全文获取类型
收费全文 | 4030篇 |
免费 | 283篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 74篇 |
妇产科学 | 77篇 |
基础医学 | 559篇 |
口腔科学 | 67篇 |
临床医学 | 375篇 |
内科学 | 931篇 |
皮肤病学 | 81篇 |
神经病学 | 268篇 |
特种医学 | 130篇 |
外科学 | 552篇 |
综合类 | 73篇 |
一般理论 | 2篇 |
预防医学 | 326篇 |
眼科学 | 237篇 |
药学 | 285篇 |
中国医学 | 29篇 |
肿瘤学 | 242篇 |
出版年
2024年 | 10篇 |
2023年 | 54篇 |
2022年 | 128篇 |
2021年 | 206篇 |
2020年 | 152篇 |
2019年 | 188篇 |
2018年 | 229篇 |
2017年 | 151篇 |
2016年 | 173篇 |
2015年 | 160篇 |
2014年 | 189篇 |
2013年 | 256篇 |
2012年 | 370篇 |
2011年 | 361篇 |
2010年 | 223篇 |
2009年 | 178篇 |
2008年 | 255篇 |
2007年 | 244篇 |
2006年 | 192篇 |
2005年 | 132篇 |
2004年 | 122篇 |
2003年 | 104篇 |
2002年 | 65篇 |
2001年 | 16篇 |
2000年 | 18篇 |
1999年 | 15篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有4350条查询结果,搜索用时 0 毫秒
81.
Mehdi Mohamadnejad Akram Pourshams Reza Malekzadeh Ashraf Mohamadkhani Afsaneh Rajabiani Ali Ali Asgari Seyed Meysam Alimohamadi Hadi Razjooyan Mamar-Abadi 《World journal of gastroenterology : WJG》2003,9(10)
AIM:The healthy ranges for serum alanine aminotransferase (ALT) levels are less well studied. The aim of this study was to define the upper limit of normal (ULN) for serum ALT levels, and to assess factors associated with serum ALT activity in apparently healthy blood donors.METHODS: A total of 1 939 blood donors were included.ALT measurements were performed for all cases using the same laboratory method. Healthy ranges for ALT levels were computed from the population at the lowest risk for liver disease. Univariate and multivariate analyses were performed to evaluate associations between clinical factors and ALT levels.RESULTS: Serum ALT activity was independently associated with body mass index (BMI) and male gender, but not associated with age. Association of ALT with BMI was more prominent in males than in females. Upper limit of normal for non-overweight women (BMI of less than 25) was 34 U/L,and for non-overweight men was 40 U/L.CONCLUSION: Serum ALT is strongly associated with sex and BMI. The normal range of ALT should be defined for male and female separately. 相似文献
82.
Sarraf-Zadegan N Sadri G Malek Afzali H Baghaei M Mohammadi Fard N Shahrokhi S Tolooie H Poormoghaddas M Sadeghi M Tavassoli A Rafiei M Kelishadi R Rabiei K Bashardoost N Boshtam M Asgary S Naderi G Changiz T Yousefie A 《Acta cardiologica》2003,58(4):309-320
The Isfahan Healthy Heart Programme (IHHP) is a five to six year comprehensive integrated community-based programme for cardiovascular diseases (CVD) prevention and control via reducing CVD risk factors and improvement of cardiovascular healthy behaviour in a target population. IHHP started late in 1999 and will be finished in 2005-2006. A primary survey was done to collect baseline data from interventional (Isfahan and Najaf-Abad) and reference (Arak) communities. In a two-stage sampling method, we randomly selected 5 to 10 percent of households from randomly selected clusters. Then individuals aged > or = 19 years were selected for the survey. This way, data from 12,600 individuals (6300 in interventional counties and 6300 in the reference county) was collected and stratified according to living area (urban vs. rural) and different age and sex groups. The samples underwent a 30-minute interview to complete validated questionnaires containing questions on demography, socioeconomic status, smoking behaviour, physical activity, nutritional habits and other behaviour regarding CVD. Blood pressure and body mass index (BMI) measurements were done and fasting blood samples were taken for two hours post load plasma glucose (2 hpp), serum (total, HDL and LDL) cholesterol and triglyceride levels. A twelve-lead electrocardiogram was recorded in all persons above 35 years of age. Community-wide surveillance of deaths, hospital discharges, myocardial infarction and stroke registry was carried out in the intervention and control areas. Four to five years of interventions based on different categories such as mass media, community partnerships, health system involvement and policy and legislation have started in the intervention area while Arak will be followed without intervention. Considering the results of the baseline surveys, (assessments needed, the objectives, existing resources and the possibility of national implementation) the interventions were planned. They were set based on specific target groups like school children, women, work-site, health personnel, high-risk persons, and community leaders were actively engaged as decision makers. A series of teams was arranged for planning and implementation of the intervention strategies. Monitoring will be done on small samples to assess the effect of different interventions in the intervention area. While four periodic surveys will be conducted on independent samples to assess health behaviours related to CVD risk factors in the intervention and reference areas, the original pre-intervention subjects aged more than 35 years will be followed in both areas to assess the individual effect of interventions and outcomes like sudden death, fatal and nonfatal MI and stroke. The whole baseline survey will be repeated on the original and an independent sample in both communities at the end of the study. 相似文献
83.
84.
85.
Mohammad Javad Nasiri Faranak Rezaei Samin Zamani Davod Darban-Sarokhalil Abbas Ali Imani Fooladi Hasan Shojaei Mohammad Mehdi Feizabadi 《Asian Pacific journal of tropical medicine》2014,7(3):193-196
Objective:To determine the patterns of resistance to first line anti-tuberculosis(TB)drugs among a collection of Mycobacterium tuberculosis(MTB)isolates from 5 provinces of Iran.Methods:A total of the 6 426 clinical specimens from patients suspected of active TB were collected from March 2010 to June 2012.All specimens were subjected for microscopy and culture tests in the TB centers of studies provinces.Drug susceptibility testing to the first line anti-TB drugs for culture positive MTB was performed on Lwenstein-Jensen(LJ)medium using proportion method.Results:Of 6 426 clinical specimens,261 were culture positive for mycobacteria,of which 252 were MTB and 9 were MOTT(mycobacteria other than tuberculosis).Of 252 MTB isolates.211(83.7%)were pan-susceptible and 41(16.3%)were resistant to at least one drug.Resistance was most common to streptomycin.30 isolates(12.0%),followed by isoniuzid,20isolates(8.0%),rifampin,15 isolates(6.0%)and ethambutol,14 isolates(5.5%).Sixteen(6.3%)MTB isolates were MDR.A clear evidence of heterogeneity amongst the 5 provinces in the proportions with resistance to one or more drugs was observed[χ~2=12.209(4 degrees of freedom),P values=0.015 9].Conclusions:The prevalence of drug resistance in this study area underscoring the need for further enforcement of TB control strategies in the Iran.Drug susceptibility testing for all TB cases to provide optimal treatment,establishing advanced diagnostic facilities for rapid detection of MDR-TB and continuous monitoring of drug resistance are recommended for prevention and control of drug-resistant TB. 相似文献
86.
Najafi M Maza NA Calvert PD 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(1):203-208
Proteins segregate into discrete subcellular compartments via a variety of mechanisms, including motor protein transport, local binding, and diffusion barriers. This physical separation of cell functions serves, in part, as a mechanism for controlling compartment activity by allowing regulation of local protein concentrations. In this study we explored how soluble protein size impacts access to the confined space within the retinal photoreceptor outer segment signaling compartment and discovered a strikingly steep relationship. We find that GFP monomers, dimers, and trimers expressed transgenically in frog rods are present in the outer segment at 1.8-, 2.9-, and 6.8-fold lower abundances, relative to the cell body, than the small soluble fluorescent marker, calcein. Theoretical analysis, based on statistical-mechanical models of molecular access to polymer meshes, shows that these observations can be explained by the steric hindrance of molecules occupying the highly constrained spaces between outer segment disc membranes. This mechanism may answer a long-standing question of how the soluble regulatory protein, arrestin, is effectively excluded from the outer segments of dark-adapted rods and cones. Generally, our results suggest an alternate mode for the control of protein access to cell domains based on dynamic, size-dependent compartmental partitioning that does not require diffusion barriers, active transport, or large numbers of immobile binding sites. 相似文献
87.
Hassan Ashktorab Omid Entezari Mehdi Nouraie Ehsan Dowlati Wayne Frederick Alfreda Woods Edward Lee Hassan Brim Duane T. Smoot Firoozeh Ghadyari Farin Kamangar Hadie Razjouyan 《Digestive diseases and sciences》2012,57(11):2924-2928
Background and Aim
Negative association has been reported between presence of Helicobacter pylori and developing gastroesophageal reflux disease (GERD) and its complications. The aim of this study was to determine whether H. pylori (HP) can be protective against GERD in an African American (AA) population.Methods
From 2004 to 2007, we studied 2,020 cases; esophagitis (58), gastritis (1,558), both esophagitis and gastritis (363) and a normal control group (41). We collected their pathology and endoscopy unit reports. HP status was determined based on staining of gastric biopsy.Results
HP data was available for 79 % (1,611) of the cases. The frequency of HP positivity in gastritis patients was 40 % (506), in esophagitis patients 4 % and in normal controls 34 % (11), while HP was positive in 34 % of the patients with both esophagitis and gastritis. After adjusting for effects of age and sex, odds ratio of HP was 0.06 (95 % CI 0.01–0.59; P value = 0.01) for the esophagitis group versus the normal group.Conclusions
Our results show H. pylori has a significant negative association with esophagitis in AAs which may point to a protective role of H. pylori in the pathogenesis of esophagitis. In addition, H. pylori may be the reason for the low GERD complications in AAs. 相似文献88.
Tahiri M Mottillo S Joseph L Pilote L Eisenberg MJ 《The American journal of medicine》2012,125(6):576-584
BackgroundAcupuncture, hypnotherapy, and aversive smoking are the most frequently studied alternative smoking cessation aids. These aids are often used as alternatives to pharmacotherapies for smoking cessation; however, their efficacy is unclear.MethodsWe carried out a random effect meta-analysis of randomized controlled trials to determine the efficacy of alternative smoking cessation aids. We systematically searched the Cochrane Library, EMBASE, Medline, and PsycINFO databases through December 2010. We only included trials that reported cessation outcomes as point prevalence or continuous abstinence at 6 or 12 months.ResultsFourteen trials were identified; 6 investigated acupuncture (823 patients); 4 investigated hypnotherapy (273 patients); and 4 investigated aversive smoking (99 patients). The estimated mean treatment effects were acupuncture (odds ratio [OR], 3.53; 95% confidence interval [CI], 1.03-12.07), hypnotherapy (OR, 4.55; 95% CI, 0.98-21.01), and aversive smoking (OR, 4.26; 95% CI, 1.26-14.38).ConclusionOur results suggest that acupuncture and hypnotherapy may help smokers quit. Aversive smoking also may help smokers quit; however, there are no recent trials investigating this intervention. More evidence is needed to determine whether alternative interventions are as efficacious as pharmacotherapies. 相似文献
89.