全文获取类型
收费全文 | 1487篇 |
免费 | 73篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 37篇 |
妇产科学 | 31篇 |
基础医学 | 152篇 |
口腔科学 | 29篇 |
临床医学 | 156篇 |
内科学 | 297篇 |
皮肤病学 | 17篇 |
神经病学 | 116篇 |
特种医学 | 101篇 |
外科学 | 291篇 |
综合类 | 15篇 |
预防医学 | 57篇 |
眼科学 | 41篇 |
药学 | 153篇 |
中国医学 | 6篇 |
肿瘤学 | 43篇 |
出版年
2024年 | 2篇 |
2023年 | 19篇 |
2022年 | 51篇 |
2021年 | 105篇 |
2020年 | 38篇 |
2019年 | 44篇 |
2018年 | 63篇 |
2017年 | 50篇 |
2016年 | 41篇 |
2015年 | 45篇 |
2014年 | 68篇 |
2013年 | 88篇 |
2012年 | 97篇 |
2011年 | 100篇 |
2010年 | 61篇 |
2009年 | 54篇 |
2008年 | 65篇 |
2007年 | 95篇 |
2006年 | 115篇 |
2005年 | 72篇 |
2004年 | 76篇 |
2003年 | 54篇 |
2002年 | 72篇 |
2001年 | 5篇 |
2000年 | 15篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1992年 | 2篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有1568条查询结果,搜索用时 435 毫秒
161.
Long term sequelae of childhood acute bacterial meningitis in a developing country. A study from the Sudan. 总被引:5,自引:0,他引:5
M A Salih O H Khaleefa M Bushara Z B Taha Z A Musa I Kamil Y Hofvander P Olcén 《Scandinavian journal of infectious diseases》1991,23(2):175-182
35 survivors of acute bacterial meningitis (ABM) from a group of 44 Sudanese children--seen during 18 months (April 1985-November 1986)--were prospectively followed to ascertain the long-term sequelae of the disease. 30 (17 with Haemophilus influenzae, 8 Neisseria meningitidis, 4 Streptococcus pneumoniae and one child with Enterobacter cloacae meningitis) could be followed during the surveillance period (3-4 years). Three (10%), including 2 with hemiplegia, died after 11-12 months. The association between motor deficit on discharge from hospital and subsequent death was significant (p = 0.04). Of the remaining 27, neuropsychologic sequelae were recorded in 9 (33%). Sensorineural hearing loss was observed in 6 (22%) patients and improved in one during surveillance. Motor deficits were found to improve with time but were replaced by the development of epilepsy about 3 years later in 11% of the survivors. The mean IQ (+/- SD) score for a subgroup of 19 post-meningitic children (92.3 +/- 13.9) was found to be significantly lower than in their nearest-age sibling controls (100.7 +/- 10.2; p = less than 0.01). Younger age at admission and longer duration of ABM symptoms before treatment were significantly associated with poorer outcome (respectively, r = 0.63, p = less than 0.01, r = 0.67, p = less than 0.01). The potential impact of vaccination against the commonest organisms causing ABM in developing countries is discussed. 相似文献
162.
Qing X Yang Jinghua Wang Christopher M Collins Michael B Smith Xiaoliang Zhang Kamil Ugurbil Wei Chen 《Magnetic resonance in medicine》2004,52(5):1016-1020
A phantom design method suitable for high-field MRI based on the RF field wave characteristics of sample and experimental validations at 7.0 T and 3.0 T are presented. The RF field distribution in a phantom with a given RF coil system is primarily determined by the sample size relative to the wavelength inside the sample, and the ratio between the displacement and conduction currents. Experimental results demonstrate that the MR image intensity patterns associated with wave behavior in human samples at a given field strength can be reproduced with a phantom at the same or different field strengths once the dimension and penetration constant are scaled by the corresponding wavelength in the sample medium. 相似文献
163.
Hasan Coskun A. Kürsad Bozkurt Gülen
Zbay Cuyan Demirkesen Kamil Kaynak Fikret Sami Vural 《ANZ journal of surgery》1995,65(1):66-68
A case of primary fibrosarcoma of the heart, which was diagnosed in a 17 year old man, is presented. Extensive tumour resection and postoperative radiation therapy was carried out. The patient is alive after 18 months after the operation. Although these tumours are associated with very poor survival. early diagnosis and combined therapy may prolong life expectancy. 相似文献
164.
Respiration-induced B0 fluctuations and their spatial distribution in the human brain at 7 Tesla. 总被引:1,自引:0,他引:1
Pierre‐Franois Van de Moortele Josef Pfeuffer Gary H. Glover Kamil Ugurbil Xiaoping Hu 《Magnetic resonance in medicine》2002,47(5):888-895
In functional magnetic resonance imaging (fMRI), it is known that physiological influences such as cardiac pulsation, respiration, and brain motion can induce fluctuations in signal intensity and phase. Some of the mechanisms potentially involved in those phenomena are expected to be amplified at higher magnetic fields. This study addresses the issue of B(0) fluctuations induced by susceptibility changes during respiration attributed to movements of chest and diaphragm, and variations in the oxygen concentration. It is demonstrated that respiration-induced resonance offsets (RIROs) are significant at 7T. Data were acquired with an RF pulse (no gradients), multislice echo-planar imaging (EPI), and dynamic 3D fast low-angle shot (3D- FLASH) imaging. Three main observations summarize the experimental findings. First, in FIDs measured after a single RF pulse, a RIRO with a large amplitude was consistently detected, although the average amplitude varied between subjects from 1.45 Hz to 4 Hz. Second, in transverse EPI images obtained in the occipital lobe, the RIRO amplitude showed a monotonic increase along the z axis toward the lungs. Third, a more detailed spatial analysis with 3D-FLASH phase maps revealed that a previously published analytical model can accurately describe the spatial distribution of RIRO. Consequential apparent motions in the EPI series, as well as the implications of slice orientation for correction strategies are discussed. 相似文献
165.
Timothy Q Duong Essa Yacoub Gregory Adriany Xiaoping Hu Kamil Ugurbil J Thomas Vaughan Hellmut Merkle Seong-Gi Kim 《Magnetic resonance in medicine》2002,48(4):589-593
With growing interest in noninvasive mapping of columnar organization and other small functional structures in the brain, achieving high spatial resolution and specificity in fMRI is of critical importance. We implemented a simple method for BOLD and perfusion fMRI with high spatial resolution and specificity. Increased spatial resolution was achieved by selectively exciting a slab of interest along the phase-encoding direction for EPI, resulting in a reduced FOV and number of phase-encoding steps. Improved spatial specificity was achieved by using SE EPI acquisition at high fields, where it is predominantly sensitive to signal changes in the microvasculature. Robust SE BOLD and perfusion fMRI were obtained with a nominal in-plane resolution up to 0.5 x 0.5 mm(2) at 7 and 4 Tesla, and were highly reproducible under repeated measures. This methodology enables high-resolution and high-specificity studies of functional topography in the millimeter to submillimeter spatial scales of the human brain. 相似文献
166.
167.
An open biopsy has minimal sampling error, but is a major procedure, with its inherent complications and morbidity. The complications of paraspinal needle biopsy of vertebral lesions are well known. Needle biopsies have a high incidence of false negatives, especially for tumors. Percutaneous transpedicular bopsy is efficacious, safe, and cost effective, and mostly performed under local anesthesia. Fluoroscopic monitoring enables real time positioning of the needle. Serious needle complications from percutaneous needle biopsy are uncommon. More than 50% of vertebral body tissue, including the disc is accessible via a unilateral transpedicular approach and amenable for biopsy. 相似文献
168.
This study investigated the humoral immune responses of goats experimentally infected with Fascioloides magna and Fasciola hepatica to F. magna excretory/secretory products (FmESP) or F. hepatica excretory/secretory products (FhESP), respectively. An enzyme-linked immunosorbent assay (ELISA) was used to determine serum
antibody responses and for possible discrimination of F. magna and F. hepatica infections in goats. Comparison of ESPs of both flukes and evaluation of ESP antigenicity was also studied applying immunoblotting
techniques. In all infected goats, antibody level was significantly increased (against negative control) since 2 weeks post
infection (WPI). However, the dynamics of antibodies varied between F. magna and F. hepatica groups during the course of the infection. The cross-reaction of antibodies developed against F. magna and F. hepatica with ESP proteins was recorded by ELISA. The species-specific proteins 40, 120 kDa from FmESP and 80, 160 kDa from FhESP
(with no antibody cross-reaction) were detected by two dimensional electrophoresis and immunoblot as the potential immunodiagnostic
markers. Our results suggest that F. magna and F. hepatica infection could be distinguished by common immunological techniques based on species-specific antigen–antibodies interaction. 相似文献
169.
Lymphotoxin-α and galectin-2 SNPs are not associated with myocardial infarction in two different German populations 总被引:2,自引:1,他引:1
Sedlacek K Neureuther K Mueller JC Stark K Fischer M Baessler A Reinhard W Broeckel U Lieb W Erdmann J Schunkert H Riegger G Illig T Meitinger T Hengstenberg C 《Journal of molecular medicine (Berlin, Germany)》2007,85(9):997-1004
Recent data provided strong evidence for the association of single nucleotide polymorphisms (SNPs) in the lymphotoxin-alpha (LTA) and galectin-2 (LGALS2) genes with myocardial infarction (MI) in a Japanese population. For populations of other genetic background, the relevance of these polymorphisms in the pathogenesis of MI remains controversial. We aimed to define the role of LTA and LGALS2 SNPs in two German MI populations with markedly different ascertainment strategies. Two different MI populations were studied. In the first population, MI patients were ascertained by a strong family history of MI (n = 1214). Controls were unrelated disease-free participants of the study (n = 1080). The second population included patients suffering from sporadic (nonfamilial) MI from the German KORA register (n = 607). The control group consisted of participants of the WHO MONICA survey in Germany (n = 1492). TaqMan assays were used to determine the genotypes of 4 SNPs in the LTA genomic region and 1 SNP in the LGALS2 gene. Single SNPs in both genomic regions as well as haplotypes in the LTA genomic region were tested for association in various models of inheritance. No association with MI could be found for any of the examined SNPs in the LTA genomic region and LGALS2 gene, or for haplotypes spanning the LTA genomic region. In two MI populations of European descent with markedly different ascertainment strategies, we were not able to identify a significant association of SNPs in the LTA genomic region or the LGALS2 gene with MI. These variants are unlikely to play a significant role in populations of European origin. 相似文献
170.
Safiye Gurel Deniz Akata Kamil Gurel Mustafa N Ozmen Okan Akhan 《Journal of ultrasound in medicine》2006,25(9):1113-20; quiz 1121-3
OBJECTIVE: The purpose of this study was to determine the sensitivity of renal color Doppler sonography in differentiating obstructive and nonobstructive urinary calculi in patients with acute renal colic and to compare findings with nonenhanced helical computed tomography (CT). METHODS: Sixty-five patients referred to the emergency department with acute renal colic underwent nonenhanced CT and renal resistive index (RI) measurement with color pulsed Doppler sonography within 8 to 10 hours of the onset of the symptoms. Computed tomographic evaluation was based on the detection of urolithiasis and classification according to location and the presence of obstruction. The mean RI of each kidney and the difference between the mean RI (DeltaRI) of both kidneys were calculated and compared with CT findings. RESULTS: A total of 164 stones were identified. Computed tomography revealed obstruction in 33 patients. Mean RI values for the obstructive and nonobstructive groups were 0.64 and 0.63, respectively. Mean DeltaRI values were 0.01312 and 0.01000 in the obstructive and nonobstructive groups. The differences in the mean RI and DeltaRI for the patients with and without obstruction were statistically insignificant (P = .73). No significant relationship was found between the RI values, calculus location, and degree of obstruction. CONCLUSIONS: The RI is insensitive for detection of obstruction in patients with acute renal colic, and its value in routine practice seems quite controversial. 相似文献