全文获取类型
收费全文 | 139篇 |
免费 | 11篇 |
专业分类
150篇 |
出版年
2021年 | 2篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 8篇 |
2012年 | 3篇 |
2011年 | 9篇 |
2010年 | 12篇 |
2009年 | 9篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1959年 | 5篇 |
1958年 | 4篇 |
1957年 | 2篇 |
1956年 | 4篇 |
1955年 | 3篇 |
1954年 | 3篇 |
1953年 | 3篇 |
1952年 | 3篇 |
1950年 | 2篇 |
1948年 | 1篇 |
排序方式: 共有150条查询结果,搜索用时 9 毫秒
51.
An extra layer of complexity in the regulation of gene expression in bacteria is now apparent through previously unanticipated
roles of noncoding and antisense RNAs. 相似文献
52.
53.
Yoshifumi Kotani Shoji Shinkai Hiroshi Okamatsu Masamichi Toba Kishiko Ogawa Hiroto Yoshida Taro Fukaya Yoshinori Fujiwara Paulo HM Chaves Keiji Kakumoto Noriyuki Kohda 《Immunity & ageing : I & A》2010,7(1):1-11
Background
Immunoglobulin A (IgA) secretion in saliva decreases with age and may be the cause of increased vulnerability of the elderly to respiratory infections. The effect of oral intake of lactic acid bacteria on salivary secretory IgA (SIgA) in the elderly has not been reported. The objective of this study was to demonstrate the acceleration of salivary SIgA secretion by oral intake of Lactobacillus pentosus strain b240 (b240) in the elderly.Results
A total of 80 healthy elderly individuals were randomly allocated to either an intervention (i.e., b240) or a control (i.e., placebo) group. The elderly individuals in the b240 group were given a sterile water beverage (125 mL) containing heat-killed b240 (4 × 109 cells), while those in the placebo group were given only a sterile water beverage (125 mL); both groups received their respective beverages once daily for 12 weeks. Saliva was collected before initiation of the study and every 2 weeks thereafter. Saliva flow rate and SIgA concentration were determined, and the SIgA secretion rate was calculated. The mean salivary SIgA secretion rate in the b240 group steadily increased until week 4 (exhibiting a 20% elevation relative to that at week 0), and then remained stable until week 12. Changes in SIgA secretion rate over the intervention period were significantly greater in the b240 group than in the placebo group. The treatment groups exhibited no significant differences in adverse events.Conclusions
Oral intake of L. pentosus strain b240 for 12 weeks significantly accelerated salivary SIgA secretion, thereby indicating its potential utility in the improvement of mucosal immunity and resistance against infection in the elderly. 相似文献54.
PJ?Baker H?Johnston M?Abel HM?Charlton PJ?O'ShaughnessyEmail author 《Reproductive biology and endocrinology : RB&E》2003,1(1):4
During mammalian testis development distinct generations of fetal and adult Leydig cells arise. Luteinising hormone (LH) is
required for normal adult Leydig cell function and for the establishment of normal adult Leydig cell number but its role in
the process of adult Leydig cell differentiation has remained uncertain. In this study we have examined adult Leydig cell
differentiation in gonadotrophin-releasing hormone (GnRH)-null mice which are deficient in circulating gonadotrophins. Adult
Leydig cell differentiation was assessed by measuring expression of mRNA species encoding four specific markers of adult Leydig
cell differentiation in the mouse. Each of these markers (3β-hydroxysteroid dehydrogenase type VI (3βHSD VI), 17β-hydroxysteroid
dehydrogenase type III (17βHSD III), prostaglandin D (PGD)-synthetase and oestrogen sulphotransferase (EST)) is expressed
only in the adult Leydig cell lineage in the normal adult animal. Real-time PCR studies showed that all four markers are expressed
in adult GnRH-null mice. Localisation of 3βHSD VI and PGD-synthetase expression by in situ hybridisation confirmed that these genes are expressed in the interstitial tissue of the GnRH-null mouse. Treatment of animals
with human chorionic gonadotrophin increased expression of 3βHSD VI and 17βHSD III within 12 hours further indicating that
differentiated, but unstimulated cells already exist in the GnRH-null mouse. Thus, while previous studies have shown that
LH is required for adult Leydig cell proliferation and activity, results from the present study show that adult Leydig cell
differentiation will take place in animals deficient in LH. 相似文献
55.
1. Road salt is a common, anthropogenic source of NaCl in many temperate ecosystems. Sodium is also an essential and potentially limiting element for inland animal populations. This suggests that Na limitation in inland ecosystems, and hence attraction to Na sources, should increase with distance from salted roads. 2. In a North Temperate forest, we tested the prediction that Na recruitment would increase, as soil [Na] decreased, with distance from a salted two‐lane highway. We presented ants with three concentrations of NaCl and sucrose solution along four pairs of transects ca 1, 10, 100, and 1000 m from the road. 3. Consistent with the Na‐limitation hypothesis, the ratio of NaCl to sucrose use increased with distance from the road from 1:13 vials at 1 m to 1:5 vials at 1 km. Genera characterised by high Na use did not accumulate farther from the road. For the common and widespread Tapinoma sessile (Say), a 10‐fold increase in distance from the road resulted in ants doubling their use of NaCl relative to sucrose. 4. Road salt is a well‐known pollutant, especially of freshwater ecosystems. However, by suppressing plants and potentially promoting consumers, road salt may have more complex effects on terrestrial ecosystems, especially those far inland from oceanic aerosols. 相似文献
56.
Lauber U Dillenburger T Schollenberger M Müller HM Drochner W 《Mycotoxin Research》2000,16(2):166-169
To examine the biotransformation of Deoxynivalenol (DON) by the normal gut flora of pigs (in reliance on toxin-source) an in-vitro system was established. Suspensions of rectum contents from different treated animals were incubated with pure DON. Despite fast adaptation of microflora (Deepoxidation of DON) of animals fed wheat diet, no effects on reduced feed consumption and weight gain were seen. Even fast adaptation of microflora (lower intestine) couldn’t avoid DON-effects in vivo. 相似文献
57.
Joyce JBC van Beers Annemiek Willemze Jeroen J Jansen Gerard HM Engbers Martin Salden Jos Raats Jan W Drijfhout Annette HM van der Helm-van Mil Rene EM Toes Ger JM Pruijn 《Arthritis research & therapy》2013,15(5):R140
Introduction
Autoantibodies against citrullinated peptides/proteins (ACPA) are found in approximately 75% of the sera of patients with rheumatoid arthritis (RA). The RA-specific ACPA are frequently present prior to disease onset and their presence associates with a more erosive disease course. ACPA can therefore be used to aid the diagnosis and prognosis of RA. Recently, it became clear that ACPA are very heterogeneous, both in an individual patient and among different patients. The aim of this study was to investigate whether clinically meaningful ACPA profiles exist in early RA patients.Methods
Twenty citrullinated peptides and the corresponding non-citrullinated control peptides were immobilized on microarray sensor chips. Sera from 374 early arthritis patients were analyzed by surface plasmon resonance imaging (iSPR) of biomolecular interactions on the sensor chip.Results
Cluster analysis of the reactivities with the citrullinated peptides, after subtraction of the reactivities with the corresponding control peptides confirmed the heterogeneity of the ACPA response in RA and revealed 12 distinct ACPA profiles. The association of the 5 most frequent profiles with clinical features at diagnosis and during the disease course was examined, showing no statistically significant associations.Conclusions
Compared to the detection of ACPA in RA sera by CCP-based assays, ACPA profiling in early arthritis patients did not reveal associations with disease activity and progression scores. 相似文献58.
Maja Bulatovi? ?alasan Oscar FC van den Bosch Marjonne CW Creemers Martijn Custers Antonius HM Heurkens Jan Maarten van Woerkom Nico M Wulffraat 《Arthritis research & therapy》2013,15(6):R217
Introduction
The aim of this study was to determine the prevalence of gastrointestinal and behavioural symptoms occurring before (anticipatory/associative) and after methotrexate (MTX) administration, termed MTX intolerance, in rheumatoid (RA) and psoriatic arthritis (PsA).Methods
Methotrexate Intolerance Severity Score (MISS), previously validated in juvenile idiopathic arthritis patients, was used to determine MTX intolerance prevalence in 291 RA/PsA patients. The MISS consisted of four domains: abdominal pain, nausea, vomiting and behavioural symptoms, occurring upon, prior to (anticipatory) and when thinking of MTX (associative). MTX intolerance was defined as ≥6 on the MISS with ≥1 point on anticipatory and/or associative and/or behavioural items.Results
A total of 123 patients (42.3%) experienced at least one gastrointestinal adverse effect. The prevalence of MTX intolerance was 11%. MTX intolerance prevalence was higher in patients on parenteral (20.6%) than on oral MTX (6.2%) (p < 0.001).Conclusion
Besides well-known gastrointestinal symptoms after MTX, RA and PsA patients experienced these symptoms also before MTX intake. RA and PsA patients on MTX should be closely monitored with the MISS for early detection of MTX intolerance, in order to intervene timely and avoid discontinuation of an effective treatment. 相似文献59.
Michał Rostkowski Mats HM Olsson Chresten R Søndergaard Jan H Jensen 《BMC structural biology》2011,11(1):6
Background
Charge states of ionizable residues in proteins determine their pH-dependent properties through their pKa values. Thus, various theoretical methods to determine ionization constants of residues in biological systems have been developed. One of the more widely used approaches for predicting pKa values in proteins is the PROPKA program, which provides convenient structural rationalization of the predicted pKa values without any additional calculations. 相似文献60.
De Rooy DP Willemze A Mertens B Huizinga TW Van der Helm-van Mil AH 《Arthritis research & therapy》2011,13(5):R180