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   27811篇
  免费   1636篇
  国内免费   268篇
耳鼻咽喉   236篇
儿科学   550篇
妇产科学   580篇
基础医学   2790篇
口腔科学   666篇
临床医学   1957篇
内科学   7909篇
皮肤病学   369篇
神经病学   2419篇
特种医学   1061篇
外科学   5440篇
综合类   54篇
一般理论   5篇
预防医学   1012篇
眼科学   554篇
药学   1636篇
中国医学   58篇
肿瘤学   2419篇
  2023年   271篇
  2022年   234篇
  2021年   912篇
  2020年   586篇
  2019年   846篇
  2018年   1008篇
  2017年   735篇
  2016年   891篇
  2015年   905篇
  2014年   1236篇
  2013年   1519篇
  2012年   2319篇
  2011年   2202篇
  2010年   1267篇
  2009年   1216篇
  2008年   1906篇
  2007年   1843篇
  2006年   1734篇
  2005年   1720篇
  2004年   1618篇
  2003年   1386篇
  2002年   1243篇
  2001年   146篇
  2000年   142篇
  1999年   156篇
  1998年   169篇
  1997年   139篇
  1996年   135篇
  1995年   150篇
  1994年   129篇
  1993年   117篇
  1992年   102篇
  1991年   70篇
  1990年   83篇
  1989年   63篇
  1988年   41篇
  1987年   43篇
  1986年   46篇
  1985年   39篇
  1984年   37篇
  1983年   34篇
  1982年   50篇
  1981年   32篇
  1980年   30篇
  1979年   17篇
  1978年   14篇
  1977年   8篇
  1976年   12篇
  1975年   8篇
  1974年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Mechanical intravascular hemolysis is frequently observed following procedures on heart valves and uncommonly observed in native valvular disease. In most cases, its severity is mild. Nevertheless, it can be clinically significant and even life threatening, requiring multiple blood transfusions and renal replacement therapy. This paper reviews the current knowledge on mechanical intravascular hemolysis in valvular disease, before and after correction, focusing on pathophysiology, approach to diagnosis, and impact of other hematological conditions on the resultant anemia. The importance of a multidisciplinary management is underscored. Laboratory data are provided about subclinical hemolysis that is commonly observed following the implantation of surgical and transcatheter valve prostheses and devices. Finally, clinical scenarios are reviewed and current medical and surgical treatments are discussed, including alternative options for inoperable patients.  相似文献   
4.
BackgroundCOVID-19 infection is particularly aggressive in frail patients, as cancer patients. Therefore, the more suitable management of the oncological patient requires a multidisciplinary assessment, to identify which patients should be treated, as inpatients or outpatients, and which treatments can be procrastinated.ConclusionsThe role of radiologist is crucial, and, all cancer patients who need an imaging evaluation will need to be studied, using the most appropriate imaging tools related to the clinical question and paying a special attention to preserve public health. Guidelines are necessary in the correct organization of a radiology unit to manage patients with suspected or confirmed COVID-19 infection, and whenever possible, a satellite radiography center with dedicated equipment should be used to decrease the transmission risk.Key words: COVID-19 infection, cancer patients, diagnostic unit, management, guideline  相似文献   
5.
BackgroundThe present analysis aims to compare the impact of 18F-fluorocholine (18F-choline) and gallium-68 prostate-specific membrane antigen (68Ga-PSMA) positron emission tomography (PET)-computed tomography (CT)–guided metastases-directed therapies (MDTs) in patients with castration-sensitive oligorecurrent prostate cancer (PC).Materials and MethodsInclusion criteria were: (1) histologically proven prostate adenocarcinoma; (2) evidence of biochemical relapse after primary tumor treatment; (3) ≤ 3 hypermetabolic oligorecurrent lesions detected by 18F-choline or 68Ga-PSMA PET-CT; (4) PET-CT imaging performed in a single nuclear medicine department; (5) patients treated with upfront stereotactic body radiotherapy (SBRT) without hormone therapy; and (6) SBRT delivered with a dose per fraction ≥ 5 Gy. In the case of oligoprogression (≤ 3 lesions outside the previous RT field) after MTD, a further course of SBRT was proposed; otherwise, androgen deprivation therapy (ADT) was administered.ResultsA total of 118 lesions in 88 patients were analyzed. Forty-four (50%) patients underwent 68Ga-PSMA PET-guided SBRT, and the remaining underwent choline PET-based SBRT. The median follow-up was 25 months (range, 5-87 months) for the entire cohort. Overall survival and local control were both 100%. Distant progression occurred in 48 (54.5%) patients, for a median distant progression-free survival of 22.8 months (range, 14.4-28.8 months). The median pre-SBRT prostate-specific antigen was 2.04 ng/mL in the choline PET cohort and 0.58 ng/mL in the PSMA-PET arm. Disease-free survival rates were 63.6% and 34%, respectively, in the 68Ga-PSMA and choline PET group (P = .06). The ADT administration rate was higher after choline-PET–guided SBRT (P = .00) owing to the higher incidence of polymetastatic disease after first-course SBRT compared with 68Ga-PSMA-based SBRT.ConclusionIn the setting of oligorecurrent castration-sensitive PC, PSMA-PET-guided SBRT produced a higher rate of ADT-free patients when compared with the 18F-choline-PET cohort. Randomized trials are advocated.  相似文献   
6.
7.
8.

Aim

We sought to assess the magnitude of functional decline and the natural history of the operated kidney residual function after zero-ischemia nephron-sparing surgery (Z-NSS) in children with unilateral renal tumor (URT).

Patients and methods

50 children were treated for URT at our surgical unit between 1992 and 2016. Of these 12 who underwent Z-NSS were available for the current analysis. Operated kidney function was assessed by 99mTc-dimercapto-succinic acid (DMSA) renal scintigraphy. Operated kidney volume was assessed by renal ultrasonography.

Results

A positive correlation between split renal function and split renal volume was found (P?=?0.001). The subset of patients with ≥ 40% preservation of operated kidney function/volume (OKF/V) had no-time dependent changes during adolescence. The subset of patients with < 40% OKF/V preservation had a catch-up growth that after puberty reached values not much different from those with ≥ 40% OKF/V preservation. At 5?years of follow-up, 3 of 5 patients with baseline dysfunction (eGFR between 40.8 and 89.4?ml/min/1.73?m2) presented with a global renal function within normal range. After puberty, all patients presented with global renal function within normal values (eGFR between 95 and 151?ml/min/1.73 m2).

Conclusions

In children with URT who underwent Z-NSS, the pattern of OKF/V recovery suggests that compensatory catch-up growth capacity during childhood minimizes OKF/V decline more than Z-NSS.

Level of evidence

Level I prognosis study — prospective cohort study with > 80% follow-up and all patients enrolled at same time point in disease.  相似文献   
9.
The development of patient‐specific induced pluripotent stem cells (iPSCs) offered interesting insights in modeling the pathogenesis of Charcot‐Marie‐Tooth (CMT) disease and thus we decided to explore the phenotypes of iPSCs derived from a single CMT patient carrying a mutant ATP1A1 allele (p.Pro600Ala). iPSCs clones generated from CMT and control fibroblasts, were induced to differentiate into neural precursors and then into post‐mitotic neurons. Control iPSCs differentiated into neuronal precursors and then into post‐mitotic neurons within 6‐8 days. On the contrary, the differentiation of CMT iPSCs was clearly defective. Electrophysiological properties confirmed that post‐mitotic neurons were less mature compared to the normal counterpart. The impairment of in vitro differentiation of CMT iPSCs only concerned with the neuronal pathway, because they were able to differentiate into mesendodermal cells and other ectodermal derivatives. ATP1A1 was undetectable in the few neuronal cells derived from CMT iPSCs. ATP1A1 gene mutation (p.Pro600Ala), responsible for a form of axonal CMT disease, is associated in vitro with a dramatic alteration of the differentiation of patient‐derived iPSCs into post‐mitotic neurons. Thus, the defect in neuronal cell development might lead in vivo to a decreased number of mature neurons in ATP1A1‐CMT disease.  相似文献   
10.
BackgroundSome patients remain deemed unsuitable for resection after portal vein embolization (PVE) because of insufficient hypertrophy of the future remnant liver (FRL). Hepatic and portal vein embolization (HPVE) has been shown to induce hypertrophy of the FRL. The aim of this study was to provide a systematic review of the available literature on HPVE as preparation for major hepatectomy.MethodsThe literature search was performed on online databases. Studies including patients who underwent preoperative HPVE were retrieved for evaluation.ResultsSix articles including 68 patients were published between 2003 and 2017. HPVE was performed successfully in all patients with no mortality and morbidity-related procedures. The degree of hypertrophy of the FRL after HPVE ranged from 33% to 63.3%. Surgical resection after preoperative HPVE could be performed in 85.3% of patients, but 14.7% remained unsuitable for resection because of insufficient hypertrophy of the FRL or tumor progression. Posthepatectomy morbidity and mortality rates were 10.3% and 5.1%, respectively. The postoperative liver failure rate was nil.ConclusionHPVE as a preparation for major hepatectomy appears to be feasible and safe and could increase the resectability of patients initially deemed unsuitable for resection because of absent or insufficient hypertrophy of the FRL after PVE alone.  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