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   9831篇
  免费   717篇
  国内免费   31篇
耳鼻咽喉   73篇
儿科学   315篇
妇产科学   268篇
基础医学   1456篇
口腔科学   180篇
临床医学   1106篇
内科学   2036篇
皮肤病学   293篇
神经病学   1087篇
特种医学   179篇
外科学   1010篇
综合类   43篇
一般理论   10篇
预防医学   1026篇
眼科学   157篇
药学   558篇
中国医学   20篇
肿瘤学   762篇
  2023年   78篇
  2022年   120篇
  2021年   407篇
  2020年   242篇
  2019年   350篇
  2018年   410篇
  2017年   284篇
  2016年   297篇
  2015年   300篇
  2014年   465篇
  2013年   581篇
  2012年   865篇
  2011年   810篇
  2010年   425篇
  2009年   378篇
  2008年   564篇
  2007年   655篇
  2006年   611篇
  2005年   582篇
  2004年   501篇
  2003年   386篇
  2002年   378篇
  2001年   61篇
  2000年   68篇
  1999年   74篇
  1998年   78篇
  1997年   58篇
  1996年   48篇
  1995年   37篇
  1994年   39篇
  1993年   28篇
  1992年   46篇
  1991年   17篇
  1990年   27篇
  1989年   18篇
  1988年   17篇
  1987年   10篇
  1986年   28篇
  1985年   16篇
  1984年   13篇
  1983年   21篇
  1982年   16篇
  1981年   9篇
  1980年   15篇
  1978年   8篇
  1977年   8篇
  1975年   7篇
  1973年   7篇
  1970年   10篇
  1933年   7篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti–β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation.  相似文献   
2.
3.

Aim

The purpose of this study is to find out whether telephone referral from Primary Health Care to Internal Medicine Consult manages to reduce waiting days as compared to traditional referral. This study also aims to know how acceptable is the telephone referral to general practitioners and their patients.

Design

No blind randomized controlled clinical trial.

Setting

Northern Huelva Health District.

Participants

154 patients.

Interventions

Patients referrals from intervention clinicians were sent via telephone consultation, whereas patients referrals from control clinicians were sent by traditional via.

Measurements

Number of days from referral request to Internal Medicine Consult. Number of telephone and traditional referrals. Number of doctors and patients denied. Denial reasons.

Results

A statistically significant difference was found between groups, with an average of 27 (21-34) days. Among General Practitioners, 8 of the first 58 total doctors after randomization and, subsequently, 6 of the 20 doctors of the test group refused to engage in the trial because they considered “excessive time and effort consuming”. 50% of patients referred by the 14 General Practitioners finally randomized to the intervention group were denied referral by telephone due to patient's complexity.

Conclusions

Telephone referral significantly reduces waiting days for Internal Medicine consult. This type of referral did not mean an “excessive time and effort consuming” to General Practitioners and was not all that beneficial to complex patients  相似文献   
4.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
5.
Hyperlipidemia is a major risk factor in etiology of cardiovascular disease. Previous studies have shown association between vegetarian diet and low total serum cholesterol as well as LDL-cholesterol which is a pointer to low risk of cardiovascular disease. Dietary fiber, antioxidants and other classes of nutrients have been reported to ameliorate cardiovascular risk factors. Fruits and vegetables being rich sources of fiber and antioxidants have been the focus in intervention studies. The current work reports the effect local fruits and vegetables on cardiovascular risk factors in African hypertensive subjects in an 8 week study. Though there was no significant difference in the Body Mass Index and HDL-cholesterol at the end of the eighth week, there were significant reductions (P < 0.05) in serum triglycerides (125.87 ± 6.0 to108.27 ± 5.49 mgdL-1); total serum cholesterol (226.60 ± 6.15 to 179.20 ± 5.78) and LDL-cholesterol (135.69 ± 5.56 to 93.07 ± 7.18 mgdL-1). We concluded that consumption of combination of local fruits and vegetables may reduce the incidence of cardiovascular risk factors in Africans.  相似文献   
6.
PINK1 mutations in sporadic early-onset Parkinson's disease.   总被引:5,自引:0,他引:5  
Pathogenic PINK1 mutations have been described in PARK6-linked Parkinson's disease (PD) patients of Asian origin. However, data on the frequency of PINK1 mutations in sporadic early-onset Parkinson's disease (EOPD) Asian patients are lacking. The objectives of this study were to report the frequency of PINK1 mutations of sporadic EOPD in an Asian cohort comprising of ethnic Chinese, Malays, and Indians, and to highlight a PINK1-positive patient who presented with restless legs symptoms. Eighty consecutive sporadic EOPD patients from the movement disorder clinics of two major tertiary institutions in the country were included. We performed sequence analysis of all the coding and exon-intron junctions of the PINK1 using specific primer sets. In addition, we genotyped polymorphisms detected from the analysis in a group of sporadic PD patients and controls. Three different mutations (two homozygous nonsense and one heterozygous missense) in the putative kinase domain were found in three patients, giving a 3.7% frequency of PINK1 mutations in our EOPD cohort. All the mutations were absent in 200 healthy controls. One patient with a novel homozygous nonsense PINK1 mutation presented unusually with restless legs symptoms. Separately, analysis of the frequency of four PINK1 polymorphisms in a group of sporadic PD and controls did not reveal any significant differences. We highlight a 3.7% frequency of PINK1 mutations in an Asian cohort (ethnic Chinese, Malay, and Indian) of EOPD. The phenotypic spectrum associated with PINK1-positive patients may be wider than previously reported. Polymorphisms of PINK1 do not appear to modulate risk of PD in our population.  相似文献   
7.
OBJECTIVE: According to a report published by the federation of Dutch patients' associations, patients would like to see a pharmacist, who acts more as a personal adviser. This raised the question, how often Dutch community pharmacists have personal consultations with their patients in daily practice, on which factors this depends, and what kind of topics are discussed during these meetings. SETTING: Community pharmacies in the Netherlands. METHOD: A questionnaire was distributed among 800 randomly selected pharmacies. Questions were restricted to consultations characterized by one-to-one contact, drug therapy related content, and adequate privacy. These consultations were labelled as pharmaceutical consultations in private to distinguish them from other contacts between pharmacists and patients. MAIN OUTCOME MEASURE: Number, content, and character of consultations. RESULTS: 198 (24.8%) community pharmacies responded. The pharmacists provide an average of roughly 1.2 consultations in private per working day. The vast majority of respondents provided face-to-face and telephone consultations (94.4 and 91.9%, respectively), only a minority gave consultations by e-mail (30.8%). These consultations primarily dealt with topics related to medication safety. The mean overall time spent was 290 min per month. A relatively high frequency of personal consultations was significantly associated with the absolute number of full-time equivalent pharmacists in the pharmacy. CONCLUSION: The frequency of pharmaceutical consultations in private is low, but may be improved by reorganisation of the pharmacist's activities. The possibility of personal consultations by e-mail is not yet well-developed. Further research is needed to assess the patient's view of pharmaceutical consultations in private.  相似文献   
8.
PTH fragments consisting of the C-terminal portion of the molecule may have biologic effects and may modify the actions of PTH. Evidence for the presence of a C-terminal PTH receptor further supports a biologic role for such fragments. Because C-PTH fragments accumulate in patients with renal insufficiency, it is possible that they may contribute to renal bone disease. The precise role of circulating C-PTH fragments in the pathogenesis, diagnosis, and management of renal osteodystrophy, however, remains to be determined. Future studies of the biologic effects and regulation of these fragments may lead to better understanding of skeletal biology and may also improve our approach to the diagnosis and treatment of renal bone disease.  相似文献   
9.
A mouse model of pulmonary tuberculosis induced by the intratracheal instillation of live and virulent mycobacteria strain H37-Rv was used to examine the relationship of the histopathological findings with the local kinetics production and cellular distribution of tumour necrosis factor-alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha) and transforming growth factor-beta (TGF-beta). The histopathological and immunological studies showed two phases of the disease: acute or early and chronic or advanced. The acute phase was characterized by inflammatory infiltrate in the alveolar-capillary interstitium, blood vessels and bronchial wall with formation of granulomas. During this acute phase, which lasted from 1 to 28 days, high percentages of TNF-alpha and IL-1 alpha immunostained activated macrophages were observed principally in the interstium-intralveolar inflammatory infiltrate and in granulomas. Electron microscopy studies of these cells, showed extensive rough endoplasmic reticulum, numerous lysosomes and occasional mycobacteria. Double labelling with colloid gold showed that TNF-alpha and IL-1 alpha were present in the same cells, but were confined to separate vacuoles near the Golgi area, and mixed in larger vacuoles near to cell membrane. The concentration of TNF-alpha and IL-1 alpha as well as their respective mRNAs were elevated in the early phase, particularly at day 3 when the bacillary count decreased. A second peak was seen at days 14 and 21-28 when granulomas appeared and evolved to full maturation. In contrast, TGF-beta production and numbers of immunoreactive cells were low in comparison with the advanced phase of the disease. The chronic phase was characterized by histopathological changes indicative of more severity (i.e. pneumonia, focal necrosis and extensive interstitial fibrosis) with a decrease in the TNF-alpha and IL-1 alpha production that coincided with the highest level of TGF-beta. The bacillary counts were highest as the macrophages became large, vacuolated foamy cells, and containing numerous bacilli with immunoreactivity to mycobacterial lipids and lipoarabinomannan (LAM). These macrophages displayed poor and scarce TNF-alpha and IL-1 alpha immunostaining but still strong immunoreactivity to TGF-beta. These cytokine production kinetics and the spatial relationship between immunostained cells and lung lesions corroborate the important role of TNF-alpha and IL-1 alpha in the constitution of granulomas and immune protection during the early phase of the infection, and also suggest an important if not primary role for TGF-beta in the immunopathogenesis of the advanced forms of pulmonary tuberculosis.  相似文献   
10.
A randomized, placebo-controlled, double-blind study involving 60 subjects, aged 6-18 years old, was conducted over a period of 3 months to determine the effect of Pycnogenol® (a proprietary mixture of water-soluble bioflavonoids extracted from French maritime pine) on mild-to-moderate asthma. After baseline evaluation, subjects were randomized into two groups to receive either Pycnogenol® or placebo. Subjects were instructed to record their peak expiratory flow with an Assess® Peak Flow Meter each evening. At the same time, symptoms, daily use of rescue inhalers (albuterol), and any changes in oral medications were also recorded. Urine samples were obtained from the subjects at the end of the run-in period, and at 1-, 2-, and 3-month visits. Urinary leukotriene C4/D4/E4 was measured by an enzyme immunoassay. Compared with subjects taking placebo, the group who took Pycnogenol® had significantly more improvement in pulmonary functions and asthma symptoms. The Pycnogenol® group was able to reduce or discontinue their use of rescue inhalers more often than the placebo group. There was also a significant reduction of urinary leukotrienes in the Pycnogenol® group. The results of this study demonstrate the efficacy of Pycnogenol® as an adjunct in the management of mild-to-moderate childhood asthma.  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