全文获取类型
收费全文 | 3564篇 |
免费 | 208篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 22篇 |
儿科学 | 66篇 |
妇产科学 | 25篇 |
基础医学 | 514篇 |
口腔科学 | 641篇 |
临床医学 | 232篇 |
内科学 | 749篇 |
皮肤病学 | 47篇 |
神经病学 | 272篇 |
特种医学 | 160篇 |
外科学 | 364篇 |
综合类 | 6篇 |
预防医学 | 191篇 |
眼科学 | 47篇 |
药学 | 240篇 |
中国医学 | 14篇 |
肿瘤学 | 197篇 |
出版年
2023年 | 22篇 |
2022年 | 39篇 |
2021年 | 94篇 |
2020年 | 55篇 |
2019年 | 72篇 |
2018年 | 110篇 |
2017年 | 77篇 |
2016年 | 96篇 |
2015年 | 96篇 |
2014年 | 157篇 |
2013年 | 172篇 |
2012年 | 289篇 |
2011年 | 304篇 |
2010年 | 180篇 |
2009年 | 168篇 |
2008年 | 308篇 |
2007年 | 246篇 |
2006年 | 271篇 |
2005年 | 196篇 |
2004年 | 206篇 |
2003年 | 189篇 |
2002年 | 118篇 |
2001年 | 31篇 |
2000年 | 31篇 |
1999年 | 26篇 |
1998年 | 15篇 |
1997年 | 31篇 |
1996年 | 20篇 |
1995年 | 24篇 |
1994年 | 13篇 |
1992年 | 17篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1966年 | 5篇 |
1932年 | 2篇 |
1914年 | 2篇 |
排序方式: 共有3787条查询结果,搜索用时 46 毫秒
1.
2.
Khaled Adil Marija Popovic Fabio L. Cury Sergio L. Faria Marie Duclos Luis Souhami 《Practical radiation oncology》2019,9(1):24-28
Purpose
This study aimed to investigate 3 planning target volume (PTV) margin expansions and determine the most appropriate volume to be used in bladder preservation therapy when using daily cone beam computed tomography (CBCT). We aimed to establish whether a smaller PTV expansion is feasible without risking geographical miss.Methods and materials
The study included patients with bladder cancer who were treated with a hypofractionated course of radiation therapy delivered with intensity modulated radiation therapy. The clinical target volume (CTV) was the whole empty bladder, and the PTV consisted of a 1.5-cm margin around the bladder (PTV1.5 cm). Patients underwent daily CBCT imaging before treatment to assess the bladder volume and ensure accurate positioning. We investigated 2 additional smaller PTV margin expansions to determine the most appropriate volume to be used with CBCT as a daily image guided radiation therapy modality. These margins were created retrospectively on every CBCT. The first additional volume was a uniform PTV margin of the surrounding 1 cm (PTV1 cm). When considering that the majority of the internal bladder movement was due to the variation in filling that occurs in the superior and anterior directions, a second volume of an anisotropic PTV margin with a 1.5-cm superior/anterior and 1 cm in other directions (PTV1/1.5 cm) was created. We recorded the frequency and measured the volume of bladder falling out of each PTV based on the daily CBCT.Results
For the purpose of this study, we considered an arbitrary 5 cm3 of CTV falling out of the designated PTV as a clinically significant volumetric miss. The frequency of such a miss when applying the uniform PTV1 cm was 1%. However, when applying the uniform PTV1.5 cm and anisotropic PTV1/1.5 cm margins, the frequency was 0.5% and 0.5%, respectively.Conclusions
The anisotropic PTV expansion of 1.5 cm superiorly and anteriorly and 1 cm in all other directions around the bladder (CTV) provides a safe PTV approach when daily CBCT imaging is used to localize an empty bladder. 相似文献3.
André Ricardo Adriano Tiago Silveira Lima Maxime Battistella Martine Bagot 《Anais brasileiros de dermatologia》2015,90(6):892-895
Granulomatous slack skin is an indolent T-cell lymphoma, considered to be a
variant of mycosis fungoides. Clinically it is characterized by areas of
redundant skin, wrinkled, inelastic, with variable erythema and
infiltration besides a poikilodermic surface. A differential diagnosis
unknown to most dermatologists is the giant cell tumor of soft tissue,
which is an extremely rare low-grade sarcoma. The authors report a patient
who had undergone extensive surgery because of a primary diagnosis of giant
cell tumor of soft tissue, but which proved to be granulomatous slack skin
after a second interventional procedure with confirmatory
histopathology. 相似文献
4.
Recent work demonstrated that crotoxin, the main toxin of Crotalus durissus terrificus venom, inhibits macrophage spreading and phagocytic activities. The crotoxin molecule is composed of two subunits, an acidic non-toxic and non-enzymatic polypeptide named crotapotin and a weakly toxic basic phospholipase A2 (PLA2). In the present work, the active subunit responsible for the inhibitory effect of crotoxin on macrophage function was investigated. Peritoneal macrophages harvested from naive rats were used. Crotapotin (2.12, 3.75, or 8.37 nM/ml), added for 2 h to the medium of peritoneal cell incubation, did not modify the spreading and phagocytic activities of these cells. On the other hand, the PLA2 (1.43, 2.86, or 6.43 nM/ml) subunit caused a significant reduction (30, 33, and 35%, respectively) of the spreading activity. The PLA2 also inhibited the phagocytosis of opsonised zymosan, opsonised sheep erythrocytes, and Candida albicans, indicating that this inhibitory effect is not dependent on the type of receptor involved in the phagocytosis process. The inhibitory effect of PLA2 was not due to loss of cell membrane integrity, since macrophage viability was higher than 95%. These findings indicate that the inhibitory effect of crotoxin on macrophage spreading and phagocytic activities is caused by the phospholipase A2 subunit. 相似文献
5.
Andrea Bernatowicz Uwe Kdel Karl Frei Adriano Fontana Hans-walter Pfister 《Journal of neuroimmunology》1995,60(1-2):53-61
Recent studies using a rat model of pneumococcal meningitis have shown that nitric oxide synthase (NOS) inhibitors greatly attenuated microvascular changes and brain edema formation. The site of NO production during bacterial meningitis is unknown. In this study we tested whether primary astrocyte cultures from neonatal rat cortex can be induced to release NO upon stimulation with pneumococci. NO production was assessed by measuring nitrite in the cell culture supernatant using the Griess reaction. Stimulation with heat-killed unencapsulated pneumococci (HKP) increased nitrite concentrations in astrocyte culture supernatants in a dose-dependent fashion. Administration of AT-nitro-L-arginine (L-NA), aminoguanidine, L-canavanine, cycloheximide, and dexamethasone prevented the increase in nitrite concentrations. Addition of L-arginine, but not of o-arginine, partially reversed the inhibitory effect of L-NA. Administration of SOD increased nitrite accumulation. Moreover, at 72 h after stimulation with heat-killed pneumococci (107 cfu/ml) astrocytes showed an inducible NOS-like immunoreactivity. Accumulation of nitrite was also observed when rat cerebellar neurons and microglia were stimulated with HKP, whereas there was only a slight increase of nitrite in media of rat C6 glioma cells, but no increase of nitrite when the human glioblastoma cell line LN-229 was stimulated with HKP. There was a stronger increase in nitrite levels when astrocytes from Lewis rats were used compared to that from Wistar rats. In conclusion, our study indicates that astrocytes, neurons and microglia are inducible for NO production upon stimulation with pneumococci. 相似文献
6.
Adriano Rizzi Gaetano Rocco Mario Robustellini Gerolamo Rossi Claudio Della Pona Giuseppe Vertemati 《World journal of surgery》1997,21(5):488-491
n
= 8), multidrug resistance
or noncompliance to the medical treatment (
n
= 11),
parenchymal sequelae (
n
= 3), suspected cancer
(
n
= 5), and for the correction of postpneumonectomy
bronchopleural fistula and empyema (
n
= 1). On
admission, eight patients presented with sputum positivity (28.6%).
Similar to previous series, tubercular predilection for upper lobes was
confirmed (21/28, 75%); accordingly, upper lobectomy through an
extrapleural approach was the most common procedure (16/28, 57.1%).
Atypical segmental resections or segmentectomies were performed in
seven patients (25%), whereas a bilobectomy was necessary in another
three patients (10.7%) and a completion pneumonectomy in one (3.6%).
Additional procedures were an open-window thoracostomy with
transpericardial closure of the main bronchus and a tailored
thoracoplasty. No operative mortality was reported. Healing was
achieved in 26 patients (93%). Bleeding, either from the chest wall or
hilar dissection, was the only reported intraoperative complication.
Median blood loss, inclusive of early postoperative collections from
chest tubes, reached 1330 ml (range 100–3700 ml). Major postoperative
complications included recurrent disease (2/28, 7%) in sputum-positive
patients and segmental pulmonary embolism (3.5%). Causes of minor
morbidity were air leaks resulting in residual space undergoing
spontaneous resolution (18%), wound breakdown (14%), and, fever
(11%). This limited series confirms the therapeutic value of the
surgical treatment of postprimary tuberculosis, provided that correct
indications, adequate pre- and postoperative medical coverage, and
meticulous technique are applied. 相似文献
7.
Adriano Chiò Elena Herrero Hernandez Gabriele Mora Consuelo Valentini Gianluigi Discalzi Enrico Pira 《Amyotrophic lateral sclerosis and other motor neuron disorders》2004,5(3):188-191
A 34-years-old floor-layer developed optic neuropathy and motor neuron disease after being accidentally exposed to a solvent mixture containing methanol and other substances. Optic neuropathy is a complication of methanol poisoning, but the onset of a motor neuron disorder resembling amyotrophic lateral sclerosis after the exposure to these substances has not been previously described. The temporal onset of the clinical symptoms, biological plausibility, young age of the patient and absence of neurological disorders in the family history raises suspicion of a possible causative relationship. 相似文献
8.
Suhny Abbara Sanjeeva Kalva Ricardo C. Cury Eric M. Isselbacher 《Journal of Cardiovascular Computed Tomography》2007,1(1):40-54
The clinical presentation of diseases involving the thoracic aorta ranges from a large number of asymptomatic patients with clinically undetectable thoracic aortic aneurysm to patients with symptoms of severe chest pain as a result of acute aortic dissection. Thoracic aortic disease often remains undiagnosed until a life-threatening complication occurs or the disease is discovered serendipitously on imaging studies performed for other purposes. Multidetector row computed tomography (MDCT) imaging of the aorta is used to diagnose various acute and chronic conditions, including aortic aneurysms, aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, traumatic injury, rupture, inflammatory disorders, and congenital malformations. This review illustrates the wide range of MDCT imaging findings of thoracic aortic disease. 相似文献
9.
Adriano Antonucci Angela Di Baldassarre Franco Di Giacomo Liborio Stuppia Giandomenico Palka 《Ultrastructural pathology》1997,21(5):449-452
Thirty-one patients affected by Down syndrome (DS) were investigated to study the presence of apoptosis in peripheral blood cells in relation to the plasma levels of zinc. Twelve patients had undergone therapy with ZnSO4, while the remaining 19 were untreated. The presence of programmed cell death was evaluated by means of electron microscopy, in situ nick translation (NT), and agarose gel electrophoresis of DNA. These approaches evidenced the presence of apoptosis in peripheral blood cells of patients before therapy with ZnSO4, while after zinc supplementation there was a reduction in the number of apoptotic cells. These results suggest that the process of programmed cell death in peripheral blood cells of patients with Down syndrome is related to the plasma levels of zinc ion. 相似文献
10.
Antonella d’Arminio Monforte Paola Cinque Luca Vago Aleandro Rocca Antonella Castagna Cristina Gervasoni Maria Rosa Terreni Roberto Novati Andrea Gori Adriano Lazzarin Mauro Moroni 《Journal of neurology》1996,244(1):35-39
Twenty patients with AIDS who had intracranial lesions underwent both brain biopsy and cerebro-spinal fluid (CSF) examination
to compare histological diagnosis with the polymerase chain reaction (CSF-PCR) for the identification of infectious agents.
CSF-PCR was performed for herpes simplex virus, varicella zoster virus, cytomegalovirus (CMV), JC virus (JCV), Epstein-Barr
virus (EBV), Toxoplasma gondii and Mycobacterium tuberculosis. A definitive diagnosis was obtained by brain biopsy in 14 patients (2 with astrocytoma, 12 with brain infection). CSF-PCR
was positive for EBV DNA in 3 of 3 cases of primary cerebral lymphoma, positive for JCV DNA in 6 of 7 biopsy-proven (and one
autopsy-proven) cases of progressive multifocal leukoencephalopathy (PML). CSF-PCR was positive for CMV DNA in one biopsy-proven
and one autopsy-proven case of CMV encephalitis (the former also had PML) and positive for M. tuberculosis DNA in one case of tuberculous encephalitis. None of the five toxoplasmic encephalitis cases (one definite, four presumptive)
were T. gondii DNA positive. There was close correlation between histology and CSF-PCR for CMV encephalitis, PML and PCL. Antitoxoplasma
therapy affected the sensitivity of both histological and CSF-PCR methods.
Received: 8 November 1995 Received in revised form: 9 July 1996 Accepted: 19 July 1996 相似文献