全文获取类型
收费全文 | 417篇 |
免费 | 32篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 13篇 |
2018年 | 13篇 |
2017年 | 10篇 |
2016年 | 20篇 |
2015年 | 20篇 |
2014年 | 17篇 |
2013年 | 22篇 |
2012年 | 27篇 |
2011年 | 27篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 5篇 |
2007年 | 16篇 |
2006年 | 13篇 |
2005年 | 13篇 |
2004年 | 9篇 |
2003年 | 14篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1973年 | 6篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1966年 | 4篇 |
1964年 | 2篇 |
1962年 | 2篇 |
1961年 | 2篇 |
1960年 | 3篇 |
排序方式: 共有449条查询结果,搜索用时 15 毫秒
71.
The ldh phylogeny for environmental isolates of Lactococcus lactis is consistent with rRNA genotypes but not with phenotypes.
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lactate dehydrogenase (ldh) gene sequences, levels of 16S rRNA group-specific probe binding, and phenotypic characteristics were compared for 45 environmental isolates and four commercial starter strains of Lactococcus lactis to identify evolutionary groups best suited to cheddar cheese manufacture, ldh sequences from the environmental isolates showed high similarity to those from two groups of L. lactis used for industrial fermentations, L. lactis subsp. cremoris and subsp. lactis. Within each phylogenetically defined subspecies, ldh sequence similarities were greater than 99.1%. Strains with phenotypic traits formerly diagnostic for both subspecies were found in each ldh similarity group, but only strains belonging to L. lactis subsp. cremoris by both the newer, genetic and the older, superseded phenotypic criteria were judged potentially suitable for the commercial production of cheddar cheese. Identical evolutionary relationships were inferred from ldh sequences and from binding of subspecies-specific, 16S rRNA-directed oligonucleotide probes. However, groups defined according to these chromosomal traits bore no relationship to patterns of arginine deamination, carbon substrate utilization, or bacteriophage sensitivity, which may be encoded by cryptic genes or sexually transmissible genetic elements. Fourteen new L. lactis subsp. cremoris isolates were identified as suitable candidates for cheddar cheese manufacture, and 10 of these were completely resistant to three different batteries of commercial bacteriophages known to reduce starter activity. 相似文献
72.
N. Swierkowski-Blanchard L. Alter S. Salama C. Muratorio M. Bergere M. Jaoul F. Vialard M. Bailly J. Selva F. Boitrelle 《Andrologie》2016,26(1):12
Background
According to our literature analysis, there are no data focused on spermatozoa emotional representations in childless men and data on the emotional repercussions of a diagnosis of infertility on men are still scarce. Thus, in this work, we investigated what the presence or absence of spermatozoa in the semen symbolize for men.Material and methods
To answer this question, 441 childless heterosexual men participated in an anonymous, prospective, Internet-based survey.Results
In response to the question “What would having a high or normal sperm count symbolize for you?” the most frequent answer was “ability to father a child”. Men living with a partner were significantly more likely than single men to answer “ability to father a child” (p?<?0.05) and less likely to answer “virility” and/or “ability to have an erection/ejaculation” (p?=?0.001). In response to the question “If you found out that you had a low sperm count or no spermatozoa at all, how would you feel?”, most of the men stated that they would be disappointed. Men living with a partner were more likely to state that they would feel ashamed (p?<?0.05) or guilty with regard to their partner (p?<?0.0001).Conclusions
These preliminary results should help us to improve (i) the way that male infertility is announced (it is easier to find the right words if one understands the possible importance of having a high sperm count) and (ii) the psychological, marital and sexual counselling provided to men with a diagnosis of infertility.73.
74.
Mohamed T. El-Saadony Ahmed M. Saad Taha F. Taha Azhar A. Najjar Nidal M. Zabermawi Maha M. Nader Synan F. AbuQamar Khaled A. El-Tarabily Ali Salama 《Saudi Journal of Biological Sciences》2021,28(12):6782-6794
The current study was performed to develop a simple, safe, and cost-effective technique for the biosynthesis of selenium nanoparticles (SeNPs) from lactic acid bacteria (LAB) isolated from human breast milk with antifungal activity against animal pathogenic fungi. The LAB was selected based on their speed of transforming sodium selenite (Na2SeO3) to SeNPs. Out of the four identified LAB isolates, only one strain produced dark red color within 32 h of incubation, indicating that this isolate was the fastest in transforming Na2SeO3 to SeNPs; and was chosen for the biosynthesis of LAB-SeNPs. The superior isolate was further identified as Lactobacillus paracasei HM1 (MW390875) based on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and phylogenetic tree analysis of 16S rRNA sequence alignments. The optimum experimental conditions for the biosynthesis of SeNPs by L. paracasei HM1 were found to be pH (6.0), temperature (35˚C), Na2SeO3 (4.0 mM), reaction time (32 h), and agitation speed (160 rpm). The ultraviolet absorbance of L. paracasei-SeNPs was detected at 300 nm, and the transmission electron microscopy (TEM) captured a diameter range between 3.0 and 50.0 nm. The energy-dispersive X-ray spectroscopy (EDX) and the Fourier-transform infrared spectroscopy (FTIR) provided a clear image of the active groups associated with the stability of L. paracasei-SeNPs. The size of L. paracasei-SeNPs using dynamic light scattering technique was 56.91 ± 1.8 nm, and zeta potential value was −20.1 ± 0.6 mV in one peak. The data also revealed that L. paracasei-SeNPs effectively inhibited the growth of Candida and Fusarium species, and this was further confirmed by scanning electron microscopy (SEM). The current study concluded that the SeNPs obtained from L. paracasei HM1 could be used to prepare biological antifungal formulations effective against major animal pathogenic fungi. The antifungal activity of the biologically synthesized SeNPs using L. paracasei HM1 outperforms the chemically produced SeNPs. In vivo studies showing the antagonistic effect of SeNPs on pathogenic fungi are underway to demonstrate the potential of a therapeutic agent to treat animals against major infectious fungal diseases. 相似文献
75.
Rita Papp Glenna C. L. Bett Agnieszka Lis Randall L. Rasmusson István Baczkó András Varró Guy Salama 《Biology of sex differences》2017,8(1):26
Background
Women have a higher risk of lethal arrhythmias than men in long QT syndrome type 2 (LQTS2), but the mechanisms remain uncertain due to the limited availability of healthy control human tissue. We have previously reported that in female rabbits, estrogen increases arrhythmia risk in drug-induced LQTS2 by upregulating L-type Ca2+ (ICa,L) and sodium-calcium exchange (INCX) currents at the base of the epicardium by a genomic mechanism. This study investigates if the effects of estrogen on rabbit ICa,L and INCX apply to human hearts.Methods
Postmortem human left ventricular tissue samples were probed with selective antibodies for regional heterogeneities of ion channel protein expression and compared to rabbit myocardium. Functionally, ICa,L and INCX were measured from female and male cardiomyocytes derived from human induced pluripotent stem cells (iPS-CMs) with the voltage-clamp technique from control and estrogen-treated iPS-CMs.Results
In women (n = 12), Cav1.2α (primary subunit of the L-type calcium channel protein 1) and NCX1 (sodium-calcium exchange protein) levels were higher at the base than apex of the epicardium (40 ± 14 and 81 ± 30%, respectively, P < 0.05), but not in men (n = 6) or postmenopausal women (n = 6). Similarly, in cardiomyocytes derived from female human iPS-CMs, estrogen (1 nM, 1–2 days) increased ICa,L (31%, P < 0.05) and INCX (7.5-fold, ??90 mV, P < 0.01) and their mRNA levels (P < 0.05). Moreover, in male human iPS-CMs, estrogen failed to alter ICa,L and INCX.Conclusions
The results show that estrogen upregulates cardiac ICa,L and INCX in women through genomic mechanisms that account for sex differences in Ca2+ handling and spatial heterogeneities of repolarization due to base-apex heterogeneities of Cav1.2α and NCX1. By analogy with rabbit studies, these effects account for human sex-difference in arrhythmia risk.76.
Dilutable nanoemulsions are potent drug delivery vehicles for ophthalmic use due to their numerous advantages as sustained
effect and high ability of drug penetration into the deeper layers of the ocular structure and the aqueous humor. The aim
of this article was to formulate the antiglaucoma drug dorzolamide hydrochloride as ocular nanoemulsion of high therapeutic
efficacy and prolonged effect. Thirty-six systems consisting of different oils, surfactants, and cosurfactants were prepared
and their pseudoternary-phase diagrams were constructed by water titration method. Seventeen dorzolamide hydrochloride nanoemulsions
were prepared and evaluated for their physicochemical and drug release properties. These nanoemulsions showed acceptable physicochemical
properties and exhibited slow drug release. Draize rabbit eye irritation test and histological examination were carried out
for those preparations exhibiting superior properties and revealed that they were nonirritant. Biological evaluation of dorzolamide
hydrochloride nanoemulsions on normotensive albino rabbits indicated that these products had higher therapeutic efficacy,
faster onset of action, and prolonged effect relative to either drug solution or the market product. Formulation of dorzolamide
hydrochloride in a nanoemulsion form offers, thus, a more intensive treatment of glaucoma, a decrease in the number of applications
per day, and a better patient compliance compared to conventional eye drops. 相似文献
77.
Shaleen K Botting Hala Fouad Kyler Elwell Bill A Rampy Salama A Salama Daniel H Freeman Concepcion R Diaz-Arrastia 《Translational oncology》2010,3(3):170-175
Cervical cancer is known to metastasize primarily by the lymphatic system. Dissemination through lymphatic vessels represents an early step in regional tumor progression, and the presence of lymphatic metastasis is associated with a poor prognosis. In patients who have undergone a radical hysterectomy, lymphovascular space invasion (LVSI), assessed on hematoxylin and eosin-stained slides, is a major factor for adjuvant therapy in patients with cervical cancer. With the advent of a lymphatic endothelial cell-specific marker, such as D2-40, it is now possible to distinguish between blood and lymphatic space invasion (LSI). In this study, the utility of D2-40 was assessed for the detection of lymphatic vessel density (LVD) and identification of LSI. The expressions of vascular endothelial growth factor receptor-3 (VEGFR-3), VEGF-C, tyrosine receptor kinase-2, and angiopoietin-1 were assessed by immunohistochemical methods on 50 patients with squamous cell carcinoma of the cervix. Clinicopathologic characteristics, including pelvic lymph node metastasis, were correlated with the above histochemical findings. We found that lymphangiogenesis, measured by an increase in peritumoral LVD, was significantly associated with positive lymph node status (P < .005). VEGFR-3 expression was significantly associated with LVD (P < .05). D2-40 staining verified LSI (P = .03) and surpassed that of hematoxylin and eosin-identified LVSI (P = .54). In conclusion, lymphangiogenic markers, specifically LVD quantified by D2-40 and VEGFR-3, are independently associated with LSI and lymph node metastasis in patients with early squamous cell carcinoma of the cervix treated with radical hysterectomy and pelvic lymphadenectomy. 相似文献
78.
Specific inherent optical properties (SIOP) of the Berau coastal waters were derived from in situ measurements and inversion
of an ocean color model. Field measurements of water-leaving reflectance, total suspended matter (TSM), and chlorophyll a (Chl a) concentrations were carried out during the 2007 dry season. The highest values for SIOP were found in the turbid waters,
decreasing in value when moving toward offshore waters. The specific backscattering coefficient of TSM varied by an order
of magnitude and ranged from 0.003 m2 g−1, for clear open ocean waters, to 0.020 m2 g−1, for turbid waters. On the other hand, the specific absorption coefficient of Chl a was relatively constant over the whole study area and ranged from 0.022 m2 mg−1, for the turbid shallow estuary waters, to 0.027 m2 mg−1, for deeper shelf edge ocean waters. The spectral slope of colored dissolved organic matter light absorption was also derived
with values ranging from 0.015 to 0.011 nm−1. These original derived values of SIOP in the Berau estuary form a corner stone for future estimation of TSM and Chl a concentration from remote sensing data in tropical equatorial waters. 相似文献
79.
Mohammed Abu El-Magd Ayman A. Saleh Reda M. Abd El-Aziz Mohammed F. Salama 《Development genes and evolution》2014,224(4-6):245-253
Expression of chick early B cell factor 1-3 (cEbf1-3) genes in regions of high retinoic acid (RA) activity, such as somites and pharyngeal arches (PAs), and regulation of other EBF members by RA raise the possibility that the internal cue RA may regulate cEbf1-3 expression in these tissues. To check this possibility, RA gain and loss of function experiments were conducted. Ectopic expression of RA led to up-regulation of cEbf2, 3 but did not change cEbf1 expression in somites. Expectedly, inhibition of RA by disulfiram resulted in downregulation of cEbf2, 3, but did not change cEbf1 expression in somites. The same RA gain and loss of function experiments did not change cEbf1-3 expression in PAs. However, ectopic expression of RA in the cranial neural tube before migration of neural crest cells downregulated cEbf1, 3 and up-regulated cEbf2 expression in the PAs. The same experiment, but with application of disulfiram, resulted in downregulation of cEbf2, but did not alter the expression of the other two genes. We conclude that the three cEbf genes act differently in response to RA signals in somitic mesoderm. cEbf1 may be not RA dependant in somites; however, the other two cEbf genes positively respond to RA signalling in somites. Additionally, only the migratory cEbf-expressing cells into the PAs are affected by RA signals. 相似文献
80.