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901.
902.
Thibault Troadec Sze‐yin Tan Christopher J. Wedge Jonathan P. Rourke Patrick R. Unwin Adrian B. Chaplin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(11):3818-3821
Oxidation of zero‐valent phosphine complexes [M(PtBu3)2] (M=Pd, Pt) has been investigated in 1,2‐difluorobenzene solution using cyclic voltammetry and subsequently using the ferrocenium cation as a chemical redox agent. In the case of palladium, a mononuclear paramagnetic PdI derivative was readily isolated from solution and fully characterized (EPR, X‐ray crystallography). While in situ electrochemical measurements are consistent with initial one‐electron oxidation, the heavier congener undergoes C−H bond cyclometalation and ultimately affords the 14 valence‐electron PtII complex [Pt(κ2PC‐PtBu2CMe2CH2)(PtBu3)]+ with concomitant formation of [Pt(PtBu3)2H]+. 相似文献
903.
Let F be a global field and \(G:=SL(2)\). We study the bilinear form \({{\mathcal {B}}}\) on the space of K-finite smooth compactly supported functions on \(G({\mathbb {A}})/G(F)\) defined by where \({{\mathcal {B}}}_{\mathrm {naive}}\) is the usual scalar product, \({{\mathrm{{CT}}}}\) is the constant term operator, and M is the standard intertwiner. This form is natural from the viewpoint of the geometric Langlands program. To justify this claim, we provide a dictionary between the classical and ‘geometric’ theory of automorphic forms. We also show that the form \({{\mathcal {B}}}\) is related to S. Schieder’s Picard–Lefschetz oscillators.
相似文献
$$\begin{aligned} {{\mathcal {B}}}(f_1,f_2):={{\mathcal {B}}}_{\mathrm {naive}}(f_1,f_2)-\langle M^{-1}{{\mathrm{{CT}}}}(f_1)\, ,{{\mathrm{{CT}}}}(f_2)\rangle , \end{aligned}$$
904.
Dr. Jonathan Rittle Prof. Jonas C. Peters 《Angewandte Chemie (International ed. in English)》2016,55(40):12262-12265
Nitrogenase enzymes mediate the six‐electron reductive cleavage of cyanide to CH4 and NH3. Herein we demonstrate for the first time the liberation of CH4 and NH3 from a well‐defined iron cyanide coordination complex, [SiPiPr3]Fe(CN) (where [SiPiPr3] represents a tris(phosphine)silyl ligand), on exposure to proton and electron equivalents. [SiPiPr3]Fe(CN) additionally serves as a useful entry point to rare examples of terminally‐bound Fe(CNH) and Fe(CNH2) species that, in accord with preliminary mechanistic studies, are plausible intermediates of the cyanide reductive protonation to generate CH4 and NH3. Comparative studies with a related [SiPiPr3]Fe(CNMe2) complex suggests the possibility of multiple, competing mechanisms for cyanide activation and reduction. 相似文献
905.
Gaolian Xu Dr. Debbie Nolder Dr. Julien Reboud Dr. Mary C. Oguike Dr. Donelly A. van Schalkwyk Dr. Colin J. Sutherland Prof. Jonathan M. Cooper 《Angewandte Chemie (International ed. in English)》2016,55(49):15250-15253
We demonstrate, for the first time, the multiplexed determination of microbial species from whole blood using the paper‐folding technique of origami to enable the sequential steps of DNA extraction, loop‐mediated isothermal amplification (LAMP), and array‐based fluorescence detection. A low‐cost handheld flashlight reveals the presence of the final DNA amplicon to the naked eye, providing a “sample‐to‐answer” diagnosis from a finger‐prick volume of human blood, within 45 min, with minimal user intervention. To demonstrate the method, we showed the identification of three species of Plasmodium, analyzing 80 patient samples benchmarked against the gold‐standard polymerase chain reaction (PCR) assay in an operator‐blinded study. We also show that the test retains its diagnostic accuracy when using stored or fixed reference samples. 相似文献
906.
Hiu C. Lam Justin T. J. Spence Dr. Jonathan H. George 《Angewandte Chemie (International ed. in English)》2016,55(35):10368-10371
Hyperjapones A–E and hyperjaponols A–C are complex natural products of mixed aromatic polyketide and terpene biosynthetic origin that have recently been isolated from Hypericum japonicum. We have synthesized hyperjapones A–E using a biomimetic, oxidative hetero‐Diels–Alder reaction to couple together dearomatized acylphloroglucinol and cyclic terpene natural products. Hyperjapone A is proposed to be the biosynthetic precursor of hyperjaponol C through a sequence of: 1) epoxidation; 2) acid‐catalyzed epoxide ring‐opening; and 3) a concerted, asynchronous alkene cyclization and 1,2‐alkyl shift of a tertiary carbocation. Chemical mimicry of this proposed biosynthetic sequence allowed a concise total synthesis of hyperjaponol C to be completed in which six carbon–carbon bonds, six stereocenters, and three rings were constructed in just four steps. 相似文献
907.
Latsavongsakda Sethaphong Jonathan K. Davis Erin Slabaugh Abhishek Singh Candace H. Haigler Yaroslava G. Yingling 《Cellulose (London, England)》2016,23(1):145-161
Seed plants express cellulose synthase (CESA) protein isoforms with non-redundant functions, but how the isoforms function differently is unknown. Compared to bacterial cellulose synthases, CESAs have two insertions in the large cytosolic loop: the relatively well-conserved Plant Conserved Region (P-CR) and a Class Specific Region (CSR) that varies between CESAs. Absent any atomic structure of a plant CESA, we used ab initio protein structure prediction and molecular modeling to explore how these plant-specific regions may modulate CESA function. We modeled P-CR and CSR peptides from Arabidopsis thaliana CESAs representing the six clades of seed plant CESAs. As expected, the predicted wild type P-CR structures were similar. Modeling of the mutant P-CR of Atcesa8 R362K (fra6) suggested that changes in local structural stability and surface electrostatics may cause the mutant phenotype. Among CSRs within CESAs required for primary wall cellulose synthesis, the amino sequence and the modeled arrangement of helices was most similar in AtCESA1 and AtCESA3. Genetic complementation of known Arabidopsis mutants showed that the CSRs of AtCESA1 and AtCESA3 can function interchangeably in vivo. Analysis of protein surface electrostatics led to ideas about how the surface charges on CSRs may mediate protein–protein interactions. Refined modeling of the P-CR and CSR regions of GhCESA1 from cotton modified their tertiary structures, spatial relationships to the catalytic domain, and preliminary predictions about CESA oligomer formation. Cumulatively, the results provide structural clues about the function of plant-specific regions of CESA. 相似文献
908.
Dr. Gregory Thiabaud Rebecca McCall Dr. Guangan He Prof. Jonathan F. Arambula Prof. Zahid H. Siddik Prof. Jonathan L. Sessler 《Angewandte Chemie (International ed. in English)》2016,55(41):12626-12631
Water‐soluble platinum(IV) prodrugs, which proved kinetically stable to reduction in the presence of physiological concentration of ascorbate, were quickly reduced to their active form, oxaliplatin, when co‐incubated with a macrocycle metallotexaphyrin (i.e., Motexafin Gadolinium (MGd)). The reduction of PtIV to PtII promoted by MGd occurs in cell culture as well, leading to an increase in the antiproliferative activity of the PtIV species in question. The mediated effect is proportional to the concentration of MGd and gives rise to an enhancement when the prodrug is relatively hydrophilic. MGd is known to localize/accumulate preferentially in tumor tissues. Thus, the present “activation by reduction” approach may allow for the cancer‐selective enhancement in the cytotoxicity of PtIV prodrugs. 相似文献
909.
910.
Dr. Pavel Zrazhevskiy Dr. Shreeram Akilesh Dr. Wanyi Tai Konstantin Queitsch Prof. Lawrence D. True Prof. Jonathan Fromm Prof. David Wu Prof. Peter Nelson Prof. John A. Stamatoyannopoulos Prof. Xiaohu Gao 《Angewandte Chemie (International ed. in English)》2016,55(31):8975-8978
Integration of imaging data across different molecular target types can provide in‐depth insight into cell physiology and pathology, but remains challenging owing to poor compatibility between target‐type‐specific labeling methods. We show that cross‐platform imaging analysis can be readily achieved through DNA encoding of molecular targets, which translates the molecular identity of various target types into a uniform in situ array of ssDNA tags for subsequent labeling with complementary imaging probes. The concept was demonstrated through multiplexed imaging of mRNAs and their corresponding proteins with multicolor quantum dots. The results reveal heterogeneity of cell transfection with siRNA and outline disparity in RNA interference (RNAi) kinetics at the level of both the mRNA and the encoded protein. 相似文献