全文获取类型
收费全文 | 1190篇 |
免费 | 72篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 19篇 |
妇产科学 | 10篇 |
基础医学 | 178篇 |
口腔科学 | 58篇 |
临床医学 | 134篇 |
内科学 | 229篇 |
皮肤病学 | 17篇 |
神经病学 | 87篇 |
特种医学 | 51篇 |
外科学 | 164篇 |
综合类 | 12篇 |
一般理论 | 2篇 |
预防医学 | 109篇 |
眼科学 | 2篇 |
药学 | 59篇 |
中国医学 | 1篇 |
肿瘤学 | 125篇 |
出版年
2023年 | 16篇 |
2022年 | 9篇 |
2021年 | 24篇 |
2020年 | 24篇 |
2019年 | 23篇 |
2018年 | 38篇 |
2017年 | 26篇 |
2016年 | 32篇 |
2015年 | 16篇 |
2014年 | 43篇 |
2013年 | 55篇 |
2012年 | 42篇 |
2011年 | 78篇 |
2010年 | 25篇 |
2009年 | 34篇 |
2008年 | 54篇 |
2007年 | 50篇 |
2006年 | 50篇 |
2005年 | 56篇 |
2004年 | 53篇 |
2003年 | 41篇 |
2002年 | 38篇 |
2001年 | 38篇 |
2000年 | 25篇 |
1999年 | 31篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1993年 | 10篇 |
1992年 | 23篇 |
1991年 | 20篇 |
1990年 | 11篇 |
1989年 | 24篇 |
1988年 | 15篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 14篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 12篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1975年 | 13篇 |
1974年 | 12篇 |
1972年 | 6篇 |
1970年 | 7篇 |
排序方式: 共有1262条查询结果,搜索用时 15 毫秒
1.
Claire M Rickard Brigit L Roberts Jonathon Foote Matthew R McGrail 《Dimensions of critical care nursing》2006,25(5):234-242
Research coordinators in intensive care are a growing specialty about which little is known. This cross-sectional study surveyed the Australia and New Zealand Intensive Care Research Coordinators' Group (n = 49) regarding demographics, education, employment history, job structure, and role content. Most research coordinators were highly qualified and experienced nurses who undertake pharmaceutical trials, multicenter projects, departmental medical and nursing research, audits and data registries, and their own projects. 相似文献
2.
C.K. Kasper J.B. Graham P.B.A. Kernoff M.J. Larrieu K.A. Rickard and Prof. P.M. Mannucci 《Vox sanguinis》1989,56(3):141-144
Since 1982, when the World Federation of Hemophilia first published a document on the state of the art of hemophilia diagnosis and care, there have been lights and shadows in this field. Although the widespread infection of hemophiliacs with the human immunodeficiency virus (HIV) contaminating clotting factor concentrates is still a threatening and formidable shadow, the gloomy picture brought about by the AIDS epidemic is partially lightened by spectacular improvements in therapy and diagnosis. Carrier detection and first-trimester prenatal diagnosis can now be performed accurately in most kindreds by analysis of DNA of the factor VIII or IX genes. An important step forward towards the elimination of the risk of blood-borne infections transmitted by plasma products was recently made through the application of virucidal methods to clotting factor concentrates. Since HIV appears more vulnerable to such methods than the hepatitis viruses, currently available concentrates can be considered substantially free from the risk of transmitting HIV infection. Even though transmission of hepatitis is much reduced but not totally abolished, virucidal methods are continuously being improved, so that it can be foreseen that concentrates will become safer and safer. Finally, factor VIII produced by recombinant DNA technology is undergoing the first clinical trials in hemophiliacs. Hopefully, it will free from the risk of transmitting infections and will be available in sufficiently large amounts to meet the need of hemophiliacs worldwide. In 1982, the World Federation of Hemophilia published a message on the status of diagnosis and treatment of hemophilia. Since then, hemophilia care has been complicated by widespread infection of hemophiliacs with human immunodeficiency virus (HIV).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
N. M. van Schoor D. L. Knol C. A. W. Glas R. W. J. G. Ostelo A. Leplège C. Cooper O. Johnell P. Lips 《Osteoporosis international》2006,17(4):543-551
Introduction Vertebral deformities are a common consequence of osteoporosis and are known to decrease quality of life. The Qualeffo–41
is a quality-of-life questionnaire especially developed for measuring quality of life in patients with vertebral deformities.
It consists of 41 questions arranged in five domains: pain, physical function, social function, general health perception,
and mental function. The objectives of this study were: (1) to develop a shorter version of the Qualeffo–41 by removing redundant
questions; and (2) to investigate the scale characteristics, reliability, and validity of this shorter version.
Methods The study was performed using data from the Qualeffo validation study and the Multiple Outcomes of Raloxifene Evaluation (MORE)
study. The analyses were performed in patients with vertebral deformities (n=579). Factor analysis on polychoric correlations and an item response theory (IRT) model, i.e., the generalized partial credit
model (GPCM), were used to create a shorter version of Qualeffo–41. Using GPCM, scoring weights were computed for all items.
Results Three items were removed from the data set because of too many missing values. Factor analysis identified three instead of
five domains: (1) pain, (2) physical function, and (3) mental function. Five items had factor loadings <0.4 and were not included
in the GPCM. After excluding several items, the domains pain (four items), physical function (18 items), and mental function
(nine items) showed a good, reasonable, and excellent fit, respectively. This indicates that the mental function domain and
the pain domain are more unidimensional than the physical function domain. All three domains showed a very high correlation
(r ≥0.95) with the corresponding domains of the Qualeffo–41.
Conclusions Qualeffo–31 was developed, consisting of three domains with a reasonable to excellent fit to the GPCM. Although the fit to
the GPCM supports the construct validity of the Qualeffo–31, validation in a new study should be performed before using it
in practice. 相似文献
4.
Tree sampling helped locate a subterranean flow of tritiated water from a low-level radioactive waste disposal site that had not been detected by well water monitoring alone. Deciduous trees growing in a natural forest on the hillsides downslope from the site were sampled for the presence of tritiated water in sap of maple trees and in leaf water extracted from oak and hickory trees. Elevated concentrations of 3H were detected in the leaf water extracted from several trees located 50 m downslope from the western boundary of the fenced exclusion zone. A 3-m-deep well drilled near these trees indicated that the source of tritiated water was a narrow zone of subterranean flow. 相似文献
5.
Jan Frisell Gunnar Eklund Lars Hellström Ulla Glas Anders Somell 《Breast cancer research and treatment》1989,13(1):79-87
In screening programmes it is important to assess a preliminary effectiveness of the screening method as soon as possible in order to forecast survival figures. In March 1981 a controlled single-view mammographic screening trial for breast cancer was started in the south of Stockholm. The population invited for screening mammography consisted of 40,000 women aged 40–64 years, and 20,000 women served as a well-defined control group. The main aim of the trial was to determine whether repeated mammographic screening could reduce the mortality in the study population (SP) compared to the control population (CP).The cumulative number of advanced mammary carcinomas in the screening and the control populations from the first five years of screening have shown a tendency towards more favourable stages in the screened population aged 40–64 years. A breakdown by age suggests an effect in age group 50–59 years, but not yet in age groups 40–49 and 60–64 years.When comparing the rates of stage II+ cancer, an increased number is found in the study group. As the total rate of breast cancer is higher in SP than in CP, there ought to be a concealed group of stage II+ cancers in the CP which makes the comparison biased. A new approach has been designed, where an estimation of the hidden number of stage II+ cancers in CP is added to the clinically detected cases, and in this respect a comparison has shown a decrease in the cumulative number of advanced cancers in the SP in relation to the CP (p<0.05). According to this it could be important to add the estimated number of undetected, hidden cases in the control group in order to utilize the difference in detection rate in the screening- and control group respectively. 相似文献
6.
Ulf Träff Anna Levén Rickard Östergren Daniel Schöld 《Developmental neuropsychology》2020,45(3):139-153
ABSTRACT This study examined if children (Mage = 14.60) with Mild Intellectual Disabilities (MID) display weaknesses in number processing and verbal working memory. An age-matched and mental age-matched (MA, Mage = 6.17) design extended by a group of 9–10-year-olds, and a group of 11–12-year-olds were used. The MID children’s working memory was equal to the MA group but poorer than the other groups. On number tasks, the MID group was faster than the MA group but slower than the other groups. All groups obtained equal Weber fraction scores and distance effects on the number comparison tasks. The MID group performed subitizing and counting faster than the MA group, but slower than the 11–12-year-olds. The results demonstrate that number processing and working memory in children with MID is characterized by a developmental delay, not a deficit. Their main problem is to access the quantitative meaning of Arabic numerals. The development of different types of cognitive abilities is differently affected by educational experience and intellectual ability. The innate number system appears to be unaffected by intellectual capacity or educational experience, while the innate working memory ability is affected by intellectual capacity but not by educational experience. Culturally acquired symbolic number abilities are strongly affected by educational experience. 相似文献
7.
8.
Folwaczny M Glas J Török HP Fricke K Folwaczny C 《Clinical immunology (Orlando, Fla.)》2003,109(3):325-329
A 32-base-pair deletion in the CCR5 gene was previously shown to influence the susceptibility for several infectious diseases. The present study compared the frequency of the CCR5-Delta32 mutation among subjects with periodontal disease and healthy control individuals. The prevalence of the CCR5-Delta32 mutation was determined in 81 patients with generalized periodontitis and 121 healthy controls. Standardized clinical and radiographic criteria were used for the diagnosis of periodontitis for each subject. The CCR5-Delta32 mutation was identified by PCR amplification and subsequent agarose gel electrophoresis. Genotype and allele frequencies among both study groups were compared using Fisher's exact test at a level of significance of 5% (P<0.05). The frequency of the CCR5-Delta32 allele was 9.9% (16/162) for periodontitis patients and 10.7% (26/216) for the healthy controls. The allele frequencies between periodontitis patients and the control group for the CCR5-Delta32 mutation were not significantly different (P=0.801). The present study revealed no association between the CCR5-Delta32 mutation and susceptibility to periodontal disease. 相似文献
9.
A mechanism to account for mouse strain variation in resistance to the larval cestode, Taenia taeniaeformis. 总被引:6,自引:0,他引:6 下载免费PDF全文
Mice of various inbred strains differ markedly in resistance to first infection with Taenia taeniaeformis. Hypothymic nude mice of relatively resistant (e.g. BALB/c) and relatively susceptible (e.g. CBA/H) genotypes are highly susceptible but both can be protected against infection by injection of serum from infected mice. Using differential pH elution of "immune serum" from protein A-Sepharose, evidence was obtained that a combination of the pH 6 eluate (enriched for IgG1 molecules) plus the pH 3 or 4 eluate (enriched for IgG2 molecules) was more effective than either eluate alone at transferring protection to nude mice. By using whole serum transfer techniques, the rate of appearance of "host protective serum activity" (presumably antibody) was shown to be increased in genetically resistant versus susceptible mouse strains. It is suggested that, in relatively resistant mouse strains, host protective antibodies prejudice the establishment (or subsequent survival) of larvae prior to the full expression of protective mechanisms in the establishing larvae. In keeping with a host-protective effect of an accelerated immune response early in infection, a high dose challenge with eggs actually resulted in lower infection levels in genetically resistant mouse strains such as BALB/c and C57B1/6. The proposed mechanism of immunologically mediated, genetically based variation in susceptibility to T. taeniaeformis should not influence the effectiveness of a model vaccine against first infection in all strains of mice. 相似文献
10.
William E Berger Linda B Ford Todd Mahr Robert A Nathan Courtney Crim Lisa Edwards Donna S Wightman William R Lincourt Kathleen Rickard 《Annals of allergy, asthma & immunology》2002,89(4):393-399
BACKGROUND: Studies have shown fluticasone propionate (FP) 100, 200, and 500 microg administered once daily to be effective in the treatment of asthma. The efficacy of a once daily regimen of FP 250 microg has not been evaluated previously. OBJECTIVE: We sought to evaluate the efficacy and safety of inhaled FP 250 microg administered once daily in patients currently receiving inhaled short-acting beta-agonists (SABA) alone or inhaled corticosteroids (ICS). METHODS: In two separate studies, 408 patients in the SABA study and 401 patients in the ICS study were randomly assigned to receive FP 250 microg or placebo for 12 weeks through the Diskus device (GlaxoSmithKline, Research Triangle Park, NC) each morning. RESULTS: At the study endpoint, SABA patients treated with FP and placebo had mean increases in forced expiratory volume in 1 second from baseline of 0.23 +/- 0.03 L and 0.10 +/- 0.03 L, respectively (P < 0.001). ICS patients treated with FP had a mean increase of 0.08 +/- 0.02 L compared with a decrease in forced expiratory volume in 1 second of -0.08 +/- 0.03 L with placebo (P < 0.001). Changes of similar magnitude in morning peak expiratory flow rates were seen with FP in both the SABA and ICS studies. Fewer FP-treated ICS study patients were withdrawn from the study as a result of predetermined asthma stability criteria and, therefore, those patients had a greater probability of remaining in the study than placebo-treated patients (P < 0.001). CONCLUSIONS: FP 250 microg, once daily, produced greater improvements in pulmonary function and asthma symptom control than placebo. This new treatment regimen provides clinicians with an additional therapeutic option for patients with asthma previously treated with either beta2-agonists alone or ICS. 相似文献