全文获取类型
收费全文 | 169篇 |
免费 | 8篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 3篇 |
2015年 | 9篇 |
2014年 | 13篇 |
2013年 | 6篇 |
2012年 | 15篇 |
2011年 | 11篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 6篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 15 毫秒
1.
2.
The Wageningen Delivery of Functionality symposium covered all aspects involved with food structural design to arrive at high-quality
foods which meet demanding customer expectations and regulatory requirements. The symposium integrated aspects from the structural
organization of foods at molecular and supramolecular scales to dedicated techniques required to describe and visualize such
structures, the gastro-intestinal events and how to model these in a laboratory setting, and finally the impact those food
structures and ingredients have on the consumer’s physiology and on the human perception. As an interdisciplinary platform,
bringing together more than 160 researchers from academia and industry, the symposium meanwhile fulfills an important role
in the food science community. 相似文献
3.
Two experiments were carried out to assess the efficacy of estrus detection and fertility in Zebu cattle after synchronization with prostaglandin F2a or a progestagen. The first experiment compared estrus detection rates and fertility following insemination in 42 cows previously synchronized with either 25 mg of PGF2a or with a 6 mg of Norgestomet implant plus 5 mg i.m. of estradiol valerate (SMB). Differences were observed in the percentage of cows detected in estrus (54 vs 95%, respectively, P < 0.05), but not in fertility at the first synchronized estrus (26 vs 15%), nor in the detection rate and fertility at the subsequent estrous period (38 v 47%). The second experiment evaluated the efficacy of estrus detection at different time intervals in 30 cows, comparing estrus synchronized with PGF2a with the subsequent estrous period. The observation periods were continuous, day and night, for 100 h both after PGF2a treatment and from Day 18 of the treatment cycle (Period 1). In addition, the animals were administered PGF2a again on Day 10 of the second cycle and observed continuously from 0600 to 1800 h, and from Day 18 of the treatment cycle (Period 2). Finally, the same treatment regimen was used except that the observation was between 0600 to 0700 h and 1800 to 1900 h (Period 3). No differences were obtained in the percentage of cows detected in estrus in the synchronized and nonsynchronized groups (average 75%); however, accuracy in the detection of estrus in Period 3 differed in the nonsynchronized and synchronized estrus groups by 40% (P < 0.05) compared with the other two, more intense observation periods. 相似文献
4.
M. J. Duchateau 《Journal of Ethology》1989,7(2):141-151
The first aim of this study was to investigate whether specific changes in the frequencies of behavioural characteristics
are correlated with the cause or reflect the onset of the laying of haploid eggs by the queen, and whether these changes cause
the onset of egg laying and aggressive behaviour by workers. The second aim was to obtain a better understanding of the occurrence
of the behaviours in relation to the physiology and function of the queen and the workers.
No behavioural characteristics of workers which could predict the occurrence of the queen's switch to haploid egg laying was
found nor did any such behaviour indicate that the switch had already occurred. The onset of worker oviposition was not found
to be the consequence of the level or the type of agonistic actions between the workers and the queen.
With the onset of worker oviposition the agonistic behaviours called trembling and buzzing, which are directed at the queen,
disappear. At the same time the frequency of a non-directed behaviour, called humming, increases. This behaviour is seen particularly
in the small housebees with developed ovaries.
Before worker oviposition begins, the frequencies with which individual workers perform agonistic behaviour are not correlated
with the conditions of their ovaries nor correlated with other characteristics of the workers. However, these frequencies
are related to the sequence in which workers emerge. The correlations with age are due to the fact that workers of the first
brood have higher activity levels than those of the later broods. The first egg layers are to be found among the first workers.
In the period of worker oviposition, humming and the aggressive behaviours of darting and attack are performed by workers
with developed ovaries. These behaviours are directed particularly towards workers who also have active ovaries.
If the queen has disappeared 1 worker usually becomes dominant. This worker is characterized by the relatively high frequency
with which she engages in darting and attacks. In addition, this worker is characterized by a specific behaviour, called pumping,
which is directed at workers that have mature eggs in their ovaries. Behavioural domination, however, is no guarantee that
the bee concerned will eventually become the most productive one.
Although at an apparently pre-determined moment in the ontogeny of the colony the queen loses control over worker oviposition
and related behaviours, she remains dominant in various other behavioural hierarchies. It is therefore concluded that the
queen never loses dominance completely. 相似文献
5.
Demonstration of auto-anti-idiotypic antibody cross-reacting with public idiotypic determinants in the serum of rye-sensitive allergic patients 总被引:5,自引:0,他引:5
R Bose D G Marsh J Duchateau A H Sehon G Delespesse 《Journal of immunology (Baltimore, Md. : 1950)》1984,133(5):2474-2478
The present study documents the presence, in the serum of one allergic individual, of auto-anti-idiotypic antibodies cross-reacting with public idiotypic determinants expressed on human IgE and IgG anti-Rye I antibodies. Sera from rye-sensitive patients were tested for specific IgG and IgE antibodies to Rye I by double antibody. The IgG fraction, isolated from the serum of a patient with a history of previous hyposensitization therapy, was repeatedly absorbed on Rye-I-Sepharose as well as on IgM- and IgG-Sepharose to remove anti-Rye I antibodies as well as any possible anti-heavy or light chain activity. This IgG fraction, named anti-idiotypic fraction (a-IdF), blocked in a dose-dependent fashion the reaction of IgG and IgE anti-Rye I antibodies with Rye I antigen. The a-IdF also blocked the binding of anti-rye antibodies to Rye I antigen in the serum of 20 unrelated allergic patients, indicating that these anti-Rye I antibodies bore public idiotypic determinants. 相似文献
6.
Bacterial populations in different parts of the rhizosphere of rice and banana in Sri lanka were examined. On rice, the number of aerobic bacteria and the population of fluorescent bacteria were higher in the rhizoplane as compared to the exorhizosphere. However, the opposite was observed with banana. Percentage of fluorescent bacteria was significantly higher on banana (10.8%) than on rice from the wet and dry zones of Sri Lanka (4.3% and 2.7%, respectively). In the endorhizosphere fraction of rice, bacterial populations were very low. Fluorescent bacteria were absent.Based on 33 phenotypical tests, 89 fluorescent isolates were grouped into 5 clusters. The three major clusters covered the isolates belonging to the Pseudomonas fluorescens-putida group, whereas the remaining small clusters contained other UV-fluorescent bacteria. SDS-PAGE of total cell proteins enabled classification of the isolates into one of 12 different protein-polymorphic types. Only a partial correlation was found between the latter classification and the phenotypical one. Cyanogenesis was observed with strains of P. fluorescens only. Isolates P. fluorescens RW9S1 and P. cepacia RW5P1 displayed a potent antagonism against several fungi. 相似文献
7.
Stephen GS Vreden Jeetendra K Jitan Rakesh D Bansie Malti R Adhin 《Memórias do Instituto Oswaldo Cruz》2013,108(8):968-973
The emerging resistance to artemisinin derivatives that has been reported in
South-East Asia led us to assess the efficacy of artemether-lumefantrine as the first
line therapy for uncomplicated Plasmodium falciparum infections in
Suriname. This drug assessment was performed according to the recommendations of the
World Health Organization in 2011. The decreasing number of malaria cases in
Suriname, which are currently limited to migrating populations and gold miners,
precludes any conclusions on artemether efficacy because adequate numbers of patients
with 28-day follow-up data are difficult to obtain. Therefore, a comparison of day 3
parasitaemia in a 2011 study and in a 2005/2006 study was used to detect the
emergence of resistance to artemether. The prevalence of day 3 parasitaemia was
assessed in a study in 2011 and was compared to that in a study in 2005/2006. The
same protocol was used in both studies and artemether-lumefantrine was the study
drug. Of 48 evaluable patients in 2011, 15 (31%) still had parasitaemia on day 3
compared to one (2%) out of 45 evaluable patients in 2005/2006. Overall, 11 evaluable
patients in the 2011 study who were followed up until day 28 had negative slides and
similar findings were obtained in all 38 evaluable patients in the 2005/2006 study.
The significantly increased incidence of parasite persistence on day 3 may be an
indication of emerging resistance to artemether. 相似文献
8.
Apoptosis in the canine endometrium during the estrous cycle 总被引:1,自引:0,他引:1
Apoptotic cell death in the endometria of 58 female dogs in different stages of the estrous cycle was assessed (in formalin-fixed, paraffin-embedded sections) with both the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay and immunohistochemical detection of caspase-3 activity. For both techniques, the apoptotic index was determined in the surface epithelium, stroma, crypts, and basal glands by counting the percentage of stained cells in a total of 500 cells in each category. In the surface epithelium and stroma, TUNEL- and caspase-3-positive cells were rare (apoptotic index<1) throughout the estrous cycle. However, caspase-3 detection showed a significant increase in the apoptotic index in the stroma during anestrus as well as an increase in the index in both the stroma and surface epithelium in late metestrus. The apoptotic index increased during late metestrus and anestrus in the crypts and basal glands; in the crypts, this increase was significant only when caspase-3 detection was used, whereas in basal glands, significant differences were found for both techniques. In conclusion, apoptosis was present in canine endometrial cells during the estrous cycle, but caspase-3 detection showed more significant differences than the TUNEL assay. Furthermore, a high apoptotic index (suggestive of endometrial desquamation) was not detected in the surface epithelium and there was no significant correlation between the apoptotic index in any cell group and serum progesterone concentrations. 相似文献
9.
Analysis of hABC1 gene 5' end: additional peptide sequence, promoter region, and four polymorphisms 总被引:3,自引:0,他引:3
Pullinger CR Hakamata H Duchateau PN Eng C Aouizerat BE Cho MH Fielding CJ Kane JP 《Biochemical and biophysical research communications》2000,271(2):451-455
Evidence linking mutations in ATP-binding-cassette transporter gene 1 (ABC1) to Tangier disease suggests it functions in the active transport of free cholesterol out of cells. Since its mRNA level is regulated in response to cellular cholesterol stores it is of interest to explore its promoter response elements, and to investigate polymorphisms for their contributions to the prevalence of low levels of HDL in the population that promotes premature coronary heart disease. Investigation of the 5' end of the gene by 5' RACE analysis revealed 455 nucleotides additional to published sequences, and predicts another 60 amino acid N-terminal residues, resulting in a 2261-residue protein. Protein sequence analysis predicts a membrane-spanning region and possible signal peptide. The 5' flanking region was located by a Human Research Project BLAST search. This region contains regulatory elements that potentially control ABC1 gene expression. In addition to numerous SP1 binding sites there are four putative sterol regulatory elements (SREs). Our studies uncovered three single nucleotide substitution polymorphisms, one in the promoter region and two in the 5' untranslated region (5'UTR), plus an insertion/deletion polymorphism. 相似文献
10.
A Simple 13C NMR Method for the Discrimination of Complex Mixtures of Stereoisomers: All Eight Stereoisomers of α‐Tocopherol Resolved
下载免费PDF全文
![点击此处可从《Chirality》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A simple one‐dimensional 13C NMR method is presented to discriminate between stereoisomers of organic compounds with more than one chiral center. By means of this method it is possible to discriminate between all eight stereoisomers of α‐tocopherol. To achieve this the chiral solvating agent (S)‐(+)‐1‐(9‐anthryl)‐2,2,2‐trifluoroethanol and the compound of interest were dissolved in high concentrations in chloroform‐d, and the nuclear magnetic resonance (NMR) spectrum was recorded at a low temperature. The individual stereoisomers of α‐tocopherol were assigned by spikes of the reference compounds. The method was also applied to six other representative examples. Chirality 27:850–855, 2015. © 2015 Wiley Periodicals, Inc. 相似文献