全文获取类型
收费全文 | 2204篇 |
免费 | 122篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 178篇 |
妇产科学 | 27篇 |
基础医学 | 258篇 |
口腔科学 | 58篇 |
临床医学 | 268篇 |
内科学 | 512篇 |
皮肤病学 | 75篇 |
神经病学 | 103篇 |
特种医学 | 401篇 |
外科学 | 126篇 |
综合类 | 47篇 |
预防医学 | 105篇 |
眼科学 | 26篇 |
药学 | 98篇 |
2篇 | |
肿瘤学 | 114篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 18篇 |
2020年 | 18篇 |
2019年 | 19篇 |
2018年 | 37篇 |
2017年 | 27篇 |
2016年 | 23篇 |
2015年 | 42篇 |
2014年 | 49篇 |
2013年 | 63篇 |
2012年 | 42篇 |
2011年 | 44篇 |
2010年 | 91篇 |
2009年 | 97篇 |
2008年 | 63篇 |
2007年 | 102篇 |
2006年 | 65篇 |
2005年 | 66篇 |
2004年 | 36篇 |
2003年 | 23篇 |
2002年 | 32篇 |
2001年 | 43篇 |
2000年 | 39篇 |
1999年 | 39篇 |
1998年 | 130篇 |
1997年 | 156篇 |
1996年 | 133篇 |
1995年 | 109篇 |
1994年 | 114篇 |
1993年 | 98篇 |
1992年 | 28篇 |
1991年 | 40篇 |
1990年 | 36篇 |
1989年 | 60篇 |
1988年 | 49篇 |
1987年 | 45篇 |
1986年 | 52篇 |
1985年 | 48篇 |
1984年 | 26篇 |
1983年 | 17篇 |
1982年 | 25篇 |
1981年 | 29篇 |
1980年 | 26篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 18篇 |
1976年 | 25篇 |
1975年 | 15篇 |
1972年 | 4篇 |
排序方式: 共有2401条查询结果,搜索用时 31 毫秒
1.
JM Martín† L Calduch† C Monteagudo‡ I Molina† D Ramón† V Alonso† E Jordᆠ《Journal of the European Academy of Dermatology and Venereology》2006,20(4):428-431
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified. 相似文献
2.
3.
J M Mason D A Grande M Barcia R Grant R G Pergolizzi A S Breitbart 《Gene therapy》1998,5(8):1098-1104
A commonly encountered problem in orthopedics is bone and cartilage tissue injury which heals incompletely or without full structural integrity. This necessitates development of improved methods for treatment of injuries which are not amenable to treatment using current therapies. An already large and growing number of growth factors which play significant roles in bone remodeling and repair have been identified in the past few years. It is well established that bone morphogenic proteins induce the production of new bone and cartilage. An efficient method of delivery of these growth factors by conventional pharmacological means has yet to be elucidated. We wished to evaluate the use of retroviral vector-mediated gene transfer to deliver genes of therapeutic relevance for bone and cartilage repair. To determine the feasibility of using amphotropically packaged retroviral vectors to transduce primary rabbit mesenchymal stem cells of periosteal origin, primary periosteal cells were isolated from New Zealand white rabbits, transduced in vitro with a retroviral vector bearing both the nuclear localized lacZ marker gene and the neo(r) gene, and selected in G418. We used a convenient model for analysis of in vivo stability of these cells which were seeded on to polymer scaffold grafts and implanted into rabbit femoral osteochondral defects. The nuclear localized beta-galactosidase protein was expressed in essentially 100% of selected cells in vitro and was observed in the experimental explants from animals after both 4 and 8 weeks in vivo, while cells transduced with a retroviral vector bearing only the neo(r) gene in negative control explants showed no blue staining. We extended our study by delivering a gene of therapeutic relevance, human bone morphogenic protein 7 (hBMP-7), to primary periosteal cells via retroviral vector. The hBMP-7 gene was cloned from human kidney 293 cell total RNA by RT-PCR into a retroviral vector under control of the CMV enhancer/promoter. Hydroxyapatite secretion, presumably caused by overexpression of hBMP-7, was observed on the surface of the transduced and selected periosteal cells, however, this level of expression was toxic to both PA317 producer and primary periosteal cells. Subsequently, the strong CMV enhancer/promoter driving the hBMP-7 gene was replaced in the retroviral vector by a weaker enhancer/promoter from the rat beta-actin gene. Nontoxic levels of expression of hBMP-7 were confirmed at both the RNA and protein levels in PA317 producer and primary periosteal cell lines and cell supernatants. This work demonstrates the feasibility of using a gene therapy approach in attempts to promote bone and cartilage tissue repair using gene-modified periosteal cells on grafts. 相似文献
4.
JM Vilanova J Figueras-Aloy J Roselló G Gómez E Gelpí R Jiménez 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(5):588-592
The aim of this study was to evaluate the cerebral synthesis of eicosanoids in the asphyctic newborn and to investigate the relation between the prostanoid profiles in cerebrospinal fluid (CSF) and the appearance and severity of hypoxic-ischaemic encephalopathy (HIE). Levels of 6-keto-PGF 1-α, TXB2 , PGE2 and PGF2-α in CSF were measured in 40 full term newborns during the first day of life. Thirty of these newborns had birth asphyxia and were divided into three groups: 10 without HIE, 12 with mild HIE and 8 with moderate-severe HIE. They were compared to a control group of 10 non-hypoxic newborns. Determinations of the metabolites in CSF were performed by RIA and expressed as pg/ml (mean ± SD). The CSF TXB2 (thromboxane A2 metabolite) in asphyxiated newborns was always higher than in the control group (28.12 ± 10.6), and related to the severity of HIE ( p = 0:005): without HIE (50.84 ± 16.4; p = 0:02), mild HIE (80.65 ± 12.64; p ± 0:01) and moderate-severe HIE (178.14 ± 20.5; p < 0:01). The CSF 6-keto-PGF 1-α (prostacyclin metabolite) in asphyxiated newborns was always higher than in the control group (80.55 ± 12.56), but indirectly related to the severity of HIE: without HIE (240.95 ± 28.12; p < 0:01), mild HIE (183.65 ± 30.1; p < 0:01) and moderate-severe HIE (140.55 ± 25.12; p < 0:01). In the moderate-severe HIE group, the increase in TXB2 was higher than the rise in 6-keto-PGF 1-α . 相似文献
5.
6.
Occurrence of the t(2;5)(p23;q35) in non-Hodgkin's lymphoma 总被引:9,自引:3,他引:6
Weisenburger DD; Gordon BG; Vose JM; Bast MA; Chan WC; Greiner TC; Anderson JR; Sanger WG 《Blood》1996,87(9):3860-3868
Primary CD30(Ki-1)-positive anaplastic large-cell lymphoma (ALCL) is considered by some to be a distinct clinicopathologic entity associated with the t(2;5) (p23;q35). However, the specificity of t(2;5) for ALCL has not been carefully studied. Therefore, we performed a detailed analysis of all cases of ALCL with abnormal cytogenetics results in the Nebraska Lymphoma Study Group registry, as well as all other cases of non-Hodgkin's lymphoma with t(2;5) in the registry. We found the t(2;5) in only five of 10 cases of ALCL, four of whom were young patients. However, we also found the t(2;5) in 11 other cases of nonanaplastic lymphoma, including eight children with typical peripheral T-cell lymphomas of various types. The t(2;5) was also found in three older adults with B-cell lymphomas of various types. Thus, the t(2;5) was not specific for CD30+ ALCL. However, t(2;5) may define a clinicopathologic entity in children and young adults characterized by variable morphologies with a T-cell or indeterminate phenotype, CD30-positivity, nodal disease with frequent extranodal involvement, advanced stage, and an excellent response to therapy, including bone marrow transplantation for relapsed disease. The clinical relevance of the t(2;5) in older patients requires further study. 相似文献
7.
8.
9.
10.