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971.
Carmen Lai Hugo M Horlings Marc J van de Vijver Eric H van Beers Petra M Nederlof Lodewyk FA Wessels Marcel JT Reinders 《BMC bioinformatics》2007,8(1):422
Background
Array comparative genome hybridization (aCGH) provides information about genomic aberrations. Alterations in the DNA copy number may cause the cell to malfunction, leading to cancer. Therefore, the identification of DNA amplifications or deletions across tumors may reveal key genes involved in cancer and improve our understanding of the underlying biological processes associated with the disease. 相似文献972.
973.
Junker B Maciejak W Darnell B Lester M Pollack M 《Bioprocess and biosystems engineering》2007,30(5):313-326
The feasibility of in situ measurement device for bubble size and distribution was explored. A novel in situ probe measurement
system, the EnviroCam™, was developed. Where possible, this probe incorporated strengths, and minimized weaknesses of historical
and currently available real-time measurement methods for bubbles. The system was based on a digital, high-speed, high resolution,
modular camera system, attached to a stainless steel shroud, compatible with standard Ingold ports on fermenters. Still frames
and/or video were produced, capturing bubbles passing through the notch of the shroud. An LED light source was integral with
the shroud. Bubbles were analyzed using customized commercially available image analysis software and standard statistical
methods. Using this system, bubble sizes were measured as a function of various operating parameters (e.g., agitation rate,
aeration rate) and as a function of media properties (e.g., viscosity, antifoam, cottonseed flour, and microbial/animal cell
broths) to demonstrate system performance and its limitations. For selected conditions, mean bubble size changes qualitatively
compared favorably with published relationships. Current instrument measurement capabilities were limited primarily to clear
solutions that did not contain large numbers of overlapping bubbles. 相似文献
974.
Lester W. Sinton Robin R. Braithwaite Carollyn H. Hall Margaret L. Mackenzie 《Applied microbiology》2007,73(24):7917-7925
The survival of enteric bacteria was measured in bovine feces on pasture. In each season, 11 cow pats were prepared from a mixture of fresh dairy cattle feces and sampled for up to 150 days. Four pats were analyzed for Escherichia coli, fecal streptococci, and enterococci, and four inoculated pats were analyzed for Campylobacter jejuni and Salmonella enterica. Two pats were placed on drainage collectors, and another pat was fitted with a temperature probe. In the first 1 to 3 weeks, there were increases (up to 1.5 orders of magnitude) in the counts of enterococci (in four seasons), E. coli (three seasons), fecal streptococci (three seasons), and S. enterica (two seasons), but there was no increase in the counts of C. jejuni. Thereafter, the counts decreased, giving an average ranking of the times necessary for 90% inactivation of C. jejuni (6.2 days from deposition) < fecal streptococci (35 days) < S. enterica (38 days) < E. coli (48 days) < enterococci (56 days). The pat temperature probably influenced bacterial growth, but the pattern of increases and decreases was primarily determined by desiccation; growth occurred when the water content was greater than 80%, but at a water content of 70 to 75% counts decreased. E. coli and enterococcus regrowth appeared to result from pat rehydration. Of 20 monthly leaching losses of E. coli, 16 were <10% of the total counts in the pat, and 12 were <1%. Drainage losses of C. jejuni (generally <1%) were detected for only 1 to 2 months. Although enterococci exhibited the best survival rate, higher final counts suggested that E. coli is the more practical indicator of bovine fecal pollution. 相似文献
975.
Yonghong Zhao Lester Gutshall Haiyan Jiang Audrey Baker Eric Beil Galina Obmolova Jill Carton Susann Taudte Bernard Amegadzie 《Protein expression and purification》2009,67(2):182-189
Fab (fragment that having the antigen binding site) of a monoclonal antibody (mAb) is widely required in biopharmaceutical research and development. At Centocor, two routes of Fab production and purification were used to enable a variety of research and development efforts, particularly, crystallographic studies of antibody–antigen interactions. One route utilizes papain digestion of an intact monoclonal antibody for Fab fragment production. After digestion, separation of the Fab fragment from the Fc (fragment that crystallizes) and residual intact antibody was achieved using protein A affinity chromatography. In another route, His-tagged Fab fragments were obtained by transient expression of an appropriate construct in mammalian cells, and typical yields are 1–20 mg of Fab fragment per liter of cell culture. The His-tagged Fab fragments were first captured using immobilized metal affinity chromatography (IMAC). To provide high quality protein sample for crystallization, Fabs from either proteolytic digestion or from direct expression were further purified using size-exclusion chromatography (SEC) and/or ion-exchange chromatography (IEC). The purified Fab fragments were characterized by mass spectrometry, SDS–PAGE, dynamic light scattering, and circular dichroism. Crystallization experiments demonstrated that the Fab fragments are of high quality to produce diffraction quality crystals suitable for X-ray crystallographic analysis. 相似文献
976.
Daniel Hayes Michael Jones Nigel Lester Cindy Chu Susan Doka John Netto Jason Stockwell Bradley Thompson Charles K. Minns Brian Shuter Nicholas Collins 《Reviews in Fish Biology and Fisheries》2009,19(3):295-312
One of the major challenges facing fishery scientists and managers today is determining how fish populations are influenced
by habitat conditions. Many approaches have been explored to address this challenge, all of which involve modeling at one
level or another. In this paper, we explore a process-oriented model approach whereby the critical population processes of
birth and death rates are explicitly linked to habitat conditions. Application of this approach to five species of Great Lakes
fishes including: walleye (Sander vitreus), lake trout (Salvelinus namaycush), smallmouth bass (Micropterus dolomieu), yellow perch (Perca flavescens), and rainbow trout (Onchorynchus mykiss), yielded a number of insights into the modeling process. One of the foremost insights is that processes determining movement
and transport of fish are critical components of such models since these processes largely determine the habitats fish occupy.
Because of the importance of fish location, an individual-based model appears to be a nearly inescapable modeling requirement.
There is, however, a paucity of field-based data directly relating birth, death, and movement rates to habitat conditions
experienced by individual fish. There is also a paucity of habitat information at a fine temporal and spatial scale for many
important habitat variables. Finally, the general occurrence of strong ontogenetic changes in the response of different life
stages to habitat conditions emphasizes the need for a modeling approach that considers all life stages in an integrated fashion. 相似文献
977.
978.
Herman MJ Sontrop Perry D Moerland René van den Ham Marcel JT Reinders Wim FJ Verhaegh 《BMC bioinformatics》2009,10(1):389-22
Background
Large discrepancies in signature composition and outcome concordance have been observed between different microarray breast cancer expression profiling studies. This is often ascribed to differences in array platform as well as biological variability. We conjecture that other reasons for the observed discrepancies are the measurement error associated with each feature and the choice of preprocessing method. Microarray data are known to be subject to technical variation and the confidence intervals around individual point estimates of expression levels can be wide. Furthermore, the estimated expression values also vary depending on the selected preprocessing scheme. In microarray breast cancer classification studies, however, these two forms of feature variability are almost always ignored and hence their exact role is unclear. 相似文献979.
980.
Richard T. Lester Xiao-Dan Yao T. Blake Ball Lyle R. McKinnon Were R. Omange Rupert Kaul Charles Wachihi Walter Jaoko Kenneth L. Rosenthal Francis A. Plummer 《PloS one》2009,4(5)