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   46988篇
  免费   3384篇
  国内免费   190篇
耳鼻咽喉   375篇
儿科学   1518篇
妇产科学   1215篇
基础医学   6628篇
口腔科学   595篇
临床医学   5063篇
内科学   9830篇
皮肤病学   877篇
神经病学   5566篇
特种医学   1124篇
外国民族医学   1篇
外科学   4174篇
综合类   381篇
一般理论   58篇
预防医学   5708篇
眼科学   618篇
药学   2993篇
中国医学   86篇
肿瘤学   3752篇
  2024年   59篇
  2023年   651篇
  2022年   1089篇
  2021年   2145篇
  2020年   1298篇
  2019年   1772篇
  2018年   2037篇
  2017年   1364篇
  2016年   1519篇
  2015年   1665篇
  2014年   2032篇
  2013年   2629篇
  2012年   4207篇
  2011年   4161篇
  2010年   2109篇
  2009年   1855篇
  2008年   2951篇
  2007年   2912篇
  2006年   2790篇
  2005年   2578篇
  2004年   2289篇
  2003年   2053篇
  2002年   1745篇
  2001年   200篇
  2000年   155篇
  1999年   225篇
  1998年   357篇
  1997年   269篇
  1996年   216篇
  1995年   177篇
  1994年   127篇
  1993年   121篇
  1992年   76篇
  1991年   78篇
  1990年   68篇
  1989年   71篇
  1988年   61篇
  1987年   44篇
  1986年   40篇
  1985年   42篇
  1984年   48篇
  1983年   45篇
  1982年   33篇
  1981年   41篇
  1980年   29篇
  1979年   18篇
  1978年   14篇
  1977年   20篇
  1975年   10篇
  1973年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Introduction: Lenvatinib (LEN) is a multi-kinase anti-angiogenic drug recently approved in several cancers. LEN is not easily manageable due to its complex safety profile. Proteinuria and renal failure (RF) were reported among the most frequent LEN-induced adverse events (AEs), often leading to discontinuations or dose modifications. Understanding the pathogenesis of these AEs could ameliorate the management of LEN-induced renal toxicity.

Areas covered: We present two cases of LEN-induced renal failure (LIRF) with different pathogenesis. 1) LIRF with severe proteinuria in a man treated for a metastatic papillary thyroid carcinoma. Kidney biopsy showed a glomerular damage secondary to LEN, having excluded other causes of RF. 2) LIRF without proteinuria in a woman with metastatic adenoid cystic carcinoma of minor salivary gland. A tubulointerstitial nephropathy was supposed by clinical evaluation and laboratory tests. Effective management was obtained by oral steroids without interrupting LEN.

Expert opinion: The case 1 presented for the first time the histological picture of LIRF with a classical glomerular damage leading to secondary proteinuria and tubular failure. Case 2 showed an alternative LIRF pattern of likely tubulointerstitial injury without proteinuria. These reports reflect two sides of the same coin, both to be considered in case of LIRF.  相似文献   

992.

Purpose

Abundance of receptors on tumor vasculature presents a prominent target for theranostic applications. The alphavbeta3 integrin receptors expressed on vascular endothelial cells during angiogenesis were therefore considered targets for imaging. Non-invasive visualization of tumor growth and/or delivery systems can appreciate tumor localization and disposition kinetics of carriers, respectively. Herein, we report near-infrared fluorescence imaging (NIRFI) of solid tumors using targeted fluorescence nanoliposomes in vivo.

Methods

Fluorescence nanoliposomes surface modified with cRGD-peptide were injected into CD1 athymic (nu/nu) mice bearing C6 glioblastoma xenografts (300 mm3). At different time points, mice were subjected to NIRFI for visualization of tumor xenografts and nanocarrier tracing in vivo.

Results

NIRFI showed tumor localization of 1,1′-dioctadecyl-3,3,3′,3′-tetramethyl indotricarbocyanine iodide (DiR18)-incorporated-targeted liposomes with maximum tumor-to-tissue occurring at 24-h post-liposome administration. Interaction of integrin receptors with targeted liposomes had contributed to an intense NIRF signal. Molecular studies showed an elevated expression of alphavbeta3 integrin receptors in tumor xenografts.

Conclusion

From the studies, it can be concluded that non-invasive localization of tumors and tracing of liposome carriers had been achieved using receptor targeting and NIRFI approaches.
  相似文献   
993.
994.
995.
BackgroundReverse total shoulder arthroplasty (rTSA) improves shoulder elevation in patients treated for cuff tear arthropathy (CTA) or irreparable massive cuff tears. Patient satisfaction can be limited by reduced active external rotation (AER). Rotator cuff muscles that externally rotate the shoulder are infraspinatus and teres minor (TM).AimThe purpose of this study was to assess the correlation between preoperative TM fatty degeneration and postoperative AER after rTSA performed for CTA or irreparable cuff tears.MethodsConstant scores and active range of motion were consecutively collected for 109 shoulders in 97 patients (mean: 75.73 ± 8.94 years; 31 male, 66 female) over a 10-year period. AER was evaluated with the humerus in adduction (AER1) and in abduction. TM muscle atrophy was scored according to Goutallier's classification, assessed on preoperative computed tomography scans.ResultsMultivariate analysis showed that TM fatty infiltration was a predictor of AER1. AER1 decreased by 4.9 degrees preoperatively and by 6.4 degrees at the final follow-up, for each increment in Goutallier grade (P = .02). Postoperatively, AER evaluated with humerus in abduction improved significantly (P < .001), but did not correlate with TM Goutallier grade. At a mean follow-up of 38 months (range: 24 to 96), mean Constant score improved from 20.5 ± 11.1 to 68.4 ± 14.9 (P < .001), as did shoulder active range of motion in all planes including AER1 (P < .001).ConclusionThis is the first study to quantify the inverse correlation between AER and TM Goutallier grade, both preoperatively and after rTSA; this information guides prognosis for patients with TM degeneration undergoing rTSA. Further studies are necessary to have a better understanding and find reliable solutions.Level of evidenceLevel III; Case Series  相似文献   
996.
997.
International Urology and Nephrology - The aim of this prospective cohort study was: to identify the association between different biomarkers [proprotein convertase subtilisin/kexin 9-PCSK9,...  相似文献   
998.
World Journal of Surgery - Trauma is a leading cause of morbidity and mortality worldwide, and patients in low- and middle-income countries are disproportionately affected. Organized trauma...  相似文献   
999.

This study describes and characterizes a narrow, hollow tubular structure, termed as duct-like diverticulum (DV), found specifically at the basal midline of papillary craniopharyngiomas (PCPs) located within the third ventricle (3V). The presence of this structure was systematically investigated on autopsy studies and magnetic resonance imaging (MRI) scans of 3536 craniopharyngioma (CP) cases published in the medical literature from 1911 to 2021, as well as in other twelve 3V tumor categories (n?=?1470 cases). A basal DV was observed in a total of 50 PCPs, including two of our own cases. This DV corresponds to a tubular-shaped recess invaginated at the midline bottom of the tumor, following the same angled trajectory as the pituitary stalk. It can be easily seen as a hypointense linear structure on T1- and T2-weighted MRI scans, with two main length types: long DVs (74%), which reach the tumor center, and short DVs (26%), which penetrate the tumor only a few millimeters. The DV sign identifies the papillary CP type with a specificity of 100% and a sensitivity of 33% in the overall CP population. This finding also serves to establish the strictly intra-3V location of the lesion with a 95% specificity and 42% sensitivity among papillary CPs. No similar basal DV was found in adamantinomatous CPs nor among other categories of strictly 3V tumors. Consequently, the presence of a diverticulum in a 3V tumor represents a morphological signature pathognomonic of the papillary type and a valuable sign to reliably define the strictly 3V topography.

  相似文献   
1000.
The accurate determination of cerebrovascular reserve (CVR), especially in elderly subjects, entails several technical issues. From a review of the literature, the optimal technique employs quantitative 15O-water PET imaging determinations of cerebral blood flow (CBF) and acetazolamide (ACZ) (1 g iv with measurements at 10- to 20-min post-administration) as the vasodilating agent. CBF and CVR measurements were made using this methodology on 12 elderly subjects (3 males, 9 females, 66-84 years of age) meeting criteria for mild cognitive impairment (MCI) without other significant medical problems. Applying this quantitative technique, the cognitive and emotional status of the subject during the imaging procedure influenced the magnitude of the measurements. The semiquantitative measures resulted in even more pronounced subject state influences. The conditions under which CBF or CVR measurements are made should be controlled and reported. If semiquantitative techniques (e.g., single-photon emission-computed tomography [SPECT] imaging) must be employed for the determination of CVR, the validity of any measurement is dependent on the careful control of the general physiological status (e.g., heart rate, blood pressure, level of anxiety) of the patient.  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