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   6419篇
  免费   317篇
  国内免费   65篇
耳鼻咽喉   47篇
儿科学   189篇
妇产科学   143篇
基础医学   643篇
口腔科学   146篇
临床医学   443篇
内科学   1696篇
皮肤病学   127篇
神经病学   384篇
特种医学   381篇
外科学   1145篇
综合类   18篇
预防医学   219篇
眼科学   53篇
药学   297篇
中国医学   8篇
肿瘤学   862篇
  2024年   10篇
  2023年   90篇
  2022年   128篇
  2021年   252篇
  2020年   154篇
  2019年   218篇
  2018年   272篇
  2017年   169篇
  2016年   195篇
  2015年   201篇
  2014年   308篇
  2013年   358篇
  2012年   504篇
  2011年   517篇
  2010年   283篇
  2009年   251篇
  2008年   403篇
  2007年   384篇
  2006年   342篇
  2005年   403篇
  2004年   338篇
  2003年   307篇
  2002年   259篇
  2001年   34篇
  2000年   28篇
  1999年   36篇
  1998年   63篇
  1997年   45篇
  1996年   38篇
  1995年   32篇
  1994年   27篇
  1993年   23篇
  1992年   12篇
  1991年   10篇
  1990年   15篇
  1989年   12篇
  1988年   13篇
  1987年   6篇
  1986年   12篇
  1985年   5篇
  1984年   7篇
  1983年   3篇
  1982年   5篇
  1981年   4篇
  1980年   6篇
  1977年   3篇
  1975年   2篇
  1971年   2篇
  1965年   2篇
  1904年   2篇
排序方式: 共有6801条查询结果,搜索用时 15 毫秒
41.

Objectives

Breastfeeding is a well-recognised investment in the health of the mother-infant dyad. Nevertheless, many professionals still advise breastfeeding mothers to temporarily discontinue breastfeeding after contrast media imaging. Therefore, we performed this review to provide health professionals with basic knowledge and skills for appropriate use of contrast media.

Methods

A joint working group of the Italian Society of Radiology (SIRM), Italian Society of Paediatrics (SIP), Italian Society of Neonatology (SIN) and Task Force on Breastfeeding, Ministry of Health, Italy prepared a review of the relevant medical literature on the safety profile of contrast media for the nursing infant/child.

Results

Breastfeeding is safe for the nursing infant of any post-conceptional age after administration of the majority of radiological contrast media to the mother; only gadolinium-based agents considered at high risk of nephrogenic systemic fibrosis (gadopentetate dimeglumine, gadodiamide, gadoversetamide) should be avoided in the breastfeeding woman as a precaution; there is no need to temporarily discontinue breastfeeding or to express and discard breast milk following the administration of contrast media assessed as compatible with breastfeeding.

Conclusions

Breastfeeding women should receive unambiguous professional advice and clear encouragement to continue breastfeeding after imaging with the compatible contrast media.

Key Points:

? Breastfeeding is a well-known investment in the health of the mother-infant dyad. ? Breastfeeding is safe after administration of contrast media to the mother. ? There is no need to temporarily discontinue breastfeeding following administration of contrast media.  相似文献   
42.

Purpose

This paper discusses the technique and preliminary results of right thoracic paravertebral block (TPVB) for percutaneous thermal ablation of liver tumours.

Materials and methods

Between October 2011 and August 2012 we treated 36 lesions (25 hepatocellular carcinoma and 11 metastases) in 30 patients aged 47–85 years (mean 67.5). Patients received ultrasound (US)-guided injection of 7 ml of naropin 0.75 % in T7, T9 and T11 levels, below the costo-vertebral ligament, until we observed an anterior displacement of the parietal pleura. For the subcapsular lesions, a cervical right phrenic nerve block was associated. The level of analgesia was evaluated during and after the percutaneous procedures with the Numerical Rating Scale. Finally, we investigated statistical correlations between pain and lesions (histological type, site, dimensions), and ablation time and technique (microwave or radiofrequency ablation).

Results

Technical success was achieved in all patients. Despite the correct anaesthetic diffusion during the ablation, 10 patients (33.3 %) reported medium/severe pain and intravenous sedation was required. Pain was not found to correlate with any variable. No complications were observed.

Conclusions

In most cases, TPVB is a safe and effective technique for conscious anaesthesia during percutaneous thermal ablation of liver tumours. Failures probably derive from left sympathetic and parasympathetic fibre stimulation. We recommend performing a TPVB in the presence of the anaesthetist.  相似文献   
43.

Purpose

To evaluate the relationships among myocardial sympathetic innervation, perfusion and mechanical synchronicity assessed with cardiac cadmium-zinc-telluride (CZT) scintigraphy.

Methods

A group of 29 patients underwent an evaluation of myocardial perfusion with 99mTc-tetrofosmin CZT scintigraphy and adrenergic innervation with 123I-metaiodobenzylguanidine (MIBG) CZT scintigraphy. The summed rest score (SRS), motion score (SMS) and thickening score (STS), as well as the summed 123I-MIBG defect score (SS-MIBG), were determined. Regional tracer uptake for both 99mTc-tetrofosmin and 123I-MIBG was also calculated. Finally, the presence of significant myocardial mechanical dyssynchrony was evaluated in phase analysis on gated CZT images and the region of latest mechanical activation identified.

Results

Significant mechanical dyssynchrony was present in 17 patients (59 %) and associated with higher SRS (P?=?0.030), SMS (P?<?0.001), STS (P?=?0.003) and early SS-MIBG (P?=?0.037) as well as greater impairments in left ventricular ejection fraction (P?<?0.001) and end-diastolic volume (P?<?0.001). In multivariate analysis a higher end-diastolic volume remained the only predictor of mechanical dyssynchrony (P?=?0.047). Interestingly, while in the whole population regional myocardial perfusion and adrenergic activity were strongly correlated (R?=?0.68), in patients with mechanical dyssynchrony the region of latest mechanical activation was predicted only by greater impairment in regional 123I-MIBG uptake (P?=?0.012) that overwhelmed the effect of depressed regional perfusion.

Conclusion

Left ventricular mechanical dyssynchrony is associated with greater depression in contractile function and greater impairments in regional myocardial perfusion and sympathetic activity. In patients with dyssynchrony, the region of latest mechanical activation is characterized by a significantly altered adrenergic tone.  相似文献   
44.

Objective

To evaluate the efficacy and safety of combined radiofrequency ablation (RFA) and ethanol injection with a multipronged needle in the treatment of medium (3.1–5.0 cm) and large (5.1–7.0 cm) hepatocellular carcinoma (HCC).

Methods

A total of 65 patients with 67 HCC nodules were enrolled in this prospective study. All of them received the treatment of combined RFA and multipronged ethanol injection percutaneously.

Results

The average volume of injected ethanol was 14.4?±?4.1 ml (range, 9–30 ml). The average number of RFA electrode insertions was 1.7?±?0.8 (range, 1–4). The rate of initial local complete response (CR) was 94.0 % (63/67). After additional treatment, technical success was achieved in all HCC nodules. There were no treatment-related deaths, and major complications were observed in 3 (4.6 %) patients. After a mean follow-up of 20.0?±?7.6 months, local tumour progression was observed in 10 (10/67, 14.9 %) tumours, whereas distant recurrence developed in 32 (32/65, 49.2 %) patients. The 1-year and 2-year survival rates were 93.1 % and 88.1 %, respectively.

Conclusion

The combination of RFA and multipronged ethanol injection in the treatment of medium and large HCC is safe and effective with a high rate of local tumour control.

Key Points

? Combined radiofrequency ablation and multipronged ethanol injection is a new therapeutic strategy ? Treatment is safe and effective for medium and large hepatocellular carcinoma (HCC) ? A multipronged needle allows for a homogeneous ethanol distribution  相似文献   
45.
BACKGROUND: Ischemia/reperfusion (I/R) injury after organ transplantation is a major cause of delayed graft function. Following I/R, locally produced CXC chemokines attract and activate granulocytes, which in turn promote graft damage. METHODS: We examined the involvement of granulocyte recruitment via the CXCR2 pathway in a rat model of 4 hours cold ischemia followed by kidney transplantation. Serum creatinine and intragraft granulocyte infiltration were monitored in the early phase posttransplant. A CXCR2 inhibitor, repertaxin, was given to recipients before transplantation (at -24 hours or -8 hours or -2 hours), immediately before reperfusion and 2 hours later. RESULTS: An increase of granulocyte chemoattractant CINC-1/interleukin-8 (IL-8) mRNA expression after I/R both in syngeneic and allogeneic transplantation was associated with a marked infiltration of granulocytes in renal tissue. In syngeneic transplantation, Lewis rats given 15 mg/kg repertaxin 24 hours before surgery had granulocyte graft infiltration and serum creatinine levels significantly reduced in respect to vehicle-treated animals. Intermediate effects were observed with 5 mg/kg, whereas the dose of 30 mg/kg had toxic effects. We found that reducing the pretreatment time to 8 hours before surgery was still effective. Prevention of granulocyte infiltration and serum creatinine increase was also obtained in allogeneic transplantation, when Brown Norway recipients of Lewis kidneys were given 15 mg/kg repertaxin starting 8 hours before surgery. CONCLUSION: Repertaxin treatment of the recipient animal was effective in preventing granulocyte infiltration and renal function impairment both in syngeneic and in allogeneic settings. The possibility to modulate I/R injury in this rat model opens new perspectives for preventing posttransplant delayed graft function in humans.  相似文献   
46.
The Pediatric End-Stage Liver Disease (PELD) score was designed to reduce subjectivity in liver allocation and to advantage patients with a higher probability of waiting list mortality. The aims of this study were to determine the impact of PELD implementation for children with chronic liver disease and to assess whether PELD met its goal of standardization of liver allocation for children. This study used data reported to the United Network for Organ Sharing (UNOS) registry for children with chronic liver disease receiving primary cadaveric liver transplant between January 2000 and December 2001 (pre-PELD) and March 2002 and July 2003 (PELD). PELD reduced the percentage of children transplanted while in an intensive care unit and as status 1. A calculated PELD score was used for allocation in only 52% of recipients. Thirty percent were status 1 at transplant and PELD scores granted by exception were used for allocation in 18% of patients. There was regional variation in PELD score at allocation and use of exception scores with a significant relationship between PELD score and percentage of exception cases. Regional variation suggests that PELD has not resulted in standardization of listing practices in pediatric liver transplantation.  相似文献   
47.

Purpose

To validate and compare the values of “MIC” and “trifecta” as predictors of operated kidney functional preservation in a multi-institutional cohort of patients undergoing minimally invasive PN.

Methods

We retrospectively reviewed records of consecutive cases of minimally invasive PN performed for cT1 renal masses in 4 centers from 2009 to 2013. Inclusion criteria consisted of availability of a renal scan obtained within 2 weeks prior to surgery and follow-up renal scan 3–6 months after the surgery. The primary endpoint of the study was to compare the degree of ipsilateral renal function preservation assessed by MAG3 renal scan in relation to achievement of MIC and trifecta.

Results

Total of 351 patients met our inclusion criteria. The rates of trifecta achievement for cT1a and cT1b tumors were 78.9 and 60.6 %, respectively. The rate of MIC achievement for cT1a tumors and cT1b tumors was 60.3 and 31.7 %, respectively. On multivariable linear regression model, only the degree of tumor complexity assessed by R.E.N.A.L nephrometry score [coefficient B ?1.8 (?2.7, ?0.9); p < 0.0001] and the achievement of trifecta [coefficient B 6.1 (2.4,9.8); p = 0.014] or MIC (coefficient B 7.2 (3.8,0.6); p < 0.0001) were significant clinical factors predicting ipsilateral split function preservation.

Conclusions

Achievement of both MIC and “trifecta” is associated with higher proportion of split renal function preservation for cT1 tumors after minimally invasive PN. Thus, these outcome measures can be regarded not only as markers of surgical quality, but also as reliable surrogates for predicting functional outcome in the operated kidney.
  相似文献   
48.

Aim

Surgical myotomy of the lower esophageal sphincter has a 5-year success rate of approximately 91 %. Peroral endoscopic myotomy can provide similar results for controlling dysphagia. Some patients experience either persistent or recurrent dysphagia after myotomy. We present here a retrospective analysis of our experience with redo myotomy for recurrent dysphagia in patients with achalasia.

Methods

From March 1996 to February 2015, 234 myotomies for primary or recurrent achalasia were performed in our center. Fifteen patients (6.4 %) had had a previous myotomy and were undergoing surgical redo myotomy (n?=?9) or endoscopic redo myotomy (n?=?6) for recurrent symptoms.

Results

Patients presented at a median of 10.4 months after previous myotomy. Median preoperative Eckardt score was 6. Among the nine patients undergoing surgical myotomy, three esophageal perforations occurred intraoperatively (all repaired immediately). Surgery lasted 111 and 62 min on average (median) in the surgical and peroral endoscopic myotomy (POEM) groups, respectively. No postoperative complications occurred in either group. Median postoperative stay was 3 and 2.5 days in the surgical and POEM groups, respectively. In the surgical group, Eckardt score was <3 for seven out of nine patients after a mean follow-up of 19 months; it was <3 for all six patients in the POEM group after a mean follow-up of 5 months.

Conclusions

A redo myotomy should be considered in patients who underwent myotomy for achalasia and presenting with recurrent dysphagia. Preliminary results using POEM indicate that the technique can be safely used in patients who have undergone previous surgical myotomy.
  相似文献   
49.
The treatment of gastric cancer requires a multidisciplinary approach in which surgery plays the main role. The diffusion of minimally invasive surgery for gastric cancer treatment is limited by the complexity of performing an extended lymphadenectomy. This surgical step can be facilitated through the use of a robot-assisted system. To date, there are few published articles discussing a full robotic approach that precisely show the different surgical steps. The aim of this study is to describe our experience, surgical techniques and the short-term results of a consecutive series of full robotic gastrectomies using the Da Vinci Surgical System. From November 2011 to January 2015, 17 patients with gastric cancer underwent curative resection by robotic approach for locally advanced tumors. In summary, there were 15 total gastrectomies with a Roux-en-Y esophagojejunostomy, one total gastrectomy with transverse colectomy and one sub-total gastrectomy. Resection margins were negative in all cases. Conversions occurred in two patients. Robot-assisted gastrectomy with extended lymphadenectomy is a safe technique and successfully allows an adequate lymph node harvest and optimal R0-resection rates with low postoperative morbidity. The learning curve appears to be shorter than in laparoscopic surgery. Further follow-up and randomized clinical trials are required to confirm the role of a robotic approach in gastric cancer surgery.  相似文献   
50.
“勃起功能障碍观测研究”(Erectile Dysfunction Observational Study,EDOS)是一项为期6个月的多中心前瞻性研究,研究对象包括被要求开始接受治疗或改变治疗方式的ED病人。本研究旨在分析ED的治疗模式,并比较不同治疗模式的疗效。研究对象为到医院看病并诊断需要进行ED治疗的患者。他们接受ED治疗,并在治疗开始时、治疗3个月、6个月时回答来自IIEF(International Index of Erectile Function),EDITS(Erectile Dysfunction Inventory of Treatment Satisfaction),SF-PAIRS(Short Form of the Psychological and Interpersonal Relationship Scale)/nq卷的问题。医生可以给病人开出市场上现有的任何疗法,并可以在治疗过程中任何时间改变疗法。在完成为期6个月的分析的1338名病人中,有624人(47%)改变了疗法,714人(53%)一直接受最初诊断的疗法,其中接受治疗的病人持续接受一种疗法的比率显著高于接受西地那非或伐地那非治疗的病人。其它影响这一比率的变量包括性欲低下和ED。各种PDE-5抑制剂在效力、病人满意度、自信心、自发性等方面无显著差异。接受他达拉非治疗的病人的SF—PAIRS“时间相关”项的分数显著优于接受其它治疗的病人。结果显示现有的三种PDE-5抑制剂的临床实践和临床实验结果相似,但病人如果要终止或改变用药,他达拉非的风险较低。  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