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41.
This paper describes the genetic control of two new water-soluble proteins in barley. Water-soluble proteins (WSPs) of mature barley seed form part of the albumin/globulin class of seed proteins. They can be extracted from hand-milled grain with water, though some WSPs are more efficiently extracted with a solution of 10 mM dithiothreitol. Polymorphisms for WSPs were detected in isoelectric focusing gels incorporating various ampholine combinations. Two new controlling genes (Wsp4 andWsp5) have been identified and located using wheat/barley chromosome addition lines and barley doubled haploids.Wsp4 is located on chromosome 2 (2H), andWsp5 was found to be tightly linked toWsp2 on the long arm of chromosome 7 (5HL). Segregation of a sixth gene (Wsp6) is also described, but this has not been mapped. The results are discussed with respect to other previously mappedWsp loci.This work was funed by the Scottish Office of Agriculture and Fisheries Department and the Agricultural and Food Research Council. 相似文献
42.
Rhodium-catalyzed synthesis of 2(5H)-furanones from alkynes under water-gas shift reaction conditions was studied. By improving the reaction conditions for internal alkynes reported previously, the reaction could be extended to terminal alkynes. Terminal alkynes are selectively converted into 3- and 4-substituted 2(5H)-furanones (2 and 3). When acetylene itself is used, 2(5H)-furanone (2n) is obtained in a good yield. Examination of reaction solutions by IR spectroscopy and some other experimental findings suggest that the active species would be an alkyne-coordinated monomeric rhodium anion. A new reaction path is proposed. 相似文献
43.
Tri-1-alkynyltin compounds [R2Sn(CCR1)3 (1), R2 = Me, R1 = Me (a), nBu (b), tBu (c), Me3Si (d), 1-(1-cyclohexenyl) (e); R2 = Et, R1 = Me (a(Et)), nBu (b(Et)), tBu (c(Et)), SiMe3 (d(Et)); R2 = nBu, R1 = Me (a(Bu)), nBu (b(Bu))] were prepared, and their reactivity towards trialkylboranes Et3B (2) and iPr3B (3) in 1,1-organoboration reactions was studied. The first step in each reaction is an intermolecular 1,1-alkytoboration. Afterwards, intramolecular 1,1-vinyloboration or 1,1-alkyloboration compete with further intermolecular 1,1-alkyloboration. Various triorganotin cations (4-7), stabilized by intramolecular side-on coordination to the CC bond of an alkynylborate moiety, were detected as highly fluxional intermediates prior to rearrangement into heterocyclic systems such as stannoles (9-11), 1-stanna-4-bora-2, 5-cyclohexadienes (8, 12). The reactions between 1a or 1a(Bu) and an excess of Et3B (2) afford the tris(alkenyl)tin compounds 13 via threefold intermolecular 1, 1-ethyloboration. 13 rearrange to the 3-stannolenes (14a or 14a(Bu)). The intermediates and final products were characterized by multinuclear one- and two-dimensional 1H, 11B, 13C, 29Si and 119Sn NMR. 相似文献
44.
Treatment of the A-ring aromatic steroids estrone 3-methyl ether and β-estradiol 3, 17-dimethyl ether with Mn(CO)5+BF4− in CH2Cl2 yields the corresponding [(steroid)Mn(CO)3]BF4 salts 1 and 2 as mixtures of and β isomers. The X-ray structure of [(estrone 3-methyl ether)Mn(CO)3]BF4 · CH2Cl2 (1) having the Mn(CO)3 moiety on the side of the steroid is reported: space group P21 with a=10.3958(9), b=10.9020(6), c=12.6848(9) Å, β=111.857(6)°, Z=2, V=1334.3(2) Å3, calc=.481 cm−3, R=0.0508, and wR=0.0635. The molecule has the traditional ‘piano stool’ structure with a planar arene ring and linear Mn---C---O linkages. The nucleophiles NaBH4 and LiCH2C(O)CMe3 add to [(β-estradiol 3,17-dimethyl ether)Mn(CO)3]BF4 (2) in high yield to give the corresponding - and β-cyclohexadienyl manganese tricarbonyl complexes (3). The nucleophiles add meta to the arene -OMe substituent and exo to the metal. The and β isomers of 3 were separated by fractional crystallization and the X-ray structure of the β isomer with an exo-CH2C(O)CMe3 substituent is reported (complex 4): space group P212121 with a=7.5154(8), b=15.160(2), c=25.230(3) Å, Z=4, V=2874.4(5) Å3, calc=1.244 g cm−3, R=0.0529 and wR2=0.1176. The molecule 4 has a planar set of dienyl carbon atoms with the saturated C(1) carbon being 0.592 Å out of the plane away from the metal. The results suggest that the manganese-mediated functionalization of aromatic steroids is a viable synthetic procedure with a range of nucleophiles of varying strengths. 相似文献
45.
The allylidene complex (CO)5W=CH---C(Ph)=C(Ph)H (4) reacts with cyclopentadiene by stereospecific transfer of the carbene ligand to one of the two double bonds of cyclopentadiene to give a cis-divinylcyclopropane complex 5. The divinylcyclopropane ligand coordinates to the metal via the unsubstituted double bond. Addition of bromide to solutions of 5 gives rise to the formation of [(CO)5WBr]− and a bicyclo[3.2.1]octadiene (6), the Cope rearrangement product of the free divinylcyclopropane. Thermolysis of 5 affords 6 and its (CO)5W complex. The reaction of 4 with furan (8a), 2-methylfuran (8b) and 3-methylfuran (8c) affords the (CO)5W(bicyclo[3.2.1]oxahepta- diene) complexes (9a–c), The formation of 9a–c which is chemo-, regio- and stereospecific is explained by a tandem cyclopropanation/Cope rearrangement sequence. The bicyclic ligands 10a–c are liberated from the metal either by thermolysis of solutions of 9a–c or by addition of bromide. 相似文献
46.
Marianna F. Asaroa Andreas Mayr Bart Kahra Donna Van Engen 《Inorganica chimica acta》1994,220(1-2):335-346
Reaction of the allylidene tungsten complex [W(CPhCHCHMe)Br2(CO)2(4-picoline)] (1) with the dithiocarbamates MS2CNR2 (a: M=Na, R=Et; b: M=Na, R=Me; c: M=Li, R=Ph) in THF at 50 °C affords the vinylketene tungsten complexes [W(S2CNR2)2(OCCPhCHCHMe)(CO)] (2a–c). At lower temperatures, four reaction intermediates (3–6) may be discerned. Spectroscopic studies indicate that these compounds contain η4-allyldithiocarbamate ligands which are generated by addition of dithiocarbamate across the metal-carbon double bond of the allylidene-tungsten unit in 1. The structures of [W(S2CNEt2)2(OCCPhCHCHMe)(CO)] (2a) and of one intermediate, [W(η4-Et2NCS2CPhCHCHMe)(S2CNEt2)(CO)2] (5a) were elucidated by X-ray crystallography. 相似文献
47.
V. Patinec J. J. Yaouanc H. Handel J. C. Clment H. des Abbayes 《Inorganica chimica acta》1994,220(1-2):347-348
After reaction with alkyl iodides and subsequent oxidative removal of the M(CO)3 triprotection, molybdenum and chromium fac-LM(CO)3 complexes of cyclen (L) unexpectedly lead to N1,N7-dialkylated cyclen derivatives. 相似文献
48.
The interactions of VO2+ with phytate to form both soluble and insoluble complexes, have been studied by electronic absorption spectroscopy. A soluble
1∶1 VO2+: phytate complex is formed at pH <1. At higher pH-values insoluble complexes are produced. Two different solid complexes,
obtained respectively at pH=2 and 4, were isolated and characterized. The maximal bonding ratio of VO2+: phytate was found to be 4, on the basis of a pH binding profile. 相似文献
49.
Grażyna Kowalewska 《Aquatic Ecology》1994,28(2):149-156
Sediments of the southern Baltic Sea were analysed for content of steryl chlorin esters, the chlorin compounds discovered
recently in the marine environment. The chlorin esters occur in the Baltic sediments in substantial amounts and form a considerable
fraction of the total chlorin content. Among the physicochemical parameters studied the highest correlation with the steryl
chlorins showed organic carbon content in sediments and the content of fraction of sediments smaller than 10 μm. A significant
correlation was observed between the steryl chlorins content and other chlorins as chlorophylla, phaeophytina, pyrophaeophytina as well as with β-carotene, the distinctly less significant correlation was with phaeophorbidea. This indicates an other way of formation of the steryl chlorins from algae than zooplankton grazing. 相似文献
50.
Evidence for the Presence of "Metabolic Sterols" in Pneumocystis: Identification and Initial Characterization of Pneumocystis carinii Sterols 总被引:1,自引:0,他引:1
EDNA S. KANESHIRO JAYNE E. ELLIS KOKA JAYASIMHULU DAVID H. BEACH 《The Journal of eukaryotic microbiology》1994,41(1):78-85
Mixed life cycle stages of rat-derived Pneumocystis carinii were isolated from host lungs and their sterols were compared with those present in lungs from normal and immunosuppressed uninfected rats. Gas-liquid chromatography consistently detected, resolved, and quantified 9, 10, and 20 sterol components in the total nonsaponifiable neutral lipid fraction of lungs from normal rats, lungs from immunosuppressed uninfected rats, and P. carinii preparations, respectively. In all samples, cholesterol was the most abundant sterol present, comprising 97%, 93%, and 78% of total sterols in lungs from normal rats, lungs from immunosuppressed uninfected rats, and P. carinii , respectively. Tentative identifications of several rat lung and P. carinii minor sterols were made based on gas-liquid chromatogram retention times and fragmentation patterns from mass spectral analyses. Campesterol (ergost-5-en-3-ol), cholest-5-en-3-one, and β -sitosterol (stigmast-5-en-3-ol) were among the minor components present in both types of lung controls, and were also components of P. carinii sterols. In contrast to lung controls, the sterols of P. carinii were enriched in C28 and C29 sterols with one or two double bonds, and a hydroxyl group at C-3 (ergost-5-en-3-ol, ergost-7-en-3-ol, ergosta-dien-3-ol, stigmast-5-en-3-ol, stigmast-7-en-3-ol and stigmasta-dien-3-ol). Steryl esters of P. carinii , probably stored in cytoplasmic lipid droplets, were dominated by those present in the host lung. In separate studies. 3-hydroxy-3-methylglutaryl coenzyme A activity, a key enzyme in the regulation of sterol biosynthesis, was detected in purified P. carinii preparations and incorporation of radiolabeled squalene and mevalonate was observed. Together, these results suggest that the parasite readily takes up and incorporates host sterols, and that the organism synthesizes some of its own "metabolic sterols" 相似文献