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1.
Vyacheslav L. L'vov Irina K. Verner Larisa Yu. Musina Alexander V. Rodionov Anatoly V. Ignatenko Alexander S. Shashkov 《Archives of microbiology》1992,157(2):131-134
On the basis of chemical and NMR data the partial structure of lipid A from lipooligosaccharide (LOS) of Neisseria meningitidis group B, strain BC5S No 125 was established. Lipid A consisted of disaccharide 2-deoxy-6-O-[2-deoxy-2-(3-hydroxytetradecanoylamino)--gluco-pyranosyl]-2-(3-hydroxytetradecanoylamino)--glucopyranose carrying the -(2-aminoethyl)pyrophosphate residue at 0–4 and the pyrophosphate or phosphate residue at 0–1. On hydrolysis of the acidic form of LOS with 1% acetic acid the substituent at 0–1 was practically completely removed whereas that at 0–4 was stable. The analogous hydrolysis of the Mg-salt of LOS was accompanied by splitting off the pyrophosphate linkage in the substituent at 0–4. Hydrolysis of LOS at pH 4.5 in the presence of SDS led mainly to a lipid A preparation retaining both pyrophosphate residues.Abbreviations KDO
2-keto-3-deoxyoctulosonic acid
- LA-I, LA-II
preparations of lipid A
- LOS
lipooligosaccharide
- LOS-H+
the acidic form of LOS
- OS
oligosaccharide
- TLC
thin-layer chromatography
- GLC-MS
gas-liquid chromatography/mass spectrometry 相似文献
2.
Rolands Vegners Irina Shestakova Ivars Kalvinsh Robert M. Ezzell Paul A. Janmey 《Journal of peptide science》1995,1(6):371-378
A dipeptide of the formula Fmoc-Leu-Asp and some other related dipeptides were synthesized in solution by standard methods. When such peptides are dissolved in water at concentrations below 1% at 100 °C and cooled below 60 °C they form turbid solutions and eventaully visocelastic gels at lower temperatures. Such gels are thermoreversible and can also be disrupted by mechanical agitation. At a concentration of 2 mg/ml the peptide Fmoc-Leu-Asp forms an aqueous gel at 60 °C with a shear modulus of 80 Pa measured at a frequency of 1 rad/s. Peptide solutions undergo an abrupt increase in light scattering between 1 and 1.5 mg/ml at both 23 and 60 °C. By analogy with previous observations of other systems, this increse appears to be due to the formation of filamentous micelles and the aggregation of filamaents into a three-dimensional network. When low molecular weight adamantanamine derivatives, which are inherently non-antigenci antiviral drugs, were incorporated into the Fmoc-Leu-Asp gel and injected into rabbits, high titre specific antibodies were efficiently produced without the need for additional adjuvant. Both the physical properties of the gel and its effect on the antigenicity of low molecular weight compounds suggest a number of practical applications. 相似文献
3.
Efficient generation of chimaeric mice using embryonic stem cells after long-term culture in the presence of ciliary neurotrophic factor 总被引:2,自引:0,他引:2
Eckhard Wolf Rainer Kramer Irina Polejaeva Hans Thoenen Gottfried Brem 《Transgenic research》1994,3(3):152-158
The aim of our study was to evaluate whether ciliary neurotrophic factor (CNTF) can substitute for leukaemia inhibitory factor (LIF) in maintaining pluripotential embryonic stem (ES) cells in culture. Two subclones of D3 ES cells were used to assess cell proliferation and differentiation in the presence of CNTF, LIF or Buffalo rat liver (BRL) cell-conditioned medium, or in the absence of exogenous differentiation inhibiting factors. ES cells maintained in medium supplemented with CNTF for up to four weeks were injected into blastocysts to investigate theirin vivo pluripotency in terms of chimaera formation. CNTF inhibited ES cell differentiation in a dose-dependent manner. The most effective concentration was 10 ng CNTF per ml of medium. The effects of CNTF on ES cell differentiation and proliferation were comparable to those of LIF at the same concentration. BRL cell-conditioned medium was less effective at preventing ES cell differentiation but induced their proliferation very markedly. Both ES cell clones efficiently formed chimaeras after long-term culture with CNTF as the only differentiation inhibiting agent. The ability of these ES cells to colonize the germ-line is the ultimate proof that CNTF can preserve the pluripotency of ES cells. 相似文献
4.
Andrei O. Zalensky John W. Breneman Irina A. Zalenskaya B. R. Brinkley E. Morton Bradbury 《Chromosoma》1993,102(8):509-518
The localization of centromeres in mature human sperm was shown by immunofluorescent labeling and nonisotopic in situ hybridization. In the decondensed nucleus structural elements (dimers, tetramers, linear arrays and V shape structures) formed by individual centromeres of nonhomologous chromosomes were observed. They organize the compact chromocenter, which was shown for nuclei decondensed to a low extent. The chromocenter is buried inside the nucleus; in contrast, telomeric regions of chromosomes were tentatively localized on the periphery. Thus, a gross architecture, which can influence selective unpackaging of the paternal genome upon fertilization, exists in human sperm. 相似文献
5.
Irina Zaitseva Vjacheslav Zaitsev Graeme Card Kirill Moshkov Benjamin Bax Adam Ralph Peter Lindley 《Journal of biological inorganic chemistry》1996,1(1):15-23
The X-ray structure of human serum ceruloplasmin has been solved at a resolution of 3.1?Å. The structure reveals that the molecule is comprised of six plastocyanin-type domains arranged in a triangular array. There are six copper atoms; three form a trinuclear cluster sited at the interface of domains 1 and 6, and there are three mononuclear sites in domains 2, 4 and 6. Each of the mononuclear coppers is coordinated to a cysteine and two histidine residues, and those in domains 4 and 6 also coordinate to a methionine residue; in domain 2, the methionine is replaced by a leucine residue which may form van der Waals type contacts with the copper. The trinuclear centre and the mononuclear copper in domain 6 form a cluster essentially the same as that found in ascorbate oxidase, strongly suggesting an oxidase role for ceruloplasmin in the plasma. 相似文献
6.
Mozhaev Vadim V. Kudryashova Elena V. Efremova Nadezhda V. Topchieva Irina N. 《Biotechnology Techniques》1996,10(11):849-854
Summary -Chymotrypsin has been modified with poly(ethylene glycols) and proxanols, block-copolymers of poly(propylene oxide) and poly(ethylene oxide). These conjugates were several-fold more thermostable and showed high catalytic activity at elevated concentrations of water-miscible organic cosolvents (alcohols and dimethyl sulfoxide) which caused inactivation of free (non-modified) -chymotrypsin. 相似文献
7.
Anna M. Gusakova Tatiana E. Suslova Maria A. Kercheva Irina V. Kologrivova Tamara R. Ryabova Vyacheslav V. Ryabov 《Journal of Medical Biochemistry》2022,41(4):441
BackgroundThe study of laboratory biomarkers that reflect the development of adverse cardiovascular events in the postinfarction period is of current relevance. The aim of the present study was evaluation of oncostatin M (OSM) concentration changes in the early and late stages of myocardial infarction and evaluation of the possibility of its use in prediction of adverse left ventricular (LV) remodeling in patients with myocardial infarction with ST-elevated segment (STEMI).MethodsThe study involved 31 patients with STEMI admitted in the first 24 hours after the onset of MI and 30 patients with chronic coronary artery disease as a control group. Echocardiographic study was performed on day 3 and in 6 months after STEMI. The serum levels of biomarkers were evaluated on the day of hospital admission and 6 months after MI using multiplex immunoassay.ResultsOSM level increased during the first 24 h after the onset of the disease, with the following decrease in 6 months. OSM concentration at admission had correlated with echocardiography parameters and Nt-proBNP, troponin I, CK-MB levels. Our study has demonstrated association of the increased levels of OSM at the early stages of STEMI with development of the adverse LV remodeling in 6 months after the event.ConclusionsElevation of OSM levels in the first 24 h after STEMI is associated with the development of the adverse LV remodeling in the long-term post-infarction period. 相似文献
8.
Gospodinov A Tsaneva I Anachkova B 《The international journal of biochemistry & cell biology》2009,41(4):925-933
Chromatin modification plays an important role in modulating the access of homologous recombination proteins to the sites of DNA damage. TIP49 is highly conserved component of chromatin modification/remodeling complexes, but its involvement in homologous recombination repair in mammalian cells has not been examined in details. In the present communication we studied the role of TIP49 in recruitment of the key homologous recombination protein RAD51 to sites of DNA damage. RAD51 redistribution to chromatin and nuclear foci formation induced by double-strand breaks and interstrand crosslinks were followed under conditions of TIP49 depletion by RNA interference. TIP49 silencing reduced RAD51 recruitment to chromatin and nuclear foci formation to about 50% of that of the control. Silencing of TIP48, which is closely related to TIP49, induced a similar reduction in RAD51 foci formation. RAD51 foci reduction in TIP49-silenced cells was not a result of defective DNA damage checkpoint signaling as judged by the normal histone H2AX phosphorylation and cell cycle distribution. Treatment with the histone deacetylase inhibitor sodium butyrate restored RAD51 foci formation in the TIP49-depleted cells. The results suggest that as a constituent of chromatin modification complexes TIP49 may facilitate the access of the repair machinery to the sites of DNA damage. 相似文献
9.
Nikulin A Eliseikina I Tishchenko S Nevskaya N Davydova N Platonova O Piendl W Selmer M Liljas A Drygin D Zimmermann R Garber M Nikonov S 《Nature structural biology》2003,10(2):104-108
The L1 protuberance of the 50S ribosomal subunit is implicated in the release/disposal of deacylated tRNA from the E site. The apparent mobility of this ribosomal region has thus far prevented an accurate determination of its three-dimensional structure within either the 50S subunit or the 70S ribosome. Here we report the crystal structure at 2.65 A resolution of ribosomal protein L1 from Sulfolobus acidocaldarius in complex with a specific 55-nucleotide fragment of 23S rRNA from Thermus thermophilus. This structure fills a major gap in current models of the 50S ribosomal subunit. The conformations of L1 and of the rRNA fragment differ dramatically from those within the crystallographic model of the T. thermophilus 70S ribosome. Incorporation of the L1-rRNA complex into the structural models of the T. thermophilus 70S ribosome and the Deinococcus radiodurans 50S subunit gives a reliable representation of most of the L1 protuberance within the ribosome. 相似文献
10.
Konstantin K Turoverov Vladislav V Verkhusha Mikhail M Shavlovsky Alexander G Biktashev Olga I Povarova Irina M Kuznetsova 《Biochemistry》2002,41(3):1014-1019
The kinetics of actin unfolding induced by guanidine hydrochloride has been studied. On the basis of obtained experimental data a new kinetic pathway of actin unfolding was proposed. We have shown that the transition from native to inactivated actin induced by guanidine hydrochloride (GdnHCl) passes through essential unfolding of the protein. This means that inactivated actin should be considered as the off-pathway species rather than an intermediate conformation between native and completely unfolded states of actin, as has been assumed earlier. The rate constants of the transitions that give rise to the inactivated actin were determined. At 1.0-2.0 M GdnHCl the value of the rate constant of the transition from native to essentially unfolded actin exceeds that of the following step of inactivated actin formation. It leads to the accumulation of essentially unfolded macromolecules early in the unfolding process, which in turn causes the minimum in the time dependencies of tryptophan fluorescence intensity, parameter A, characterizing the intrinsic fluorescence spectrum position, and tryptophan fluorescence anisotropy. 相似文献