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   3500篇
  免费   174篇
  国内免费   29篇
耳鼻咽喉   31篇
儿科学   90篇
妇产科学   22篇
基础医学   400篇
口腔科学   56篇
临床医学   226篇
内科学   1052篇
皮肤病学   60篇
神经病学   252篇
特种医学   188篇
外科学   654篇
综合类   27篇
预防医学   91篇
眼科学   16篇
药学   176篇
中国医学   19篇
肿瘤学   343篇
  2023年   20篇
  2022年   75篇
  2021年   94篇
  2020年   64篇
  2019年   87篇
  2018年   103篇
  2017年   77篇
  2016年   73篇
  2015年   72篇
  2014年   120篇
  2013年   144篇
  2012年   226篇
  2011年   238篇
  2010年   158篇
  2009年   129篇
  2008年   190篇
  2007年   212篇
  2006年   204篇
  2005年   193篇
  2004年   149篇
  2003年   185篇
  2002年   158篇
  2001年   45篇
  2000年   53篇
  1999年   46篇
  1998年   36篇
  1997年   40篇
  1996年   28篇
  1995年   31篇
  1994年   25篇
  1993年   20篇
  1992年   33篇
  1991年   25篇
  1990年   24篇
  1989年   34篇
  1988年   26篇
  1987年   20篇
  1986年   34篇
  1985年   16篇
  1984年   18篇
  1983年   14篇
  1981年   16篇
  1979年   12篇
  1978年   9篇
  1977年   13篇
  1976年   10篇
  1975年   11篇
  1974年   13篇
  1969年   14篇
  1967年   7篇
排序方式: 共有3703条查询结果,搜索用时 31 毫秒
101.
Colorectal cancer (CRC) is one of the most common types of cancer and a significant cause of cancer mortality worldwide. Further improvements of CRC therapeutic approaches are needed. BCL2‐associated athanogene 6 (BAG6), a multifunctional scaffold protein, plays an important role in tumor progression. However, regulation of BAG6 in malignancies remains unclear. This study showed that guided entry of tail‐anchored proteins factor 4 (GET4), a component of the BAG6 complex, regulates the intercellular localization of BAG6 in CRC. Furthermore, GET4 was identified as a candidate driver gene on the short arm of chromosome 7, which is often amplified in CRC, by our bioinformatics approach using the CRC dataset from The Cancer Genome Atlas. Clinicopathologic and prognostic analyses using CRC datasets showed that GET4 was overexpressed in tumor cells due to an increased DNA copy number. High GET4 expression was an independent poor prognostic factor in CRC, whereas BAG6 was mainly overexpressed in the cytoplasm of tumor cells without gene alteration. The biological significance of GET4 was examined using GET4 KO CRC cells generated with CRISPR‐Cas9 technology or transfected CRC cells. In vitro and in vivo analyses showed that GET4 promoted tumor growth. It appears to facilitate cell cycle progression by cytoplasmic enrichment of BAG6‐mediated p53 acetylation followed by reduced p21 expression. In conclusion, we showed that GET4 is a novel driver gene and a prognostic biomarker that promotes CRC progression by inducing the cytoplasmic transport of BAG6. GET4 could be a promising therapeutic molecular target in CRC.  相似文献   
102.
A 77-year-old man complained of postmeal vomiting and sustained general fatigue. An abdominal computed tomography scan showed massive gastric expansion and fluid storage. Gastroscopy revealed four gastric bezoars that were considered to have caused pyloric ring obstruction. The patient was asked to drink 500 mL per day of Coca-Cola for 4 days. On the fourth day, we performed endoscopic crushing and removal by injecting Coca-Cola, cutting the softened bezoar with endoscopic snares, and collecting the pieces with endoscopic nets. We herein report (with a video presentation) a rare case of tannin-phytobezoars endoscopically removed with the administration and injection of Coca-Cola.  相似文献   
103.
The Nobel Prize in Chemistry was awarded in 1987 and 2016 for research in supramolecular chemistry on the “development and use of molecules with structure-specific interactions of high selectivity” and the “design and production of molecular machines”, respectively. This confirmed the explosive development of supramolecular chemistry. In addition, attempts have been made in systems chemistry to embody the complex functions of living organisms as artificial non-equilibrium chemical systems, which have not received much attention in supramolecular chemistry. In this review, we explain recent developments in supramolecular chemistry through four categories: stimuli-responsiveness, time evolution, dissipative self-assembly, and hierarchical expression of functions. We discuss the development of non-equilibrium supramolecular systems, including the use of molecules with precisely designed properties, to achieve functions found in life as a hierarchical chemical system.  相似文献   
104.

Purpose

Although obesity is considered as a risk factor for postoperative morbidity in abdominal surgery, its effect on the outcomes of laparoscopic-assisted colectomy (LAC) is still unclear. The technical difficulty and risk factor for postoperative complication in LAC are thought to be influenced by visceral obesity. The aim of this prospective study was to evaluate the impact of visceral fat on the surgical outcomes of LAC.

Methods

Between April 2005 and December 2010, consecutive patients with preoperatively diagnosed colon cancer, excluding medium and low rectal cancer, who underwent LAC, were enrolled. Their visceral fat area (VFA) and body mass index (BMI) were prospectively collected. The VFA was assessed by Fat Scan software. The patients were classified into two groups as follows: VFA nonobese with VFA <100 cm2 (VNO) and VFA obese with VFA ≧100 cm2 (VO). The predictive factors for surgical complications of LAC were evaluated by univariate and logistic regression analyses.

Results

A total of 338 consecutive patients were enrolled in this study. Of the 338 patients, 194 (57.4 %) and 138 (42.6 %) were classified into the VNO and VO groups, respectively. Logistic regression analysis showed that high BMI (≧25 kg/m2) and VO independently predicted the incidence of overall postoperative complications (p?=?0.040 and 0.007, respectively). VO was more highly related to the incidence of overall postoperative complications, anastomotic leakage (p?=?0.021), and surgical site infection (SSI) (p?=?0.013) than high BMI.

Conclusions

VFA is a more useful parameter than BMI in predicting surgical outcomes after LAC.  相似文献   
105.
Human multipotent adipose-derived stem cells (hMADSCs) have recently been isolated featuring extensive expansion capacity ex vivo. We tested the hypothesis that hMADSC transplantation might contribute to cardiac functional recovery by its direct or indirect effect on myocardial infarction (MI). Nude rats were either transplanted with hMADSCs or PBS (control) in ischemic myocardium immediately following MI. Echocardiographical assessment of cardiac function after MI with hMADSCs showed significant improvement of each parameter compared to that with PBS. Histological analysis also showed significantly reduced infarct size and increased capillary density in peri-infarct myocardium by hMADSC treatment. However, remarkable transdifferentiation of hMADSCs into cardiac or vascular lineage cells was not observed. Despite the less transdifferentiation capacity, hMADSCs produced robust multiple pro-angiogenic growth factors and chemokines, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and stromal cell-derived factor-1α (SDF-1α). Specifically, hMADSC-derived SDF-1α had a crucial role for cooperative angiogenesis, with the paracrine effect of hMADSCs and Tie2-positive bone marrow (BM) progenitor recruitment in ischemic myocardium. hMADSCs exhibit a therapeutic effect on cardiac preservation following MI, with the production of VEGF, bFGF, and SDF-1α showing paracrine effects and endogenous BM stem/progenitor recruitment to ischemic myocardium rather than its direct contribution to tissue regeneration.  相似文献   
106.
Background: The Q‐switched laser is the treatment of choice when attempting to improve dermal pigmented lesions. However, purpura and dyspigmentation are frequently observed after treatment. Objective: To compare the efficacy and complications of the Q‐switched alexandrite laser when delivered with versus without compression in the treatment of dermal pigmented lesions. Methods: Ten patients with dermal lesions were enrolled in the study. Each patient had a lesion treated with the Q‐switched alexandrite laser delivered with compression. Each patient also had a lesion treated with the Q‐switched alexandrite laser delivered without compression with the same fluence and spot size. The patients were evaluated for efficacy and treatment‐related side effects. Results: There was no significant difference in efficacy, but purpura and dyspigmentation were more likely when pigmented lesions were treated without compression. Conclusion: Purpura from Q‐switched laser treatment in darkly pigmented skin is due to mechanical injury of blood vessels. It is well known that pressure ‘diascopy’ eliminates blood from cutaneous vessels by coapting the vessel lumen. In this study, we used pressure applied by a glass window on the Q‐switched laser handpiece to remove cutaneous blood during laser exposure, making it possible to reduce purpura and dyspigmentation.  相似文献   
107.
Therapeutic strategies preventing late target lesion revascularization (TLR) after drug-eluting stent implantation have not been yet adequately investigated. In 13,087 consecutive patients undergoing first percutaneous coronary intervention in the CREDO-Kyoto Registry Cohort-2, we identified 10,221 patients who were discharged alive after implantation of sirolimus-eluting stents (SESs) only (SES stratum 5,029) or bare-metal stents (BMSs) only (BMS stratum 5,192). Impact of statin therapy at time of discharge from the index hospitalization on early (within the first year) and late (1 year to 4 years) TLR, was assessed in the SES stratum (statin group 2,735; nonstatin group 2,294) and in the BMS stratum (statin group 2,576; nonstatin group 2,616). Despite a significantly lower incidence of early TLR (7.8% vs 22.2%, p <0.0001), SES use compared to BMS use was associated with a significantly higher incidence of late TLR (7.7% vs 3.0%, p <0.0001). In the SES and BMS strata, the incidence of early TLR was similar regardless of statin use. In the SES stratum, the incidence of late TLR was significantly lower in the statin group than in the nonstatin group (6.1% vs 9.6%, p = 0.002), whereas no significant difference was found in the BMS stratum (2.6% vs 3.3%, p = 0.38). After adjusting confounders, risk for late TLR significantly favored statin use in the SES stratum (hazard ratio 0.73, 95% confidence interval 0.54 to 0.98, p = 0.04), whereas the risk decrease was not significant in the BMS stratum (hazard ratio 0.74, 95% confidence interval 0.46 to 1.20, p = 0.23). In conclusion, statin therapy at hospital discharge was associated with a significantly lower risk for late TLR after SES implantation.  相似文献   
108.
A 60-year-old Japanese woman was diagnosed with celiac disease (CeD) and treated with a gluten-free diet. For five years, she had a good clinical course. However, she complained of inappetence and nausea. Colonoscopy revealed ulcerative tumors in the terminal ileum. A histological examination of biopsy specimens from the ulcerative tumor showed diffuse infiltration of large atypical lymphocytes. Immunohistologically, the atypical lymphoid cells were positive for cluster of differentiation (CD)10 and CD20. Many Epstein-Barr virus-encoded small RNA (EBER)-positive atypical lymphocytes were detected by in situ hybridization. This represents the first reported case of Epstein-Barr virus-positive intestinal diffuse large B-cell lymphoma complicated with CeD.  相似文献   
109.
This study aimed to clarify the characteristics and treatment of bowel obstruction associated with feeding jejunostomy in patients who underwent esophagectomy for esophageal cancer. In this single-center retrospective study, 363 patients underwent esophagectomy with mediastinal lymph node dissection for esophageal cancer at the Wakayama Medical University Hospital between January 2014 and June 2021. All patients who underwent esophagectomy routinely underwent feeding jejunostomy or gastrostomy. Feeding jejunostomy was used in the cases of gastric tube reconstruction through the posterior mediastinal route or colon reconstruction, while feeding gastrostomy was used in cases of retrosternal route gastric tube reconstruction. Nasogastric feeding tubes and round ligament technique were not used. Postoperative small bowel obstruction occurred in 19 of 197 cases of posterior mediastinal route reconstruction (9.6%), but in no cases of retrosternal route reconstruction because of the feeding gastrostomy (P < .0001). Of the 19 patients who had bowel obstruction after feeding jejunostomy, 10 patients underwent reoperation (53%) and the remaining 9 patients had conservative treatment (47%). The cumulative incidence of bowel obstruction after feeding jejunostomy was 6.7% at 1 year and 8.7% at 2 years. Feeding jejunostomy following esophagectomy is a risk factor for small bowel obstruction. We recommend feeding gastrostomy inserted from the antrum to the jejunum in the cases of gastric tube reconstruction through the retrosternal route or nasogastric feeding tube in the cases of reconstruction through the posterior mediastinal route.  相似文献   
110.
4‐(4‐Hydroxyphenyl)‐2‐butanol (rhododendrol, RD), a skin‐whitening agent, was reported to cause skin depigmentation in some users, which is attributed to its cytotoxicity to melanocyte. It was reported that cytotoxicity to melanocyte is possibly mediated by oxidative stress in a tyrosinase activity‐dependent manner. We examined the effect of UV radiation (UVR) on RD‐induced melanocyte cytotoxicity as an additional aggravating factor. UVR enhanced RD‐induced cytotoxicity in normal human epidermal melanocytes (NHEMs) via the induction of endoplasmic reticulum (ER) stress. Increased generation of intracellular reactive oxygen species (ROS) was detected. Pretreatment with N‐acetyl cysteine (NAC), antioxidant and precursor of glutathione significantly attenuated ER stress‐induced cytotoxicity in NHEMs treated with RD and UVR. Increase in cysteinyl‐RD‐catechol and RD‐pheomelanin in NHEMs treated with RD and UVR suggested that, after UVR excitation, RD or RD metabolites are potent ROS‐generating substances and that the tendency to produce RD‐pheomelanin during melanogenesis amplifies ROS generation in melanocytes. Our results help to elucidate the development mechanisms of RD‐induced leukoderma and provide information for innovation of safe skin‐whitening compounds.  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