全文获取类型
收费全文 | 996篇 |
免费 | 123篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 70篇 |
妇产科学 | 5篇 |
基础医学 | 121篇 |
口腔科学 | 26篇 |
临床医学 | 126篇 |
内科学 | 225篇 |
皮肤病学 | 15篇 |
神经病学 | 150篇 |
特种医学 | 136篇 |
外科学 | 51篇 |
综合类 | 28篇 |
预防医学 | 89篇 |
眼科学 | 8篇 |
药学 | 83篇 |
中国医学 | 1篇 |
肿瘤学 | 31篇 |
出版年
2021年 | 7篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 22篇 |
2013年 | 43篇 |
2012年 | 29篇 |
2011年 | 32篇 |
2010年 | 35篇 |
2009年 | 35篇 |
2008年 | 28篇 |
2007年 | 52篇 |
2006年 | 27篇 |
2005年 | 29篇 |
2004年 | 21篇 |
2003年 | 23篇 |
2002年 | 23篇 |
2001年 | 19篇 |
2000年 | 32篇 |
1999年 | 26篇 |
1998年 | 49篇 |
1997年 | 43篇 |
1996年 | 43篇 |
1995年 | 30篇 |
1994年 | 24篇 |
1993年 | 26篇 |
1992年 | 22篇 |
1991年 | 20篇 |
1990年 | 28篇 |
1989年 | 42篇 |
1988年 | 43篇 |
1987年 | 32篇 |
1986年 | 28篇 |
1985年 | 22篇 |
1984年 | 12篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1978年 | 6篇 |
1977年 | 13篇 |
1976年 | 8篇 |
1975年 | 13篇 |
1973年 | 9篇 |
1972年 | 7篇 |
1971年 | 7篇 |
1968年 | 8篇 |
排序方式: 共有1169条查询结果,搜索用时 15 毫秒
101.
102.
胎儿和新生儿同种免疫性血小板减少症(alloimmune thrombocytopenia,AIT)的发生是由于胎儿的血小板特异性抗原刺激母体产生同种抗体而引起的。胎儿的这种特异性抗原来源于父亲。通常,胎儿和新生儿发生严重AIT绝大多数是由于胎儿-母体PIA1抗原不相容所致,估计这种病例有20%可并发颅内出血。最近,在挪威和苏格兰进行的AIT发生率的前瞻性研究中发现因PIA1所致的新生儿AIT的发病率大约是1%。由于AIT与其他病因引起的新生儿血小板减少症的治疗方法不同,故对AIT的快速诊断将有助于患儿获得最佳治疗。本研究比较了血清学诊断为AIT的新生儿与血清学不支持诊断为 相似文献
103.
胎儿和新生儿同种异体免疫性血小板减少症(AIT)是引起胎儿和新生儿严重血小板减少的最常见原因.母亲针对源自父亲的胎儿血小板抗原的IgG抗体,在妊娠早期就可通过胎盘,通常导致胎儿严重血小板减少.由于一些血小板减少症临界值(50、100或150×109/L)的不同,他们的发生率亦各不相同.但在多数未经选择的人群中,AIT影响1/1 000到1/2 000活产数.在新生儿病房,临床确诊的重症AIT很罕见,可能只有1:10 000分娩数. 相似文献
104.
Group a streptococcal antigens cross-reactive with myocardium. Purification of heart-reactive antibody and isolation and characterization of the streptococcal antigen 总被引:25,自引:17,他引:25
下载免费PDF全文
![点击此处可从《The Journal of experimental medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Heart-reactive antibody (HRA) appears in the sera of experimental animals inoculated with group A streptococci as well as patients with acute rheumatic fever. Adsorption of either serum with group A streptococcal membranes will remove the HRA. Blocking experiments between these two types of HRAs have demonstrated that the antibodies are directed towards different antigenic determinants on either the same or different molecules. To isolate and purify the antigen from the group A streptococcus cross-reactive with sarcolemmal sheaths of cardiac myofibers, it became necessary to purify the HRA from rheumatic fever patients’ sera. Isolated gamma globulin containing all of the HRA was adsorbed onto human sarcolemmal sheaths. The specific HRA was released by using potassium iodide. Over 99 percent of the purified HRA was shown to bind the sarcolemmal sheath whereas less than 1 percent of the antibody would bind nonspecifically to other material. Preparations of group A streptococcal membrane will bind HRA purified from the sera of acute rheumatic patients at levels of 97 percent or greater. The cross-reactive antigen solubilized by nonionic detergent was purified 120-fold by column chromatography. On sodium dodecyl sulfate polyacrylamide electrophoresis, the antigen was demonstrated to be composed of four polypeptides with mol wt of 32,000, 28,000, 26,000, and 22,000 daltons, respectively. Only proteolytic enzymes could destroy the antigenic determinant whereas glycosidases and lipases had no effect. The purified antigen blocked the binding of purified HRA to normal human heart sections. 相似文献
105.
JB Robins MRCOG 《International journal of clinical practice》1995,49(3):164-165
SUMMARY A case of cord presentation associated with the presence of a complex true knot is described and the aetiology and risks reconsidered. 相似文献
106.
Prevalence of cytomegalovirus antibody in hemophiliacs and homosexuals infected with human immunodeficiency virus type 1 总被引:1,自引:0,他引:1
We determined the prevalence of antibody to cytomegalovirus (CMV) in the sera of non-homosexual hemophilia patients and homosexual men infected with the human immunodeficiency virus type 1 (HIV-1). CMV antibody testing by latex agglutination revealed 33 of 58 HIV-1 infected hemophiliacs (57%) were antibody-positive compared with 54 of 54 HIV-1 infected asymptomatic non-hemophiliac homosexuals (100%) (p less than .001). Nine of 15 hemophiliacs (60%) with symptomatic HIV-1 infection were CMV antibody-positive. We also tested 22 HIV-1 antibody-negative hemophiliacs who had received non-heat treated factor concentrates. 14 of these 22 (64%) were CMV antibody-positive compared with 57% of HIV-1 antibody-positive hemophiliacs. We conclude 1) there is little correlation between transmission of HIV-1 and CMV by factor concentrates, 2) the presence of CMV antibody does not appear to be associated with clinical stage of HIV-1 infection in hemophiliacs, and 3) there may be a significant number of CMV antibody-negative hemophiliacs with HIV-1 infection at risk for primary infection and subsequent disease if CMV seronegative blood products are not provided for future transfusions. 相似文献
107.
Hans HCM Savelberg Nicolaas C Schaper Paul JB Willems Ton LH de Lange Kenneth Meijer 《BMC musculoskeletal disorders》2009,10(1):16
Background
Patients with diabetic polyneuropathy (DPN) are often confronted with ulceration of foot soles. Increased plantar pressure under the forefoot has been identified as a major risk factor for ulceration. This study sets out to test the hypothesis that changes in gait characteristics induced by DPN related muscle weakness are the origin of the elevated plantar pressures. 相似文献108.
Laura Silveira-Moriyama Janice L. Holton Ann Kingsbury Hilary Ayling Aviva Petrie William Sterlacci Werner Poewe Hans Maier Andrew J. Lees Tamas Revesz 《Neuroscience letters》2009
We studied α-synuclein pathology in the rhinencephalon of ten cases of Parkinson's disease (PD) and twelve neurologically normal controls, of which seven had incidental Lewy bodies in the substantia nigra at autopsy and five had no pathological evidence of neurological disease. In all PD and incidental Lewy bodies cases, α-synuclein pathology was found in all five subregions of the primary olfactory cortex that were sampled, and amongst them the pathology was significantly more severe in the temporal division of the piriform cortex than in the frontal division of the piriform cortex, olfactory tubercle or anterior portions of the entorhinal cortex. The orbitofrontal cortex, which is an area of projection from the primary olfactory cortex, was affected in some cases but overall the α-synuclein pathology was less severe in this area than in the primary olfactory cortex. Because different areas of the rhinencephalon are likely to play different roles in olfaction and our data indicate a differential involvement by α-synuclein deposition of structures implicated in smell, future prospective studies investigating the pathophysiological basis of hyposmia in PD should consider to examine the areas of primary olfactory cortex separately. 相似文献
109.
Osama Al‐Jabrah BDS MSc JBPD Raghda Al‐Shammout BDS JBOrth Waddah El‐Naji BDS JBRestDent Mahasen Al‐Ajarmeh BDS JBPD Abdel‐Hakeem Al‐Quran BDS JB 《Journal of prosthodontics》2010,19(4):286-293
Purpose: The aims of this study were to compare gender differences in the width and length of the maxillary right central incisor and the horizontal and vertical overlap of the anterior teeth and to determine the relationships of these two intraoral dental biometric measurements with the amount of gingival display during smiling. Materials and Methods: A total of 61 men and 66 women were included in this study. For each participant, the gingival tissue display during smiling was judged to be either visible or not, and the maximum mesiodistal and incisogingival dimensions of the maxillary right central incisor were measured, along with the amount of horizontal and vertical overlap of anterior teeth using a digital caliper. Gender differences in these parameters and the relationship between subjects showing gingival display when smiling and the two intraoral dental biometric measurements were determined. Statistical analyses of data were performed using SPSS (V11) software. The mean scores for gender were calculated, and a Student's t‐test was used to identify significant differences between both groups. Significance level was set to 0.05. Results: The age of the participants ranged between 23 and 52, with a mean of 33.47 ± 9.07 years. A relatively small percentage of the subjects (22.05%) displayed gingiva when smiling. More women displayed gingiva when smiling than men, with a 2:1 female:male ratio. Men exhibited significantly (p < 0.05) wider (8.76 ± 0.66 mm) and longer (10.28 ± 0.88 mm) central incisors compared to women (7.92 ± 0.72 mm; 9.27 ± 0.93 mm width and length, respectively). No gender differences were found in the width‐to‐length ratio. Subjects with gingival display had significantly more horizontal (4.28 ± 1.21 mm; p < 0.001), and vertical (3.52 ± 0.66 mm; p < 0.05) overlap of anterior teeth compared to those who did not display gingiva when smiling (2.40 ± 1.03 and 2.30 ± 0.93 mm, respectively). Conclusions: Significantly more women displayed gingiva in smiling. Men had significantly wider and longer central incisors. No differences were recorded between men and women relative to both the horizontal and vertical anterior tooth overlap. Subjects who displayed gingiva when smiling had more horizontal and vertical overlap of anterior teeth. 相似文献
110.
CE Vitor CP Figueiredo DB Hara AF Bento TL Mazzuco JB Calixto 《British journal of pharmacology》2009,157(6):1034-1044