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   1648篇
  免费   96篇
  国内免费   15篇
耳鼻咽喉   8篇
儿科学   36篇
妇产科学   74篇
基础医学   178篇
口腔科学   31篇
临床医学   141篇
内科学   465篇
皮肤病学   26篇
神经病学   170篇
特种医学   44篇
外科学   133篇
综合类   4篇
预防医学   89篇
眼科学   16篇
药学   198篇
中国医学   7篇
肿瘤学   139篇
  2024年   2篇
  2023年   15篇
  2022年   37篇
  2021年   56篇
  2020年   32篇
  2019年   47篇
  2018年   53篇
  2017年   43篇
  2016年   49篇
  2015年   68篇
  2014年   71篇
  2013年   85篇
  2012年   139篇
  2011年   134篇
  2010年   69篇
  2009年   53篇
  2008年   95篇
  2007年   107篇
  2006年   97篇
  2005年   109篇
  2004年   72篇
  2003年   97篇
  2002年   73篇
  2001年   18篇
  2000年   19篇
  1999年   18篇
  1998年   17篇
  1997年   5篇
  1996年   10篇
  1995年   9篇
  1994年   4篇
  1993年   4篇
  1992年   11篇
  1991年   8篇
  1990年   4篇
  1989年   3篇
  1988年   6篇
  1987年   6篇
  1986年   3篇
  1985年   5篇
  1984年   1篇
  1983年   4篇
  1964年   1篇
排序方式: 共有1759条查询结果,搜索用时 15 毫秒
21.

Objective

To investigate whether oldest-old age (≥85y) is an independent predictor of exclusion from stroke rehabilitation.

Design

Retrospective cohort study.

Setting

Stroke unit (SU) of a tertiary hospital.

Participants

Elderly patients (N=1055; aged 65–74y, n=230; aged 75–84y, n=432; aged ≥85y, n=393) who, between 2009 and 2012, were admitted to the SU with acute stroke and evaluated by a multiprofessional team for access to rehabilitation. The study excluded patients for whom rehabilitation was unnecessary or inappropriate.

Interventions

Not applicable.

Main Outcome Measures

Access to an early mobilization (EM) protocol during SU stay and subsequent access to postacute rehabilitation after SU discharge. Analyses were adjusted for prestroke and stroke-related characteristics.

Results

32.2% of patients were excluded from EM. Multivariable-adjusted odds ratios (ORs) of EM exclusion were 1.30 (95% confidence interval [CI], .76–2.21) for ages 75 to 84 years and 2.07 (95% CI, 1.19–3.59) for ages ≥85 years compared with ages 65 to 74 years. Of 656 patients admitted to EM and who, at SU discharge, had not yet fully recovered their prestroke functional status, 18.4% were excluded from postacute rehabilitation. For patients able to walk unassisted at SU discharge, the probability of exclusion did not change across age groups. For patients unable to walk unassisted at SU discharge, ORs of exclusion from postacute rehabilitation were 3.74 (95% CI, 1.26–11.13) for ages 75 to 84 years and 9.15 (95% CI, 3.05–27.46) for ages ≥85 years compared with ages 65 to 74 years.

Conclusions

Oldest-old age is an independent predictor of exclusion from stroke rehabilitation.  相似文献   
22.
23.
Background Botulin toxin (BTX) has been proposed as a potential obesity treatment.Methods In a pilot study, the short-term efficacy and safety of BTX was assessed in eight subjects (four men, four women; median age, 46 years; range, 35–57 years) with severe obesity (median body mass index [BMI], 47.1 kg/m2; range 38.2–56.7 kg/m2) and multiple dietary treatment failures. In a single endoscopic session, 500 UI of BTX-A was injected in the gastric antral region.Results No clinically significant side effects were observed. In all patients, despite their not being on a specific diet, a reduction of body weight was observed at 1 month (median baseline weight, 124.4 kg vs 121.8 kg at 1 month; P < 0.05). Two treatment-unrelated dropouts were observed. At 4 months, three of the six patients had a further weight loss. The treatment effect was apparently independent of changes in hunger or satiety, or of changes in fasting and postprandial plasma ghrelin and serum leptin, thus suggesting a different pharmacological mechanism.Conclusions BTX-A treatment appears to be safe and well tolerated by obese patients, while its short-term efficacy varied widely.  相似文献   
24.
Somatic mutations of genes codifying for key regulatory proteins are the cause of different types of hormone-secreting adenomas. Natriuretic peptides (NP) are the strongest inhibitors of aldosterone secretion but aldosterone-secreting adenomas (aldosteronomas) are resistant to this inhibition and have reduced binding sites for NPs. The objective of this study was to sequence the entire coding region of the NP receptor type A (NPRA, codified by the Npr1 gene) to find loss-of-function somatic mutations. Total RNA was extracted from eight aldosteronomas and cDNA was synthesized. NPRA mRNA expression was evaluated by Northern blot analysis and compared with beta-actin mRNA as the housekeeping gene. Twelve primer couples were designed on the basis of the Npr1 gene organization to amplify, by PCR, all 22 coding exons of the gene. The two strands of amplified DNAs were purified and directly sequenced by automated capillary sequencer. NPRA mRNA expression did not differ among aldosteronomas. Npr1 open reading frame sequences obtained from eight aldosteronomas did not contain any mutation. The coding sequences of all 22 exons were identical in all samples and identical to published sequences. In the 3'-untranslated region (3'-UTR) a new length difference 3C/4C polymorphism was found at position 15 129 (three adenomas were 3C/4C and two were 3C/3C). Such a 3C/4C polymorphism was present in genomic DNA from 80 control subjects (25, 4C/4C; 40, 3C/4C; 15, 3C/3C). Mutations in the coding exons of the Npr1 gene do not appear to be a common cause of aldosteronomas. Moreover, the exons of Npr1 encoding for the translated portion of mRNA do not appear to be prone to polymorphisms. The polymorphism identified in the 3'-UTR might affect mRNA stability resulting in lower receptor synthesis, but it is not likely to confer a predisposition to the development of aldosteronomas.  相似文献   
25.
BACKGROUNDThe significant risks posed to mothers and fetuses by COVID-19 in pregnancy have sparked a worldwide debate surrounding the pros and cons of antenatal SARS-CoV-2 inoculation, as we lack sufficient evidence regarding vaccine effectiveness in pregnant women and their offspring. We aimed to provide substantial evidence for the effect of the BNT162b2 mRNA vaccine versus native infection on maternal humoral, as well as transplacentally acquired fetal immune response, potentially providing newborn protection.METHODSA multicenter study where parturients presenting for delivery were recruited at 8 medical centers across Israel and assigned to 3 study groups: vaccinated (n = 86); PCR-confirmed SARS-CoV-2 infected during pregnancy (n = 65), and unvaccinated noninfected controls (n = 62). Maternal and fetal blood samples were collected from parturients prior to delivery and from the umbilical cord following delivery, respectively. Sera IgG and IgM titers were measured using the Milliplex MAP SARS-CoV-2 Antigen Panel (for S1, S2, RBD, and N).RESULTSThe BNT162b2 mRNA vaccine elicits strong maternal humoral IgG response (anti-S and RBD) that crosses the placenta barrier and approaches maternal titers in the fetus within 15 days following the first dose. Maternal to neonatal anti-COVID-19 antibodies ratio did not differ when comparing sensitization (vaccine vs. infection). IgG transfer ratio at birth was significantly lower for third-trimester as compared with second trimester infection. Lastly, fetal IgM response was detected in 5 neonates, all in the infected group.CONCLUSIONAntenatal BNT162b2 mRNA vaccination induces a robust maternal humoral response that effectively transfers to the fetus, supporting the role of vaccination during pregnancy.FUNDINGIsrael Science Foundation and the Weizmann Institute Fondazione Henry Krenter.  相似文献   
26.
Recent clinical reports have shown an increasing number of patients afflicted by eating disorders in the western world. There are numerous causes and mechanisms leading to eating disorders that affect the psychoneuroendocrinoimmune system. In this study, we define a novel psychoneuroendocrinoimmune nursing approach for anorexic and bulimic patients&rsquo; treatment. According to the specific diagnostic items deriving from the Diagnostic and Statistical Manual of Mental Disorders and the International Classification of Diseases, and clinical guidelines in eating disorders formulated by the National Institute for Clinical Excellence, we carried out a qualitative study on the nursing treatment chosen by 210 international centers considered as a sample. This study was based on a no structured interview via e-mail to better understand the nursing approach in anorexia and bulimia nervosa. Thanks to the selected centers&rsquo; answers, four different levels of nursing care were identified, that include:
  1. the nursing role analyzing the spectrum of patients&rsquo; problems;

  2. the nursing intervention in inpatient care;

  3. the nursing intervention in outpatient care;

  4. the day hospital treatment.

All four prove to be especially useful in the nursing practice.  相似文献   
27.
Tumor progression is deeply influenced by epigenetic changes induced by tumor stroma. Cancer-associated fibroblasts (CAFs) have been reported to promote epithelial–mesenchymal transition in cancer cells, thereby enhancing their aggressiveness and stem-like properties. As CAFs are able to recruit endothelial progenitor cells (EPCs) to tumor site, we aim to investigate their interplay for prostate carcinoma progression. Both prostate CAFs and cancer cells actively recruit EPCs, known to affect tumor progression through increased vasculogenesis. EPCs synergize with CAFs to further promote epigenetic plasticity of cancer cells, through a mesenchymal-to-amoeboid transition. Indeed, after fibroblasts have engaged epithelial–mesenchymal transition in cancer cells, a further shift towards amoeboid motility is promoted by EPCs through contact-mediated triggering of the bidirectional ephrinA1/EphA2 signaling. The activation of ephrinA1 reverse pathway enhances EPC-induced neo-vascularization, thus promoting tumor growth, while EphA2 forward signaling elicits mesenchymal–amoeboid transition in cancer cells, favoring their adhesion to endothelium, transendothelial migration, and lung metastatic colonization. We therefore underscore that the metastatic advantage given by tumor microenvironment embraces different motility strategies and propose EphA2-targeted tools as useful adjuvants in anti-metastatic treatments.  相似文献   
28.
Clinical Oral Investigations - With only limited information available on dimensional changes after jaw cyst surgery, postoperative cyst shrinkage remains largely unpredictable. We aimed to propose...  相似文献   
29.
Angiotensin-converting enzyme (ACE) is a dipeptidylcarboxypeptidase that occurs in three types of cells: endothelial, epithelial, and neuroepithelial. ACE activity is present in plasma, urine, and vascular endothelium. High levels of ACE are found in the brush border of human small bowel. The aim of this study was to evaluate ACE activity in human stools and to find a correlation with the intestinal loss of epithelial cells. Fifteen healthy subjects (HS) (8 males, 7 females; age range 6–56 years), 20 patients with celiac disease (CD) (11 males, 9 females; age range 15–53 years), and 18 patients with CD in remission after a gluten-free diet (CD-GFD) (8 males, 10 females; age range 14–54 years) were enrolled in the study. The fecal ACE activity was measured in all groups. Fecal samples were kept at –20°C for a subsequent test. In HS, fecal ACE activity was 21.03±16.17 nmol/min/100 g (mean ±sd). In patients with CD with subtotal mucosa atrophy, ACE activity was significantly higher (113 ± 88.94) than in HS and CD on GFD (36.65±23.9). We have demonstrated ACE activity in human stools. ACE activity in stools seems to derive from the microvilli of the intestinal mucosa, thus suggesting the potential usefulness of ACE determination as an index of enterocyte damage.  相似文献   
30.
We report a new case of benign solitary fibrous tumor (SFT) of the liver. A 65‐year‐old man presented to our unit with upper right abdominal discomfort. On examination abdominal distension was present and palpation showed a large firm mass in the right hypochondrium and epigastrium. The patient's past medical history was not significant and laboratory tests were normal. Ultrasonography and computed tomography showed a large tumor, 20 cm in diameter, in the right lobe of the liver. An extended right hepatectomy was performed. The tumor measured 30 × 28 × 14 cm and weighed 4725 g. Microscopic evaluation showed a benign SFT of the liver with tumor cells typically positive for vimentin and CD34. The postoperative course was uneventful, and the patient is alive 30 months after surgery. This is a rare neoplasm of mesenchymal origin that occasionally involves the liver in adult patients. Most SFTs are benign, but some may have malignant histological features and recur locally or metastasize. Because of their rarity, overall experience has not been significant and little has been published concerning this tumor, Including the present one, 28 cases have been reported in the English literature. Surgery is the mainstay of treatment. Little can be said about the benefits of adjuvant radiochemotherapy in these patients. As SFT of the liver is often a benign neoplasm, chemotherapy or radiotherapy should not be necessary, and should be reserved for when resection is incomplete and/or histological examination reveals features of malignancy. Surgeons must be aware of SFT of the liver, and this neoplasm should be included in the differential diagnosis of a single large hepatic mass.  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