全文获取类型
收费全文 | 3079篇 |
免费 | 356篇 |
国内免费 | 200篇 |
出版年
2024年 | 19篇 |
2023年 | 101篇 |
2022年 | 129篇 |
2021年 | 142篇 |
2020年 | 157篇 |
2019年 | 148篇 |
2018年 | 128篇 |
2017年 | 105篇 |
2016年 | 107篇 |
2015年 | 125篇 |
2014年 | 139篇 |
2013年 | 224篇 |
2012年 | 110篇 |
2011年 | 138篇 |
2010年 | 91篇 |
2009年 | 139篇 |
2008年 | 142篇 |
2007年 | 143篇 |
2006年 | 153篇 |
2005年 | 181篇 |
2004年 | 175篇 |
2003年 | 126篇 |
2002年 | 102篇 |
2001年 | 54篇 |
2000年 | 43篇 |
1999年 | 43篇 |
1998年 | 37篇 |
1997年 | 32篇 |
1996年 | 30篇 |
1995年 | 28篇 |
1994年 | 32篇 |
1993年 | 23篇 |
1992年 | 12篇 |
1991年 | 16篇 |
1990年 | 19篇 |
1989年 | 12篇 |
1988年 | 9篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 24篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 16篇 |
1981年 | 21篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 25篇 |
1977年 | 18篇 |
1976年 | 11篇 |
1975年 | 11篇 |
排序方式: 共有3635条查询结果,搜索用时 203 毫秒
991.
AIMS: The aim was to develop a novel and simple technique for the entrapment of fungal hyphae. METHODS AND RESULTS: A novel immobilization technique was developed by using a structural fibrous network (SFN) of papaya wood as an immobilizing matrix. The technique is simple and a stable entrapment was achieved simply by inoculating the Aspergillus terreus hyphae within culture medium containing SFN pieces for 3 days, without any prior chemical treatment. Results show that SFN has no detrimental effect both on growth and bioactivity of fungi. A 23.5% increase in the itaconic acid production by SFN-immobilized A. terreus was noted when compared with free biomass. SFN-immobilized fungal biomass retained 95% itaconic acid productivity for five repeated batch cycles, 7 days each, without any disintegration/release of hyphae in the production medium. CONCLUSIONS: This is the first report on the use of SFN, a structural material, as an immobilizing matrix for the entrapment of any kind of microbial biomass and its application in organic acid. SIGNIFICANCE AND IMPACT OF THE STUDY: The low cost of SFN and simplicity of the technique applied for immobilization of fungal hyphae within/onto SFN make its use ideal for the immobilization of fungal biomass to produce commercially valuable products. 相似文献
992.
Arendall WB Tempel W Richardson JS Zhou W Wang S Davis IW Liu ZJ Rose JP Carson WM Luo M Richardson DC Wang BC 《Journal of structural and functional genomics》2005,6(1):1-11
The high throughput of structure determination pipelines relies on increased automation and, consequently, a reduction of time spent on interactive quality control. In order to meet and exceed current standards in model accuracy, new approaches are needed for the facile identification and correction of model errors during refinement. One such approach is provided by the validation and structure-improvement tools of the MOLPROBITY web service. To test their effectiveness in high-throughput mode, a large subset of the crystal structures from the SouthEast Collaboratory for Structural Genomics (SECSG) has used protocols based on the MOLPROBITY tools. Comparison of 29 working-set and 19 control-set SECSG structures shows that working-set outlier scores for updated Ramachandran-plot, sidechain rotamer, and all-atom steric criteria have been improved by factors of 5- to 10-fold (relative to the control set or to a Protein Data Bank sample), while quality of covalent geometry, Rwork, Rfree, electron density and difference density are maintained or improved. Some parts of this correction process are already fully automated; other parts involve manual rebuilding of conformations flagged by the tests as trapped in the wrong local minimum, often altering features of functional significance. The ease and effectiveness of this technique shows that macromolecular crystal structures from either traditional or high-throughput determinations can feasibly reach a new level of excellence in conformational accuracy and reliability. 相似文献
993.
Automatic imaging and scoring of crystallization drops is an essential step in high-throughput crystallography. Presently,
white-light images of crystallization drops are acquired robotically and the images are analyzed and scored using pattern
recognition algorithms. However, the scoring part remains unreliable as crystals and microcrystals are not always recognized
by existing feature-extraction and recognition algorithms. We propose a fundamental shift in crystal monitoring through spectroscopic
imaging of crystallization drops. This method converts the problem of automatic crystal detection from one of pattern recognition
into one of intensity (concentration) analysis. The latter can be more robust and reliable. 相似文献
994.
Kim SH Shin DH Liu J Oganesyan V Chen S Xu QS Kim JS Das D Schulze-Gahmen U Holbrook SR Holbrook EL Martinez BA Oganesyan N DeGiovanni A Lou Y Henriquez M Huang C Jancarik J Pufan R Choi IG Chandonia JM Hou J Gold B Yokota H Brenner SE Adams PD Kim R 《Journal of structural and functional genomics》2005,6(2-3):63-70
The initial aim of the Berkeley Structural Genomics Center is to obtain a near-complete structural complement of two minimal
organisms, closely related pathogens Mycoplasma genitalium and M. pneumoniae. The former has fewer than 500 genes and the latter fewer than 700 genes. To achieve this goal, the current protein targets
have been selected starting with those predicted to be most tractable and likely to yield new structural and functional information.
During the past 3 years, the semi-automated structural genomics pipeline has been set up from cloning, expression, purification,
and ultimately to structural determination. The results from the pipeline substantially increased the coverage of the protein
fold space of M. pneumoniae and M. genitalium. Furthermore, about 1/2 of the structures of ‘unique’ protein sequences revealed new and novel folds, and over 2/3 of the
structures of previously annotated ‘hypothetical proteins’ inferred their molecular functions. 相似文献
995.
Jeon WB Aceti DJ Bingman CA Vojtik FC Olson AC Ellefson JM McCombs JE Sreenath HK Blommel PG Seder KD Burns BT Geetha HV Harms AC Sabat G Sussman MR Fox BG Phillips GN 《Journal of structural and functional genomics》2005,6(2-3):143-147
The Center for Eukaryotic Structural Genomics (CESG) has established procedures for the purification of Arabidopsis proteins in a high-throughput mode. Recombinant proteins were fused with (His)(6)-MBP tags at their N-terminus and expressed in Escherichia coli. Using an automated AKTApurifier system, fusion proteins were initially purified by immobilized metal affinity chromatography (IMAC). After cleavage of (His)(6)-MBP tags by TEV protease, (His)(6)-MBP tags were separated from target proteins by a subtractive 2nd IMAC. As a part of quality assurance, all purified proteins were subjected to MALDI-TOF and ESI mass spectrometry to confirm target identity and integrity, and determine incorporation of seleno-methionine (SeMet) and (15)N and (13)C isotopes. The protocols have been used successfully to provide high quality proteins that are suitable for structural studies by X-ray crystallography and NMR. 相似文献
996.
Bonanno JB Almo SC Bresnick A Chance MR Fiser A Swaminathan S Jiang J Studier FW Shapiro L Lima CD Gaasterland TM Sali A Bain K Feil I Gao X Lorimer D Ramos A Sauder JM Wasserman SR Emtage S D'Amico KL Burley SK 《Journal of structural and functional genomics》2005,6(2-3):225-232
Structural GenomiX, Inc. (SGX), four New York area institutions, and two University of California schools have formed the
New York Structural GenomiX Research Consortium (NYSGXRC), an industrial/academic Research Consortium that exploits individual
core competencies to support all aspects of the NIH-NIGMS funded Protein Structure Initiative (PSI), including protein family
classification and target selection, generation of protein for biophysical analyses, sample preparation for structural studies,
structure determination and analyses, and dissemination of results. At the end of the PSI Pilot Study Phase (PSI-1), the NYSGXRC
will be capable of producing 100–200 experimentally determined protein structures annually. All Consortium activities can
be scaled to increase production capacity significantly during the Production Phase of the PSI (PSI-2). The Consortium utilizes
both centralized and de-centralized production teams with clearly defined deliverables and hand-off procedures that are supported
by a web-based target/sample tracking system (SGX Laboratory Information Data Management System, LIMS, and NYSGXRC Internal
Consortium Experimental Database, ICE-DB). Consortium management is provided by an Executive Committee, which is composed
of the PI and all Co-PIs. Progress to date is tracked on a publicly available Consortium web site (http://www.nysgxrc.org)
and all DNA/protein reagents and experimental protocols are distributed freely from the New York City Area institutions. In
addition to meeting the requirements of the Pilot Study Phase and preparing for the Production Phase of the PSI, the NYSGXRC
aims to develop modular technologies that are transferable to structural biology laboratories in both academe and industry.
The NYSGXRC PI and Co-PIs intend the PSI to have a transforming effect on the disciplines of X-ray crystallography and NMR
spectroscopy of biological macromolecules. Working with other PSI-funded Centers, the NYSGXRC seeks to create the structural
biology laboratory of the future. Herein, we present an overview of the organization of the NYSGXRC and describe progress
toward development of a high-throughput Gene→Structure platform. An analysis of current and projected consortium metrics reflects
progress to date and delineates opportunities for further technology development. 相似文献
997.
Singh S Cornilescu CC Tyler RC Cornilescu G Tonelli M Lee MS Markley JL 《Protein science : a publication of the Protein Society》2005,14(10):2601-2609
We report the three-dimensional structure of a late embryogenesis abundant (LEA) protein from Arabidopsis thaliana gene At1g01470.1. This protein is a member of Pfam cluster PF03168, and has been classified as a LEA14 protein. LEA proteins are expressed under conditions of cellular stress, such as desiccation, cold, osmotic stress, and heat. The structure, which was determined by NMR spectroscopy, revealed that the At1g01470.1 protein has an alphabeta-fold consisting of one alpha-helix and seven beta-strands that form two antiparallel beta-sheets. The closest structural homologs were discovered to be fibronectin Type III domains, which have <7% sequence identity. Because fibronectins from animal cells have been shown to be involved in cell adhesion, cell motility, wound healing, and maintenance of cell shape, it is interesting to note that in plants wounding or stress results in the overexpression of a protein with fibronectin Type III structural features. 相似文献
998.
Structural characterization of the maytansinoid-monoclonal antibody immunoconjugate, huN901-DM1, by mass spectrometry 总被引:1,自引:0,他引:1
Wang L Amphlett G Blättler WA Lambert JM Zhang W 《Protein science : a publication of the Protein Society》2005,14(9):2436-2446
Immunoconjugates are being explored as novel cancer therapies with the promise of target-specific drug delivery. The immunoconjugate, huN901-DM1, composed of the humanized monoclonal IgG1 antibody, huN901, and the maytansinoid drug, DM1, is being tested in clinical trials to treat small cell lung carcinoma (SCLC). huN901-DM1 contains an average of three to four DM1 drug molecules per huN901 antibody molecule. The drug molecules are linked to huN901 through random modification of huN901 at epsilon-amino groups of lysine residues, thus yielding a heterogeneous population of conjugate species. We studied the drug distribution profile of huN901-DM1 by electrospray time-of-flight mass spectrometry(ESI-TOFMS), which showed that one to six DM1 drug molecules were attached to an antibody molecule. Both light and heavy chains contained linked drugs. The conjugation sites in both chains were determined by peptide mapping using trypsin and Asp-N protease digestion. Trypsin digestion identified modified lysine residues, since these residues were no longer susceptible to enzymatic cleavage after conjugation with the drug. With respect to Asp-N digestion, modified peptides were identified by observing a mass increase corresponding to the modification. The two digestion methods provided consistent results, leading to the identification of 20 modified lysine residues in both light and heavy chains. Each lysine residue was only partially modified. No conjugation sites were found in complementarity determining regions (CDRs). Using structural models of human IgG1, it was found that modified lysine residues were on the surface in areas of structural flexibility and had large solvent accessibility. 相似文献
999.
Wu Z Delaglio F Wyatt K Wistow G Bax A 《Protein science : a publication of the Protein Society》2005,14(12):3101-3114
The solution structure of murine gammaS-crystallin (gammaS) has been determined by multidimensional triple resonance NMR spectroscopy, using restraints derived from two sets of dipolar couplings, recorded in different alignment media, and supplemented by a small number of NOE distance restraints. gammaS consists of two topologically similar domains, arranged with an approximate twofold symmetry, and each domain shows close structural homology to closely related (approximately 50% sequence identity) domains found in other members of the gamma-crystallin family. Each domain consists of two four-strand "Greek key" beta-sheets. Although the domains are tightly anchored to one another by the hydrophobic surfaces of the two inner Greek key motifs, the N-arm, the interdomain linker and several turn regions show unexpected flexibility and disorder in solution. This may contribute entropic stabilization to the protein in solution, but may also indicate nucleation sites for unfolding or other structural transitions. The method used for solving the gammaS structure relies on the recently introduced molecular fragment replacement method, which capitalizes on the large database of protein structures previously solved by X-ray crystallography and NMR. 相似文献
1000.
Protein surface analysis for function annotation in high-throughput structural genomics pipeline 总被引:3,自引:0,他引:3
Binkowski TA Joachimiak A Liang J 《Protein science : a publication of the Protein Society》2005,14(12):2972-2981
Structural genomics (SG) initiatives are expanding the universe of protein fold space by rapidly determining structures of proteins that were intentionally selected on the basis of low sequence similarity to proteins of known structure. Often these proteins have no associated biochemical or cellular functions. The SG success has resulted in an accelerated deposition of novel structures. In some cases the structural bioinformatics analysis applied to these novel structures has provided specific functional assignment. However, this approach has also uncovered limitations in the functional analysis of uncharacterized proteins using traditional sequence and backbone structure methodologies. A novel method, named pvSOAR (pocket and void Surface of Amino Acid Residues), of comparing the protein surfaces of geometrically defined pockets and voids was developed. pvSOAR was able to detect previously unrecognized and novel functional relationships between surface features of proteins. In this study, pvSOAR is applied to several structural genomics proteins. We examined the surfaces of YecM, BioH, and RpiB from Escherichia coli as well as the CBS domains from inosine-5'-monosphate dehydrogenase from Streptococcus pyogenes, conserved hypothetical protein Ta549 from Thermoplasm acidophilum, and CBS domain protein mt1622 from Methanobacterium thermoautotrophicum with the goal to infer information about their biochemical function. 相似文献