全文获取类型
收费全文 | 40019篇 |
免费 | 2616篇 |
国内免费 | 172篇 |
专业分类
耳鼻咽喉 | 411篇 |
儿科学 | 1163篇 |
妇产科学 | 910篇 |
基础医学 | 5730篇 |
口腔科学 | 2136篇 |
临床医学 | 3329篇 |
内科学 | 9390篇 |
皮肤病学 | 1252篇 |
神经病学 | 3300篇 |
特种医学 | 713篇 |
外国民族医学 | 1篇 |
外科学 | 3763篇 |
综合类 | 156篇 |
一般理论 | 35篇 |
预防医学 | 4365篇 |
眼科学 | 648篇 |
药学 | 2990篇 |
中国医学 | 220篇 |
肿瘤学 | 2295篇 |
出版年
2024年 | 42篇 |
2023年 | 422篇 |
2022年 | 972篇 |
2021年 | 1739篇 |
2020年 | 964篇 |
2019年 | 1466篇 |
2018年 | 1793篇 |
2017年 | 1189篇 |
2016年 | 1116篇 |
2015年 | 1386篇 |
2014年 | 1839篇 |
2013年 | 2282篇 |
2012年 | 3442篇 |
2011年 | 3660篇 |
2010年 | 1833篇 |
2009年 | 1557篇 |
2008年 | 2551篇 |
2007年 | 2510篇 |
2006年 | 2186篇 |
2005年 | 2002篇 |
2004年 | 1706篇 |
2003年 | 1531篇 |
2002年 | 1369篇 |
2001年 | 402篇 |
2000年 | 390篇 |
1999年 | 325篇 |
1998年 | 211篇 |
1997年 | 189篇 |
1996年 | 140篇 |
1995年 | 114篇 |
1994年 | 110篇 |
1993年 | 76篇 |
1992年 | 182篇 |
1991年 | 144篇 |
1990年 | 109篇 |
1989年 | 105篇 |
1988年 | 94篇 |
1987年 | 87篇 |
1986年 | 77篇 |
1985年 | 77篇 |
1984年 | 52篇 |
1983年 | 40篇 |
1982年 | 25篇 |
1981年 | 26篇 |
1980年 | 26篇 |
1979年 | 26篇 |
1978年 | 20篇 |
1977年 | 23篇 |
1975年 | 20篇 |
1973年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Roberto Rivera-Luna Marta Zapata-Tarrés Aurora Medina-Sansón Enrique López-Aguilar Ana Niembro-Zúñiga J. Amador Zarco Alfonso Marhx-Bracho Fernando Rueda-Franco Leticia Bornstein-Quevedo 《Child's nervous system》2007,23(5):543-547
Objective The purpose of this study is to analyze clinical aspects and disease-free survival (DFS) in children less than 3 years of
age diagnosed with low-grade astrocytoma.
Methods In a period of 24 years (1980–2004), a total of 43 (5.4%) children were registered with these characteristics. Twenty-three
patients had pilocytic astrocytoma, 18 diffused, and 2 mixed. Thirty-one (72.1%) children had incomplete surgical tumor resection
and 12 (27.9%) had a complete tumor resection. Twelve (27.9%) patients had cranial radiotherapy and 17 (39.5%) received chemotherapy.
Overall survival was recorded in 23 (53%). DFS was 50% at 250 months of follow-up for the whole group. DFS for the supratentorial
group was 60% at 250 months, whereas, for the infratentorial, it was 22% at 120 months (p = 0.008).
Conclusion The only favorable prognostic pattern was the supratentorial presentation. Radiotherapy and chemotherapy did not alter the
outcome. 相似文献
82.
Gregory C Gray Troy McCarthy Mark G Lebeck David P Schnurr Kevin L Russell Adriana E Kajon Marie L Landry Diane S Leland Gregory A Storch Christine C Ginocchio Christine C Robinson Gail J Demmler Michael A Saubolle Sue C Kehl Rangaraj Selvarangan Melissa B Miller James D Chappell Danielle M Zerr Deanna L Kiska Diane C Halstead Ana W Capuano Sharon F Setterquist Margaret L Chorazy Jeffrey D Dawson Dean D Erdman 《Clinical infectious diseases》2007,45(9):1120-1131
BACKGROUND: Recently, epidemiological and clinical data have revealed important changes with regard to clinical adenovirus infection, including alterations in antigenic presentation, geographical distribution, and virulence of the virus. METHODS: In an effort to better understand the epidemiology of clinical adenovirus infection in the United States, we adopted a new molecular adenovirus typing technique to study clinical adenovirus isolates collected from 22 medical facilities over a 25-month period during 2004-2006. A hexon gene sequence typing method was used to characterize 2237 clinical adenovirus-positive specimens, comparing their sequences with those of the 51 currently recognized prototype human adenovirus strains. In a blinded comparison, this method performed well and was much faster than the classic serologic typing method. RESULTS: Among civilians, the most prevalent adenovirus types were types 3 (prevalence, 34.6%), 2 (24.3%), 1 (17.7%), and 5 (5.3%). Among military trainees, the most prevalent types were types 4 (prevalence, 92.8%), 3 (2.6%), and 21 (2.4%). CONCLUSIONS: For both populations, we observed a statistically significant increasing trend of adenovirus type 21 detection over time. Among adenovirus isolates recovered from specimens from civilians, 50% were associated with hospitalization, 19.6% with a chronic disease condition, 11% with a bone marrow or solid organ transplantation, 7.4% with intensive care unit stay, and 4.2% with a cancer diagnosis. Multivariable risk factor modeling for adenovirus disease severity found that age <7 years (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.4-7.4), chronic disease (OR, 3.6; 95% CI, 2.6-5.1), recent transplantation (OR, 2.7; 95% CI, 1.3-5.2), and adenovirus type 5 (OR, 2.7; 95% CI, 1.5-4.7) or type 21 infection (OR, 7.6; 95% CI, 2.6-22.3) increased the risk of severe disease. 相似文献
83.
Edgar Krtzsch Arturo Surez‐Colín Rosa M. Salgado Ana M.Z. Apis 《Wound repair and regeneration》2004,12(2):A35-A35
Venous leg ulcers derived from tissue destruction is the consequence of a chronic inflammatory process that produces pain and physical disability, diminishing quality of life in patients. In this work, Lassar ointment and lyophilized collagen‐polyvinylpyrrolidone were administered separated each on one half in the same ulcer to 9 patients at the beginning and every 4 days. On day 16, all patients were auto‐grafted with partial thickness skin. Granulation tissue and graft integration were assessed clinically during 3 months. Inflammatory infiltrate, type I and III collagens, elastic fibers, alkaline phosphatase as well as blood vessels were evaluated histologically or histochemically in biopsies taken at the beginning and 16 days after the local treatment. Clinically and morphologically, both treatments demonstrated appropriate granulation tissue promotion and optimal graft integration since the beginning. Nevertheless, in Lassar ointment treated group regionalization of alkaline phosphatase activity was observed, as well as the presence of granuloma in 2 of the 9 patients. In conclusion, Lassar ointment or lyophilized collagen‐polyvinylpyrrolidone are two different promoters of granulation tissue in venous leg ulcers, however Lassar ointment has the capability to produce granuloma and an exacerbated immune response; in consequence, ulcer recidivism could be present, may be due to mineral deposits in the wound. 相似文献
84.
María de Oña Navarro Santiago Melón Susana Méndez Beatriz Iglesias Ana Palacio María J. Bernardo José L. Rodriguez-Lambert Ernesto Gómez 《Transplant international》2002,15(11):570-573
Ganciclovir (GCV) prophylaxis or pre-emptive therapy significantly reduce the rate of cytomegalovirus (CMV) disease and viremia, but increase the potential for emergence of ganciclovir-resistant CMV strains. The inhibitor concentration at 50% (IC(50)) of GCV from 156 CMV isolates from 59 renal or heart transplant recipients was calculated by means of a rapid phenotypic susceptibility assay. Twenty-seven strains were from 14 patients undergoing GCV therapy. The IC(50) was higher in patients under the prophylaxis regimen. One CMV strain, from a heart transplant recipient, became GCV-resistant after 1 month of therapy (IC(50)=13.7 micromol/l). These data, together with clinical and virological markers, suggested that a switch to foscarnet was necessary, and good evolution was observed. Thus, assay of CMV susceptibility to GCV could be helpful in clinical management. 相似文献
85.
86.
F Ledesma Casta?o S Echevarria Vierna J L Lozano Polo R Oloriz Rivas C Alvarez Moreno F Pons Romero 《European journal of clinical nutrition》1992,46(7):527-533
Interleukin-1 (IL-1) is a cytokine produced by the macrophage-monocyte system that has important effects on immunological responses and inflammatory reactions. Several clinical studies have shown that severe protein energy malnutrition adversely effects cell-mediated immune responses and the functional state of macrophages. The objective of this study was to analyse IL-1 production by adherent cells stimulated in vitro with lipopolysaccharide B (LPS) from patients with alcoholic cirrhosis of the liver and its possible relationship with nutritional states. Forty-five patients with alcoholic cirrhosis and 28 healthy donors were investigated. A combined index of nine anthropometric and biochemical parameters was used to evaluate nutritional status of cirrhotic patients, allowing a distinction to be made between those patients with acceptable nutrition (group I: 40%), those with slight malnutrition (group II: 37.7%), and those with severe malnutrition (group III: 22.3%). IL-1 activity was significantly lower in the cirrhosis patients than in the controls (P less than 0.001). This activity also was significantly lower in samples obtained from cirrhotics with severe malnutrition than in those with acceptable nutrition (P less than 0.05); the combined index and the sole anthropometric index gave the same results, suggesting that malnutrition may play a role in the immunoregulatory disturbances in the pathogenesis of alcoholic liver disease. 相似文献
87.
88.
R Pereiro García F Alava Moreno M E Díaz García A Sanz-Medel R Narayanaswamy 《Clinica chimica acta; international journal of clinical chemistry》1992,207(1-2):31-40
A fibre optic potassium ion sensor has been developed based on reflectance measurements of the pH-dependent chromogenic crown ether 'Takagi reagent' immobilized on the non-ionic polymeric resin Amberlite XAD2. The sensor response is in the 1.5-100 mM range with a detection limit of 0.25 mM K+. The selectivity factor over sodium is 20. The proposed sensor works with a reproducibility of +/- 0.8% at the 5 mM K+ level. Advantageous design features include ease of construction, simplicity of use, reversibility, short response time (approximately 1 min) and an optimum working pH range (7.0-8.0) for biological fluids. This optical sensor was applied successfully to the direct determination of potassium in human serum. Aqueous potassium standards containing 0.13 M NaCl and a buffer of pH 8 were used for calibration. 相似文献
89.
90.
Congenital oesophagobronchial fistula in an adult involving left main bronchus. 总被引:1,自引:0,他引:1 下载免费PDF全文
M Moreno Azcoita J C Ruiz de Adana L Snchez Urdazpal C Crcamo J M Jover Navaln J L Ramos Rodriguez 《Thorax》1994,49(8):835-836
Congenital fistulae between the tracheobronchial tree and oesophagus usually originate from the lower end of the trachea or right main bronchus. The case history is presented of a man in whom a fistula between the oesophagus and left main bronchus was not diagnosed until the age of 48. 相似文献