全文获取类型
收费全文 | 1428篇 |
免费 | 59篇 |
国内免费 | 2篇 |
专业分类
1489篇 |
出版年
2024年 | 3篇 |
2023年 | 15篇 |
2022年 | 47篇 |
2021年 | 81篇 |
2020年 | 47篇 |
2019年 | 57篇 |
2018年 | 62篇 |
2017年 | 57篇 |
2016年 | 88篇 |
2015年 | 114篇 |
2014年 | 107篇 |
2013年 | 159篇 |
2012年 | 133篇 |
2011年 | 120篇 |
2010年 | 62篇 |
2009年 | 53篇 |
2008年 | 43篇 |
2007年 | 42篇 |
2006年 | 35篇 |
2005年 | 36篇 |
2004年 | 25篇 |
2003年 | 23篇 |
2002年 | 14篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1967年 | 1篇 |
排序方式: 共有1489条查询结果,搜索用时 15 毫秒
991.
Temporality among episodes of a prostaglandin F2alpha metabolite (PGFM), progesterone (P4), luteinizing hormone (LH), and estradiol (E2) were studied during preluteolysis and luteolysis. A vehicle group (n = 10) and a group with an E2-induced PGFM pulse (n = 10) were used. Blood sampling was done every 0.25 h for 8 h. An episode was identified by comparing its coefficient of variation (CV) with the intra-assay CV. Pulsatility of PGFM, P4, LH, and E2 in individual heifers was inferred if the autocorrelation functions were different (P < 0.05) from zero. About four nonrhythmic fluctuations of PGFM/8 h were superimposed on PGFM pulses. Pulsatility was detected for LH but not for P4 and E2. A transient increase in P4 was not detected during the ascending portion of a PGFM pulse. Progesterone decreased (P < 0.003) during Hours -1.25 to -0.50 of the PGFM pulse (Hour 0 = peak) and ceased to decrease temporally with an increase (P < 0.05) in LH. Maximum P4 concentration occurred 0.25 h after an LH pulse peak, and an increase (P < 0.005) in E2 began at the LH peak. Nadirs of LH pulses were greater (P < 0.05) and the nadir-to-nadir interval was shorter (P < 0.003) in the E2 group, which is consistent with reported characteristics during luteolysis. The results did not support the hypothesis of a transient P4 increase early in a PGFM pulse and indicated a balance between a luteolytic effect of PGF and a luteotropic effect of LH within the hours of a PGFM pulse. 相似文献
992.
Nur Izreena Ismail Khairul Najmi Muhammad Nawawi Deborah Chew Chia Hsin Kok Wei Hao Nik Ritza Kosai Nik Mahmood Gary Lee Chong Chearn Zhiqin Wong Azmi Mohd Tamil Hazel Joseph Raja Affendi Raja Ali 《Helicobacter》2023,28(6):e13017
Background
Despite multiple therapy regimens, the decline in the Helicobacter pylori eradication rate poses a significant challenge to the medical community. Adding Lactobacillus reuteri probiotic as an adjunct treatment has shown some promising results. This study aims to investigate the efficacy of Lactobacillus reuteri DSM 17648 in H. pylori eradication and its effect in ameliorating gastrointestinal symptoms and adverse treatment effects.Materials and Methods
This randomized, double-blinded, placebo-controlled trial involved treatment-naïve H. pylori-positive patients. Ninety patients received standard triple therapy for 2 weeks before receiving either a probiotic or placebo for 4 weeks. The posttreatment eradication rate was assessed via a 14C urea breath test in Week 8. The Gastrointestinal Symptom Rating Scale (GSRS) questionnaire and an interview on treatment adverse effects were conducted during this study.Results
The eradication rate was higher in the probiotic group than in the placebo group, with a 22.2% difference in the intention-to-treat analysis (91.1% vs. 68.9%; p = 0.007) and 24.3% difference in the per-protocol analysis (93.2% vs. 68.9%; p = 0.007). The probiotic group showed significant pre- to post-treatment reductions in indigestion, constipation, abdominal pain, and total GSRS scores. The probiotic group showed significantly greater reductions in GSRS scores than the placebo group: indigestion (4.34 ± 5.00 vs. 1.78 ± 5.64; p = 0.026), abdominal pain (2.64 ± 2.88 vs. 0.89 ± 3.11; p = 0.007), constipation (2.34 ± 3.91 vs. 0.64 ± 2.92; p = 0.023), and total score (12.41 ± 12.19 vs. 4.24 ± 13.72; p = 0.004). The probiotic group reported significantly fewer adverse headache (0% vs. 15.6%; p = 0.012) and abdominal pain (0% vs. 13.3%; p = 0.026) effects.Conclusions
There was a significant increase in H. pylori eradication rate and attenuation of symptoms and adverse treatment effects when L. reuteri was given as an adjunct treatment. 相似文献993.
The majority of people have back pain at some point in their lives and most are cured without any intervention. However, some patients develop chronic back pain and persistent disability. There is strong evidence that psychological factors significantly correlate with the development of chronic back pain. Back pain has also emerged as the strongest predictor of major depression. Assessing and treating patients in a manner that integrates psychosocial and biological aspects of care is the essence of excellent family medicine. This case illustrates the importance for primary care physicians of screening for depression and other psychosocial factors in assessing patients with persistent back pain. 相似文献
994.
995.
Seo PS Jeong JJ Zeng L Takoudis CG Quinn BJ Khan AA Hanada T Chishti AH 《Biochimica et biophysica acta》2009,1793(2):281-289
Direct physical linkage of MAGUKs to the actin cytoskeleton was first established by the interaction of erythrocyte p55 with the FERM domain of protein 4.1R. Subsequently, it was reported that p55 binds to a 51-amino acid peptide, encoded by exon 10, located within the FERM domain of protein 4.1R. In this study, we investigated the nature of the p55-FERM domain binding interface and show that p55 binds to a second 35-amino acid peptide, encoded by an alternatively spliced exon 5, located within the FERM domain of protein 4.1R. Competition and Surface Plasmon Resonance-binding measurements suggest that the peptides encoded by exons 5 and 10 bind to independent sites within the D5 domain of p55. Interestingly, the full length 135 kDa isoform of protein 4.1R containing both exons 5 and 10 was targeted exclusively to the plasma membrane of epithelial cells whereas the same isoform without exon 5 completely lost its membrane localization capacity. Together, these results indicate that p55 binds to two distinct sites within the FERM domain, and the alternatively spliced exon 5 is necessary for the membrane targeting of protein 4.1R in epithelial cells. Since sequences similar to the exon 5-peptide of protein 4.1R and D5 domain of p55 are conserved in many proteins, our findings suggest that a similar mechanism may govern the membrane targeting of other FERM domain containing proteins. 相似文献
996.
Muhamad Azhar Abd Wahid Megat Johari Megat Mohd Noor Masafumi Goto Norio Sugiura Nor’azizi Othman Zuriati Zakaria 《Bioscience, biotechnology, and biochemistry》2017,81(8):1642-1649
The natural coagulant Moringa oleifera lectin (MoL) as cationic protein is a promising candidate in coagulation process of water treatment plant. Introducing the gene encoding MoL into a host, Pichia pastoris, to secrete soluble recombinant protein is assessed in this study. Initial screening using PCR confirmed the insertion of MoL gene, and SDS-PAGE analysis detected the MoL protein at 8 kDa. Cultured optimization showed the highest MoL protein at 520 mg/L was observed at 28 °C for 144 h of culturing by induction in 1% methanol. Approximately, 0.40 mg/mL of recombinant MoL protein showed 95 ± 2% turbidity removal of 1% kaolin suspension. In 0.1% kaolin suspension, the concentration of MoL at 10 μg/mL exhibits the highest turbidity reduction at 68 ± 1%. Thus, recombinant MoL protein from P. pastoris is an effective coagulant for water treatment. 相似文献
997.
Saif Ahmad Inayat Saleem Fazli Arshad Jamal Mohd Iqbal Malik Zainul Abdin 《Journal of Plant Biology》2007,50(3):351-357
Field experiments were conducted to determine the interactive effect of sulfur (S) and nitrogen (N) applications on seed yield
fromPsoralea corylifolia L. Six treatments were tested: T1 = control (without manure and fertilizers), T2 = manure @ 9 kg plot-1 (10 t ha-1), T3 = S0 N20 Ko P40, T4 = S20 N20 K40 P40, T5 = S20+20 N20 K40 P40, and T6 = S20+20 N20+20 K40P40. Activities of nitrate reductase (NR) and ATP-sulfurylase in the leaves were measured at various phenological stages. These
two enzymes catalyze the rate-limiting steps in the respective assimilatory pathways for nitrate and sulfate. Enzyme activity
was strongly correlated with seed yield, with the greatest performance being achieved with treatment T5. This might be attributed to the optimization of leaf soluble protein and photosynthetic rate, both of which are influenced
by S and N assimilation. 相似文献
998.
Mohd. Azlan J 《Biodiversity and Conservation》2006,15(3):1013-1025
A comprehensive survey on large mammal diversity from a disturbed forest in Peninsular Malaysia has been carried out for over
a period of 21 months. A total of 24 camera traps which accumulated to 5972 trap days. A total of 33 species 27 genera and
15 families of mammals were recorded via camera trapping and observations. The use of camera traps provides detailed information
on diversity of some cryptic and secretive mammals. Secondary forest may support a wide diversity of mammals at a stable condition
where intrusion, excision and fragmentation are reduced or avoided. The threats to mammals in the study are also discussed. 相似文献
999.
Khan A Vaibhav K Javed H Moshahid Khan M Tabassum R Ahmed ME Srivastava P Khuwaja G Islam F Saeed Siddiqui M Shafi MM Islam F 《Molecular and cellular biochemistry》2012,369(1-2):55-65
Beta-amyloid (Aβ) peptides are considered to play a major role in the pathogenesis of Alzheimer's disease (AD) and compounds that can prevent pathways of Aβ-induced neurotoxicity may be potential therapeutic agents for treatment of AD. This study examined the hypothesis that thymoquinone (TQ) would reduce oxidative stress and mitochondrial dysfunction in differentiated pheochromocytoma (PC 12) cells exposed to Aβ fragment 25-35 (Aβ(25-35)). To test this hypothesis, Aβ was used to induce an in vitro model of AD in differentiated PC 12 cell line of rat. After 24?h of exposure with Aβ(25-35), a significant reduction in cell viability and mitochondrial membrane potential (MMP) was observed. In addition, a significant elevation in the TBARS content and nitric oxide (NO) and activity of acetylcholine esterase (AChE) was observed which was restored significantly by TQ pretreatment. Furthermore, TQ also ameliorated glutathione and its dependent enzymes (glutathione peroxidase, glutathione reductase) which were depleted by Aβ(25-35) in PC 12 cells. These results were supported by the immunocytochemical finding that has shown protection of cells by TQ from noxious effects of Aβ(25-35). These results indicate that TQ holds potential for neuroprotection and may be a promising approach for the treatment of neurodegenerative disorders including AD. 相似文献
1000.
Ahmed W Ajmal M Sadeque A Whittall RA Rafiq S Putt W Khawaja A Imtiaz F Ahmed N Azam M Humphries SE Qamar R 《Molecular biology reports》2012,39(7):7365-7372
The majority of patients with the autosomal dominant disorder familial hypercholesterolemia (FH) carry novel mutations in the low density lipoprotein receptor (LDLR) that is involved in cholesterol regulation. In different populations the spectrum of mutations identified is quite different and to date there have been only a few reports of the spectrum of mutations in FH patients from Pakistan. In order to identify the causative LDLR variants the gene was sequenced in a Pakistani FH family, while high resolution melting analysis followed by sequencing was performed in a panel of 27 unrelated sporadic hypercholesterolemia patients. In the family a novel missense variant (c.1916T > G, p.(V639G)) in exon 13 of LDLR was identified in the proband. The segregation of the identified nucleotide change in the family and carrier status screening in a group of 100 healthy subjects was done using restriction fragment length polymorphism analysis. All affected members of the FH family carried the variant and none of the non-affected members nor any of the healthy subjects. In one of the sporadic cases, two sequence changes were detected in exon 9, one of these was a recurrent missense variant (c.1211C > T; p.T404I), while the other was a novel substitution mutation (c.1214 A > C; N405T). In order to define the allelic status of this double heterozygous individual, PCR amplified fragments were cloned and sequenced, which identified that both changes occurred on the same allele. In silico tools (PolyPhen and SIFT) were used to predict the effect of the variants on the protein structure, which predicted both of these variants to have deleterious effect. These findings support the view that there will be a novel spectrum of mutations causing FH in patients with hypercholesterolaemia from Pakistan. 相似文献