全文获取类型
收费全文 | 964篇 |
免费 | 53篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 16篇 |
妇产科学 | 10篇 |
基础医学 | 113篇 |
口腔科学 | 24篇 |
临床医学 | 54篇 |
内科学 | 247篇 |
皮肤病学 | 2篇 |
神经病学 | 48篇 |
特种医学 | 30篇 |
外科学 | 184篇 |
综合类 | 6篇 |
预防医学 | 82篇 |
眼科学 | 16篇 |
药学 | 62篇 |
中国医学 | 2篇 |
肿瘤学 | 118篇 |
出版年
2023年 | 6篇 |
2022年 | 9篇 |
2021年 | 18篇 |
2020年 | 15篇 |
2019年 | 12篇 |
2018年 | 22篇 |
2017年 | 17篇 |
2016年 | 24篇 |
2015年 | 25篇 |
2014年 | 44篇 |
2013年 | 50篇 |
2012年 | 67篇 |
2011年 | 70篇 |
2010年 | 37篇 |
2009年 | 26篇 |
2008年 | 56篇 |
2007年 | 71篇 |
2006年 | 63篇 |
2005年 | 72篇 |
2004年 | 81篇 |
2003年 | 61篇 |
2002年 | 53篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 15篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1973年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1961年 | 1篇 |
1959年 | 3篇 |
1958年 | 1篇 |
1957年 | 2篇 |
排序方式: 共有1022条查询结果,搜索用时 15 毫秒
31.
The induction of systemic and mucosal immunity to protein vaccines delivered through skin sites exposed to UVB 总被引:2,自引:0,他引:2
It has been reported that common mucosal immunity can be efficiently induced in mice following immunization through the skin with vaccine formulations containing either the active form of vitamin D, or chemical agents capable of locally enhancing cyclic adenosine monophosphate levels. Herein, we report that exposure of skin to ultraviolet radiation B (UVB) can be employed as a means to alter systemic humoral immune responses and to promote the induction of mucosal immunity to protein antigens delivered into UVB-exposed skin sites. Our data indicates that the skin, as a vaccination site, can be manipulated to allow efficient induction of common mucosal and systemic immune responses. 相似文献
32.
Vascular endothelial growth factor and prognosis in patients with node-negative breast cancer 总被引:7,自引:0,他引:7
De Paola F Granato AM Scarpi E Monti F Medri L Bianchi S Amadori D Volpi A 《International journal of cancer. Journal international du cancer》2002,98(2):228-233
Vascular endothelial growth factor (VEGF) has emerged as one of the most important angiogenic growth factors from experimental in vitro and in vivo studies. In the present study, we investigated the relationship between VEGF expression and microvessel density (MVD) and defined their prognostic relevance on a series of 242 patients with node-negative breast cancer, using immunohistochemical methods. In parallel, estrogen and progesterone receptors were quantitatively assessed using the dextran-charcoal technique and cell proliferation was evaluated as S-phase cell fraction according to (3)H-thymidine-labeling index (TLI). The percentage of VEGF-expressing cells varied from 0-95% in the different tumors and was unrelated to menopausal status, tumor size or steroid receptor status. Conversely, a significant inverse relation was observed with patient age or tumor cell proliferation, albeit with very poor correlation coefficients. A significant relation was observed between VEGF expression and MVD (r(s) = 0.55, p < 0.001). Clinical outcome analyzed as a function of high and low VEGF expression showed slight differences in terms of both disease-free survival (DFS) and overall survival (OS) that never reached statistical significance. Moreover, the trend was paradoxically in favor of patients with highly VEGF-expressing tumors. Finally, DFS and OS curves, when analyzed as a function of VEGF expression or MVD, were superimposable. In conclusion, our study did not highlight a prognostic relevance of VEGF expression in patients with node-negative breast cancer, as already observed for MVD. 相似文献
33.
Letizia Longo Dino Trecca Andrea Biondi Francesco Lo Coco Fausto Grignani Anna Teresa Maiolo Pier Giuseppe Pelicci Antonino Neri 《Leukemia & lymphoma》1993,11(5):405-410
The frequency of RAS and p53 mutations was investigated in 30 acute promyelocytic leukemias by single strand conformation polymorphism analysis and direct sequencing of ge-nomic DNA. Only two cases bore N-RAS codon 12 mutations and none had p53 mutations responsible for aminoacid substitutions. It would, therefore, seem that neither RAS nor p53 are involved in acute promyelocytic leukemogenesis. 相似文献
34.
Imad Sheiban M.D. Gianpaolo Trevi Dino Casarotto Alberto Marini Paolo Benussi Roberto Accardi Marcello Zanini Peppino Pugliese Luisa Bullian Graziano Montresor Stefano Ferrara Ludovico Antonio Scuro 《Cardiovascular and interventional radiology》1988,11(1):14-17
An attempt was made to assess noninvasively the patency of aorto-coronary bypass grafts by two-dimensional echocardiography
(2-D echo) in 21 patients who underwent myocardial revascularization. Fifteen patients had one graft while the other six had
two grafts. All 21 patients underwent angiography 6–18 months after operation. A day before angiography a 2-D echo was performed
with the aim of visualizing the bypass grafts. In 18 patients with 23 grafts (13 with 1 graft and 5 with 2 grafts) it was
possible to visualize the tract of the graft, by 2-D echo; 16 were judged patent on 2-D echo and confirmed by selective angiography,
while 5 grafts were considered occluded both on 2-D echo and angiography. The other 2 grafts were considered to be occluded
on 2-D echo but angiographic control displayed their patency. In 3 patients 2-D echo failed to visualize grafts that were
patent angiographically. These data must be considered preliminary and need validation in a larger number of patients. However
it is reasonable to conclude that 2-D echo has a reliable capacity to predict graft patency. Such an application may be of
value in sequential control of patients with aorto-coronary bypass surgery, especially when combined with other clinical and/or
technical data. 相似文献
35.
Lessandro Pulsoni Antonia Stazi Rodolfo Cotichini Bernardino Allione Raffaella Cerri Eros Di Bona Anna Maria Nosari Livio Pagano Anna Recchia Michela Ribersani Lucilla Rocchi Dino Veneri Giuseppe Visani Franco Mandelli Alfonso Mele 《European journal of haematology》1998,61(5):327-332
Abstract: Acute promyelocytic leukaemia (APL) exhibits peculiar epidemiological, clinical, cytogenetic and molecular features, compared to the other acute myeloid leukaemias (AML). Data on epidemiology and occupational risk factors for APL desumed from the GIMEMA archive are reported and compared with those of the other AML. An exploratory case-case study was designed on AML patients from 56 haematology centres in Italy. Overall, 4296 patients older than 15 yr with a new diagnosis of acute leukaemia were recorded between July 1992 and July 1997. Of these, 335 were classified as APL, and 2894 as other AML. The median age of APL patients was 43 compared to 59 yr for the other AML (p< 0.00001). In order to identify peculiar risk factors for APL development, different parameters were compared in the 2 groups. After adjusting by age no significant differences were observed with regard to education, lifetime prevalence of cancer among siblings and previous diseases in the patient's history. Occupational exposure as a possible risk factor for APL showed no increased risk compared to other AML among farmers, builders and leather workers. A significant association was found in electricians (OR = 4.4, 95% CI = 2.0–9.7) and a weak association was found in wood workers (OR = 3.2, 95% CI = 0.8–10.8). The proportion of APL with respect to other AML was significantly higher in the north east of Italy compared to the rest of the country (OR = 1.7, 95% CI = 1.3–2.2). These data confirm the younger age of APL patients compared to the other AML. A possible role of electromagnetic fields is suggested by the higher risk of APL in electrical workers and in the more industrialized areas of the country. 相似文献
36.
37.
Binding of estrogenic compounds to recombinant estrogen receptor-alpha: application to environmental analysis 总被引:2,自引:0,他引:2
Pillon A Boussioux AM Escande A Aït-Aïssa S Gomez E Fenet H Ruff M Moras D Vignon F Duchesne MJ Casellas C Nicolas JC Balaguer P 《Environmental health perspectives》2005,113(3):278-284
Estrogenic activity in environmental samples could be mediated through a wide variety of compounds and by various mechanisms. High-affinity compounds for estrogen receptors (ERs), such as natural or synthetic estrogens, as well as low-affinity compounds such as alkylphenols, phthalates, and polychlorinated biphenyls are present in water and sediment samples. Furthermore, compounds such as polycyclic aromatic hydrocarbons, which do not bind ERs, modulate estrogen activity by means of the aryl hydrocarbon receptor (AhR). In order to characterize compounds that mediate estrogenic activity in river water and sediment samples, we developed a tool based on the ER-alphaligand-binding domain, which permitted us to estimate contaminating estrogenic compound affinities. We designed a simple transactivation assay in which compounds of high affinity were captured by limited amounts of recombinant ER-alpha and whose capture led to a selective inhibition of transactivation. This approach allowed us to bring to light that water samples contain estrogenic compounds that display a high affinity for ERs but are present at low concentrations. In sediment samples, on the contrary, we showed that estrogenic compounds possess a low affinity and are present at high concentration. Finally, we used immobilized recombinant ER-alpha to separate ligands for ER and AhR that are present in river sediments. Immobilized ER-alpha, which does not retain dioxin-like compounds, enabled us to isolate and concentrate ER ligands to facilitate their further analysis. 相似文献
38.
39.
Singh K Heller JG Samartzis D Price JS An HS Yoon ST Rhee J Ledlie JT Phillips FM 《Journal of spinal disorders & techniques》2005,18(5):413-419
Osteoporotic burst fractures with neurologic symptoms are typically treated with neural decompression and multilevel instrumented fusion. These large surgical interventions are challenging because of patients' advanced ages, medical co-morbidities, and poor fixation secondary to osteoporosis. The purpose of this retrospective clinical study was to describe a novel technique for the treatment of osteoporotic burst fractures and symptomatic spinal stenosis via a limited thoracolumbar decompression with open cement augmentation [vertebroplasty (VP) or kyphoplasty (KP)]. Indications for decompression and cement augmentation were intractable pain at the level of a known osteoporotic burst fracture with symptoms of spinal stenosis. As such, 25 patients (mean age, 76.1 years) with low-energy, osteoporotic, thoracolumbar burst fractures (7 males, 18 females; 39 fractures) were included. In all cases, laminectomy of the stenotic level(s) was followed by vertebral cement augmentation (9 VP; 16 KP). When a spondylolisthesis at the decompressed level was present, instrumentation was applied across the listhetic level (n = 9). Clinical outcome (1 = poor to 4 = excellent) was assessed on last clinical follow-up (mean, 44.8 wks). In addition, a modified MacNab's grading criteria was used to objectively assess patient outcomes postoperatively. Radiographic analysis of sagittal contour was assessed preoperatively, immediately postoperatively, and at final follow-up. The average time from onset of symptoms to intervention was 19 weeks (range, 0.3-94 wks). A mean of 1.6 fractures/patient was augmented (range, 1-3 fractures) and 2.8 levels were decompressed (range, 1-6 levels). No statistical difference in anatomic distribution or number of fractures between the VP and KP groups or in the instrumented versus noninstrumented patients was noted (P > 0.05). An overall subjective outcome score of 3.4 was noted. Twenty of 25 patients were graded as excellent/good according to the modified MacNab's criteria. The choice of augmentation procedure or use of instrumentation did not predict outcome (P = 0.08). Overall, 1.7 degrees of sagittal correction was obtained at final follow-up. One patient was noted to have progressive kyphosis after KP. The use of a limited-posterior decompression and open cement augmentation via VP or KP is a safe treatment option for patients who have osteoporotic burst fractures and who are incapacitated from fracture pain and concomitant stenosis. After thoracolumbar decompression, open VP/KP provides direct visualization of the posterior vertebral body wall, allowing for safe cement augmentation of burst fractures, stabilizing the spine, and obviating the need for extensive spinal reconstruction. Although clinically successful, this technique warrants careful patient selection. 相似文献
40.
The clinical case reported here concerns a giant lipoma (22 x 12 x 10 cm; 2740 g) located in the distal region of the right thigh, in a subfascial zone. The patient was referred to our department for a relapse of thrombophlebitis of the right lower limb (occurring about two years earlier) and presented a large tumefaction of the mid third of thigh at objective examination, the presumed onset of which dated back about ten years after a traumatic accident. Ultrasonography confirmed the presence of the tumefaction but did not allow us to identify its origin with certainty. Musculoskeletal magnetic resonance imaging, however, revealed a gross expansive lesion closely connected to the distal part of the femur, suggesting its probable benign nature. The mass was totally resected without either muscle section or the sacrifice of periosteum. The histological findings indicated an atypical lipomatous tumour. The therapy of giant lipomas is invariably surgical excision. Nevertheless, the high risk of relapse (which is typical of this kind of neoplastic proliferation) despite radical resection, makes a systematic postoperative follow-up necessary. 相似文献