全文获取类型
收费全文 | 7125篇 |
免费 | 479篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 211篇 |
妇产科学 | 192篇 |
基础医学 | 1204篇 |
口腔科学 | 163篇 |
临床医学 | 662篇 |
内科学 | 1524篇 |
皮肤病学 | 286篇 |
神经病学 | 681篇 |
特种医学 | 209篇 |
外科学 | 598篇 |
综合类 | 45篇 |
一般理论 | 3篇 |
预防医学 | 675篇 |
眼科学 | 68篇 |
药学 | 510篇 |
中国医学 | 26篇 |
肿瘤学 | 536篇 |
出版年
2023年 | 51篇 |
2022年 | 73篇 |
2021年 | 159篇 |
2020年 | 165篇 |
2019年 | 207篇 |
2018年 | 216篇 |
2017年 | 165篇 |
2016年 | 201篇 |
2015年 | 231篇 |
2014年 | 288篇 |
2013年 | 367篇 |
2012年 | 557篇 |
2011年 | 554篇 |
2010年 | 319篇 |
2009年 | 265篇 |
2008年 | 460篇 |
2007年 | 481篇 |
2006年 | 463篇 |
2005年 | 431篇 |
2004年 | 361篇 |
2003年 | 350篇 |
2002年 | 301篇 |
2001年 | 82篇 |
2000年 | 63篇 |
1999年 | 57篇 |
1998年 | 63篇 |
1997年 | 48篇 |
1996年 | 46篇 |
1995年 | 36篇 |
1994年 | 28篇 |
1993年 | 25篇 |
1992年 | 33篇 |
1991年 | 35篇 |
1990年 | 35篇 |
1989年 | 22篇 |
1988年 | 26篇 |
1987年 | 21篇 |
1986年 | 28篇 |
1985年 | 24篇 |
1984年 | 12篇 |
1983年 | 14篇 |
1982年 | 22篇 |
1981年 | 21篇 |
1979年 | 13篇 |
1978年 | 16篇 |
1977年 | 14篇 |
1976年 | 15篇 |
1974年 | 13篇 |
1971年 | 14篇 |
1967年 | 11篇 |
排序方式: 共有7625条查询结果,搜索用时 31 毫秒
51.
Hrissanta Boudevska Christo Brutchkov Vera Koleva 《Macromolecular chemistry and physics.》1978,179(8):2031-2041
The solutions of methyl methacrylate (MMA) and naphthalene (N), of 2-naphthyl methacrylate (2-NM) and of 1-naphthyl methacrylate (1-NM) in chloroform, acetone, acetonitrile and N,N-dimethylformamide are studied by 1H NMR spectroscopy. In chloroform and in pure MMA, N causes a shift of the signal of the high field vinyl proton Ha of MMA to higher field, whereas in acetone and acetonitrile the signal of Ha has the τ-value for MMA in the absence of N. The Ha signals of 2-NM and 1-NM in acetone, acetonitrile and N,N-dimethylformamide shift downfield as compared with those in chloroform. The τ-value of the downfield vinyl proton Hb does not vary with a change of the solvent. The separation of the vinyl signals Δ=τ(Ha)—τ(Hb) becomes equal to that of pure MMA. The formation of 1:1 complexes between the electron donating naphthalene ring and the electron accepting methacrylic double bond is assumed. The stability constant of the MMA-N complex is 0,22 1.mol?1. Some structures for the complexes are proposed on the basis of molecular models of the monomer molecules. The results confirm the known theories for the influence of the solvents in radical polymerization of MMA. They can explain the kinetic changes of polymerization of 2-NM and 1-NM. 相似文献
52.
Mastella Giulio Darstein Lars Raufhake Carsten Schneider Vera Corletto Anna Buiatti Alessandra Mller Alexander Schuessler-Hahn Franziska Gondert Markus Gerdes Heiko Martens Eimo 《Zeitschrift fur Gesundheitswissenschaften》2022,30(1):5-10
Journal of Public Health - Offshore wind energy is a fast growing market. Accordingly, a correspondingly large number of employees are working at the wind farms. Owing to the harsh operating... 相似文献
53.
Dietermann Karina Winter Vera Schneider Udo Schreyögg Jonas 《The European journal of health economics》2021,22(5):833-846
The European Journal of Health Economics - The goal of this study is to provide empirical evidence of the impact of nurse staffing levels on seven nursing-sensitive patient outcomes (NSPOs) at the... 相似文献
54.
Leticia Faria Serpa Margarita Maria Ortiz Anne Chaves Lima Línea Bueno Paula Cristina Nogueira Cleusa Ferri Vera Lucia Conceio De Gouveia Santos 《Wound repair and regeneration》2021,29(1):79-86
This study aimed to estimate the incidence of hospital‐acquired pressure injury (PI) and its risk factors in inpatient and intensive care units of five hospitals (two public and three private) in the city of Sao Paulo, Brazil. A 6‐month follow‐up prospective cohort study (n = 1937) was conducted from April to September 2013. Baseline and follow‐up measurements included demographic and care information, as well as risk assessments for both undernutrition (NRS‐2002) and PI (Braden scale). Poisson regression with robust variance was used for data analysis. A total of 633 patients (32.60%) showed risk for PI. The incidence rate of PI was of 5.9% (9.9% in public hospitals vs 4.1% in private hospitals) and was higher in intensive care units, compared to inpatient care units (10% vs 5.7%, respectively). Risk for PI increased with age (RR = 1.05; 95% CI 1.04‐1.07); was higher in in public hospitals, compared to private hospitals (RR = 4.39; 95% CI 2.92‐6.61); in patients admitted for non‐surgical reasons compared to those admitted for surgical reasons (RR = 1.91; 95% CI 1.12‐3.27); in patients with longer hospital stays (RR = 1.04; 95% CI 1.03‐1.06); high blood pressure (RR = 1.76; 95% CI 1.17‐2.64); or had a risk for undernutrition (RR = 3.51; 95% CI 1.71‐7.24). Higher scores in the Braden scale was associated with a decreased risk of PI (RR = 0.79; 95% CI 0.75‐0.83). The results of our study indicate that 5.9% of all patients developed PI and that the most important factors that nurses should consider are: patient age, care setting, length of hospitalization, comorbidities, reason for admission and nutrition when planning and implementing PI‐preventative actions. 相似文献
55.
Charlotte V. Hobbs Jan Drobeniuc Theresa Kittle John Williams Paul Byers Panayampalli S. Satheshkumar Kengo Inagaki Meagan Stephenson Sara S. Kim Manish M. Patel Brendan Flannery CDC COVID- Response Team CDC COVID- Response Team Bailey Alston Shanna J. Bolcen Darbi Boulay Peter Browning Li Cronin Ebenezer David Tonya Hayden Han Li Travis Lim Panagiotis Maniatis Palak Patel Mathew Pauly Amanda Poe Lili Punkova Vera Semenova Evelene P. Steward-Clark Alexandra Tejada Briana Zellner 《MMWR. Morbidity and mortality weekly report》2021,70(9):312
56.
J F Guadalajara J J Gual N Valvuena A Vera I Laplaza L Salinas 《Archivos del Instituto de Cardiología de México》1990,60(6):541-546
The histologic findings of 325 necropsies of rheumatic patients at the National Institute of Cardiology in Mexico, between 1980-1985 were studied forty five of them had Aschoff nodules plus valvular inflammation-Out of these 45 cases two groups were formed: children-adolescent group (24 cases) and an adult group (21 cases). The clinical, histologic and laboratory findings were compared. Clinical records were reviewed searching for history of rheumatic fever. Active rheumatic fever was suspected in 16 patients in the younger group (67%) and only in 3 adults (14.2%). As far as Jones' criteria is concerned, the most common finding was carditis, principally in the younger group (83%). In the adult group, it appeared in 50% of the patients. All other criteria were only occasionally seen or could not be identified during the patients lifetime. The most common laboratory finding which could suggest active rheumatic fever were: a high levels of anti-streptolysin in younger patients (95%) and elevation of erythro-sedimentation in adults (83%). We conclude that in active rheumatic fever of the adult; Jones criteria are not met, so the illness is difficult to recognize, and there is clinical-histologic discrepancy. In this context the disease has a "silent" evolution. 相似文献
57.
T Vera Castillo E Iglesias Díaz M Milián Montesino J B Torres Ruiz V P Díaz Narváez 《Revista cubana de enfermería》1990,6(2):151-164
A prospective study in order to determine level knowledge of the population about health, before and after the implantation of the Integral Medical Attention Programme to the Family, was carried out at the outpatient services in the "Pedro Borrás" Teaching Community Polyclinic Health Area. Of the population attending to this outpatient area, 917 individuals older than 15 years, were selected at random. These individuals were surveyed at the beginning of the study (November 1986), in order to collect data of main necessary aspects that the population must be acquainted with on health condition and health promotion, and were surveyed again after six months of the performance of the system (May 1987), and results of both surveys were compared and shown in tables with statistical data. The main programmes for health promotion before the implantation of the new system were, known, effectively, by the population in ratios ranging 0.26-0.49. After the performance of the new programme it was observed how the level of knowledge raises to 0.31-0.70, and knowledges on obesity and sedentary habits (0.69) and on prevention of accidents (0.70) becomes significative. We consider all these changes depending on a greater educational work by the physician and nurse in charge of the plan. 相似文献
58.
Alexandra Schneider-Chaabane David Boschert Sibylle Rau Diana Lorena Guevara Solarte Vera Bleicher Ali Al-Ahmad Karen Lienkamp 《Macromolecular chemistry and physics.》2023,224(5):2200323
Facially amphiphilic polymers carrying cationic and hydrophobic groups on the same repeat unit have shown promising antimicrobial activity and biocompatibility, yet they are prone to suffer from protein adhesion which may induce biofilm formation. To overcome this problem, poly(diitaconate)-based copolymers with cationic/hydrophobic and protein-repellent/charge-neutral repeat units are synthesized. The bioactivity profile of surface-attached polymer networks made from these copolymers depends on the ratio of the cationic and charge-neutral repeat units. In all cases, the protein adhesion is substantially reduced compared to purely cationic polymers. At a 50:50 ratio, the polymer coatings are partially protein-repellent and antimicrobial, yet slightly cell toxic. At an intermediate composition of 30:70, they are still antimicrobial and the cell compatibility is substantially improved. The long-term stability of these materials still has to be determined to judge their suitability for medical applications. 相似文献
59.
60.
Chromosome 11q13 markers and D-type cyclins in breast cancer 总被引:7,自引:0,他引:7
Gordon Peters Vera Fantl Rosalind Smith Sharon Brookes Clive Dickson 《Breast cancer research and treatment》1995,33(2):125-135
Summary One in six primary human breast cancers has DNA amplification centered on the cyclin D1 gene (CCND1) on chromosome 11q13. This genetic abnormality is preferentially associated with estrogen-receptor positive tumors and may define a sub-class of patients with an adverse prognosis. AlthoughCCND1 has the credentials of a cellular oncogene, being a target for chromosomal translocation and retroviral integration, the 11q13 amplicon encompasses several other markers andCCND1 is not the only candidate for the key gene on the amplified DNA. To assess their relative importance, we have constructed a physical map of the amplified DNA and compared the extent and frequency of amplification across the region. Since it is likely that the gene providing the selective force for amplification will be expressed at elevated levels, we have also examined expression of both RNA and protein. By these criteria, cyclin D1 remains the strongest candidate for the key oncogene on the amplicon and we are currently investigating the functional consequences of its over-expression.Presented by Gordon Peters at the 16th Annual San Antonio Breast Cancer Symposium, San Antonio TX, USA, November 4, 1993; Minisymposium on Molecular Genetics in Breast Cancer. 相似文献