全文获取类型
收费全文 | 1621篇 |
免费 | 97篇 |
国内免费 | 2篇 |
出版年
2023年 | 15篇 |
2022年 | 43篇 |
2021年 | 78篇 |
2020年 | 43篇 |
2019年 | 48篇 |
2018年 | 80篇 |
2017年 | 51篇 |
2016年 | 67篇 |
2015年 | 86篇 |
2014年 | 105篇 |
2013年 | 92篇 |
2012年 | 107篇 |
2011年 | 79篇 |
2010年 | 57篇 |
2009年 | 56篇 |
2008年 | 79篇 |
2007年 | 80篇 |
2006年 | 61篇 |
2005年 | 54篇 |
2004年 | 60篇 |
2003年 | 44篇 |
2002年 | 32篇 |
2001年 | 24篇 |
2000年 | 35篇 |
1999年 | 19篇 |
1998年 | 12篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 18篇 |
1991年 | 15篇 |
1990年 | 16篇 |
1989年 | 22篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1975年 | 6篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1965年 | 2篇 |
排序方式: 共有1720条查询结果,搜索用时 31 毫秒
101.
102.
Mominul Islam Nahid Frode Fossøy Bård G. Stokke Sajeda Begum Eivin Røskaft 《Bird Study》2019,66(1):141-144
House Crows Corvus splendens lay eggs with bluish-green ground colour and black or brown blotches and only one egg morph was believed to exist. Here, we confirm the existence of an immaculate, spotless blue egg morph that is clearly different from the regular egg morph. 相似文献
103.
Louaï Benseghir Halima Kadi‐Hanifi Nour El Islam Bachari 《African Journal of Ecology》2019,57(4):466-476
The main aim of this paper was to evaluate the use of OLI spectral data as a tool to assess the steppe vegetation in a conservation context. The field sampling was conducted for two specific areas of treatment (a) an exclosure area and (b) a free grazing area. After testing several vegetation indices (VIs), the optimal results were obtained for the Normalised Difference Vegetation Index (NDVI)‐based aboveground biomass model with r2 = 0.61 and r2 = 0.72 for total and perennial biomass, respectively. No difference between observed and predicted total and perennial biomass was found (p = 0.700 and p = 0.306, respectively). The comparison between the two treatments using the field sampling revealed a significant difference on total plant cover (p = 0.016) and total biomass (p = 0.005), with a plant cover of 50.6% and a biomass of 325.771 kg dry matter per hectare (kg DM ha?1) on average in grazed area and 66.9%, 1,407.869 kg DM ha?1 in exclosure. Finally, a concordance is noted between the results obtained by the NDVI‐based biomass model and the field sampling‐based biomass. 相似文献
104.
Kazeem O. Sulaiman Temitope U. Kolapo Abdulmujeeb T. Onawole Md. Ataul Islam Rukayat O. Adegoke Suaibu O. Badmus 《Journal of biomolecular structure & dynamics》2019,37(12):3029-3040
Ebola virus (EBOV) is a lethal human pathogen with a risk of global spread of its zoonotic infections, and Ebolavirus Zaire specifically has the highest fatality rate amongst other species. There is a need for continuous effort towards having therapies, as a single licensed treatment to neutralize the EBOV is yet to come into reality. This present study virtually screened the MCULE database containing almost 36 million compounds against the structure of a Zaire Ebola viral protein (VP) 35 and a consensus scoring of both MCULE and CLCDDW docking programs remarked five compounds as potential hits. These compounds, with binding energies ranging from –7.9 to –8.9?kcal/mol, were assessed for predictions of their physicochemical and bioactivity properties, as well as absorption, distribution, metabolism, excretion, and toxicity (ADMET) criteria. The results of the 50?ns molecular dynamics simulations showed the presence of dynamic stability between ligand and protein complexes, and the structures remained significantly unchanged at the ligand-binding site throughout the simulation period. Both docking analysis and molecular dynamics simulation studies suggested strong binding affinity towards the receptor cavity and these selected compounds as potential inhibitors against the Zaire Ebola VP 35. With respect to inhibition constant values, bioavailability radar and other physicochemical properties, compound A (MCULE-1018045960-0-1) appeared to be the most promising hit compound. However, the ligand efficiency and ligand efficiency scale need improvement during optimization, and also validation via in vitro and in vivo studies are necessary to finally make a lead compound in treating Ebola virus diseases.
Communicated by Ramaswamy H. Sarma 相似文献
105.
Yu Du PhD Jing Li MS Yuluan Hou MS Chanchan Chen PhD Weilin Long MS Hongwei Jiang PhD 《Journal of cellular biochemistry》2019,120(8):i-i
Circular RNAs (circRNAs) are novel noncoding RNAs and play crucial roles in various biological processes. However, little is known about the functions of circRNAs in osteogenic differentiation. The current study aimed to investigate the differential expression of circRNAs in rat dental follicle cells (rDFCs) during osteogenic differentiation, identified by RNA high-throughput sequencing and quantitative real-time polymerase chain reaction. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to further explore the biofunctions of circRNA biofunctions. Two hundred sixty-six differentially-expressed circRNAs that are involved in several important signaling pathways, including mitogen-activated protein kinases (MAPK) and transforming growth factor-β (TGF-β) signaling pathways were revealed. Among these, circFgfr2 and its predicted downstream targets, miR-133 and BMP6 (bone morphogenetic protein-6), were identified both in vivo and in vitro. For further validation, circFgfr2 was overexpressed in rDFCs, the results showed that the expression of miR-133 was downregulated and the expression of BMP6 was upregulated. Taken together, the results revealed the circRNA expression profiles and indicated the importance of circRNAs of rDFCs. In addition, circFgfr2 might promote osteogenesis by controlling miR-133/BMP6, which is a potential new target for the manipulation of tooth regeneration and bone formation. 相似文献
106.
107.
Mohd. Amir Vijay Kumar Taj Mohammad Ravins Dohare Afzal Hussain Md. Tabish Rehman Perwez Alam Mohamed F. Alajmi Asimul Islam Faizan Ahmad Md. Imtaiyaz Hassan 《Journal of cellular biochemistry》2019,120(6):10281-10294
Protection of telomere 1 (POT1) is one of the key components of shelterin complex, implicated in maintaining the telomere homeostasis, and thus stability of the eukaryotic genome. A large number of non-synonymous single nucleotide polymorphisms (nsSNPs) in the POT1 gene have been reported to cause varieties of human diseases, including cancer. In recent years, a number of mutations in POT1 has been markedly increased, and interpreting the effect of these large numbers of mutations to understand the mechanism of associated diseases seems impossible using experimental approaches. Herein, we employ varieties of computational methods such as PROVEAN, PolyPhen-2, SIFT, PoPMuSiC, SDM2, STRUM, and MAESTRO to identify the effects of 387 nsSNPs on the structure and function of POT1 protein. We have identified about 183 nsSNPs as deleterious and termed them as “high-confidence nsSNPs.” Distribution of these high-confidence nsSNPs demonstrates that the mutation in oligonucleotide binding domain 1 is highly deleterious (one in every three nsSNPs), and high-confidence nsSNPs show a strong correlation with residue conservation. The structure analysis provides a detailed insights into the structural changes occurred in consequence of conserved mutations which lead to the cancer progression. This study, for the first time, offers a newer prospective on the role of POT1 mutations on the structure, function, and their relation to associated diseases. 相似文献
108.
109.
The small copper butterfly, Lycaena phlaeas daimio, has pupal beige/black polymorphism, the development of which is found to be controlled in an apparent association with the development of adult seasonal polymorphism (spring and summer morphs) by photoperiod and temperature in the larval stages. That is, the pupae of beige and black types developed under long-day and short-day conditions tend to develop into brown-winged and red-winged adults, respectively. In addition, a large proportion of long-day pharate pupae chilled at 4 degrees C for 5 days were observed to develop into pupae whose head-thoracic complexes and abdomens were judged to be of the black and intermediate types, respectively. They developed into adults with redder wings as compared to those obtained from unchilled pupae. The results indicate that the physiological mechanism underlying the photoperiodic control of the development of adult seasonal polymorphism may also play a significant role in the determination of pupal beige/black polymorphism in L. phlaeas daimio. Furthermore, cuticle melanization was found to be induced in the head-thoracic complexes of pupae by chilling of the pharate pupae. Melanization of pupal cuticle seems to occur in a close association with the development of reddish-winged adults. 相似文献
110.
Morikawa A Koide N Sugiyama T Mu MM Hassan F Islam S Ito H Mori I Yoshida T Yokochi T 《FEMS immunology and medical microbiology》2004,41(3):211-218
The effect of D-galactosamine (D-GalN) on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells was examined. D-GalN augmented the production of NO, but not tumor necrosis factor (TNF)-alpha in LPS-stimulated RAW 264.7 cells. Pretreatment of D-GalN augmented the NO production whereas its post-treatment did not. D-GalN augmented the NO production in RAW 264.7 cells stimulated with either TNF-alpha and interferon-gamma. The augmentation of LPS-induced NO production by D-GalN was due to enhanced expressions of an inducible type of NO synthase mRNA and proteins. Intracellular reactive oxygen species (ROS) were exclusively generated in RAW 264.7 cells stimulated with D-GalN and LPS. Scavenging of intracellular ROS abrogated the augmentation of NO production. It was therefore suggested that D-GalN might augment LPS-induced NO production through the generation of intracellular ROS. 相似文献