全文获取类型
收费全文 | 1135篇 |
免费 | 80篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 119篇 |
妇产科学 | 18篇 |
基础医学 | 87篇 |
口腔科学 | 36篇 |
临床医学 | 181篇 |
内科学 | 285篇 |
皮肤病学 | 16篇 |
神经病学 | 23篇 |
特种医学 | 218篇 |
外科学 | 77篇 |
综合类 | 35篇 |
预防医学 | 44篇 |
眼科学 | 10篇 |
药学 | 39篇 |
1篇 | |
肿瘤学 | 36篇 |
出版年
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 11篇 |
2015年 | 23篇 |
2014年 | 21篇 |
2013年 | 19篇 |
2012年 | 21篇 |
2011年 | 20篇 |
2010年 | 40篇 |
2009年 | 48篇 |
2008年 | 35篇 |
2007年 | 16篇 |
2006年 | 18篇 |
2005年 | 21篇 |
2004年 | 17篇 |
2003年 | 16篇 |
2002年 | 23篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 21篇 |
1998年 | 86篇 |
1997年 | 84篇 |
1996年 | 90篇 |
1995年 | 62篇 |
1994年 | 53篇 |
1993年 | 45篇 |
1992年 | 24篇 |
1991年 | 26篇 |
1990年 | 13篇 |
1989年 | 38篇 |
1988年 | 38篇 |
1987年 | 38篇 |
1986年 | 18篇 |
1985年 | 30篇 |
1984年 | 21篇 |
1983年 | 20篇 |
1982年 | 16篇 |
1981年 | 17篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1971年 | 2篇 |
1969年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有1226条查询结果,搜索用时 250 毫秒
1.
PJ Commerford 《Cardiovascular journal of Africa》2015,26(4):151-Aug;26(4):151
2.
Floriano P Silva-Junior Herbert L M Guedes Laura C Garvey Aniesse S Aguiar Saulo C Bourguignon Enrico Di Cera Salvatore Giovanni-De-Simone 《Toxicon》2007,50(1):18-31
BJ-48, a serine protease from the venom of Bothrops jararacussu, was purified to homogeneity using affinity chromatography on p-aminobenzamidine-agarose followed by HPLC gel filtration. BJ-48 presented 52kDa by SDS-PAGE analysis and 48,036Da by electron spray mass spectrometry. The enzyme was shown to be highly glycosylated with 42% of N-linked carbohydrates composed of Fuc(1):GalN(4):GlcN(5):Gal(1):Man(2) and a high content of sialic acid residues (8-12%). BJ-48 had optimal esterase activity at pH 7.5 and displayed maximum catalytic rate at 50 degrees C. Its hydrolytic activity was strongly inhibited by aprotinin and dithiothreitol while N-tosyl-l-phenylalanine chloromethyl ketone, 6-aminocaproic acid, E-64 and soybean trypsin inhibitor (SBTI) were ineffective. The kinetics of BJ-48 with chromogenic substrates revealed an unprecedented selectivity (10(4)-fold) for Arg over Lys in P1. BJ-48 proved to be a thrombin-like enzyme (TLE) with a specific fibrinogen-clotting activity of 73.4NIH units/mg. The TLE rapidly digested human fibrinogen Bbeta chain, but the Aalpha chain was cleaved specifically to release fibrinopeptide A with k(cat)/K(m)=2.1muM(-1)s(-1). The TLE showed no activity toward other thrombin substrates like protein C, protease-activated receptor-1 or inhibitors such as hirudin and antithrombin. A non-denaturing procedure using PNGase F and neuraminidase followed by hydrophobic interaction chromatography was employed to obtain active BJ-48 forms with variable carbohydrate content. Compared to the native enzyme, total or partially deglycosylated BJ-48 forms presented up to 2-fold reduction in their specific activities upon heating at 55/65 degrees C or treatment with SBTI. These results point out a role for BJ-48 glycosylation in thermostability and controlling the access of some canonical protein inhibitors to the active site. 相似文献
3.
Hans Bosma Martin PJ van Boxtel Gertrudis IJM Kempen Jacques ThM van Eijk Jelle Jolles 《BMC public health》2007,7(1):179
Background
The aims of this study were to examine the extent to which higher intellectual abilities protect higher socio-economic groups from functional decline and to examine whether the contribution of intellectual abilities is independent of childhood deprivation and low birth weight and other socio-economic and developmental factors in early life. 相似文献4.
5.
6.
Previous reports in the literature have described correlation of increasing repeat length with severity of the phenotype, in Kennedy syndrome. We describe male siblings with different repeat lengths, with lack of expression of the phenotype in the sibling with the longer repeat length. The phenotype was identical to motor neurone disease. There is variability of expression in Kennedy syndrome and repeat length even in siblings cannot be taken as a conclusive indicator of severity. CAG repeat length cannot be used to predict the natural history of Kennedy disease. The diagnosis of Kennedy syndrome should be considered in male patients presenting with atypical motor neurone disease. 相似文献
7.
PJ Woll PhD MRCP R Pettengell PhD FRACP 《International journal of clinical practice》1997,51(2):111-115
SUMMARY The interferons are natural glycoproteins secreted in response to various stimuli, including viral infection. They have antiviral, antiproliferative and immunomodulatory effects on different target cell populations. Since recombinant human interferons have become available, they have been tested in a wide range of malignancies. They are well established in the treatment of hairy cell leukaemia, chronic myelogenous leukaemia and multiple myeloma. Although they have documented activity against lymphoma, melanoma, renal cell cancer and carcinoid tumours, their role in the treatment of these tumours is less clear. In the common solid tumours, such as lung cancer and colorectal cancer, the use of interferons remains experimental. Here we will summarise their practice applications in oncology, using randomised studies where available to establish their place in multi-modality treatment. We will not discuss their use as antiviral or immunomodulating agents in viral and autoimmune diseases, multiple sclerosis or after organ transplantation. 相似文献
8.
9.
10.