全文获取类型
收费全文 | 45450篇 |
免费 | 3769篇 |
国内免费 | 1258篇 |
专业分类
耳鼻咽喉 | 424篇 |
儿科学 | 1149篇 |
妇产科学 | 685篇 |
基础医学 | 6319篇 |
口腔科学 | 644篇 |
临床医学 | 4562篇 |
内科学 | 8948篇 |
皮肤病学 | 868篇 |
神经病学 | 3163篇 |
特种医学 | 1669篇 |
外国民族医学 | 23篇 |
外科学 | 5401篇 |
综合类 | 3543篇 |
现状与发展 | 3篇 |
一般理论 | 3篇 |
预防医学 | 3491篇 |
眼科学 | 902篇 |
药学 | 3773篇 |
12篇 | |
中国医学 | 1345篇 |
肿瘤学 | 3550篇 |
出版年
2023年 | 427篇 |
2022年 | 1051篇 |
2021年 | 1566篇 |
2020年 | 1056篇 |
2019年 | 1249篇 |
2018年 | 1439篇 |
2017年 | 1087篇 |
2016年 | 1073篇 |
2015年 | 1346篇 |
2014年 | 1733篇 |
2013年 | 2059篇 |
2012年 | 2889篇 |
2011年 | 2993篇 |
2010年 | 1905篇 |
2009年 | 1519篇 |
2008年 | 2057篇 |
2007年 | 2187篇 |
2006年 | 2126篇 |
2005年 | 1984篇 |
2004年 | 1805篇 |
2003年 | 1917篇 |
2002年 | 1802篇 |
2001年 | 1621篇 |
2000年 | 1466篇 |
1999年 | 1296篇 |
1998年 | 509篇 |
1997年 | 468篇 |
1996年 | 382篇 |
1995年 | 332篇 |
1994年 | 319篇 |
1993年 | 258篇 |
1992年 | 595篇 |
1991年 | 581篇 |
1990年 | 541篇 |
1989年 | 486篇 |
1988年 | 504篇 |
1987年 | 423篇 |
1986年 | 411篇 |
1985年 | 389篇 |
1984年 | 268篇 |
1983年 | 193篇 |
1982年 | 126篇 |
1981年 | 107篇 |
1979年 | 220篇 |
1978年 | 112篇 |
1977年 | 125篇 |
1976年 | 113篇 |
1974年 | 130篇 |
1972年 | 128篇 |
1969年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 22 毫秒
81.
从兔网织红细胞提纯的红细胞分化调节因子(erythroid differentiation factor,EDF),能对体外培养的自发转化成纤维细胞系L929及人鼻咽癌细胞系KB产生作用。当EDF剂量为0.10μg/ml时,可引起L929细胞形态发生改变,并有细胞核固缩现象。第2d的细胞生长抑制率为64.86%,软琼脂集落形成率为0;第5d时细胞增殖为负值。~3H-TdR掺入率明显降低。EDF剂量为0.15μg/ml时,对KB细胞生长已有抑制作用。EDF剂量达0.30μg/ml时,生长抑制明显。以上结果证明了EDF对恶性细胞具有增殖抑制作用。这种作用对不同种类细胞敏感性不同,并且与剂量呈正相关。 相似文献
82.
83.
Swiedler SJ Beck M Bajbouj M Giugliani R Schwartz I Harmatz P Wraith JE Roberts J Ketteridge D Hopwood JJ Guffon N Sá Miranda MC Teles EL Berger KI Piscia-Nichols C 《American journal of medical genetics. Part A》2005,(2):144-150
A cross-sectional survey in individuals affected with the lysosomal storage disease Mucopolysaccharidosis VI (MPS VI) was conducted to establish demographics, urinary glycosaminoglycan (GAG) levels, and clinical progression of the disease. The survey evaluated 121 bona fide MPS VI-affected individuals over the age of 4 years from 15 countries across the Americas, Europe, and Australasia representing greater than 10% of the estimated world prevalence of the disease. A medical history, complete physical exam, urinary GAG determination, and assessment of several clinical measures related to physical endurance, pulmonary function, joint range of motion, strength, and quality of life were completed for each participant. Although a wide variation in clinical presentation was observed, several general findings were obtained reflecting progression of the disease. Impaired physical endurance, as measured by the distance achieved in a 6-min walk, could be demonstrated across all age groups of MPS VI-affected individuals. High urinary GAG values (>200 mug/mg creatinine) were associated with an accelerated clinical course comprised of age-adjusted short stature and low body weight, impaired endurance, compromised pulmonary function, and reduced joint range of motion. An unexpected result was the predominance of urinary GAG values <100 mug/mg creatinine for those participants over the age of 20 years. Pending the collection of longitudinal data, these results suggest that urinary GAG levels predict clinical morbidity, and longer-term survival is associated with urinary GAG levels below a threshold of 100 mug/mg creatinine. 相似文献
84.
大鼠下丘脑及邻近区域催产素免疫阳性神经元与垂体后叶的关系 总被引:8,自引:1,他引:8
本文运用免疫细胞化学PAP及ABC法,显示大白鼠下丘脑内OXT免疫阳性神经元,并于垂体后叶注射WGA-HRP,显示下丘脑中逆行标记细胞,结合免疫细胞化学方法,观察下丘脑及其邻近区域内HRP与OXT双标记细胞,证实下丘脑视上核、室旁核、穹窿前核和后核、血管周细胞群、下丘脑视前区、下丘脑前区及外侧区、背侧副细胞群内、室周部、第三脑室侧壁室管膜细胞下及室间孔部室管膜细胞下,均有OXT免疫阳性神经元,其中至少部分神经元可发出向垂体后叶的投射纤维。位于第三脑室侧壁室管膜下及室间孔部室管膜下的神经元,可能监测脑脊液中各种因素的变化,调节垂体后叶OXT的分泌,也可能直接通过共树突向脑脊液内释放OXT。 相似文献
85.
J.?Macías J.?A.?PinedaEmail author F.?Lozano J.?E.?Corzo A.?Ramos E.?León J.?A.?García-García J.?Fernández-Rivera J.?A.?Mira J.?Gómez-Mateos 《European journal of clinical microbiology & infectious diseases》2003,22(11):675-680
Coinfection with the human immunodeficiency virus (HIV) and the hepatitis C virus (HCV) is highly prevalent in southern Europe. However, there are few and contradictory data about the effect of HCV carriage on the response to highly active antiretroviral therapy (HAART). In this study, the recovery of CD4+ T cells following HAART among antiretroviral-naïve patients seropositive for HIV with and without HCV coinfection was investigated. Two hundred one HIV-infected patients without previous exposure to antiretroviral drugs were included in the study. HCV coinfection was detected in 123 (61%) patients. The time to recover 200 CD4+ cells/µl was longer in the HCV-positive group (P<0.001). In a Cox model, HCV infection and lack of persistent HIV viremia (defined as <200 copies/ml) were associated with the time to recover 200 CD4+ cells/µl. The mean increase in CD4+ cell counts was lower in the HCV-positive group during the first year of therapy. HIV/HCV-coinfected patients naïve for antiretroviral therapy show a delayed recovery of CD4+ cell counts after starting HAART. 相似文献
86.
87.
Saulot V Vittecoq O Salle V Drouot L Legoedec J Le Loët X Godin M Ducroix JP Ménard JF Tron F Gilbert D 《Journal of autoimmunity》2002,19(1-2):55-61
To identify new autoantibody populations in patients with rheumatic diseases, a cDNA expression library was immunoscreened with a rheumatoid arthritis (RA) patient's serum which contains autoantibodies binding to uncharacterized polypeptides by Western-blotting. One clone encoding the amino-terminal region (Nt) [domain L and half of domain I] of human calpastatin was selected. Different fragments of the selected cDNA were prepared and the corresponding recombinant polypeptides were produced by in vitro translation and analysed by Western blotting. Most RA sera bound to recombinant amino-terminal region and domain I but not to domain L. This prompted us to use a recombinant polypeptide corresponding to the domain I of calpastatin as the antigen in a solid-phase ELISA to test sera from patients with various systemic rheumatic diseases and healthy controls.Anti-calpastatin domain I antibodies (ACAST-DI Ab), were detected by ELISA in RA, systemic lupus erythematosus (SLE), Sj?gren's syndrome and control sera at respective frequencies of 10, 9, 0 and 1%. These Ab did not have prognostic value in early RA; high levels were significantly associated with vasculitis in SLE. Antibodies reacting with the calpastatin amino-terminal region are produced during systemic rheumatic diseases and are predominantly directed against domain I. High levels of these Ab may constitute a marker of vasculitis in SLE. 相似文献
88.
Sur l'initiative de la Direction et de l'ingénieur biomédical, une première évaluation des pratiques de programmation a été conduite au sein du centre hospitalo-universitaire de Nîmes avec l'ensemble des acteurs concernés. L'autoévaluation se poursuit avec l'inclusion de cinq CHU de référence. Les pratiques observées permettent l'élaboration d'un questionnaire. Le questionnaire est structuré selon les phases traditionnelles du processus de programmation : état de connaissance du patrimoine ; recueil des besoins ; analyse ; décision ; réalisation du programme. Par phases, plusieurs questions fermées explorent les variables. Trente établissements sont inclus. Les résultats de l'enquête et les données initialement collectées dressent un panorama des pratiques de programmation des investissements biomédicaux en établissements de soins publics. Le résultat obtenu semble être la première étape de l'élaboration d'un référentiel professionnel. L'ensemble a permis d'étayer une refonte concrète de nos pratiques de programmation.With the initiative of the top management and the biomedical engineer, the first-assessment of the biomedical pratical programmation of the Nîmes University Hospital Center (CHU), has been led by representatives of different departments of the center. The auditing has been done with five members of the Nîmes University Hospital Center (CHU). The practices that observed have helped to create a survey. This survey is structured according to the usual steps of a programmation: statement of properties, collection of needs, analysis, decision, and realisation of the programmation. By groups, several closed questions process the variables. Thirty establishments are taken into account. The results of the study and data initially collected show an array of the practises used for the programming of the biomedical investments into public healthcare establishments. The obtained result seems to be the first stage of the elaboration of a professional reference. The whole has enabled to support a change in the uses of the Nîmes University Hospital Centre (CHU). 相似文献
89.
Hami BB Le Gall F Jouan H Almange C Loire R 《Archives d'anatomie et de cytologie pathologiques》1999,47(1):53-56
Papillary fibroelastoma is a seldom reported tumour. It usually occurs in adults and develops on the aortic and mitral valves. It is not different of giant Lambl excrescences and differential diagnostic can be difficult with the myxoma. Its systematic surgical ablation is justified by the important risk of embolic complications. It has rarely been reported in children. We report a case peculiar by fortuitous diagnostic, tricuspid site, large size and occurrence in a 3-year old child. 相似文献
90.
黄皮酰胺促钾通道开放 总被引:1,自引:0,他引:1
一种新发现的具有促智作用的药物——黄皮酰胺能抑制去甲肾上腺素(NE)或KCl引起的血管平滑肌收缩。本研究旨在应用膜片钳(patch clamp)技术探讨黄皮酰胺对Wistar大鼠尾动脉平滑肌细胞膜钾离子通道的作用。单个平滑肌细胞用酶法分离,以细胞封接方式记录离子通道活动。在细胞池内注入2μM黄皮酰胺后,钾离子通道活动明显增强。用本实验室开发的计算机软件(patch clamp analysis system,Version 1.0)计算分析通道活动的特征参数。 相似文献