全文获取类型
收费全文 | 25891篇 |
免费 | 1564篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 279篇 |
儿科学 | 593篇 |
妇产科学 | 612篇 |
基础医学 | 3564篇 |
口腔科学 | 1902篇 |
临床医学 | 2841篇 |
内科学 | 5106篇 |
皮肤病学 | 521篇 |
神经病学 | 2098篇 |
特种医学 | 593篇 |
外国民族医学 | 1篇 |
外科学 | 2579篇 |
综合类 | 194篇 |
一般理论 | 15篇 |
预防医学 | 3052篇 |
眼科学 | 370篇 |
药学 | 1743篇 |
中国医学 | 140篇 |
肿瘤学 | 1323篇 |
出版年
2023年 | 185篇 |
2022年 | 458篇 |
2021年 | 745篇 |
2020年 | 547篇 |
2019年 | 753篇 |
2018年 | 872篇 |
2017年 | 602篇 |
2016年 | 682篇 |
2015年 | 770篇 |
2014年 | 1004篇 |
2013年 | 1374篇 |
2012年 | 1916篇 |
2011年 | 2022篇 |
2010年 | 1137篇 |
2009年 | 951篇 |
2008年 | 1495篇 |
2007年 | 1667篇 |
2006年 | 1414篇 |
2005年 | 1365篇 |
2004年 | 1240篇 |
2003年 | 1104篇 |
2002年 | 1013篇 |
2001年 | 472篇 |
2000年 | 447篇 |
1999年 | 404篇 |
1998年 | 198篇 |
1997年 | 173篇 |
1996年 | 138篇 |
1995年 | 139篇 |
1994年 | 124篇 |
1993年 | 103篇 |
1992年 | 167篇 |
1991年 | 158篇 |
1990年 | 160篇 |
1989年 | 128篇 |
1988年 | 120篇 |
1987年 | 116篇 |
1986年 | 95篇 |
1985年 | 94篇 |
1984年 | 106篇 |
1983年 | 86篇 |
1982年 | 77篇 |
1981年 | 49篇 |
1980年 | 53篇 |
1979年 | 65篇 |
1978年 | 53篇 |
1974年 | 43篇 |
1973年 | 41篇 |
1971年 | 35篇 |
1970年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
E P A Lopes E C Gouveia A C C Albuquerque L H B C Sette L A Mello R C Moreira M R C D Coelho 《Journal of clinical virology》2006,35(3):298-302
BACKGROUND: Elevated liver enzymes are infrequent in patients with hepatitis C virus (HCV) infection undergoing chronic hemodialysis (HD), suggesting that the alanine aminotransferase (ALT) is a poor predictor of hepatocellular damage in this population. OBJECTIVE: To establish a more appropriate cut-off value of ALT to identify biochemical activity due to HCV infection in HD patients. STUDY DESIGN: A total of 217 patients, with an average age of 51.2 years, were evaluated between January and October 2002; 130 were males (60%). Serum ALT was measured by a kinetic method in five consecutive monthly blood samples, from which an average was obtained and divided by the upper limit of normal (ULN). HCV antibodies were determined using an enzyme immunoassay, the serum HCV-RNA by nested-PCR and HCV genotype by hybridization of the amplified sequence from the 5'-non-coding region. The cut-off value of ALT was obtained from a ROC curve. RESULTS: Within the 217 patients, 18 (8.3%) were anti-HCV-positive, 17 (7.8%) of whom were also HCV-RNA-positive. Genotype distribution was: 1a=47%; 1b=18%; 3a=35%. Mean ALT/ULN (0.77+/-0.57) of the 18 anti-HCV-positive cases was higher (p<0.001) than the negative group (0.38+/-0.23). The mean ALT/ULN (0.81+/-0.57) of the 17 HCV-RNA-positive cases was also higher (p<0.0001) than the negative cases (0.37+/-0.23). The cut-off value of ALT to distinguish the anti-HCV-positive from negative patients was 0.50% or 50% of the ULN (sensitivity=67%; specificity=83%). According to the HCV-RNA, the cut-off value of ALT was 0.45% or 45% of the ULN (sensitivity=71%; specificity=80%). CONCLUSION: Reducing the cut-off of ALT by half, enables a better identification of biochemical activity in patients with HCV infection on chronic HD. 相似文献
62.
Using Triton X-114, glycolipids and proteins were extracted from heart muscle cells (HMC) infected with Trypanosoma cruzi clone Dm28c and from uninfected HMC, and analysed by SDS-PAGE and high-performance thin-layer chromatography (HPTLC). Two major differences were observed: (a) two proteins with a molecular mass of 92 kDa and 69 kDa were present in the uninfected cells but absent from the infected cells and (b) a 70-90 kDa protein band was detected only in parasitized cells. These differences would seem to constitute alterations taking place during the process of cell recognition and/or parasite interiorization. No differences were observed in the respective glycolipid compositions, of control and infected cells analysed by HPTLC. A glycolipid with the same mobility as the neutral glycolipid isolated from epimastigotes of T. cruzi was detected in the uninfected cells. This finding may lend support to the previously described hypothesis that molecular mimicry is implicated in the cardioneuropathology of Chagas' disease. 相似文献
63.
Janice M. Sigmon 《Journal of clinical apheresis》1992,7(3):163-168
Advances in medical knowledge and technology have identified the essential elements involved in the human immune system, their relationships and interactions, and offer more advanced concepts in the design, function, and maintenance of immune response. Immune response begins with the earliest progenitor cell and transfers its legacy of protection through white blood cells and the complement system. A basic understanding of immunology is essential to the hemapheresis practitioner as new treatment regimens requiring hemapheresis interventions develop. © 1992 Wiley-Liss, Inc. 相似文献
64.
Janice Winters 《AAOHN journal》2002,50(6):271-274
1. The use of standardized nursing language is important to the advancement of nursing knowledge and practice. The standardization of nursing diagnoses, interventions, and outcomes provides a means for collecting and analyzing large clinical databases. 2. The occupational health nurse has a clear role in developing health and safety programs. Standardized language using North American Nursing Diagnosis Association diagnoses, nursing outcomes classification, and nursing intervention classification can be incorporated into these programs. 3. The use of standardized taxonomies in the primary prevention of cumulative trauma disorders demonstrates how these systems are integrated into the documentation of the nursing process in a nursing care plan. 相似文献
65.
66.
Michelle Lucinda DeOliveira M.D. Tarcisio Triviño M.D. Ph.D. Gaspar de Jesus Lopes Filho M.D. Ph.D. 《Journal of gastrointestinal surgery》2006,10(8):1140-1143
Carcinoma of the papilla of Vater is classified as periampullary cancer representing 5% of all gastrointestinal tract malignancies.
Early and accurate diagnosis is important for those patients with a tumor of the papilla, as the prognosis is more favorable
than in other periampullary neoplasms. Endoscopically obtained biopsies from suspicious papillae can detect an early tumor,
although even for skilled pathologists it is often difficult to differentiate carcinomas from noninvasive lesions on the basis
of forceps biopsies. The purpose of this study was to assess the preoperative diagnostic accuracy of duodenoscopy appearance
and biopsy in all cases with suspicion of tumor. Thirty patients with suspicion of carcinoma of the papilla of Vater and with
final diagnosis established by pancreatoduodenectomy were included in this retrospective study. In each case, a comparison
was made between endoscopic biopsy and duodenoscopic appearance. Duodenoscopic appearance sensitivity and accuracy for malignancy
were 86% and 83%, respectively, whereas endoscopic biopsy sensitivity and accuracy were 65% and 67%, respectively. Although
preoperative diagnosis of carcinoma of the papilla of Vater is useful for making therapeutic decisions, the diagnostic value
of the endoscopic appearance was superior to endoscopic biopsy in this series.
Presented at the 2003 American Hepato-Pancreato-Biliary Association Congress, Miami, Florida, February 27-March 3, 2003.
Supported by FADA-CAPES/PROP 200J (M.L.D.). 相似文献
67.
Reliability of radiographic measurement of fracture angulation in children with femoral shaft fractures 下载免费PDF全文
INTRODUCTION: Clinical decisions are based on x-ray measures of radiographs. However, the reliability of assessing the angular measurement of fractured femurs in children is unknown. The purpose of this study was to determine the intra- and interrater reliability of an x-ray assessment of femoral shaft fracture angulation in children. METHODS: On 2 occasions, 3 raters evaluated 30 radiographs of children aged 4 to 10 years, 3 to 24 months after a femoral fracture. The radiographs were evaluated by an orthopedic surgeon, an orthopedic fellow and a research assistant, using a standardized methodology. Reliability was assessed with the intraclass correlation coefficient (ICC), an index of concordance that ranges from 01, where > 0.75 indicates excellent concordance. RESULTS: The ICC for the intrarater ranged from 0.75 to 0.97. The interrater reliability ICC for anterior or posterior angulation was 0.91 (95% confidence interval [CI] 0.840.95) and for varus or valgus angulation was 0.90 (95% CI 0.790.95). A change in measurement of more than 5 degrees exceeds the variation in measurement and, therefore, can be attributed to a true shift in fracture position. CONCLUSIONS: With specific standardized protocols, radiographic assessment of femoral fractures is reliable, irrespective of the examiner's level of experience. 相似文献
68.
M C F Bouzada E A Oliveira A K Pereira H V Leite A M Rodrigues L A Fagundes R P Gon?alves R L Parreiras 《Ultrasound in obstetrics & gynecology》2004,24(7):745-749
OBJECTIVE: The purpose of this study was to assess the accuracy of prenatal ultrasound measurement of anteroposterior renal pelvis diameter (APD) to discriminate between significant uropathy and idiopathic renal pelvis dilatation. METHODS: One-hundred-and-three neonates who were found to have fetal renal pelvis dilatation, defined as presence of an APD > or = 5 mm, underwent systematic investigation for uropathies and were prospectively followed. An ultrasound scan was performed after the first week of postnatal life and all infants underwent a voiding cystourethrogram. Neonates with an APD larger than 10 mm underwent renal scintigraphy. Ultrasound scans, clinical examination and laboratory reviews were scheduled at 6-month intervals. Receiver-operating characteristics (ROC) curves were constructed to determine the best cut-offs for APD to identify renal units with significant uropathy as well as those requiring surgical intervention. Significant uropathy was defined as the presence of well-established urinary tract abnormalities or when there was abnormal renal scintigraphy. RESULTS: The estimated area under the curve for APD was 0.900 (95% CI, 0.841-0.942) indicating excellent power to discriminate between idiopathic pelvis dilatation and significant uropathy. The sensitivity and specificity for the 7.5 mm cut-off point were 97.9% and 40.6%, respectively. To identify infants who required surgical intervention, the calculated area under the curve was 0.953 (95% CI, 0.908-0.980). CONCLUSION: Our results suggest that measurement of APD is an excellent test to identify fetuses with significant uropathy, as well as those requiring postnatal intervention. 相似文献
69.
Yang-Sheng Tzeng Eric Hoffman Janice Cook-Granroth Rie Maurer Niral Shah Joey Mansour Juerg Tschirren Mitchell Albert 《Magnetic resonance in medicine》2007,58(3):636-642
An anthropomorphic airway tree phantom was imaged with both hyperpolarized (HP) 3He MRI using a dynamic projection scan and computed tomography (CT). Airway diameter measurements from the HP 3He MR images obtained using a newly developed model-based algorithm were compared against their corresponding CT values quantified with a well-established method. Of the 45 airway segments that could be evaluated with CT, only 14 airway segments (31%) could be evaluated using HP 3He MRI. No airway segments smaller than approximately 4 mm in diameter and distal to the fourth generation were adequate for analysis in MRI. For the 14 airway segments measured, only two airway segments yielded a non-equivalent comparison between the two imaging modalities, while eight more had inconclusive comparison results, leaving only four airway segments (29%) that satisfied the designed equivalence criteria. Some of the potential problems in airway diameter quantification described in the formulation of the model-based algorithm were observed in this study. These results suggest that dynamic projection HP 3He MRI may have limited utility for measuring airway segment diameters, particularly those of the central airways. 相似文献
70.
Elliot L Dimberg Sheila E Crowe Joel M Trugman Russell H Swerdlow M Beatriz Lopes T David Bourne Ted M Burns 《Movement disorders》2007,22(3):407-411
We report the case of a woman with refractory celiac disease who developed abnormal spontaneous movements of the extremities and face consistent with myorhythmia. Investigation led to a diagnosis of encephalitis, confirmed by postmortem examination. The movements were likely caused by nonparaneoplastic encephalitis associated with refractory celiac disease. Etiologic and diagnostic considerations and treatment options are discussed. 相似文献