis (0.3%), and 1 renal artery nonmycotic pseudoaneurysm (0.1%). No differences were recorded between the groups in terms of donors and grafts characteristics. Complicated recipients showed a statistically higher prevalence of thromboembolism history (P = .046) and vascular atherosclerosis (P = .048). During the postoperative course, blood stream infections (P = .02), acute rejection (P = .03), bleeding from a nonmacrovascular source (P = .04), and multiple reintervention because of nonvascular complications (P = .03) were identified as significant risk factors.ConclusionsRecipient characteristics and post-RT complications rather than donor and graft characteristics are relevant risk factors for graft loss due to acute vascular complications when graft vascular anomalies are excluded.  相似文献   
5.
Male urinary incontinence is highly prevalent, leading to a miserable quality of life. The artificial urinary sphincter (AUS) is the device that closely simulates the function of the biological urinary sphincter. The precise evaluation of occlusion mechanisms and of interaction phenomena occurring between AUS cuff and urethral duct is fundamental for more reliable design. The action induced in the interaction with urethral duct under a specific pressure depends on its constitutive material and structural characteristics. The methods of experimental and computational bioengineering are exploited to investigate mechanical functionality of the coupled system, as AUS and urethral duct. Experimental tests are developed to investigate the response when the AUS is inflated around a urethral phantom. Numerical model of the cuff is developed mimicking the experimental tests for the validation. Subsequently, numerical models are exploited to interpret the interaction of the cuff with urethral phantoms considering the influence of urethral size and of tissues mechanical behavior, mimicking healthy and degraded configurations. The investigation provides useful information on the behavior of AUS cuff with urethral duct evaluating the action induced and represents a support for planning an extension of experimental tests on animal and human urethral samples.  相似文献   
6.
Clinical Oral Investigations - By means of a systematic review and network meta-analysis, this study aims to answer the following questions: (a) does the placement of a biomaterial over an...  相似文献   
7.
8.
9.

Background

Total ankle replacement (TAR) represents an alternative to fusion for the treatment of end-stage ankle osteoarthritis. The aim of the present study was to retrospectively assess the frequency of infections between TARs with anterior and lateral transfibular approach at 12-months follow-up.

Methods

81 TARs through an anterior approach and 69 TARs through a lateral approach were performed between May 2011 and July 2015. We compared surgical time and tourniquet time, as well as superficial and deep infections frequency during the first 12 postoperative months.

Results

In the anterior approach group, there were 3 (3.7%) deep infections and 4 (4.9%) superficial wound infections. In the lateral approach group, there were 1 (1.4%) deep infection and 2 superficial wound infections (2.9%). There were not statistically significant differences between the groups. There was a significant difference between anterior approach (115 minutes) and lateral approach group (179 minutes) in terms of surgical time (P < 0.001).

Conclusions

The frequency of superficial and deep periprosthetic infections during the first postoperative year was not significantly different in the lateral approach group compared to the anterior approach group, despite the significantly longer surgical time in the lateral transfibular approach group.  相似文献   
10.
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