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   1546篇
  免费   93篇
  国内免费   3篇
耳鼻咽喉   21篇
儿科学   34篇
妇产科学   85篇
基础医学   190篇
口腔科学   65篇
临床医学   107篇
内科学   413篇
皮肤病学   21篇
神经病学   132篇
特种医学   28篇
外科学   240篇
综合类   3篇
一般理论   2篇
预防医学   133篇
眼科学   22篇
药学   62篇
中国医学   1篇
肿瘤学   83篇
  2023年   4篇
  2022年   12篇
  2021年   40篇
  2020年   25篇
  2019年   37篇
  2018年   49篇
  2017年   31篇
  2016年   29篇
  2015年   36篇
  2014年   53篇
  2013年   59篇
  2012年   76篇
  2011年   96篇
  2010年   62篇
  2009年   47篇
  2008年   86篇
  2007年   81篇
  2006年   97篇
  2005年   65篇
  2004年   71篇
  2003年   69篇
  2002年   59篇
  2001年   45篇
  2000年   57篇
  1999年   44篇
  1998年   17篇
  1997年   12篇
  1996年   9篇
  1995年   5篇
  1994年   4篇
  1992年   32篇
  1991年   21篇
  1990年   19篇
  1989年   26篇
  1988年   22篇
  1987年   15篇
  1986年   19篇
  1985年   21篇
  1984年   9篇
  1983年   6篇
  1982年   10篇
  1980年   5篇
  1978年   4篇
  1976年   4篇
  1974年   8篇
  1973年   7篇
  1972年   5篇
  1971年   6篇
  1969年   3篇
  1968年   5篇
排序方式: 共有1642条查询结果,搜索用时 15 毫秒
71.
Objectives: To screen for potentially underreported behavioral changes in patients with idiopathic Parkinson's disease (PD) pre‐ and post‐deep brain stimulation (DBS), a retrospective data base review was performed. Methods: In total, 113 patients who underwent unilateral or bilateral DBS at the University of Florida in either subthalamic nucleus or globus pallidus internus for PD were screened for behavioral issues by asking about the presence or absence of seven neuropsychiatric symptoms (panic, fear, paranoia, anger, suicidal flashes, crying, and laughing). Results: There was a high prevalence of fear (16.3%), panic (14.0%), and anger (11.6%) at baseline in this cohort. In the first six months following DBS implantation, anger (32.6%), fear (26.7%), and uncontrollable crying (26.7%) were the most frequent symptoms reported. Those symptoms also were present following six months of DBS surgery (30.2%, 29.1%, and 19.8%, respectively). New uncontrollable crying occurred more in the acute postoperative stage (less than or equal to six months) (p= 0.033), while new anger occurred more in the chronic postoperative stage (greater than six months) (p= 0.017). The frequency of uncontrollable laughing significantly increased with bilateral DBS (p= 0.033). Conclusions: Many of the neuropsychiatric issues were identified at preoperative baseline and their overall occurrence was more than expected. There was a potential for worsening of these issues post‐DBS. There were subtle differences in time course, and in unilateral vs. bilateral implantations. Clinicians should be aware of these potential behavioral issues that may emerge following DBS therapy, and should consider including screening questions in preoperative and postoperative interviews. Standardized scales may miss the presence or absence of these clinically relevant issues.  相似文献   
72.
To perform the adequate treatment of upper urinary tract lesions it is very important to have an exact diagnosis. When the suspicion of an upper tract urothelial tumor is established the initial evaluation is carried out by imaging diagnostic tests (intravenous urography, pyelography, and others). The association of radiological tests and urine cytologies allows us to get to a correct diagnosis in most cases. Upper urinary tract endoscopy solves some equivocal cases, but sometimes it is impossible to clarify the nature of the lesion in spite of a comprehensive diagnostic effort. Therapeutic decision should be individualized in these cases. The objective of this article is to describe the various features of upper tract urothelial tumors in a variety of available imaging tests, and to review all conditions that may have similar images, describing the characteristic radiological findings for each of them. We discuss about differential diagnosis and perform a critical evaluation of the diagnostic difficulties that occasionally present upper urinary tract diseases.  相似文献   
73.
A multicentre study was sponsored by the International Atomic Energy Agency (Vienna) to assess the safety and efficacy of trans-arterial rhenium-188 HDD conjugated lipiodol (radioconjugate) in the treatment of patients with inoperable hepatocellular carcinoma (HCC). The radioconjugate was prepared by using an HDD (4-hexadecyl 1-2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol) kit developed in Korea, and lipiodol. Over a period of 18 months, 70 patients received at least one treatment of radioconjugate. Some patients were re-treated if there was no evidence of disease progression. The level of radioconjugate administered was based on radiation-absorbed dose to critical normal organs, calculated following a scout dose of radioconjugate. The organs at greatest risk for radiation toxicity are the normal liver, the lung and the bone marrow. An Excel spreadsheet was used to determine maximum tolerated activity (MTA), defined as the amount of radioactivity calculated to deliver no more than 12 Gy to lungs, or 30 Gy to liver, or 1.5 Gy to bone marrow. These doses have been found to be safe in multiple trials using external beam therapy, but this has not been confirmed for systemically administered radiopharmaceuticals. Patients were followed for at least 12 weeks after therapy, until recovery from all toxicity. The clinical parameters evaluated included toxicity, response as determined by contrast-enhanced computed tomography, palliation of symptoms, overall survival, performance status (Karnofsky) and hepatic function (Childs classification). Liver function tests, serum -fetoprotein (AFP) levels and complete blood counts were done at each follow-up visit. In the majority of patients, the scout dose studies indicated the radiation absorbed dose to normal liver to be the limiting factor to the treatment dose, while in a few patients dose to lung was the limiting factor. Radiation dose to bone marrow was negligible and was thus not a factor for the MTA calculations. Side-effects were minimal and usually presented as loss of appetite, right hypochondrial discomfort and low-grade fever, even at high levels of administered radioactivity. The symptoms resolved with simple supportive therapy within 3 days of onset. Liver function tests at 24 and 72 h showed no significant changes and complete blood counts at 1 week, 4 weeks and 12 weeks showed no changes (no bone marrow suppression). Sixteen patients were treated in the dose escalation phase of the study, when the activities administered started at 1.8 GBq (50 mCi) and rose to 7.7 GBq (206 mCi). In the efficacy phase of the study a further 54 patients were treated. Both groups of patients are included in this paper. The treatment activity of 188Re-lipiodol administered transarterially ranged from 1.8 to 9.8 GBq (50–265 mCi), with a mean activity of 4.6 GBq (124 mCi). Survival at 3 months was 90%, and at 6 months, 60%; 19% survived for 1 year. Mean survival after treatment in the total treated group of 70 patients was 9.5 months, with a range of 1–18 months. The results of this multicentre study show that 188Re-lipiodol is a safe and cost-effective method to treat primary HCC via the transarterial route. In terms of efficacy, it is potentially a new therapeutic approach for further evaluation by treatment of larger numbers of patients.  相似文献   
74.

Background

Adaptation after massive small bowel resection (SBR) is associated with increased rates of enterocyte proliferation (P) and apoptosis (A). In the present study, we sought to determine the effect of dual therapy designed to increase P and simultaneously reduce A.

Methods

C57Bl/6 mice underwent a 50% small bowel resection (SBR) or sham operation, and then received an inhibitor of apoptosis (pan-caspase inhibitor), a stimulus for proliferation (epidermal growth factor; EGF), a combination, or vehicle control. After 3 days, adaptive morphology (villus height, crypt depth) and rates of enterocyte turnover (proliferation and apoptosis) were measured in the remnant ileum.

Results

Adaptation in controls and treated with the inhibitor was similar. EGF-treated mice demonstrated an even greater adaptive response. Combined therapy with the inhibitor and EGF resulted in maximal adaptation as gauged by the greatest increases in villus height and crypt depth and ratio of rates of P to A.

Conclusion

The capacity for adaptation following massive SBR is maintained via tight regulation of cell production and death. Pharmacologic intervention directed at increasing enterocyte proliferation while simultaneously decreasing apoptosis augments adaptation greater than either intervention alone and may provide a useful strategy to clinically amplify adaptation.  相似文献   
75.
The aim of this study was to determine the normal planar and SPET patterns of the thoracic distribution of 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) in 20 patients who had undergone a previous median sternotomy and without infectious complications at follow-up. The study included anterior and oblique anterior planar views at 4 and 20 h. SPET of the chest was also carried out at 4 and 20 h. At 4 h, the planar views showed low background vascular activity in the lungs and cardiac region in addition to the sternal uptake, which showed two patterns: homogeneous in five patients and heterogeneous in 15. A long and narrow defect of uptake along the sternal midline was the most characteristic finding. At 4 h, in addition to the background vascular activity in the lungs and cardiac region, the greatest uptake on SPET was in the sternum anteriorly and the marrow spine posteriorly without any focal uptake, allowing visualization of the mediastinum free of focal activity. At 20 h, both the planar and SPET images showed a higher organ-to-background ratio. Knowledge of these post-surgical patterns will make it easier to interpret planar and SPET images when 99Tcm-HMPAO-labelled leukocytes are used in the diagnosis of mediastinitis and sternal infections in patients who had previously undergone median sternotomy. Planar views were better for the assessment of sternal uptake, but SPET views were better for the direct visualization of the mediastinum by eliminating overlapping sternal uptake.  相似文献   
76.
The aim of this review is to assist pulmonologists in the management of diseases involving both the upper and lower respiratory tract that are linked by a common, interrelated epidemiology, clinical signs and symptoms, and inflammatory mechanism , asthma, in particular.The document discusses the definitions of the various sinonasal phenotypes associated with asthma: allergic and non-allergic rhinitis and chronic rhinosinusitis with or without nasal polyps. Diagnostic criteria and severity levels are also listed.Particular attention has been given to the 2 main syndromes associated with asthma: (i) allergic rhinitis, the most common, and (ii) chronic rhinosinusitis with nasal polyps, the disease most closely associated with severe asthma.To summarize, the upper respiratory tract should always be evaluated in order to achieve a single diagnosis and comprehensive treatment of the “united airway”.  相似文献   
77.
78.

Background

Access for end-stage renal disease (ESRD) patients to the renal transplant (RT) waiting list can vary depending on the criteria used and how they are applied in each dialysis unit.

Methods

This study was performed in the reference area (2.5 million inhabitants) of a transplant center. Data were from a regional registry (Information System of the Autonomous Coordination of Transplants in Andalusia) of total dialysis patients. Patients were grouped according to transplant status as: effective waiting list (WL); never recorded or excluded (E); incomplete immunologic study or discharge data (IIS); temporary contraindication (TC); or active (A).

Results

There were 1424 dialysis patients. Of these, 58% were E, 18% were IIS, 14% were TC, and 10% were A. Significant differences were detected for proportion of patients listed as active status (A) in 3 hospital dialysis units (2.9%–13.4%) and 12 hemodialysis centers (4.2%–29.2%); proportion of IIS cases in the hospitals (0%–57%) and dialysis centers (0%–58%); and in proportion of TC cases in the hospitals (19%–50%) and dialysis centers (2.5%–19.3%). The mean age of patients varied significantly between IIS, TC, and A groups (60.3, 54.8, and 52.3 years old, respectively, P < .001). Accentuated differences between the 2 provinces included in the sector were verified. There are notable differences in inclusion of pre-dialysis patients between hospital units.

Conclusion

We detected considerable variability between hospital units and non-hospital dialysis centers in relation to inclusion on the active transplant waiting list and the proportion of patients with IIS or TC status. It is essential to implement a more homogeneous system for case selection through a specific intervention program from the reference center.  相似文献   
79.
The epidemiological cycle of zoonotic phlebotomine‐borne Leishmania infantum is a complex system in which domestic animals and wildlife interact and participate in its maintenance and transmission. In this study, we combined entomological surveillance, xenomonitoring of L. infantum and identification of host feeding sources of engorged females to investigate the potential contribution of a periurban wildlife park to leishmaniosis in neighbouring residential areas. Overall, 7,309 sand flies were collected in 111 trap‐days during the summers of 2016–2018 in an endemic area in south‐east Spain. Five different sand fly species were captured, with Phlebotomus perniciosus, the main L. infantum vector in this region, representing the most common species. Sand fly distribution was spatially heterogeneous in terms of species, sexes and female physiological stage (unfed, gravid and engorged females) and related to host distribution and management, and environmental features. None of the 602 sand flies analysed for L. infantum infection by kinetoplast real‐time PCR were positive. We used molecular tools to identify the vertebrate hosts of sand flies and identified 17 host species, mainly mammals. Human DNA was not identified in engorged sand flies. This study provides evidence that wildlife parks in south‐east Spain are ideal grounds for sand fly vectors but do not necessarily increase L. infantum infection risk to humans and dogs living in surrounding residential areas. This is probably because vectors feed mostly on non‐L. infantum competent hosts and this should be investigated for a better understanding of the contribution of wildlife parks to the local epidemiology of L. infantum.  相似文献   
80.
There is notable heterogeneity in the implementation of cytomegalovirus (CMV) prevention practices among CMV‐seropositive (R+) kidney transplant (KT) recipients. In this prospective observational study, we included 387 CMV R+ KT recipients from 25 Spanish centers. Prevention strategies (antiviral prophylaxis or preemptive therapy) were applied according to institutional protocols at each site. The impact on the 12‐month incidence of CMV disease was assessed by Cox regression. Asymptomatic CMV infection, acute rejection, graft function, non‐CMV infection, graft loss, and all‐cause mortality were also analyzed (secondary outcomes). Models were adjusted for a propensity score (PS) analysis for receiving antiviral prophylaxis. Overall, 190 patients (49.1%) received preemptive therapy, 185 (47.8%) antiviral prophylaxis, and 12 (3.1%) no specific intervention. Twelve‐month cumulative incidences of CMV disease and asymptomatic infection were 3.6% and 39.3%, respectively. Patients on prophylaxis had lower incidence of CMV disease [PS‐adjusted HR (aHR): 0.10; 95% confidence interval (CI): 0.01–0.79] and asymptomatic infection (aHR: 0.46; 95% CI: 0.29–0.72) than those managed preemptively, with no significant differences according to the duration of prophylaxis. All cases of CMV disease in the prophylaxis group occurred after prophylaxis discontinuation. There were no differences in any of the secondary outcomes. In conclusion, antiviral prophylaxis was associated with a lower occurrence of CMV disease in CMV R+ KT recipients, although such benefit should be balanced with the risk of late‐onset disease.  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