全文获取类型
收费全文 | 486篇 |
免费 | 24篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 29篇 |
妇产科学 | 4篇 |
基础医学 | 48篇 |
口腔科学 | 28篇 |
临床医学 | 49篇 |
内科学 | 110篇 |
皮肤病学 | 6篇 |
神经病学 | 7篇 |
特种医学 | 110篇 |
外科学 | 19篇 |
综合类 | 9篇 |
预防医学 | 35篇 |
眼科学 | 2篇 |
药学 | 25篇 |
中国医学 | 2篇 |
肿瘤学 | 45篇 |
出版年
2022年 | 2篇 |
2019年 | 12篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 11篇 |
2014年 | 8篇 |
2013年 | 23篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 25篇 |
2009年 | 28篇 |
2008年 | 8篇 |
2007年 | 17篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 16篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 29篇 |
1997年 | 31篇 |
1996年 | 26篇 |
1995年 | 24篇 |
1994年 | 24篇 |
1993年 | 18篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 14篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 15篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 13篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 6篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1941年 | 1篇 |
排序方式: 共有529条查询结果,搜索用时 15 毫秒
111.
112.
113.
114.
Benacerraf BR; Greene MF; Saltzman DH; Barss VA; Penso CA; Nadel AS; Heffner LJ; Stryker JM; Sandstrom MM; Frigoletto FD Jr 《Radiology》1988,169(3):709-710
Early amniocentesis at 11-14 weeks gestation was evaluated in 100 consecutive patients to see how this technique compares with later amniocentesis. There were no complications as a consequence of the procedure or related pregnancy losses of chromosomally normal fetuses. Samples obtained from three (3%) patients showed insufficient cell growth; two of these patients elected a repeat procedure, which yielded a normal karyotype in each case. There were five abnormal karyotypes, one of which was a culture artifact; in the latter case, repeat amniocentesis at 15 weeks yielded a normal result. Of the 95 pregnancies with normal karyotypes, 94 were progressing normally at follow-up, and one patient elected pregnancy termination because of maternal indications. It appears that early amniocentesis may be an attractive alternative to traditional amniocentesis, in that it provides results at an earlier gestational age and may avoid certain disadvantages of chorionic villus sampling. 相似文献
115.
Hercus TR; Cambareri B; Dottore M; Woodcock J; Bagley CJ; Vadas MA; Shannon MF; Lopez AF 《Blood》1994,83(12):3500-3508
Residues within the first and fourth helices of human granulocyte- macrophage colony-stimulating factor (hGM-CSF) were analyzed for their role in biologic activity and interaction with the alpha- and beta- chains of the hGM-CSF receptor. Within the first helix substitution of the surface residues Glu14, Asn17, Gln20, Arg23, Arg24, and Asn27 or the buried residues Ala18, Leu25, and Leu28 did not significantly impair bioactivity or receptor binding. Substitutions at the buried residues Ala22 and Leu26 had intermediate bioactivity. However, substitutions of the surface residue Glu21 or the buried residue Ile19 reduced the relative bioactivity of the analogues to as little as 0.45% and 0.3%, respectively. Substitution of the charged surface residues of the fourth helix showed that substitution at Glu104, Lys107, and Lys111 had no significant effect on bioactivity, but substitution at Glu108 and Asp112 reduced the potency of the analogues to 34% and 7%, respectively. Receptor binding studies showed that, whereas Glu21 is the critical residue for binding to the hGM-CSF-receptor beta-chain, Asp112 is likely to be involved in binding to the GM-CSF-receptor alpha- chain. These results establish the relative contribution of residues in the first and fourth helices for GM-CSF bioactivity and receptor binding, and support a model where the fourth helix of GM-CSF interacts with the alpha-chain, and the first helix with the beta-chain of the GM- CSF receptor. 相似文献
116.
117.
病理医生对胃癌癌前病变特别感兴趣,西方国家和日本已提出用不同名称来确定这种病变。因此重要的是取得国际共识,以便在不同研究机构之间,特别在日本和西方研究者之间进行比较。文中提出的这一分类是由不同国家的病理学专家专门提出的,下列序号为原分类编号。1 无异型增生1.0 正常 粘膜成分即胃小凹、腺颈部、腺体和间质完好地保持其位置和比例,炎细胞浸润轻微或缺乏。1.1 反应性胃小凹上皮增生 见于胃粘膜对有丝分裂刺激物反应时,可能是感染性的,也可能是化学性的,或是在糜烂、溃疡后的增生。胃小凹延长、弯曲;细胞核增大,有时染色质… 相似文献
118.
Hematopoietic stem cell gene therapy holds the promise of being able to treat a variety of inherited and acquired diseases of the hematopoietic stem cell. However, to date, genetic modification of the human hematopoietic stem cell has been relatively inefficient. Here, we report the results of using a bioreactor system to expand hematopoietic cells after a brief retrovirus infection using a high titer, replication defective virus encoding for murine CD18. The retrovirus transduced culture continued to produce genetically modified hematopoietic progenitors for up to 6 weeks, the duration of the culture period. Up to one-third of the long-term culture initiating cell (LTC-IC) are genetically modified by the culture conditions. Murine CD18 can be expressed on the cell surface of up to 20% of the mature cells generated by the culture system, suggesting that clinically significant levels of gene transfer may be occurring. These results demonstrate the feasibility of using continuous perfusion bioreactors as a method of efficiently modifying human hematopoietic stem cells. 相似文献
119.
Immunologic characterization of a helper T-cell lymphoma 总被引:3,自引:0,他引:3
The lymphocytes of a patient with a T-cell non-Hodgkin's lymphoma with peripheral blood involvement and polyclonal hypergammaglobulinemia were characterized in terms of surface markers and immunologic functions. Using the fluorescence-activated cell sorter and employing various monoclonal antibodies against T-cell surface antigens, it was shown that almost all of the patient's peripheral blood lymphocytes were positive for OKT4 and 9.3, antibodies that recognize helper T-cell subset. The circulating lymphoma cells had typical characteristics for T cells; they formed spontaneous rosettes with sheep erythrocytes and stained with the pan-T-cell antibodies 9.6 and 10.2, but did not react with other anti-T-cell monoclonal reagents such as OKT3, UCHT-1, and 3A1. The cells appeared to be mature by the fact that they did not stain with OKT6, and terminal deoxynucleotidyl transferase was undetectable. Functionally, they were able to provide "help" for antibody production, and they could be stimulated to produce moderate amounts of interleukin-2, while unable to proliferate in response to mitogens. Morphologically, some of the lymphocytes showed a deeply cleaved nucleus. 相似文献
120.
Limited usefulness of CA125 measurement in the management of Hodgkin's and non-Hodgkin's lymphoma 总被引:1,自引:0,他引:1
Bonnet C Beguin Y Fassotte MF Seidel L Luyckx F Fillet G 《European journal of haematology》2007,78(5):399-404
BACKGROUND: Several papers have reported an association of high CA125 serum levels with advanced non-Hodgkin's lymphoma (NHL) as well as a relationship between high CA125 values and poor outcome. PATIENTS AND METHODS: Ninety-nine patients with NHL or Hodgkin's disease (HD) underwent serum CA125 assessment at diagnosis. Gender, age, presence of B symptoms, performance status (PS), histology, sites of tumor involvement, presence of effusion, clinical stage, age-adjusted International Prognostic Index, C-reactive protein (CRP), Hb, lactate deshydrogenase (LDH) and beta2-microglobulin were evaluated for their association with serum CA125 levels. The impact of CA125 levels and other features on overall (OS) and progression-free (PFS) survival was also assessed. RESULTS: CA125 serum levels were elevated in 34% of the patients, including 19% of patients with aggressive NHL, 45% of patients with indolent NHL, and 29% of patients with HD. Univariate analyses showed that CA125 levels correlated with poor PS, the presence of B symptoms, advanced clinical stage, abdominal, bone marrow or mediastinal involvement, presence of effusions, high aaIPI, low Hb levels and high CRP, LDH or beta2-microglobulin levels. In multivariate analysis, bone marrow involvement, the presence of effusions, and high aaIPI were all associated with high CA125 serum levels. In univariate analyses, OS and PFS were affected by age (PFS only), poor PS, B symptoms, advanced clinical stage, bone marrow or abdominal involvement (PFS only), high aaIPI, low Hb, high CRP or beta2-microglobulin levels. OS and PFS were not different in patients with normal or elevated CA125 levels. Multivariate analyses showed significantly inferior OS and PFS in patients with high beta2-microglobulin but no influence of CA125. CONCLUSION: While CA125 serum level correlates significantly with a number of features associated with more aggressive disease, it does not enhance the performance of standard prognostic markers in the management of patients with NHL or HD. 相似文献