全文获取类型
收费全文 | 1225027篇 |
免费 | 100412篇 |
国内免费 | 3700篇 |
专业分类
耳鼻咽喉 | 19863篇 |
儿科学 | 40099篇 |
妇产科学 | 30929篇 |
基础医学 | 157169篇 |
口腔科学 | 31223篇 |
临床医学 | 120803篇 |
内科学 | 249923篇 |
皮肤病学 | 31575篇 |
神经病学 | 95874篇 |
特种医学 | 49199篇 |
外国民族医学 | 201篇 |
外科学 | 202875篇 |
综合类 | 22168篇 |
现状与发展 | 72篇 |
一般理论 | 268篇 |
预防医学 | 81468篇 |
眼科学 | 28129篇 |
药学 | 87544篇 |
7篇 | |
中国医学 | 2838篇 |
肿瘤学 | 76912篇 |
出版年
2021年 | 10667篇 |
2020年 | 10596篇 |
2019年 | 9879篇 |
2018年 | 18333篇 |
2017年 | 15841篇 |
2016年 | 18101篇 |
2015年 | 19287篇 |
2014年 | 30125篇 |
2013年 | 37283篇 |
2012年 | 36415篇 |
2011年 | 38202篇 |
2010年 | 29133篇 |
2009年 | 31478篇 |
2008年 | 35991篇 |
2007年 | 36492篇 |
2006年 | 39318篇 |
2005年 | 35033篇 |
2004年 | 33030篇 |
2003年 | 30853篇 |
2002年 | 29845篇 |
2001年 | 63664篇 |
2000年 | 64381篇 |
1999年 | 54038篇 |
1998年 | 15919篇 |
1997年 | 14284篇 |
1996年 | 14187篇 |
1995年 | 13375篇 |
1994年 | 11191篇 |
1993年 | 10320篇 |
1992年 | 39082篇 |
1991年 | 37627篇 |
1990年 | 36764篇 |
1989年 | 35403篇 |
1988年 | 31834篇 |
1987年 | 30801篇 |
1986年 | 29065篇 |
1985年 | 27144篇 |
1984年 | 19691篇 |
1983年 | 16614篇 |
1982年 | 9297篇 |
1979年 | 17328篇 |
1978年 | 11722篇 |
1977年 | 10606篇 |
1976年 | 9071篇 |
1975年 | 10343篇 |
1974年 | 11876篇 |
1973年 | 11497篇 |
1972年 | 11051篇 |
1971年 | 10288篇 |
1970年 | 9495篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
The synthesis of barbituric acid derivatives containing α-phenylskatyl residues substituted at C(5) is described. The initial compound was α-phenylnorgramine, which had been previously successfully used for the alkylation of a series of CH-acids, in particular, for the synthesis of diethyl-1H-indol-3-yl(phenyl)methylmalonate. This compound has been used to obtain a series of 2-thiobarbituric acid derivatives, which are expected to possess antioxidant, membrane protector, and radioprotector properties.__________Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 39, No. 1, pp. 29 – 33, January, 2005. 相似文献
962.
963.
Manuela Kusch Claudia Grundmann Stefanie Keitel Rainer Seitz Herbert K?nig 《Blood coagulation & fibrinolysis》2006,17(7):575-580
A novel assay for factor XIII is described that utilizes exclusively small synthetic peptides as substrates for the cross-linking reaction catalyzed by activated factor XIII (FXIIIa). The acyl donor substrate (selection peptide) is immobilized on a microplate via biotin while the acyl acceptor substrate (detection peptide) is labeled with the fluorochrome Oregon green to allow sensitive detection without the need for secondary enzyme systems for signal amplification. Starting with an amino acid sequence from the fibrin gamma-chain (GQQHHLGGAKQAGDV) as a prototype peptide, the influence of amino acid exchanges were investigated with respect to their impact on the FXIIIa-catalyzed reaction. It was found that FXIIIa readily accepts a broad range of substrate peptides, with a proline neighboring the essential lysine having the most detrimental effect. The assay appears to be valuable for the molecular characterization of factor XIII and may be used for a deeper investigation into the substrate requirements of this final enzyme of wound repair, and eventually also for the characterization of other transglutaminases. 相似文献
964.
G K Zherlov S V Kozlov N S Rudaia T G Zherlova 《Experimental & clinical gastroenterology》2006,(3):44-50, 71
The article presents an original method of laparoscopic anti-reflux surgery, immediate and long-term results of the treatment of 132 patients with esophageal opening hernia. It also describes the analysis of the life quality of patients with the gastroesophageal reflux disease before and after the surgery. 相似文献
965.
Allergic autoimmune reaction after exposure to heavy metals such as mercury may play a causal role in autism, a developmental disorder of the central nervous system. As metallothionein (MT) is the primary metal-detoxifying protein in the body, we conducted a study of the MT protein and antibodies to metallothionein (anti-MT) in normal and autistic children whose exposure to mercury was only from thimerosal-containing vaccines. Laboratory analysis by immunoassays revealed that the serum level of MT did not significantly differ between normal and autistic children. Furthermore, autistic children harboured normal levels of anti-MT, including antibodies to isoform MT-I (anti-MT-I) and MT-II (anti-MT-II), without any significant difference between normal and autistic children. Our findings indicate that because autistic children have a normal profile of MT and anti-MT, the mercury-induced autoimmunity to MT may not be implicated in the pathogenesis of autism. 相似文献
966.
967.
968.
P B Schneider U Denk M Breitenbach K Richter P Schmid-Grendelmeier S Nobbe M Himly A Mari C Ebner B Simon-Nobbe 《Clinical and experimental allergy》2006,36(12):1513-1524
BACKGROUND: Alternaria alternata is one of the most important allergenic fungi worldwide. Mannitol dehydrogenase (MtDH) has previously been shown to be a major allergen of Cladosporium herbarum and cross-reactivity has been demonstrated for several fungal allergens. OBJECTIVE: The present study's objective was to clone the MtDH from an A. alternata cDNA library, express and purify the recombinant non-fusion protein and test its IgE-binding properties. Methods A cDNA library prepared from A. alternata hyphae and spores was screened for mannitol dehydrogenase by DNA hybridization with the radioactively labelled C. herbarum homologue as a probe. The resulting clone was sequenced and heterologously expressed in Escherichia coli as a recombinant non-fusion protein, which was purified to homogeneity and analysed for its IgE-binding capacity. RESULTS: The coding sequence of the full-length cDNA clone comprises 798 bp encoding a protein with a molecular mass of 28.6 kDa and a predicted pI of 5.88. Protein sequence analysis revealed an identity of 75% and a homology of 86% between the MtDHs of A. alternata and C. herbarum. The functional mannitol dehydrogenase was expressed in the E. coli strain BL21(DE3) transformed with the vector pMW172 and purified to homogeneity. The enzyme catalyses the NADPH-dependent conversion of d-fructose to d-mannitol. In IgE-ELISA and immunoblots, MtDH is recognized by 41% of A. alternata-allergic patients. In vivo immunoreactivity of the recombinant MtDH was verified by skin prick testing. Finally, inhibition-ELISA experiments confirmed cross-reactivity between the MtDHs of A. alternata and C. herbarum. CONCLUSION: Mannitol dehydrogenase (Alt a 8) represents an important new allergen of the ascomycete A. alternata that might be suitable for improving diagnostic and therapeutic procedures. 相似文献
969.
970.