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   932篇
  免费   57篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   62篇
妇产科学   9篇
基础医学   89篇
口腔科学   23篇
临床医学   80篇
内科学   170篇
皮肤病学   11篇
神经病学   155篇
特种医学   158篇
外科学   42篇
综合类   21篇
预防医学   91篇
眼科学   3篇
药学   48篇
肿瘤学   26篇
  2021年   4篇
  2020年   3篇
  2019年   5篇
  2018年   10篇
  2017年   5篇
  2016年   4篇
  2015年   8篇
  2014年   18篇
  2013年   28篇
  2012年   16篇
  2011年   23篇
  2010年   42篇
  2009年   30篇
  2008年   22篇
  2007年   30篇
  2006年   31篇
  2005年   36篇
  2004年   26篇
  2003年   33篇
  2002年   19篇
  2001年   24篇
  2000年   20篇
  1999年   27篇
  1998年   36篇
  1997年   27篇
  1996年   27篇
  1995年   30篇
  1994年   27篇
  1993年   20篇
  1992年   14篇
  1991年   14篇
  1990年   17篇
  1989年   22篇
  1988年   20篇
  1987年   19篇
  1986年   14篇
  1985年   19篇
  1984年   12篇
  1983年   13篇
  1982年   23篇
  1981年   18篇
  1980年   16篇
  1979年   24篇
  1978年   21篇
  1977年   13篇
  1976年   34篇
  1975年   18篇
  1973年   3篇
  1972年   9篇
  1971年   4篇
排序方式: 共有990条查询结果,搜索用时 15 毫秒
81.
82.
The present study assessed the patterns of cortical gray matter (GM) loss in patients with amnestic mild cognitive impairment (aMCI) with distinct profiles of memory impairment, i.e. aMCI patients failing on both recall and recognition memory vs. aMCI patients showing impaired recall but preserved recognition memory. This distinction is usually not taken into account in studies on aMCI and the aim of the present study was to assess whether this distinction is useful. Twenty-eight aMCI patients and 28 matched controls subjects were included. All aMCI patients failed a recall memory task (inclusion criteria). All underwent a visual recognition memory task (DMS48). However, 12 succeeded on this task while 16 failed. Relative gray matter (GM) loss was measured using voxel-based morphometry. When comparing aMCI patients to controls regardless of the profile of memory impairment, GM loss was found in temporal, parietal and frontal areas. However, in aMCI patients with preserved recognition (but impaired recall), GM loss was confined to frontal areas. This contrasted with GM loss in the right medial temporal lobe and bilateral temporo-parietal regions in aMCI patients with impaired recall and recognition memory, a pattern of GM loss usually described in early AD. We conclude that different profiles of memory impairment in aMCI patients are associated with distinct patterns of GM loss.  相似文献   
83.
We report on M.S., an 83-year-old patient with isolated pure progressive amnesia. This rare, recently identified, form of amnesia has been described in elderly patients. Neuropathological studies suggest that this syndrome is an atypical clinical presentation of Alzheimer's disease. The aim of our study was to characterize the neuropsychological pattern of pure progressive amnesia in comparison with other amnestic syndromes and memory dissociations reported in the literature. Our results indicate that pure progressive amnesia is characterized by a highly unusual dissociation in the realm of memory, with severe deficits on tests based on recognition and recall of verbal and visual single items, contrasting with relatively preserved anterograde autobiographical and spatial memory and normal recall of complex material such as stories. These findings suggest that memory for single items could depend on an independent system. One hypothesis is that M.S.'s unusual memory profile results from relative dysfunction of the ventral medial temporal lobe pathway. An alternative explanation implicates cognitive reserve. Further studies are required in order to progress on this matter. In any case, pure progressive amnesia is a clinical syndrome that may provide further insight into the organization of declarative memory.  相似文献   
84.
幽门螺杆菌感染处理的当前观念——MaastrichtⅢ共识报告   总被引:8,自引:0,他引:8  
名词缩写 欧洲幽门螺杆菌研究小组:European Helicobacter Study Group,EHSG 胃食管反流病:gastro-esophageal reflux disease,GERD  相似文献   
85.
86.
87.

Background

To avoid ischemic hand complications, the percutaneous transradial approach is only performed in patients with patent hand collateral arteries, which is usually evaluated with the modified Allen's test (MAT). This qualitative test measures the time needed for maximal palmar blush after release of the ulnar artery compression with occlusive pressure of the radial artery. The objectives were to evaluate the patency of the hand collateral arteries and to compare MAT with combined plethysmography (PL) and pulse oximetry (OX) tests before the percutaneous transradial approach.

Methods

Patients referred to the catheterization laboratory were prospectively examined with MAT, PL, and OX tests. PL readings during radial artery compression were divided into 4 types: A, no damping; B, slight damping of pulse tracing; C, loss followed by recovery; or D, no recovery of pulse tracing within 2 minutes. OX results were either positive or negative. Results of both tests were compared in 1010 consecutive patients.

Results

MAT results ≤9 seconds on either hand were seen in 93.7% of patients. PL and OX types A, B, or C on either hand were seen in 98.5% of patients. On the basis of the MAT ≤9 seconds criteria, 6.3% of patients were excluded from the transradial approach, whereas with PL and OX types A, B, and C, only 1.5% of patients were excluded. There was more exclusion in men and with increasing age by using both methods.

Conclusions

In the evaluation of hand collaterals, PL and OX were found to be more sensitive than MAT. When applied to transradial approach screening, only 1.5% of patients were not suitable candidates for the transradial approach.  相似文献   
88.
The EDTNA/ERCA survey of the treatment of water for dialysis was the third project organised through the Collaborative Research Programme (CRP). Data was collected from 69 haemodialysis facilities in 14 countries. Water quality in European dialysis units was mainly self‐regulated. The majority of centres aimed to meet the requirements of the European Pharmacopoeia, but only 50% carried out tests to check compliance. All facilities used reverse osmosis to treat water for dialysis, most also used softening and carbon adsorption. There was a wide variation in policies for the maintenance of carbon filters, and for the control and monitoring of contamination in the distribution system. Endotoxin tests carried out in 27 facilities showed that higher levels of contamination are associated with systems that are infrequently disinfected, and also with older system designs. The survey indicated that guidelines for water treatment are urgently needed. EDTNA/ERCA guidelines for microbiological monitoring are now being drafted, additional guidelines are under consideration.  相似文献   
89.
ObjectiveTo ascertain the socio-cultural factors influencing the rate of utilization of insecticide treated bed nets (ITNs) in a malaria endemic city of Makurdi, north central Nigeria.MethodsThe study was cross-sectional in nature using systematic sampling method to identify households. Both quantitative and qualitative data was generated from adult women using structured and semi structured questionnaires, and focused group discussions (FGDs) to obtain information on rate and patterns of utilization of ITNs. Information such as age, educational level, marital status, awareness or otherwise of the existence of malaria, and factors influencing rate of ownership and utilization of ITNs were obtained. FGDs were used to obtain qualitative information on rate of utilization of ITNs not captured in the questionnaires. Data obtained was analysed using Epi Info 6 statistical software.ResultsAmong the respondents interviewed, 97.0% (2 013/2 075) were aware of existence of malaria and 87.0% of these (1 751/2 013) would associate it with mosquitoes. The rate of ownership of any bed net, ITNs and untreated bed nets (UTNs) was 25.1%, 17.0% and 8.3%, respectively. Utilization of ITNs among children was 30.0% (112/373) and UTNs 12.9% (48/373). Positive contributors to ITNs utilization were literacy, enhanced economy, experience of marriage, and being gainfully employed (P<0.05); while negative contributors were ignorance, poverty and some cultural beliefs and values.ConclusionsA more synchronized advocacy should be carried out on the potential benefits of ITNs utilization and sustained. Also ITNs should be made available to the people of the community at minimal or no cost.  相似文献   
90.
The goal of this phase II multicenter clinical trial was to evaluate a new intensive chemotherapy program for adults with untreated acute lymphoblastic leukemia (ALL) and to examine prospectively the impact of clinical and biologic characteristics on the outcome. One hundred ninety-seven eligible and evaluable patients (16 to 80 years of age; median, 32 years of age) received cyclophosphamide, daunorubicin, vincristine, prednisone, and L-asparaginase; 167 patients (85%) achieved a complete remission (CR), 13 (7%) had refractory disease, and 17 (9%) died during induction. A higher CR rate was observed in younger patients (94% for those < 30 years old, 85% for those 30 to 59 years old, and 39% for those > or = 60 years old, P < .001) and in those who had a mediastinal mass (100%) or blasts with a T-cell immunophenotype. Eighty percent of B-lineage and 97% of T-cell ALL patients achieved a CR (P = .01). The coexpression of myeloid antigens did not affect the response rate or duration. Seventy percent of those with cytogenetic or molecular evidence of the Philadelphia (Ph) chromosome and 84% of those without such evidence achieved a CR (P = .11). Patients in remission received multiagent consolidation treatment, central nervous system prophylaxis, late intensification, and maintenance chemotherapy for a total of 24 months. After a median follow-up time of 43 months, the median survival for all 197 patients is 36 months; the median remission duration for the 167 CR patients is 29 months. Favorable pretreatment characteristics relative to remission duration or survival are younger age, the presence of a mediastinal mass or lymphadenopathy, a white blood cell count (WBC) less than 30,000/microL, L1 morphology, T or TMy immunophenotype, and the absence of the Ph chromosome. The estimates of the proportion surviving at 3 years are 69% for patients less than 30 years old, 39% for those 30 to 59 years old, 89% for those who had a mediastinal mass, 59% with WBC less than 30,000/microL, 63% with L1 morphology, 69% for T or TMy antigen expression, and 62% for those who lack the Ph chromosome. Fifteen patients (8%) had no unfavorable prognostic factors and have an estimated probability of survival at 5 years of 100% (95% confidence interval, 77% to 100%). This intensive chemotherapy regimen produces a high remission rate and a high proportion of durable remissions in adults with ALL.  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