全文获取类型
收费全文 | 185285篇 |
免费 | 10726篇 |
国内免费 | 490篇 |
专业分类
耳鼻咽喉 | 2296篇 |
儿科学 | 5824篇 |
妇产科学 | 4069篇 |
基础医学 | 25615篇 |
口腔科学 | 7674篇 |
临床医学 | 13916篇 |
内科学 | 41670篇 |
皮肤病学 | 4457篇 |
神经病学 | 15537篇 |
特种医学 | 5778篇 |
外国民族医学 | 27篇 |
外科学 | 23340篇 |
综合类 | 1527篇 |
现状与发展 | 1篇 |
一般理论 | 67篇 |
预防医学 | 18674篇 |
眼科学 | 3278篇 |
药学 | 11236篇 |
中国医学 | 709篇 |
肿瘤学 | 10806篇 |
出版年
2023年 | 928篇 |
2022年 | 2020篇 |
2021年 | 3809篇 |
2020年 | 2542篇 |
2019年 | 3646篇 |
2018年 | 5114篇 |
2017年 | 3801篇 |
2016年 | 3599篇 |
2015年 | 4250篇 |
2014年 | 5827篇 |
2013年 | 7445篇 |
2012年 | 11516篇 |
2011年 | 12126篇 |
2010年 | 6260篇 |
2009年 | 5679篇 |
2008年 | 9620篇 |
2007年 | 10208篇 |
2006年 | 9543篇 |
2005年 | 9904篇 |
2004年 | 9292篇 |
2003年 | 8559篇 |
2002年 | 6628篇 |
2001年 | 5095篇 |
2000年 | 5075篇 |
1999年 | 4511篇 |
1998年 | 1773篇 |
1997年 | 1502篇 |
1996年 | 1442篇 |
1995年 | 1259篇 |
1994年 | 1226篇 |
1993年 | 1123篇 |
1992年 | 2785篇 |
1991年 | 2661篇 |
1990年 | 2420篇 |
1989年 | 2410篇 |
1988年 | 2177篇 |
1987年 | 2012篇 |
1986年 | 1891篇 |
1985年 | 1800篇 |
1984年 | 1322篇 |
1983年 | 1061篇 |
1982年 | 634篇 |
1981年 | 596篇 |
1980年 | 536篇 |
1979年 | 960篇 |
1978年 | 644篇 |
1977年 | 501篇 |
1975年 | 572篇 |
1974年 | 559篇 |
1973年 | 561篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
L.J. Mackintosh† M.N.C. de Koning‡ W.G.V. Quint‡ J. ter Schegget‡ I.M. Morgan R.M. Herd† M.S. Campo 《The British journal of dermatology》2009,161(1):56-62
Background Nonmelanoma skin cancer (NMSC) has been linked to cutaneous human papillomaviruses of the genus beta (betaPV).
Objectives We sought to assess the presence of betaPV in NMSC biopsies from a group of Scottish skin cancer patients, both immunocompetent (IC) patients and immunosuppressed (IS) organ transplant recipients.
Methods One hundred and twenty-one paraffin-embedded skin tumours (27 actinic keratosis, 41 intraepidermal carcinoma, 53 squamous cell carcinoma) and 11 normal skin samples were analysed for the presence of betaPV by a polymerase chain reaction–reverse hybridization assay designed to detect the presence of the 25 known betaPV genotypes.
Results In IC patients, betaPV was detected in 30 of 59 (51%) tumours and two of 11 (18%) normal skin samples ( P = 0·046). In IS patients, betaPV was found in 27 of 62 (44%) tumours; no normal skin samples were available for comparison. The most frequently found genotypes were HPV-24, HPV-15 and HPV-38. Of those tumours infected with betaPV, 28 of 57 (49%) were infected with more than one genotype (range 2–8). Tumours from IS patients were from a younger age group (mean age 57·4 years) than IC patients (mean age 73·8 years). Multiple infections were more common in tumours from IC patients (21 of 30; 70%) compared with those from IS patients (seven of 27; 26%) ( P < 0·001). In the IC group, age did not appear to influence the distribution of single and multiple infections whereas in IS patients the proportion of multiple infections to single infections increased with age. There were no multiple infections in normal skin.
Conclusions A wide spectrum of betaPV types was detected in our samples. Further characterization of betaPV in vivo is needed in order to determine the mechanisms by which the virus contributes to cutaneous carcinogenesis. 相似文献
Objectives We sought to assess the presence of betaPV in NMSC biopsies from a group of Scottish skin cancer patients, both immunocompetent (IC) patients and immunosuppressed (IS) organ transplant recipients.
Methods One hundred and twenty-one paraffin-embedded skin tumours (27 actinic keratosis, 41 intraepidermal carcinoma, 53 squamous cell carcinoma) and 11 normal skin samples were analysed for the presence of betaPV by a polymerase chain reaction–reverse hybridization assay designed to detect the presence of the 25 known betaPV genotypes.
Results In IC patients, betaPV was detected in 30 of 59 (51%) tumours and two of 11 (18%) normal skin samples ( P = 0·046). In IS patients, betaPV was found in 27 of 62 (44%) tumours; no normal skin samples were available for comparison. The most frequently found genotypes were HPV-24, HPV-15 and HPV-38. Of those tumours infected with betaPV, 28 of 57 (49%) were infected with more than one genotype (range 2–8). Tumours from IS patients were from a younger age group (mean age 57·4 years) than IC patients (mean age 73·8 years). Multiple infections were more common in tumours from IC patients (21 of 30; 70%) compared with those from IS patients (seven of 27; 26%) ( P < 0·001). In the IC group, age did not appear to influence the distribution of single and multiple infections whereas in IS patients the proportion of multiple infections to single infections increased with age. There were no multiple infections in normal skin.
Conclusions A wide spectrum of betaPV types was detected in our samples. Further characterization of betaPV in vivo is needed in order to determine the mechanisms by which the virus contributes to cutaneous carcinogenesis. 相似文献
92.
Milena Soares Santos Guilherme de Sousa Ribeiro Tainara Queiroz Oliveira Renan Cardoso Nery Santos Edilane Gouveia Kátia Salgado Daniele Takahashi Cleuber Fontes Leila Carvalho Campos Mitermayer Galvão Reis Albert Icksang Ko Joice Neves Reis 《International journal of infectious diseases》2009,13(4):456-461
93.
Marieke Peeters Ludo Verhoeven Jan de Moor Hans van Balkom 《Research in developmental disabilities》2009,30(4):712-726
The goal of this longitudinal study was to investigate the precursors of early reading development in 52 children with cerebral palsy at kindergarten level in comparison to 65 children without disabilities. Word Decoding was measured to investigate early reading skills, while Phonological Awareness, Phonological Short-term Memory (STM), Speech Perception, Speech Production and Nonverbal Reasoning were considered reading precursors. Children with cerebral palsy lag behind on all reading precursors at the beginning of the second year of kindergarten. For the children without disabilities, early reading skills in Grade 1 were best predicted by Phonological Awareness and Phonological STM while Speech Production was the most important predictor of early reading success for the children with cerebral palsy, followed by Phonological Awareness and Speech Perception. Furthermore, for children with cerebral palsy, Speech Production appears to dominate reading development, as Speech Production measured at the beginning of the second year of kindergarten was strongly predictive of all other reading precursors measured at the end of the second year of kindergarten. The results of this study reveal that children with cerebral palsy with additional speech impairments are at risk for limited literacy development. Clinical implications are discussed. 相似文献
94.
Drug-resistance in Streptococcus pneumoniae isolates among Spanish middle aged and older adults with community-acquired pneumonia 总被引:1,自引:0,他引:1
Angel Vila-Corcoles Ferran Bejarano-Romero Elisabeth Salsench Olga Ochoa-Gondar Cinta de Diego Frederic Gomez-Bertomeu Xavier Raga-Luria Xavier Cliville-Guasch Victoria Arija 《BMC infectious diseases》2009,9(1):36
Background
Pneumococcal diseases remain a major cause of morbidity and mortality worldwide. Updated data on drug-resistance from different populations may be important to recognize changes in disease patterns. This study assessed current levels of penicilin resistance among Streptococcus Pneumoniae causing pneumonia in Spanish middle age and older adults. 相似文献95.
96.
97.
Aneurisma de aorta abdominal infrarrenal en asociación con riñón en herradura: aportación de un caso
Nerea Senarriaga Ruiz de la Illa Reyes Vega Manrique Isabel Lacasa Viscasillas Iñaki Iriarte Soldevilla Miguel Unda Urzaiz 《Actas urologicas espa?olas》2009,33(10):1141-1144
We review the association between surgically resolvable aortic disease and horseshoe kidney with a discussion of diagnostic problems and therapeutic options.Male patient 81 years of age with horseshoe kidney and an abdominal aortic aneurysm that was discovered by chance in an abdominal ultrasound during a check-up for his prostate condition.A retroperitoneal approach was used in order to resect the aneurysm and perform an aorto-aortic bypass with no complications occurring. Two years after the diagnosis, the patient is still asymptomatic from a vascular point of view.The co-presence of horseshoe kidney and aortic disease needing surgical correction is infrequent, but it significantly increases the technical complexity of aortic reconstruction. A literature review is included. 相似文献
98.
99.
P M de Vries H B Folkers C W de Fijter J van der Meulen M Luitingh-van der Veen C Popp-Snijders L P Oe 《The American journal of clinical nutrition》1991,53(2):469-473
Adipose tissue fatty acid composition, serum lipid profile, and dietary intake of 37 patients on maintenance hemodialysis were studied. In August 1982, 1984, and 1986, analyses were carried out in 15 normotriglyceridemic (NTG) and 22 hypertriglyceridemic (HTG; type IV hyperlipidemia) patients. No correlations were found between dietary intake of polyunsaturated fatty acids (PUFAs), ratio of polyunsaturated to saturated fatty acids (P-S ratio), and carbohydrate content on the one hand and serum lipid concentrations on the other in the two groups. Adipose tissue linolenic acid correlated negatively with serum cholesterol in both groups. Strong correlations were found between dietary intake of PUFAs and adipose tissue linoleic acid content, between PUFAs and the double-bond index, between P-S ratio and adipose tissue linoleic acid content, and between P-S ratio and the double-bond index. No significant differences in dietary intake or adipose tissue fatty acid composition were observed between NTG and HTG patients. Thus, no evidence was found for exogenous dietary influences on serum lipid concentrations. The adipose tissue linoleic acid content did reflect the dietary intake of PUFAs. 相似文献
100.
Human immunodeficiency virus infection in urban Rwanda. Demographic and behavioral correlates in a representative sample of childbearing women 总被引:9,自引:0,他引:9
S Allen C Lindan A Serufilira P Van de Perre A C Rundle F Nsengumuremyi M Carael J Schwalbe S Hulley 《JAMA》1991,266(12):1657-1663
OBJECTIVE.--To determine behavioral and demographic risk factors for human immunodeficiency virus (HIV) infection in central Africa. DESIGN.--Cross-sectional survey. SETTING.--Kigali, Rwanda. PARTICIPANTS.--A representative sample of 1458 childbearing women aged 19 to 37 years who were recruited from outpatient prenatal and pediatric clinics at the only community hospital in the city. MAIN OUTCOME MEASURE.--Antibodies to HIV assessed by enzyme immunoassay and confirmed by Western blot or indirect immunofluorescence. RESULTS.--The HIV seroprevalence was 32% overall. Infection rates were higher in women who were single, in those in steady relationships that began after 1981, and in the 33% of women reporting more than one lifetime sexual partner. Women in legal marriages or monogamous partnerships had lower rates of infection, but even low-risk women had prevalences on the order of 20%. History of venereal disease in the past 5 years, although the strongest risk factor in a multiple logistic analysis (odds ratio, 2.7; 95% confidence interval, 2.0 to 3.7), was reported by only 30% of those infected. Having a male sexual partner who drank alcohol or who had higher income were significant risk factors for HIV infection in the multivariate analysis, but use of oral contraceptives and having an uncircumcised partner were not. CONCLUSIONS.--The epidemic of the acquired immunodeficiency syndrome in Rwanda has spread beyond high-risk groups to the general population of women without known risk factors. For most of these women, a steady male partner is the source of their HIV risk and therefore a vital target for intervention efforts. 相似文献