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61.
Xue‐Mei Gao Ming‐Zhu Cui Ting Yu Qiu‐Fen Hu Jian‐Xin Pu Xue Du Tian‐Cheng Liu Kathy Qian Luo 《Helvetica chimica acta》2013,96(3):494-498
One novel xanthone, oliganthone A ( 1 ), was isolated from the stems of the plant Garcinia oligantha. It features the O‐bearing C(3)‐atom and absence of C(4) compared with the structures of related known xanthones, which have never been reported before. The structure of this compound was elucidated by spectroscopic analysis. Compound 1 showed strong HeLa cell growth‐inhibiting effects with IC50 values below 10 μM . 相似文献
62.
Kathy Driver Helmut Prodinger Carsten Schneider J. A. C. Weideman 《The Ramanujan Journal》2006,11(2):139-158
Combinatorial identities that were needed in [25] are proved, mostly with C. Schneider’s computer algebra package Sigma. The form of the Padé approximation of the logarithm of arbitrary order is stated as a conjecture.
2000 Mathematics Subject Classification Primary—41A21, 05A19, 33F10
Supported by NRF-grant 2047226.
Supported by NRF-grant 2053748.
Supported by the Austrian Academy of Sciences, by the John Knopfmacher Research Centre for Applicable Analysis and Number
Theory, and by the SFB-grant F1305 and the grant P16613-N12 of the Austrian FWF.
Supported by NRF-grant 2053756. 相似文献
63.
Michiko Watanabe Midori Hitomi Kathy van der Wee Florence Rothenberg Steven A Fisher Robert Zucker Kathy K H Svoboda Edie C Goldsmith Kaisa M Heiskanen Anna-Liisa Nieminen 《Microscopy and microanalysis》2002,8(5):375-391
Programmed cell death or apoptosis occurs in many tissues during normal development and in the normal homeostasis of adult tissues. Apoptosis also plays a significant role in abnormal development and disease. Increased interest in apoptosis and cell death in general has resulted in the development of new techniques and the revival of old ones. Each assay has its advantages and disadvantages that can render it appropriate and useful for one application, but inappropriate or difficult to use in another. Understanding the strengths and limitations of the assays would allow investigators to select the best methods for their needs. 相似文献
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67.
Nuclear pore complexes (NPCs) are macromolecular pores that span the nuclear envelope and undergo conformational changes in response to changes in cisternal calcium levels. Depletion of cisternal calcium leads to the appearance of a mass within the pore. The identity and role of this central mass remain unknown, although some studies suggest they are vault complexes. Vault complexes are 13 MDa ribonucleoproteins found in the cytoplasm and recently in the nuclei of some species, suggesting that they associate with NPCs to cross the nuclear envelope. Using Förster resonance energy transfer (FRET) measurements between labeled vaults and NPCs, we find significant energy transfer suggesting that vaults and NPCs are closely associated at the nuclear envelope. This is supported by high‐resolution electron microscopy measurements revealing significant spatial correlations between gold‐labeled vaults and NPCs. As the location of the central mass in the NPC is dependent on cisternal calcium levels, FRET signals under conditions of varying cisternal calcium were also measured and shown to undergo significant changes. Together, these findings suggest that the central mass observed in NPCs may be, at least in part, due to the presence of vaults in the pore. Possible roles in cyto‐nuclear trafficking are discussed. 相似文献
68.
Kovalishyn Vasyl Zyabrev Volodymyr Kachaeva Maryna Ziabrev Kostiantyn Keith Kathy Harden Emma Hartline Caroll James Scott H. Brovarets Volodymyr 《Journal of computer-aided molecular design》2021,35(12):1177-1187
Journal of Computer-Aided Molecular Design - The problem of designing new antiviral drugs against Human Cytomegalovirus (HCMV) was addressed using the Online Chemical Modeling Environment (OCHEM).... 相似文献
69.
Yamada T Peng CG Matsuda S Addepalli H Jayaprakash KN Alam MR Mills K Maier MA Charisse K Sekine M Manoharan M Rajeev KG 《The Journal of organic chemistry》2011,76(5):1198-1211
We have previously demonstrated that conjugation of small molecule ligands to small interfering RNAs (siRNAs) and anti-microRNAs results in functional siRNAs and antagomirs in vivo. Here we report on the development of an efficient chemical strategy to make oligoribonucleotide-ligand conjugates using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) or click reaction. Three click reaction approaches were evaluated for their feasibility and suitability for high-throughput synthesis: the CuAAC reaction at the monomer level prior to oligonucleotide synthesis, the solution-phase postsynthetic "click conjugation", and the "click conjugation" on an immobilized and completely protected alkyne-oligonucleotide scaffold. Nucleosides bearing 5'-alkyne moieties were used for conjugation to the 5'-end of the oligonucleotide. Previously described 2'- and 3'-O-propargylated nucleosides were prepared to introduce the alkyne moiety to the 3' and 5' termini and to the internal positions of the scaffold. Azido-functionalized ligands bearing lipophilic long chain alkyls, cholesterol, oligoamine, and carbohydrate were utilized to study the effect of physicochemical characteristics of the incoming azide on click conjugation to the alkyne-oligonucleotide scaffold in solution and on immobilized solid support. We found that microwave-assisted click conjugation of azido-functionalized ligands to a fully protected solid-support bound alkyne-oligonucleotide prior to deprotection was the most efficient "click conjugation" strategy for site-specific, high-throughput oligonucleotide conjugate synthesis tested. The siRNA conjugates synthesized using this approach effectively silenced expression of a luciferase gene in a stably transformed HeLa cell line. 相似文献
70.
Kathy R. Chaurasiya Thayaparan Paramanathan Micah J. McCauley Mark C. Williams 《Physics of life reviews》2010,7(3):299-341
Single molecule force spectroscopy is a powerful method that uses the mechanical properties of DNA to explore DNA interactions. Here we describe how DNA stretching experiments quantitatively characterize the DNA binding of small molecules and proteins. Small molecules exhibit diverse DNA binding modes, including binding into the major and minor grooves and intercalation between base pairs of double-stranded DNA (dsDNA). Histones bind and package dsDNA, while other nuclear proteins such as high mobility group proteins bind to the backbone and bend dsDNA. Single-stranded DNA (ssDNA) binding proteins slide along dsDNA to locate and stabilize ssDNA during replication. Other proteins exhibit binding to both dsDNA and ssDNA. Nucleic acid chaperone proteins can switch rapidly between dsDNA and ssDNA binding modes, while DNA polymerases bind both forms of DNA with high affinity at distinct binding sites at the replication fork. Single molecule force measurements quantitatively characterize these DNA binding mechanisms, elucidating small molecule interactions and protein function. 相似文献