全文获取类型
收费全文 | 1339篇 |
免费 | 61篇 |
国内免费 | 1篇 |
出版年
2023年 | 8篇 |
2022年 | 19篇 |
2021年 | 45篇 |
2020年 | 22篇 |
2019年 | 23篇 |
2018年 | 26篇 |
2017年 | 23篇 |
2016年 | 36篇 |
2015年 | 76篇 |
2014年 | 83篇 |
2013年 | 99篇 |
2012年 | 105篇 |
2011年 | 139篇 |
2010年 | 81篇 |
2009年 | 64篇 |
2008年 | 91篇 |
2007年 | 96篇 |
2006年 | 68篇 |
2005年 | 48篇 |
2004年 | 48篇 |
2003年 | 52篇 |
2002年 | 30篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 14篇 |
1998年 | 9篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 10篇 |
排序方式: 共有1401条查询结果,搜索用时 15 毫秒
101.
Developments in insect transgenesis using transposons combined with available mass rearing technology for insects such as
the Medfly, Ceratitis capitata, provide opportunity for the production of protein for industrial, agricultural and healthcare purposes on a very large scale.
In this study, we report the germ-line transformation and expression of a cDNA encoding human growth hormone (hGH) in transgenic
Drosophila using the Minos transposon. Production and secretion of a bioactive hGH into the haemolymph of transgenic larvae was demonstrated by immunoblot
analysis, ELISA and a proliferation bioassay. Stable expression of hGH was observed over 50 generations. The results indicate
that mass reared transgenic diptera with a rapid period of larval growth could provide cost effective production systems for
the manufacture of therapeutic and other high value proteins. 相似文献
102.
Radioiodination of new EGFR inhibitors as potential SPECT agents for molecular imaging of breast cancer 总被引:1,自引:0,他引:1
Fernandes C Oliveira C Gano L Bourkoula A Pirmettis I Santos I 《Bioorganic & medicinal chemistry》2007,15(12):3974-3980
In our search for the development of novel SPECT radioligands for EGFR positive tumours, new potentially irreversible tyrosine kinase (TK) inhibitors are being explored. The radioiodination of N-{4-[(3-chloro-4-fluorophenyl) amino]quinazoline-6-yl}-3-bromopropionamide, a novel EGFR-TK inhibitor synthesised in our laboratory, was accomplished via halogen exchange. Purification by RP-HPLC gave [125I]-N-{4-[(3-chloro-4-fluorophenyl)amino]quinazoline-6-yl}-3-iodopropionamide with a radiochemical purity higher than 95% and a high specific activity. In vitro studies indicate that both iodinated quinazoline and its bromo precursor inhibit A431 cell growth and also possess higher potency than the parent quinazoline to inhibit the EGFR autophosphorylation. In vivo stability studies suggest metabolization of the radioiodinated quinazoline indicating a short biological half-life. The in vitro results point out that these quinazoline derivatives could be promising candidates for SPECT imaging of EGFR positive tumours provided that they are selectively modified in order to achieve better in vivo radiochemical stability. 相似文献
103.
Extracellular matrix: from atomic resolution to ultrastructure 总被引:1,自引:0,他引:1
The extracellular matrix (ECM) is a highly organized multimolecular structure, essential for life in higher organisms. Although substantial high-resolution structural information is available for relatively small fragments of ECM components, the inherent difficulty in preparing and analyzing samples of large, fibrous polymers impedes structural efforts. Here, we review recent advances in understanding the structure of three important ECM components: collagen, fibrillin and fibronectin. Emphasis is placed on the key role of intermolecular interactions in assembling larger, microm scale, structures. 相似文献
104.
Valakos ED Kourkouli A Skopeliti M Pafilis P Poulakakis N Voutsas IF Lymberakis P Simou C Voelter W Tsitsilonis OE 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2007,147(1):1-10
Most recent molecular studies revealed the phylogeny of Greek Podarcis species, which for years remained elusive, due to discordant data produced from various chromosomal, complement fixation and protein studies. In this report, we analyzed cellular immune responses of spleen-derived lymphocytes from six allopatric Podarcis species encountered in Greece, by assessing two-way mixed lymphocyte reaction (MLR)-induced proliferation. On the basis of stimulation indices (S.I.) as determined from cultures set up from xenogeneic splenocytes coincubated in pairs, we generated a phylogenetic tree, fully consistent with the phylogenetic relationships of Podarcis as determined by parallel analyses based on partial mitochondrial (mt) DNA sequences. Although the exact mechanisms triggering lymphocyte responses in lizard two-way xenogeneic MLR are not fully understood, our results show the potential use of cell-mediated immune responses as an additional approach to mtDNA analysis, for species delimitation within specific lizard taxa. 相似文献
105.
Orchard S Salwinski L Kerrien S Montecchi-Palazzi L Oesterheld M Stümpflen V Ceol A Chatr-aryamontri A Armstrong J Woollard P Salama JJ Moore S Wojcik J Bader GD Vidal M Cusick ME Gerstein M Gavin AC Superti-Furga G Greenblatt J Bader J Uetz P Tyers M Legrain P Fields S Mulder N Gilson M Niepmann M Burgoon L De Las Rivas J Prieto C Perreau VM Hogue C Mewes HW Apweiler R Xenarios I Eisenberg D Cesareni G Hermjakob H 《Nature biotechnology》2007,25(8):894-898
A wealth of molecular interaction data is available in the literature, ranging from large-scale datasets to a single interaction confirmed by several different techniques. These data are all too often reported either as free text or in tables of variable format, and are often missing key pieces of information essential for a full understanding of the experiment. Here we propose MIMIx, the minimum information required for reporting a molecular interaction experiment. Adherence to these reporting guidelines will result in publications of increased clarity and usefulness to the scientific community and will support the rapid, systematic capture of molecular interaction data in public databases, thereby improving access to valuable interaction data. 相似文献
106.
Vamvakoudis E Vrabas IS Galazoulas C Stefanidis P Metaxas TI Mandroukas K 《Journal of strength and conditioning research / National Strength & Conditioning Association》2007,21(3):930-936
The purpose of this study was to examine the effects of prolonged basketball skills training on maximal aerobic power, isokinetic strength, joint mobility, and body fat percentage, in young basketball players, and controls of the same age. Twenty basketball players and 18 control boys participated in the study. Basketball players participated both in their school's physical education program and in a children's basketball team training program. Controls participated only in their school's physical education program. All subjects were tested every 6 months (18 months total, 11(1/2), 12, 12(1/2), 13 years old) for VO(2)max, peak torque values of the quadriceps and hamstrings at 180 and 300 degrees x s(-1) and range of motion of the knee and hip joints. Body fat percentage was assessed at the beginning and the end of the experimental period. Results showed that the basketball group had lower heart rate values in all ages and higher VO(2) values in the initial test compared with the control in submaximal intensity. The VO(2)max was altered in both groups on the final test, when compared to the initial test. However, the basketball group had a higher VO(2)max on each of the 6-month follow-up measurements, compared to the control group (p < 0.001). At the end of the 18-month follow-up period no significant differences were observed in isokinetic strength and joint mobility of the lower limbs between the 2 groups. On the contrary, the boys of the trained group had significantly lower percentage body fat values, compared to controls. In conclusion, regular basketball training increased aerobic power and decreased body fat percentage of prepubescent boys, while it did not affect muscle strength and joint mobility of the lower limbs. The major implication suggested by the findings of the present study is that, in order to improve the basic physical components, specific training procedures should be incorporated during the basketball training sessions. It is recommended that all children should be involved in some type of cardiovascular and resistance training program. 相似文献
107.
Oxidative stress biomarkers responses to physical overtraining: implications for diagnosis 总被引:1,自引:0,他引:1
Margonis K Fatouros IG Jamurtas AZ Nikolaidis MG Douroudos I Chatzinikolaou A Mitrakou A Mastorakos G Papassotiriou I Taxildaris K Kouretas D 《Free radical biology & medicine》2007,43(6):901-910
Overtraining syndrome is characterized by declining performance and transient inflammation following periods of severe training with major health implications for the athletes. Currently, there is no single diagnostic marker for overtraining. The present investigation examined the responses of oxidative stress biomarkers to a resistance training protocol of progressively increased and decreased volume/intensity. Twelve males (21.3+/-2.3 years) participated in a 12-week resistance training consisting of five 3-week periods (T1, 2 tones/week; T2, 8 tones/week; T3, 14 tones/week; T4, 2 tones/week), followed by a 3-week period of complete rest. Blood/urine samples were collected at baseline and 96 h following the last training session of each period. Performance (strength, power, jumping ability) increased after T2 and declined thereafter, indicating an overtraining response. Overtraining (T3) induced sustained leukocytosis, an increase of urinary isoprostanes (7-fold), TBARS (56%), protein carbonyls (73%), catalase (96%), glutathione peroxidase, and oxidized glutathione (GSSG) (25%) and a decline of reduced glutathione (GSH) (31%), GSH/GSSG (56%), and total antioxidant capacity. Isoprostanes and GSH/GSSG were highly (r=0.764-0.911) correlated with performance drop and training volume increase. In conclusion, overtraining induces a marked response of oxidative stress biomarkers which, in some cases, was proportional to training load, suggesting that they may serve as a tool for overtraining diagnosis. 相似文献
108.
Little SJ Lynch MA Manku M Nicolaou A 《Prostaglandins, leukotrienes, and essential fatty acids》2007,77(3-4):155-162
The age-related decline in cognitive function has been associated with biochemical changes that can be attenuated following n-3 polyunsaturated fatty acid treatment. Dietary supplementation with docosahexaenoic acid (DHA) has been shown to reverse age-related changes in synaptic function. Here, lipidomic analyses were undertaken to examine changes in lipid classes and phospholipid species in cortical tissue of young (2-4 months) and aged (20-22 months), control- and DHA-treated (10mg daily) rats following treatment for 8 weeks, aiming to explore the mechanism of DHA action. Dietary supplementation normalised the age-related decrease in unsaturation index, reduced the levels of arachidonic acid-containing phospholipids in both young and aged animals, and gave rise to production of new phosphatidylserine and phosphatidylinositol species. These findings suggest that DHA may mediate some of its effects through alterations in the membrane lipid composition that can consequently affect the production of pro-inflammatory mediators and signalling molecular species. 相似文献
109.
Encapsulation and exfoliation of inorganic lamellar fillers into polycaprolactone by electrospinning
The present paper reports, for the first time, the successful fabrication of layered double hydroxide (Mg-Al LDH)-reinforced polycaprolactone (PCL) nanofibers by electrospinning. Either the LDH in carbonate form or an LDH organically modified with 12-hydroxydodecanoic acid (LDH-HA) were incorporated into PCL and electrospun using a voltage of 20 KV. The LDH-HA was prepared by an ionic exchange reaction from pristine LDH and encapsulated into PCL from acetone solutions at 15 wt %. The morphological analysis showed pure PCL fibers with an average diameter of 600 +/- 50 nm, and this dimension was maintained in the fibers with LDH, with the inorganic component residing outside the fibers and not exfoliated. At variance, the fibers with the LDH-HA showed a significantly lower average diameter in the range of 350 +/- 50 nm, indicating the improved electrospinnability of PCL. Moreover, the inorganic lamellae were exfoliated, as shown by X-rays and residing inside the nanofibers as demonstrated by energy dispersive X-ray spectroscopy analysis. The structural parameters, such as degradation temperature and crystallinity, were investigated for all the samples and correlated with the electrospinning process. 相似文献
110.