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991.
Jang K Sato K Igawa K Chung UI Kitamori T 《Analytical and bioanalytical chemistry》2008,390(3):825-832
In this work, we demonstrated that biological cells could be cultured in a continuous-perfusion glass microchip system for
drug screening. We used mouse Col1a1GFP MC-3T3 E1 osteoblastic cells, which have a marker gene system expressing green fluorescent
protein (GFP) under the control of osteoblast-specific promoters. With our microchip-based cell culture system, we realized
automated long-term monitoring of cells and sampling of the culture supernatant system for osteoblast differentiation assay
using a small number of cells. The system successfully monitored cells for 10 days. Under the 3D microchannel condition, shear
stress (0.07 dyne/cm2 at a flow rate of 0.2 μL/min) was applied to the cells and it enhanced the GFP expression and differentiation of the osteoblasts.
Analysis of alkaline phosphatase (ALP), which is an enzyme marker of osteoblasts, supported the results of GFP expression.
In the case of differentiation medium containing bone morphogenetic protein 2, we found that ALP activity in the culture supernatant
was enhanced 10 times in the microchannel compared with the static condition in 48-well dishes. A combined system of a microchip
and a cell-based sensor might allow us to monitor osteogenic differentiation easily, precisely, and noninvasively. Our system
can be applied in high-throughput drug screening assay for discovering osteogenic compounds. 相似文献
992.
Tomonori Mori Dr. Shuhei Higashibayashi Dr. Taiji Goto Mitsunori Kohno Yukiko Satouchi Kazuyuki Shinko Kengo Suzuki Shunya Suzuki Hiraku Tohmiya Kimiko Hashimoto Prof. Dr. Masaya Nakata Prof. Dr. 《化学:亚洲杂志》2008,3(6):984-1012
The five practical segments for the total synthesis of siomycin A, that is, the dehydropiperidine segment A ( 5 ), the pentapeptide segment B ( 3 ), the dihydroquinoline segment C ( 6 ), and the β‐phenylselenoalanine dipeptide segments D ( 7 ) and E ( 4 ), were synthesized. Segment A ( 5 ) was constructed by the coupling of the azomethine ylide and the chiral sulfinimine, followed by the stereoselective reduction of the six‐membered imine function. Segment B ( 3 ) was synthesized by the phenylselenylation of the β‐lactone, stereoselective vinylzinc addition to the chiral sulfinimine, and oxazoline–thioamide conversion. Segment C ( 6 ) was prepared by the one‐pot olefination of the tetrahydroquinoline N‐oxide using triflic anhydride and triethylamine, stereoselective reduction of the methyl ketone function, and regioselective Yb(OTf)3‐catalyzed epoxide opening by the amino group. Segments D ( 7 ) and E ( 4 ) were synthesized by coupling of the properly protected β‐phenylselenoalanines. 相似文献
993.
Tomonori Mori Dr. Shuhei Higashibayashi Dr. Taiji Goto Mitsunori Kohno Yukiko Satouchi Kazuyuki Shinko Kengo Suzuki Shunya Suzuki Hiraku Tohmiya Kimiko Hashimoto Prof. Dr. Masaya Nakata Prof. Dr. 《化学:亚洲杂志》2008,3(6):1013-1025
The total synthesis of siomycin A ( 1 ), a representative compound of the thiostrepton family of peptide antibiotics, was achieved by incorporating the five synthetic segments A ( 2 ), B ( 3 ), C ( 4 ), D ( 5 ), and E ( 6 ). The dehydropiperidine segment A ( 2 ) was esterified with the dihydroquinoline segment C ( 4 ), and the subsequent coupling with the β‐phenylselenoalanine dipeptide segment D ( 5 ) at the segment C portion followed by lactamization between the segments A and D gave segment A‐C‐D ( 27 ). This was amidated with the pentapeptide segment B ( 3 ) at the segment A portion followed by one‐pot cyclization (between segments A and B) and elongation (with the β‐phenylselenoalanine dipeptide segment E ( 6 ) at the segment A portion), thus furnishing siomycin A ( 1 ). 相似文献
994.
995.
996.
Kuramoto M Sakata Y Terai K Kawasaki I Kunitomo J Ohishi T Yokomizo T Takeda S Tanaka S Ohishi Y 《Organic & biomolecular chemistry》2008,6(15):2772-2781
A series of 2-(2-aminothiazol-4-yl)benzo[b]furan and 3-(2-aminothiazol-4-yl)benzo[b]furan derivatives were prepared, and their leukotriene B(4) inhibitory activity and growth inhibitory activity in cancer cell lines were evaluated. Several compounds showed strong inhibition of calcium mobilization in CHO cells overexpressing human BLT(1) and BLT(2) receptors and growth inhibition to human pancreatic cancer cells MIA PaCa-2. 3-(4-Chlorophenyl)-2-[5-formyl-2-[(dimethylamino)methyleneamino]thiazol-4-yl]-5-methoxybenzo[b]furan 8b showed the most potent and selective inhibition for the human BLT(2) receptor, and its IC(50) value was smaller than that of the selected positive control compound, ZK-158252. 3-(4-Chlorophenyl)-2-[2-[(dimethylamino)methyleneamino]-5-(2-hydroxyethyliminomethyl)thiazol-4-yl]-5-methoxybenzo[b]furan 9a displayed growth inhibitory activity towards MIA PaCa-2. 相似文献
997.
Ozawa K Yamamura Y Yasuzuka S Mori H Kutsumizu S Saito K 《The journal of physical chemistry. B》2008,112(39):12179-12181
Structure of a complex superstructure self-organized by thermotropic mesogen, 1,2-bis(4'- n-alkoxybenzoyl)hydrazine [BABH(n), where n is the number of carbon atoms in an alkoxy chain] was studied while paying special attention to the structure at the molecular level. Maximum entropy (MEM) analysis revealed that the molecular cores form two kinds of aggregates: Jungle gym with 3-fold junctions roughly on P minimal surface and spherical shells. 相似文献
998.
Pesticide analysis by MEKC on a microchip with hydrodynamic injection from organic extract 总被引:1,自引:0,他引:1
Smirnova A Shimura K Hibara A Proskurnin MA Kitamori T 《Journal of separation science》2008,31(5):904-908
An integrated microchip for monitoring carbamate pesticides in environmental water using continuous flow chemical processes is under development, i. e., the integration of hydrolysis, azo-derivatization, liquid-liquid extraction, electrophoretic separation, and quantification. The separation of the derivatives of four carbamate pesticides (carbaryl, carbofuran, propoxur, and bendiocarb) extracted in the continuous flow of a 1-butanol phase was studied in a silica microchip using micellar EKC. A baseline separation of four pesticide derivatives was achieved on a silica chip using hydrodynamic injection with electroosmotic gating. Detection using a thermal lens microscope showed good linearity in the concentration range of 10(-6 )-10(-5 )M with an LOD of 5 x 10(-7) M, which is superior to that of conventional CE with UV absorption detection at a level of 10(-4) M. 相似文献
999.
Dr. Takahiro Mori Xin Sun Dr. Stanislav Kadlcik Dr. Jiri Janata Prof. Dr. Ikuro Abe 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304989
The S-glycosyltransferase LmbT, involved in the biosynthesis of lincomycin A, is the only known enzyme that catalyzes the enzymatic incorporation of rare amino acid L-ergothioneine (EGT) into secondary metabolites. Here, we show the structure and function analyses of LmbT. Our in vitro analysis of LmbT revealed that the enzyme shows promiscuous substrate specificity toward nitrogenous base moieties in the generation of unnatural nucleotide diphosphate (NDP)-D-α-D-lincosamides. Furthermore, the X-ray crystal structures of LmbT in its apo form and in complex with substrates indicated that the large conformational changes of the active site occur upon binding of the substrates, and that EGT is strictly recognized by salt-bridge and cation-π interactions with Arg260 and Trp101, respectively. The structure of LmbT in complex with its substrates, the docking model with the EGT-S-conjugated lincosamide, and the structure-based site-directed mutagenesis analysis revealed the structural details of the LmbT-catalyzed SN2-like S-glycosylation reaction with EGT. 相似文献
1000.
You Osanai Eiko Soejima Takeshi Noro Hirotoshi Mori Ma San Mon Mariusz Klobukowski Eisaku Miyoshi 《Chemical physics letters》2008,463(1-3):230-234
We have produced new relativistic model core potentials (spdsMCPs) for the second-row transition-metal atoms from Y to Cd treating explicitly 4s and 4p electrons in addition to 4d and 5s electrons in the same manner as for the first-row transition-metal atoms given in [Y. Osanai, M.S. Mon, T. Noro, H. Mori, H. Nakashima, M. Klobukowski, E. Miyoshi, Chem. Phys. Lett. 452 (2008) 210]. Using suitable correlating functions together with the split valence MCP functions, we demonstrate that the present MCP basis sets show reasonable performance in predicting the electronic structures of atoms and molecules, bringing about accurate excitation energies for atoms and reasonable spectroscopic constants for AgH. 相似文献