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   1433篇
  免费   95篇
  国内免费   11篇
耳鼻咽喉   6篇
儿科学   38篇
妇产科学   39篇
基础医学   189篇
口腔科学   56篇
临床医学   143篇
内科学   295篇
皮肤病学   38篇
神经病学   94篇
特种医学   51篇
外科学   253篇
综合类   25篇
一般理论   1篇
预防医学   88篇
眼科学   41篇
药学   113篇
中国医学   10篇
肿瘤学   59篇
  2023年   35篇
  2022年   52篇
  2021年   80篇
  2020年   75篇
  2019年   88篇
  2018年   115篇
  2017年   53篇
  2016年   66篇
  2015年   57篇
  2014年   70篇
  2013年   86篇
  2012年   123篇
  2011年   111篇
  2010年   51篇
  2009年   38篇
  2008年   61篇
  2007年   52篇
  2006年   41篇
  2005年   49篇
  2004年   38篇
  2003年   49篇
  2002年   24篇
  2001年   15篇
  2000年   12篇
  1999年   11篇
  1998年   4篇
  1997年   2篇
  1995年   3篇
  1994年   4篇
  1993年   3篇
  1992年   4篇
  1991年   5篇
  1989年   8篇
  1988年   7篇
  1987年   4篇
  1986年   5篇
  1985年   5篇
  1984年   4篇
  1983年   4篇
  1980年   1篇
  1979年   2篇
  1978年   4篇
  1974年   1篇
  1973年   1篇
  1972年   2篇
  1971年   3篇
  1970年   1篇
  1969年   3篇
  1966年   1篇
  1965年   1篇
排序方式: 共有1539条查询结果,搜索用时 15 毫秒
1.
Purpose: Traffic accidents are one of the major health problems in the world, being the first cause of burden of illness and the second leading cause of death in Iran. The Sistan-Baluchestan province is one of the most accidental provinces of Iran with the highest rate of accidents-caused deaths. This study was conducted to determine the risk factors associated with traffic accidents in Zahedan through 2013 to 2016. Methods: This analytical cross-sectional study was carried out on 223 drivers from Zahedan who were traumatized by traffic accident and sent to Zahedan hospitals. The data were obtained through interviews taken by the trained interviewers via refereeing to the medical records and collected in the researcher-made checklist. Census was obtained from the study subjects. For data analysis, independent t-test, one-way ANOVA, Chi-square and logistic regression were used with the Stata software version 11.0. Results: In this study, 223 male subjects with the mean age of (32.54 ± 12.95) years, 39.8% single and 60.2% married, entered for investigation. Most accidents (38.8%) occurred between 12:00 to 17:59. While driving, 47.1% of the study subjects were using cell phones, 89.1% had manual use of mobile phones, 21.9% had a habit of sending short message service (SMS) and 23.4% had sent SMS within 10 min before the accident. The one way analysis of variance showed that the mean age of individuals with marital status, driving experience, education and accident with motorcycle were significantly different (p < 0.05). Also, the multivariate logistic regression test indicated a significant relationship of smoking, ethnicity, insurance and SMS typing while driving with motorcycle accident (p < 0.05). Conclusion: In this study, SMS and smoking while driving had the highest risk among the variables studied in the motorcycle accidents. Therefore, effective education attempting to enhance people''s awareness about the consequences of using cell phone and smoking during driving to reduce traffic accidents seems necessary.  相似文献   
2.
A Sahar 《Neurosurgery》1986,19(1):144-145
  相似文献   
3.
4.
DNA fingerprinting of Candida dubliniensis isolates using the species-specific probe Cd25 previously showed that this species consists of two distinct groups, termed Cd25 group I and Cd25 group II. The present study investigated the population structure of 30 C. dubliniensis oral isolates from Saudi Arabia and Egypt using Cd25 fingerprinting and rRNA gene internal transcribed spacer region-based genotyping. Cd25 fingerprinting analysis of these isolates revealed two distinct populations, the first of which consisted of 10 closely related genotype 1 isolates (average similarity coefficient [S(AB)] value, 0.86). The second population of 20 isolates was much more heterogeneous (average S(AB) value, 0.35) and consisted of two distinct subpopulations, one of which consisted of genotype 3 isolates (n = 13) and the other of genotype 4 isolates (n = 7). A mixed dendrogram generated from the fingerprint data from the 30 Saudi Arabian and Egyptian isolates, 5 Israeli isolates, and 51 previously characterized international isolates (32 of Cd25 group I and 19 of Cd25 group II) revealed the presence of three distinct main clades. The first corresponded to the previously described Cd25 group I and contained all the Saudi Arabian, Egyptian, and Israeli genotype 1 isolates mixed with international isolates. The second clade corresponded to the previously described Cd25 group II and contained three Israeli isolates, one genotype 2 isolate, one genotype 3 isolate, and a genotype 4 variant isolate, which were mixed with international isolates. The third clade has not been described before and consisted solely of the 20 Saudi Arabian and Egyptian genotype 3 and 4 isolates identified in this study and a previously described genotype 4 Israeli isolate. All 20 Cd25 group III isolates exhibited high-level resistance to 5-flucytosine (MIC > or = 128 microg/ml), whereas all Cd25 group I and Cd25 group II isolates tested (10 Saudi Arabian and Egyptian, 16 Israeli, and 24 international) were susceptible to 5-flucytosine (MIC < or = 0.125 microg/ml). The results of this study show for the first time the presence of a novel 5-flucytosine-resistant clade of C. dubliniensis (Cd25 group III) that is predominant among isolates from Saudi Arabia and Egypt and absent from a previously characterized international collection of 98 isolates from 15 countries.  相似文献   
5.
I Yron  R Erlich  M Efrati  L Shohat  I P Witz  E Sahar 《Immunobiology》1988,177(4-5):449-459
Natural killer (NK) cells originating in mouse peripheral blood were studied with regard to their lytic activity against YAC-1 target cells and to their expression of asialo-GM1 marker on their surface. In Balb/c, CBA/LAK and A/J mice, PBL were found to be approximately twice as effective as splenocytes. Splenic and peripheral NK cells were shown by flow cytometry to have similar lytic potential per cell; the difference in NK activity found in the spleen and in PBL was solely due to the differences in the size of the NK cell population found in the two sites. Strain distribution of NK activity in PBL followed the same pattern observed in splenocytes. The difference in NK activity between CBA and Balb/c mice was shown to be due to the fact that the lytic potential per NK cell was approximately twice as high in the former.  相似文献   
6.
International Urology and Nephrology - Successful in vitro transplantation of spermatogonial stem cells (SSCs) demands effective culture systems for SSCs proliferation and differentiation. Natural...  相似文献   
7.
Coexistence of spondyloarthritis (SpA) and Takayasu’s arteritis is not a common finding, but such cases have been discussed, particularly in the context of choice of therapy. Inhibition of inflammation by tumor necrosis factor inhibitors (TNFi) is a key aspect of the treatment of SpA and also positive effects of such treatment in concomitant large vessel vasculitis have been reported. However, TNFi is also associated with the possibility of initiating vasculitis.The present article based on a case study and the available literature is an attempt to discuss coexistence of these two diseases and the impact of treatment with biological drugs from the anti-TNF group in the course of SpA with Takayasu’s arteritis.  相似文献   
8.
The efficacy of spirulina platensis (S. platensis) as an add-on therapy to metformin and its effect on atherogenic keys in patients with uncontrolled Type 2 Diabetes Mellitus (T2DM) was evaluated. Sixty patients were randomly assigned to S. platensis (2 g/day) or placebo group for three months while continuing metformin as their usual treatment. The efficacy of S. platensis was determined using the pre- and post-intervention HbA1c levels (primary outcome) as well as tracking FBS and lipid profiles levels (TC, LDL-C, TG, and HDL-C) as secondary outcomes at the different treatment time points (0,30,60,90 days). During the three–month intervention period, supplementation with S. platensis resulted in a significant lowering of HbA1c (↓1.43, p < 0.001) and FBS (↓ 24.94 mg/dL, p < 001) levels. Mean TG in the intervention group was found to be significantly lower in the intervention group than in controls (p < 0.001). Total cholesterol (TC) and its fraction, LDL-C, exhibited a fall (↓41.36 mg/dL and ↓38.4 mg/dL, respectively; p < 0.001) coupled with a marginal increase in the level of HDL-C (↑3 mg/dL; p < 0.001). Add-on therapy with S. platensis was superior to metformin regarding long-term glucose regulation and controlling blood glucose levels of subjects with T2DM. Also, as a functional supplement, S. platensis has a beneficial effect on atherogenic keys (TG and HDL-C) with no adverse events.  相似文献   
9.
Despite national guidelines, medical practices and kidney transplant waiting list registration policies may differ from one dialysis/transplant unit to another. Benefit risk assessment variations, especially for elderly patients, have also been described. The aim of this study was to identify sources of variation in early kidney transplant waiting list registration in France. Among 16 842 incident patients during the period 2016–2017, 4386 were registered on the kidney transplant waiting list at the start of, or during the first year after starting, dialysis (26%). We developed various log-linear mixed effect regression models on three levels: patients, dialysis networks, and transplant centers. Variability was expressed as variance from the random intercepts (± standard error). Although patient characteristics have an important impact on the likelihood of registration, the overall magnitude of variability in registration was low and shared by dialysis networks and transplant centers. Between-transplant center variability (0.23 ± 0.08) was 1.8 higher than between-dialysis network variability (0.13 ± 0.004). Older age was associated with a lower probability of registration and greater variability between networks (0.04, 0.20, & 0.93 in the 18–64, 65–74, and 75–84 age groups). Targeted interventions should focus on elderly patients and/or certain regions with greater variability in waiting list access.  相似文献   
10.
Portilla-Fernández  Eliana  Hwang  Shih-Jen  Wilson  Rory  Maddock  Jane  Hill  W. David  Teumer  Alexander  Mishra  Pashupati P.  Brody  Jennifer A.  Joehanes  Roby  Ligthart  Symen  Ghanbari  Mohsen  Kavousi  Maryam  Roks  Anton J. M.  Danser  A. H. Jan  Levy  Daniel  Peters  Annette  Ghasemi  Sahar  Schminke  Ulf  Dörr  Marcus  Grabe  Hans J.  Lehtimäki  Terho  Kähönen  Mika  Hurme  Mikko A.  Bartz  Traci M.  Sotoodehnia  Nona  Bis  Joshua C.  Thiery  Joachim  Koenig  Wolfgang  Ong  Ken K.  Bell  Jordana T.  Meisinger  Christine  Wardlaw  Joanna M.  Starr  John M.  Seissler  Jochen  Then  Cornelia  Rathmann  Wolfgang  Ikram  M. Arfan  Psaty  Bruce M.  Raitakari  Olli T.  Völzke  Henry  Deary  Ian J.  Wong  Andrew  Waldenberger  Melanie  O’Donnell  Christopher J.  Dehghan  Abbas 《European journal of epidemiology》2021,36(11):1143-1155

Common carotid intima-media thickness (cIMT) is an index of subclinical atherosclerosis that is associated with ischemic stroke and coronary artery disease (CAD). We undertook a cross-sectional epigenome-wide association study (EWAS) of measures of cIMT in 6400 individuals. Mendelian randomization analysis was applied to investigate the potential causal role of DNA methylation in the link between atherosclerotic cardiovascular risk factors and cIMT or clinical cardiovascular disease. The CpG site cg05575921 was associated with cIMT (beta?=??0.0264, p value?=?3.5?×?10–8) in the discovery panel and was replicated in replication panel (beta?=??0.07, p value?=?0.005). This CpG is located at chr5:81649347 in the intron 3 of the aryl hydrocarbon receptor repressor gene (AHRR). Our results indicate that DNA methylation at cg05575921 might be in the pathway between smoking, cIMT and stroke. Moreover, in a region-based analysis, 34 differentially methylated regions (DMRs) were identified of which a DMR upstream of ALOX12 showed the strongest association with cIMT (p value?=?1.4?×?10–13). In conclusion, our study suggests that DNA methylation may play a role in the link between cardiovascular risk factors, cIMT and clinical cardiovascular 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