全文获取类型
收费全文 | 15084篇 |
免费 | 1196篇 |
国内免费 | 284篇 |
专业分类
耳鼻咽喉 | 163篇 |
儿科学 | 416篇 |
妇产科学 | 156篇 |
基础医学 | 767篇 |
口腔科学 | 230篇 |
临床医学 | 878篇 |
内科学 | 3326篇 |
皮肤病学 | 303篇 |
神经病学 | 1084篇 |
特种医学 | 245篇 |
外科学 | 1408篇 |
综合类 | 1335篇 |
预防医学 | 4558篇 |
眼科学 | 226篇 |
药学 | 531篇 |
2篇 | |
中国医学 | 52篇 |
肿瘤学 | 884篇 |
出版年
2024年 | 17篇 |
2023年 | 232篇 |
2022年 | 484篇 |
2021年 | 610篇 |
2020年 | 573篇 |
2019年 | 668篇 |
2018年 | 719篇 |
2017年 | 528篇 |
2016年 | 504篇 |
2015年 | 540篇 |
2014年 | 1177篇 |
2013年 | 1111篇 |
2012年 | 865篇 |
2011年 | 981篇 |
2010年 | 815篇 |
2009年 | 839篇 |
2008年 | 791篇 |
2007年 | 761篇 |
2006年 | 626篇 |
2005年 | 531篇 |
2004年 | 363篇 |
2003年 | 316篇 |
2002年 | 265篇 |
2001年 | 253篇 |
2000年 | 216篇 |
1999年 | 193篇 |
1998年 | 162篇 |
1997年 | 145篇 |
1996年 | 112篇 |
1995年 | 103篇 |
1994年 | 90篇 |
1993年 | 85篇 |
1992年 | 102篇 |
1991年 | 85篇 |
1990年 | 84篇 |
1989年 | 51篇 |
1988年 | 59篇 |
1987年 | 53篇 |
1986年 | 39篇 |
1985年 | 77篇 |
1984年 | 49篇 |
1983年 | 40篇 |
1982年 | 35篇 |
1981年 | 46篇 |
1980年 | 27篇 |
1979年 | 32篇 |
1978年 | 20篇 |
1977年 | 19篇 |
1976年 | 25篇 |
1975年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Heritability of C-Reactive Protein and Association with Apolipoprotein E Genotypes in Japanese Americans 总被引:1,自引:0,他引:1
M. A. Austin C. Zhang S. E. Humphries W. L. Chandler P. J. Talmud K. L. Edwards D. L. Leonetti M. J. Mcneely W. Y. Fujimoto 《Annals of human genetics》2004,68(3):179-188
Numerous studies have demonstrated that increased C‐reactive protein (CRP) levels predict coronary heart disease, stroke, peripheral vascular disease, and diabetes, and are associated with features of the metabolic syndrome. Only three previous studies have investigated the heritability of CRP levels, primarily in samples of Caucasian families.The purpose of the present study was to estimate the magnitude of genetic influences on CRP levels, and to examine potential associations between variation in the APOE gene and CRP levels, using a sample of 562 individual Japanese Americans from 68 extended kindreds. In general, correlation coefficients between first‐degree relatives for CRP were approximately 0.2, and spouse correlations did not differ from zero, consistent with genetic influences. Heritability estimates were approximately 0.3 (p < 0.01), even with adjustment for factors known to influence CRP levels. A significant relationship was seen between unadjusted CRP levels and APOE genotypes (p = 0.02), with the highest mean CRP level among ?2 carriers (1.20 mg/L), and nearly the same mean levels among ?3/?3 subjects and ?4 carriers (0.72 and 0.74 mg/L, respectively). However, this relationship was diminished with adjustment for covariates (p = 0.07). These results demonstrate the presence of both genetic and environmental effects on CRP levels among Asian Americans, and additional studies are needed to determine if the APOE gene contributes to these genetic influences. 相似文献
92.
93.
R. Saito S. Okugawa W. Kumita K. Sato T. Chida N. Okamura K. Moriya K. Koike 《Clinical microbiology and infection》2007,13(12):1204-1206
This study investigated the clinical characteristics of ciprofloxacin-resistant Proteus mirabilis isolates from urine samples associated with nosocomial infection or colonisation, and identified the risk-factors for ciprofloxacin resistance. Data for patients with ciprofloxacin-resistant P. mirabilis isolates (n=13) were compared with those for randomly selected patients with ciprofloxacin-susceptible P. mirabilis isolates (n=40) who were matched by temporal occurrence as control patients. The majority of ciprofloxacin-resistant P. mirabilis isolates were multiresistant, and ciprofloxacin resistance was associated significantly with previous use of fluoroquinolones and production of extended-spectrum beta-lactamases. 相似文献
94.
宫脂属线虫是鱼类寄生线虫的重要类群。本文从分类学、流行病学、生态学以及生活史等方面对宫脂属线虫的研究进展进行了论述。 相似文献
95.
The prevalence of TT virus (TTV) infection and its relationship to hepatitis in children 总被引:4,自引:0,他引:4
Iriyama M Kimura H Nishikawa K Yoshioka K Wakita T Nishimura N Shibata M Ozaki T Morishima T 《Medical microbiology and immunology》1999,188(2):83-89
TT virus (TTV) is a newly discovered virus from a patient with post-transfusion hepatitis. We investigated the frequency
and pathogenesis of TTV infection in children. A semi-nested PCR assay was used to amplify TTV-DNA in serum samples from 254
ambulatory children without liver disease, 20 with hepatitis of unknown etiology, and 18 transfusion recipients or hemophiliacs.
In positive samples, TTV-DNA was quantified by real-time quantitative PCR using a fluorescent probe. We detected TTV-DNA in
20% of children with hepatitis of unknown etiology, which was not statistically different from the 23% prevalence in ambulatory
children. In transfusion recipients or hemophiliacs, the frequency was higher (50%) than that in ambulatory children (P = 0.01). Among ambulatory children, TTV-DNA was frequently detected in children with acute gastroenteritis (36%). TTV-DNA
was detected in 10% of the infants under 6 months old, and 20% of the children from 7 to 12 months old. The prevalence was
constant after the age of 1 year; however, the copy number of TTV-DNA was significantly higher in children under 1 year of
age (mean: 105.4 versus 103.8 copies/ml, P= 0.008). Finally, TTV-DNA was quantified serially in three children with chronic hepatitis who were positive for TTV-DNA.
The presence or amount of TTV-DNA was unrelated to the serum alanine aminotransferase level. These results indicate that TTV
infection is common in children. The larger quantity of TTV-DNA in infants and the high prevalence of TTV in children of all
ages suggest that TTV may be transmitted in early childhood. Its relationship to hepatitis is doubtful in children.
Received: 8 April 1999 相似文献
96.
Ghazi Kayali Sharon F. Setterquist Ana W. Capuano Kendall P. Myers James S. Gill Gregory C. Gray 《Journal of clinical virology》2008,43(1):73-78
BACKGROUND: The hemagglutination inhibition (HI) assay is a frequently used method to screen human sera for antibodies against influenza A viruses. Because HI has relatively poor sensitivity in detecting antibodies against avian influenza A strains, a more complicated microneutralization (MN) assay is often preferred. Recent research suggests that the sensitivity of the HI assay can be improved by switching from the traditionally used turkey, guinea pig, human, or chicken RBCs to horse RBCs. OBJECTIVE: To evaluate the performance of the horse RBC HI when screening for human antibodies against avian influenza types H3, H4, H5, H6, H7, H9, H11, and H12. STUDY DESIGN: We evaluated the reproducibility of horse RBC HI and its agreement with MN results using sera from people exposed or not exposed to wild and domestic birds. RESULTS: The horse RBC HI assay had high reliability (90%-100%) and good agreement with MN assay results (52%-100%). CONCLUSION: The horse RBC HI assay is reliable, less expensive, less complex, and faster than the MN assay. While MN will likely remain the gold standard serologic assay for avian viruses, the horse RBC HI assay may be very useful as a screening assay in large-scale epidemiologic studies. 相似文献
97.
M. Linde H. Hinrichsen S. Schubert W. Kirch 《Journal of molecular medicine (Berlin, Germany)》1990,68(18):921-926
Summary The clinical courses of 214 patients with infective endocarditis treated between 1958 and 1987 at the First Medical Hospital of the University of Kiel (FRG) were analyzed retrospectively. A decrease in the incidence of endocarditis occurred during the 30-year observation period. The mean age of patients was 48 years, and men were more frequently affected than women. In the course of the investigation, a rise in isolated aortic valve disease was noted, whereas the number of patients with isolated involvement of the mitral valve and combined mitral-aortic valvular defects declined. Streptococci (57%) were the most frequent pathogens isolated; as opposed to their increase, the percentages ofStaphylococcus aureus and enterococci decreased. Otolaryngological, dentogenic and urogenital diseases were most frequently held to be responsible for the development of infective endocarditis. Prior cardiosurgical interventions became increasingly significant as a cause of the disease. In this connection, a rising percentage of endocarditis cases was linked with prosthetically replaced heart valves. Complications and concomitant symptoms of endocarditis included the development of heart failure, cerebral embolism and encephalitis, splenomegaly, and renal inflammation. Finally, the marked decrease in mortality contrasted with a simultaneous rise in the number of endocarditis cases achieving full recovery. 相似文献
98.
The relationship between bladder cancer and alcohol consumption was investigated in a case-control study conducted in 546 patients (453 males and 53 females) with diagnoses of papillary urothelial carcinoma during 1978–1982 at La Paz hospital (Madrid), and an equal number of controls matched for age, sex and date of admission to the hospital. The results showed that the risk of bladder cancer does not increase with the intake of beer, wine and spirit beverages. However, a high risk of bladder cancer was associated with consumption of wine mixed with gaseosa (a refreshment beverage consisiting of carbonated water plus artificial sweeteners). 相似文献
99.
Dr. M. L. Farina Italian Group on Intensive Care Evaluation 《European journal of clinical pharmacology》1987,31(5):507-512
Summary Clinically relevant events possibly attributable to drug exposure have been monitored prospectively over a period of six months in 27 general intensive care units. Fifty-four events attributed to drugs were reported in 51 patients during their stay in hospital, corresponding to an overall incidence of 1.35%. The behaviour of the physicians following attribution of the events to a prescribed drug is analyzed and discussed in detail with respect to its relationship to the quality and severity of the reaction, and the classes of drugs. Twenty-four of the 4537 monitored admissions during the six months were due to life-threatening emergencies linked to the administration of drugs (14) and radio-contrast media (10) (overall incidence 0.5%). While the clinical burden attributable to adverse drug reactions in Intensive Care Units appears to be relatively small, the analysis shows that there is ample room for a greater reduction in their incidence.
Coordinators: Drs M. L. Farina and G. Tognoni, Istituto di Ricerche Farmacologiche Mario Negri, Milan; Dr F. Procaccio, Neurosurgical ICU, Ospedale Ca' Granda, Niguarda, Milan.Investigators: Drs G. Barusco, Rovigo; F. Bassi, Milan; L. Bianchetti, Torino; E. Carchietti, Udine; G. Chilloni, Reggio Emilia; G. Costantini, Savigliano (CN); P. Ferrero, Aosta; E. Geat, Trento; F. Gorgerino, Torino; A. Lusini, Empoli (FI); G. Mantovani, Ferrara; S. Marchi, Bologna; P. Marcovigi, Forli; G. Marraro, Merate (CO); F. Merlo, Vicenza; E. Pagni, Bagno a Ripoli (FI); R. Pellegrino, Cuneo; C. Peruselli, Milan; A. Piovesano, Pordenone; R. Rinaldo, Cremona; R. Ruggerini, Piacenza; S. Sammartino, Torino; A. Sartore, Cittadella (PD); A. Scaglioli, Carpi (MO); G. Scopa, Terni; G. Zeffiro, Treviso; P. Zuccoli, Parma 相似文献
100.
H. Hafner S. Haas M. Pfeifer-Kurda S. Eichhorn S. Michitsuji 《European archives of psychiatry and clinical neuroscience》1987,236(6):333-342
Summary The unusual finding of an abnormal seasonal distribution of schizophrenic births, showing an excess of 10% in the winter or spring months and an equal deficit in the summer or autumn months, cannot be explained by artefacts. It has not yet been established whether the finding is specific to schizophrenia. We observed an excess of schizophrenic births of some 10% in March to May, significant at the 5% level, and a deficit of approximately the same size in June to August on the birth data of first-admission patients with the clinical diagnosis of schizophrenia. The data, obtained from the Mannheim Psychiatric Case Register, were compared with those of the Mannheim population and a control group matched by birth year and sex. The total population of mentally retarded children aged 7 to 16 years from the Mannheim population showed an excess of some 20% in April to June and an equal deficit in the last two quarters of the year, compared with the Mannheim population of the same birth years. The finding was not significant, but allowance must be made for the low case number of 415. We also compared 3409 first-admission patients with depressive syndromes (ICD 296 and 300.4) and 5615 first-admission patients with the diagnosis of neurosis and personality disorders (ICD 300–302, except 300.4, and 305–309) from the Mannheim Case Register with a control population and a parallel control group. Depressed males showed an excess of births in March to May, which was significant at the 1% level; the birth peak for females was smaller and not significant. The same findings were obtained for the category of neurosis and personality disorders, i.e. an excess of about 10% in March to May for males, significant at the 1% level, and a non-significant excess for females. Our findings are awaiting replication. Causal explanations will be discussed with great reservation. The procreational hypothesis, assuming those factors that lead to an equidirectional seasonal pattern of births with a slight deviation from the average of a year in the general population, to be reinforced in the disease categories mentioned, is regarded as the most simple and plausible explanation. It is based on the assumption that some of the parents of individuals suffering from schizophrenia, mental retardation or probably also some other mental disorders running from generation to generation, have a higher threshold in partner-seeking behaviour, which is overcome more easily in the summer months with the consequence of increased pregnancies. 相似文献