全文获取类型
收费全文 | 1233篇 |
免费 | 62篇 |
国内免费 | 1篇 |
专业分类
1296篇 |
出版年
2024年 | 6篇 |
2023年 | 16篇 |
2022年 | 54篇 |
2021年 | 100篇 |
2020年 | 54篇 |
2019年 | 72篇 |
2018年 | 85篇 |
2017年 | 51篇 |
2016年 | 61篇 |
2015年 | 52篇 |
2014年 | 69篇 |
2013年 | 117篇 |
2012年 | 70篇 |
2011年 | 77篇 |
2010年 | 41篇 |
2009年 | 48篇 |
2008年 | 34篇 |
2007年 | 51篇 |
2006年 | 28篇 |
2005年 | 21篇 |
2004年 | 19篇 |
2003年 | 17篇 |
2002年 | 16篇 |
2001年 | 15篇 |
2000年 | 16篇 |
1999年 | 3篇 |
1997年 | 3篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1977年 | 2篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1968年 | 4篇 |
1962年 | 3篇 |
1956年 | 1篇 |
1948年 | 1篇 |
1940年 | 1篇 |
排序方式: 共有1296条查询结果,搜索用时 15 毫秒
381.
382.
Memy H. Hassan Mohamed Ghobara Gamil M. Abd‐Allah 《Journal of biochemical and molecular toxicology》2014,28(8):337-346
Doxorubicin‐induced renal toxicity overshadows its anticancer effectiveness. This study is aimed at assessing the possible modulator effects of meloxicam, a cyclooxigenase‐2 inhibitor, on doxorubicin‐induced nephrotoxicity in mice and exploring some of the modulator mechanisms. Forty male mice were divided for treatment, for 2 weeks, with saline, meloxicam (daily), doxorubicin (twice/week), or both meloxicam and doxorubicin. Doxorubicin induced a significant increase in relative kidney weight to body weight, kidney lipid perooxidation, plasma levels of interleukin‐6 and tumor necrosis factor‐α, kidney caspase‐3 activity, and kidney prostaglandin E2 (PGE2) content. Doxorubicin disturbed kidney histology, abrogated renal function tests (serum creatinine, uric acid, and blood urea nitrogen), induced a significant decrease in antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, and catalase) and reduced glutathione (GSH) content. The administration of meloxicam with doxorubicin mitigated all doxorubicin‐disturbed parameters. Meloxicam ameliorated doxorubicin‐induced renal injury via inhibition of inflammatory PGE2, inflammatory cytokines, caspase‐3 activity, antioxidant effect, and free radical scavenging activity. 相似文献
383.
J Lemke S von Karstedt M Abd El Hay A Conti F Arce A Montinaro K Papenfuss M A El-Bahrawy H Walczak 《Cell death and differentiation》2014,21(3):491-502
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in many cancer cells without causing toxicity in vivo. However, to date, TRAIL-receptor agonists have only shown limited therapeutic benefit in clinical trials. This can, most likely, be attributed to the fact that 50% of all cancer cell lines and most primary human cancers are TRAIL resistant. Consequently, future TRAIL-based therapies will require the addition of sensitizing agents that remove crucial blocks in the TRAIL apoptosis pathway. Here, we identify PIK-75, a small molecule inhibitor of the p110α isoform of phosphoinositide-3 kinase (PI3K), as an exceptionally potent TRAIL apoptosis sensitizer. Surprisingly, PI3K inhibition was not responsible for this activity. A kinome-wide in vitro screen revealed that PIK-75 strongly inhibits a panel of 27 kinases in addition to p110α. Within this panel, we identified cyclin-dependent kinase 9 (CDK9) as responsible for TRAIL resistance of cancer cells. Combination of CDK9 inhibition with TRAIL effectively induced apoptosis even in highly TRAIL-resistant cancer cells. Mechanistically, CDK9 inhibition resulted in downregulation of cellular FLICE-like inhibitory protein (cFlip) and Mcl-1 at both the mRNA and protein levels. Concomitant cFlip and Mcl-1 downregulation was required and sufficient for TRAIL sensitization by CDK9 inhibition. When evaluating cancer selectivity of TRAIL combined with SNS-032, the most selective and clinically used inhibitor of CDK9, we found that a panel of mostly TRAIL-resistant non-small cell lung cancer cell lines was readily killed, even at low concentrations of TRAIL. Primary human hepatocytes did not succumb to the same treatment regime, defining a therapeutic window. Importantly, TRAIL in combination with SNS-032 eradicated established, orthotopic lung cancer xenografts in vivo. Based on the high potency of CDK9 inhibition as a cancer cell-selective TRAIL-sensitizing strategy, we envisage the development of new, highly effective cancer therapies. 相似文献
384.
Background
Various proteins that display carbohydrate-binding activity in a Ca2+-dependent manner are classified into the C-type lectin family. They have one or two C-type carbohydrate-recognition domains (CRDs) composed of 110–130 amino acid residues in common. C-type lectins mediate cell adhesion, non-self recognition, and immuno-protection processes in immune responses and thus play significant roles in clearance of invaders, either as cell surface receptors for microbial carbohydrates or as soluble proteins existing in tissue fluids. The lectin of Spodoptera littoralis is still uncharacterized.Methodology
A single orf encoding a deduced polypeptide consisting of an 18-residue signal peptide and a 291-residue mature peptide, termed SpliLec, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using RACE-PCR. Sequence analyses of the data revealed that SpliLec consists of two CRDs. Short-form CRD1 and long-form CRD2 are stabilized by two and three highly conserved disulfide bonds, respectively. SpliLec shares homology with some dipteran lectins suggesting possible common ancestor. The purified SpliLec exhibited a 140-kDa molecular mass with a subunit molecular mass of 35 kDa. The hemagglutination assays of the SpliLec confirmed a thermally stable, multisugar-binding C-type lectin that binds different erythrocytes. The purified SpliLec agglutinated microorganisms and exhibited comparable antimicrobial activity against gram (+) and gram (−) bacteria too.Conclusions
Our results suggested an important role of the SpliLec gene in cell adhesion and non-self recognition. It may cooperate with other AMPs in clearance of invaders of Spodoptera littoralis. 相似文献385.
Asmaliza Abd Ghani Sae Adachi Hirokazu Shiga Tze Loon Neoh Shuji Adachi 《Bioscience, biotechnology, and biochemistry》2017,81(4):705-711
Encapsulating fish oil by spray drying with an adequate wall material was investigated to determine if stable powders containing emulsified fish-oil-droplets can be formed. In particular, the dextrose equivalent (DE) of maltodextrin (MD) affects the powder structure, surface-oil ratio, and oxidative stability of fish oil. The carrier solution was prepared using MD with different DEs (DE = 11, 19, and 25) and sodium caseinate as the wall material and the emulsifier, respectively. The percentage of microcapsules having a vacuole was 73, 39, and 38% for MD with DE = 11, 19, and 25, respectively. Peroxide values (PVs) were measured for the microcapsules incubated at 60 °C. The microcapsules prepared with MD of DE = 25 and 19 had lower PVs than those prepared with MD of DE = 11. The difference in PV can be ascribed to the difference in the surface-oil ratio of the spray-dried microcapsules. 相似文献
386.
Wajid Mumtaz Pham Lam Vuong Likun Xia Aamir Saeed Malik Rusdi Bin Abd Rashid 《Cognitive neurodynamics》2017,11(2):161-171
Screening alcohol use disorder (AUD) patients has been challenging due to the subjectivity involved in the process. Hence, robust and objective methods are needed to automate the screening of AUD patients. In this paper, a machine learning method is proposed that utilized resting-state electroencephalography (EEG)-derived features as input data to classify the AUD patients and healthy controls and to perform automatic screening of AUD patients. In this context, the EEG data were recorded during 5 min of eyes closed and 5 min of eyes open conditions. For this purpose, 30 AUD patients and 15 aged-matched healthy controls were recruited. After preprocessing the EEG data, EEG features such as inter-hemispheric coherences and spectral power for EEG delta, theta, alpha, beta and gamma bands were computed involving 19 scalp locations. The selection of most discriminant features was performed with a rank-based feature selection method assigning a weight value to each feature according to a criterion, i.e., receiver operating characteristics curve. For example, a feature with large weight was considered more relevant to the target labels than a feature with less weight. Therefore, a reduced set of most discriminant features was identified and further be utilized during classification of AUD patients and healthy controls. As results, the inter-hemispheric coherences between the brain regions were found significantly different between the study groups and provided high classification efficiency (Accuracy = 80.8, sensitivity = 82.5, and specificity = 80, F-Measure = 0.78). In addition, the power computed in different EEG bands were found significant and provided an overall classification efficiency as (Accuracy = 86.6, sensitivity = 95, specificity = 82.5, and F-Measure = 0.88). Further, the integration of these EEG feature resulted into even higher results (Accuracy = 89.3 %, sensitivity = 88.5 %, specificity = 91 %, and F-Measure = 0.90). Based on the results, it is concluded that the EEG data (integration of the theta, beta, and gamma power and inter-hemispheric coherence) could be utilized as objective markers to screen the AUD patients and healthy controls. 相似文献
387.
The potential of fine excipient materials to improve the performance of carrier-based dry powder inhalation mixtures is well acknowledged. The mechanisms underlying this potential are, however, open to question till date. Elaborate understanding of these mechanisms is a requisite for rational rather than empirical development of ternary dry powder inhalation mixtures. While effects of fine excipient materials on drug adhesion to and detachment from surfaces of carrier particle have been extensively investigated, effects on other processes, such as carrier–drug mixing, capsule/blister/device filling, or aerosolization in inhaler devices, have received little attention. We investigated the influence of fine excipient materials on the outcome of the carrier–drug mixing process. We studied the dispersibility of micronized fluticasone propionate particles after mixing with α-lactose monohydrate blends comprising different fine particle concentrations. Increasing the fine (D < 10.0 μm) excipient fraction from 1.84 to 8.70% v/v increased the respirable drug fraction in the excipient–drug mixture from 56.42 to 67.80% v/v (p < 0.05). The results suggest that low concentrations of fine excipient particles bind to active sites on and fill deep crevices in coarse carrier particles. As the concentration of fine excipient particles increases beyond that saturating active sites, they fill the spaces between and adhere to the surfaces of coarse carrier particles, creating projections and micropores. They thereby promote deagglomeration of drug particles during carrier–drug mixing. The findings pave the way for a comprehensive understanding of contributions of fine excipient materials to the performance of carrier-based dry powder inhalation mixtures. 相似文献
388.
A cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) technique has been developed for enantioseparation of vinpocetine using an inexpensive 2-hydroxypropyl-β-CD (HP-β-CD) as the chiral selector (CS). The best chiral separation was achieved using 40 mM HP-β-CD as the CS in 50 mM phosphate buffer (pH 7.0) consisting of 40 mM sodium dodecyl sulfate (SDS) at a separation temperature and separation voltage of 25°C and 25 kV, respectively. To the author's best knowledge, this is the first CD-MEKC study able to successfully separate the four stereoisomer of vinpocetine in separation time of 9.5 min and resolution of 1.04-3.87. 相似文献
389.
Elsaedany Samir Kamel AbdEllatif zein Mohamed AbdElRehim Elsayed Mohmoud Keshk Reda Mohammed 《Russian Journal of Bioorganic Chemistry》2021,47(2):552-560
Russian Journal of Bioorganic Chemistry - Novel derivatives of pyrido[2,3-d]pyrimidin-2,4(1H,3H)-dithione, 2,3-dimethylpyrido[2,3-d]pyrimidin-4-one, 4-chloro-2-methypyrido[2,3-d]pyrimidine and... 相似文献