全文获取类型
收费全文 | 538篇 |
免费 | 37篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 26篇 |
妇产科学 | 11篇 |
基础医学 | 44篇 |
口腔科学 | 17篇 |
临床医学 | 60篇 |
内科学 | 99篇 |
皮肤病学 | 6篇 |
神经病学 | 19篇 |
特种医学 | 109篇 |
外科学 | 116篇 |
综合类 | 12篇 |
预防医学 | 10篇 |
眼科学 | 13篇 |
药学 | 29篇 |
肿瘤学 | 22篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 14篇 |
2020年 | 17篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 22篇 |
2014年 | 20篇 |
2013年 | 23篇 |
2012年 | 35篇 |
2011年 | 30篇 |
2010年 | 26篇 |
2009年 | 26篇 |
2008年 | 16篇 |
2007年 | 24篇 |
2006年 | 34篇 |
2005年 | 15篇 |
2004年 | 18篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 19篇 |
1997年 | 18篇 |
1996年 | 26篇 |
1995年 | 14篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 13篇 |
1988年 | 20篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有594条查询结果,搜索用时 187 毫秒
1.
Burcin Ustbas Gul Deniz Kilic Yanilmaz Dilan Arslan Mehmet Bayramicli Ozge Akbulut 《Journal of plastic, reconstructive & aesthetic surgery》2019,72(3):477-483
Background
There is a need for a peripheral nerve model on which surgeons-in-training can simulate the repair of nerve injuries at their own pace. Although practicing on animal models/cadavers is considered the “gold standard” of microsurgical training, the proposed model aims to provide a platform for improving the technical skills of surgical trainees prior to their practice on cadaver/animal models. In addition, this model has the potential to serve as a standardized test medium for assessing the skill sets of surgeons.Methods
Several formulations of silicone were utilized for the design and fabrication of a model which realizes the hierarchical structure of peripheral nerves. The mechanical properties were characterized via the Universal Testing Machine; the damage caused by the needle on the entry sites was assessed through scanning electron microscopy (SEM).Results
Mechanical properties of the formulations of silicone were tested to mimic human peripheral nerves. A formulation with 83.3?wt% silicone oil and 0.1?wt% cotton fiber was chosen to be used as nerve fascicles. Both 83.3?wt% silicone oil with cotton fiber and 66.6?wt% silicone oil without fiber provided a microsuturing response similar to that of epineurium at a wall thickness of 1?mm. SEM also confirmed that the entry of the needle did not introduce significant holes at the microsuturing sites.Conclusions
The proposed peripheral nerve model mimicked human tissues mechanically and cosmetically, and a simulation of the repair of a fifth-degree nerve injury was achieved. 相似文献2.
A new range of stand magnifiers has been released by the COIL company in the United Kingdom. Examination of these magnifiers reveals that they fail to deliver the rated magnifications labelled prominently on the appliances, as a result of the manufacturer's conformance with the requirements of the German DIN standard and the use of back vertex power (F'v) rather than equivalent dioptric power (Fm) of the magnifier. In this study we provide information on the optometric parameters of these new stand magnifiers that will assist the more accurate specification of improvements in vision expected from their use. 相似文献
3.
4.
Burcin Ozer Muserref Tatman-Otkun Dilek Memis Metin Otkun 《Central European Journal of Medicine》2010,5(2):203-208
The aim of this study was to determine the types nosocomial infections (NIs) and the risk factors for NIs in the central intensive
care unit (ICU) of Trakya University Hospital. The patients admitted to the ICU were observed prospectively by the unit-directed
active surveillance method based on patient and the laboratory over a 9-month-period. The samples of urine, blood, sputum
or tracheal aspirate were taken from the patients on the first and the third days of their hospitalization in ICU; the patients
were cultured routinely. Other samples were taken and cultured if there was suspicion of an infection. Infections were considered
as ICU-associated if they developed after 48 hours of hospitalization in the unit and 5 days after discharge from the unit
if the patients had been sent to a different ward in the hospital. The rate of NIs in 135 patients assigned was found to be
68%. The most common infection sites were lower respiratory tract, urinary tract, bloodstream, catheter site and surgical
wound. Hospitalization in ICU for more than 6 days and colonization was found to be the main risk factor for NIs. Prolonged
mechanical ventilation and tracheostomy, as well as frequently changed nasogastric catheterization, were found to be risk
factors for lower respiratory tract infections. For bloodstream infections, both prolonged insertion of and frequent change
of arterial catheters, and for urinary tract infections, female gender, period and repeating of urinary catheterization were
risk factors. A high prevalence rate of nosocomial infections was found in this study. Invasive device use and duration of
use continue to greatly influence the development of nosocomial infection in ICU. Important factors to prevent nosocomial
infections are to avoid long hospitalization and unnecessary device application. Control and prevention strategies based on
continuing education of healthcare workers will decrease the nosocomial infections in the intensive care unit. 相似文献
5.
Pheochromocytoma and paraganglioma: comparison of MR imaging with CT and I-131 MIBG scintigraphy 总被引:6,自引:0,他引:6
To ascertain the magnetic resonance (MR) imaging characteristics of pheochromocytomas and paragangliomas and to compare MR with computed tomography (CT) and iodine-131 metaiodobenzylguanidine (I-131 MIBG), 19 patients (18 with pheochromocytomas, one with a paraganglioma) were studied. The 18 patients with pheochromocytomas had had positive findings with I-131 MIBG scintigraphy. Abdominal pheochromocytomas were generally hypointense compared with normal liver on T1-weighted MR images and extremely hyperintense on T2-weighted MR images. MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization, particularly in the patient with hypertension and borderline catecholamine levels. For patients with recurrent or metastatic disease, the data suggest that I-131 MIBG scintigraphy is the examination of choice. 相似文献
6.
7.
8.
9.
Chaperonin-mediated assembly of wild-type and mutant subunits of human propionyl-CoA carboxylase expressed in Escherichia coli 总被引:1,自引:0,他引:1
We developed a bacterial expression system for the human alpha and beta
cDNAs of propionyl-CoA carboxylase (PCC). These cDNAs (less the putative
mitochondrial matrix targeting presequences) were co-expressed in
Escherichia coli on one plasmid vector with each cDNA having its own
IPTG-inducible promoter. Only negligible amounts of active PCC were
measured despite the presence of both alpha and beta subunits as indicated
by Western blot analysis and the almost complete biotinylation of the alpha
subunit. Co-expression of this plasmid with a second plasmid vector
over-expressing the E. coli chaperonin proteins, groES and groEL, resulted
in a several hundred-fold increase in PCC specific activity, to a level
comparable with that found in crude human liver extracts. PCC was partially
purified on monomeric avidin affinity resin and the presence of both alpha
and beta subunits was demonstrated, thereby confirming the assembly of both
subunits into an active enzyme. Deficiency of either alpha PCC or beta PCC
results in propionic acidemia, an autosomal recessive disorder. We used
this expression system to characterize one missense mutation previously
described in five Japanese alleles, namely C1283T (Thr428lle) in beta PCC.
This mutation, when expressed in E.coli under the same conditions as that
of wild-type PCC, had null activity, despite the presence of assembled
alpha PCC and beta PCC subunits. This bacterial expression system can be
useful for analysis of either alpha PCC or beta PCC mutations. Our findings
indicated that the groES and groEL chaperonin proteins were essential for
folding and assembly of the human PCC heteromeric subunits.
相似文献
10.
Pal L; Leykin L; Schifren JL; Isaacson KB; Chang YC; Nikruil N; Chen Z; Toth TL 《Human reproduction (Oxford, England)》1998,13(7):1837-1840
A case series of eight cycles of in-vitro fertilization (IVF) in five women
diagnosed with malignant disorders is presented. These patients chose to
defer definitive treatment for a chance for preservation of potential
fertility. The response of these patients to ovarian stimulation, and the
outcome, was compared with 17 IVF cycles in 12 age- matched patients with
isolated tubal infertility. An apparent adverse influence of malignant
disease on the quality and behaviour of oocytes was observed. Despite a
comparable total number of oocytes per cycle in the two groups, a
significantly reduced percentage of mature oocytes was retrieved per cycle
from patients with malignant diseases. The oocytes from patients with
malignant disorders were of a poorer quality and exhibited a significantly
impaired fertilization rate compared to the controls. We propose that
neoplastic processes, irrespective of the site or cell of origin, may have
a detrimental impact on the biology of oocytes, an effect akin to that seen
on spermatozoa in men with certain malignancies.
相似文献