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171.
Erdem Yavuz Gülay Bayramoğlu B. Filiz Şenkal M. Yakup Arıca 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2009,877(14-15):1479-1486
Crosslinked-poly(vinylbenzylchloride), poly(VBC), beads were prepared by suspension polymerization and poly(glycidylmethacrylate) was grafted by surface-initiated-atom radical polymerization (SI-ATRP) technique. Epoxy groups of the grafted poly(GMA) were reacted with hydrazine and ammonia to create an affinity binding sites. The hydrazine and amine functionalized poly(VBC-g-GMA) beads were used as an affinity support for adsorption of invertase from solution and yeast crude extract. The influence of pH, equilibrium time, ionic strength and initial invertase concentration on the adsorption capacities of both hydrazine and amine functionalized beads has been investigated. Maximum invertase adsorptions onto hydrazine and amine functionalized beads, were 86.7 and 30.4 mg/g at pH 4.0 and 5.5, respectively. The experimental equilibrium data fitted well to the Temkin isotherm model. Finally, the hydrazine functionalized poly(VBC-g-GMA) beads were used for the purification of invertase from crude yeast extract in a batch system and the purity of the eluted invertase from the hydrazine functionalized beads was determined as 92% by HPLC from single step purification protocol. 相似文献
172.
Manuel A. Arteaga Juan D. Delgado Rüdiger Otto José M. Fernández-Palacios José R. Arévalo 《Biological invasions》2009,11(4):1071-1086
Islands are paradigms of the pervasive spread of alien plants, but little work has been done assessing pattern and cause of
the distribution of such plants in relation to roads on oceanic islands. We studied richness, composition, and distribution
of alien plants and compared them with native species along roads on Tenerife (Canary Islands). We studied a single road transect
that sampled two contrasting wind-facing aspects (leeward versus windward) and ran from coastal Euphorbia scrubland through thermophilous scrubland to Makaronesian laurel forest at the top of a mountainous massif. We evaluated
the effects of elevation, aspect, distance to urban nuclei, and several road-edge features (including road-edge width and
management—implying disturbance intensity), using regression models, analysis of variance, and multivariate ordination methods.
Richness of both endemics and native nonendemics was explained by elevation (related to well-defined vegetation belts), steepness
of the edge slope, and cover of rocky ground. Despite a short elevational gradient (0–650 m), we found clear altitudinal zonation
by biogeographic origin of both nonendemic natives and aliens, and altitudinal distribution of aliens followed the same zonation
as that of natives. Alien species’ richness was related to management intensity determining edge disturbance, road-edge width,
and distance to the nearest urban nuclei (propagule sources). Different variables explained distribution patterns of natives,
endemics, and aliens along roadsides on leeward and windward aspects. Altitude and aspect also had a strong influence on the
frequency of life strategies (woody species, annuals and biennial/perennial herbs) of roadside plant communities. Due to harsher
environmental filters operating on the leeward aspect, alien species were distributed along the altitudinal gradient in apparent
consistency with general biogeographical affinities. Tropical/subtropical taxa showed exponential decrease with increasing
elevation, Mediterranean taxa showed a unimodal response (i.e., maximum richness at mid elevation, minimum at the extremes
of the gradient), and temperate taxa showed linear increase with elevation. Native but nonendemic species followed analogous
trends to those of aliens. This suggests climatic matching as a prerequisite for successful invasion of this topographically
complex island. Other road traits, such as edge width, slope steepness, soil cover, and road-edge disturbance intensity may
play a complementary role, at a more local scale, to shape the distribution of alien plants on these island roads. 相似文献
173.
J. R. Arévalo R. Otto C. Escudero S. Fernández-Lugo M. Arteaga J. D. Delgado J. M. Fernández-Palacios 《Plant Ecology》2010,209(1):23-35
Biological homogenization is defined as a process that occurs when native species are replaced by common and dominant exotic
species or due to depletion and expansion of native species, reducing the beta diversity between areas or habitats. Islands
are particularly vulnerable to plant invasion, and as a consequence, homogenization is a process that can become faster and
more intense in islands than in continental areas. We recorded vascular plant species composition in roadside communities
along a strong altitudinal gradient using plots beside the road and at two distances from the road (0–50 and 50–100 m). We
analyzed the results separately for each group of plots with a Detrended Correspondence Analysis (DCA) including and excluding
exotic species. The results revealed that where exotic species were most abundant, i.e., at the road edge, they can create
an effect of floristic homogenization where three similar roads are compared. At a distance of >50 m from the road, where
exotic species are less frequent, this effect has already disappeared, indicating that it is a local phenomenon, closely related
to the highly disturbed roadside environment. Furthermore, floristic homogenization seems to be more important at higher altitudes
(>1000 m), probably related to higher diversity in native plant communities and lower levels of human disturbances. Roads
allow humans to reach relatively remote and sometimes well-conserved areas, and, at the same time, facilitate the spread of
exotic plants and the most common native species which can locally create floristic homogenization in roadside communities
on this oceanic island. A deeper understanding of the effects of these anthropogenic corridors at the local and regional scales
is therefore required to integrate road planning and management with the aim of conserving the value of the natural areas. 相似文献
174.
Marlen Castellanos Zurina Cinza Zaily Dorta Gloria Veliz Héctor Vega Irma Lorenzo Sergio Ojeda Santiago Dueñas‐Carrera Liz Alvarez‐Lajonchere Gillian Martínez Elena Ferrer Miladys Limonta Marbelis Linares Odalis Ruiz Boris Acevedo Dinorah Torres Gabriel Márquez Luis Herrera Enrique Arús 《The journal of gene medicine》2010,12(1):107-116
175.
CD34(+)-selected stem cell boost for delayed or insufficient engraftment after allogeneic stem cell transplantation 总被引:1,自引:0,他引:1
Oyekunle A Koehl U Schieder H Ayuk F Renges H Fehse N Zabelina T Fehse B Klingebiel T Sputtek A Zander A Kröger N 《Cytotherapy》2006,8(4):375-380
BACKGROUND: Poor graft function without rejection may occur after stem cell transplantation (SCT). CD34(+) stem cell boost (SCB) can restore marrow function but may induce or exacerbate GvHD. We therefore investigated the feasibility and efficacy of CD34(+)-selected SCB in some patients with poor graft function. We present the results for eight patients (median age 46 years) transplanted initially for myelofibrosis, acute leukemia, myeloma and NHL. Six patients had received HLA-matched and two mismatched grafts (PB, BM; n=5, 3). After a median of 128 days post-transplant, the median leukocyte and platelet counts were, respectively, 2.05/nL and 18/nL. None had achieved platelet counts >50/nL even though donor chimerism was >95% in seven recipients. METHODS: Positive selection of CD34(+) stem cells was performed on a CliniMACS device, observing GMP and achieving a median of 98.5% purity. The patients received a median of 1.7 x 10(6)/kg CD34(+) cells and 2.5 x 10(3)/kg CD3(+) T lymphocytes. RESULTS: Hemograms at days +30, +60 and +90, respectively, showed steadily increasing median leukocyte (2.55, 3.15 and 4.20/nL) and platelet (29, 39 and 95/nL) counts. After a median follow-up of 144 days, five patients remained alive. No patient had developed acute or chronic GvHD. One patient died of leukemic relapse and two others of systemic mycosis. DISCUSSION: These preliminary results point to the possibility of safely improving graft function using CD34(+) positively selected stem cells without necessarily increasing the incidence of GvHD in patients with poor graft function post-SCT. Experience with more patients and longer follow-up should clarify the optimal role for this procedure. 相似文献
176.
Nuria González-Montalbán Elena García-Fruitós Salvador Ventura Anna Arís Antonio Villaverde 《Microbial cell factories》2006,5(1):26-9
Background
The molecular mechanics of inclusion body formation is still far from being completely understood, specially regarding the occurrence of properly folded, protein species that exhibit natural biological activities. We have here comparatively explored thermally promoted, in vivo protein aggregation and the formation of bacterial inclusion bodies, from both structural and functional sides. Also, the status of the soluble and insoluble protein versions in both aggregation systems have been examined as well as the role of the main molecular chaperones GroEL and DnaK in the conformational quality of the target polypeptide. 相似文献177.
Gefen E Ar A 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2006,144(1):58-62
Scorpions of the family Buthidae have been shown to be more desiccation resistant in comparison with sympatric Scorpionidae species. This has been attributed to the surface-dwelling existence of the former, which unlike most other scorpion species do not avoid environmental extremes by burrowing. Still, within Buthidae, the mesic Buthotus judaicus showed better osmoregulatory capacities than the xeric Leiurus quinquestriatus, largely as a result of its high resistance to water loss. However, B. judaicus exhibited poor ability to regulate its haemolymph osmolarity at 37 degrees C. In this study we report a sharp increase in water loss rates of B. judaicus at the 30-35 degrees C temperature range compared to that measured for L. quinquestriatus, which could explain the poor osmoregulatory performance of the former at higher ambient temperatures. The increase in water loss rates of B. judaicus at high temperatures is not coupled with a similar increase in respiratory rate, suggesting an increase in cuticular permeability. We suggest that this increase in cuticular permeability, which may result from a relatively low critical transition temperature, contributes to limiting the distribution of B. judaicus to habitats of moderate environmental conditions. 相似文献
178.
Aráoz R Honoré N Banu S Demangel C Cissoko Y Arama C Uddin MK Hadi SK Monot M Cho SN Ji B Brennan PJ Sow S Cole ST 《Microbes and infection / Institut Pasteur》2006,8(8):2270-2276
In addition to multidrug therapy, elimination of leprosy requires improved diagnostic methods. Using a comparative genomics approach, 17 potential protein antigens (MLP) that are restricted to Mycobacterium leprae, or of limited distribution, were produced and tested for antigen-specific immune responses on leprosy patients, healthy contacts of leprosy patients, and tuberculosis patients in Mali and Bangladesh, as well as on non-endemic controls. T-cell antigenicity of MLP was confirmed by IFN-gamma production in whole-blood assays with the highest responses observed in paucibacillary leprosy patients and healthy contacts. Four MLP behaved well in both countries and induced significantly different responses between the study groups. Peptides carrying T cell epitopes from one of the antigens gave promising results in restimulation assays in mice and immune responses were not influenced by prior exposure to BCG or environmental mycobacteria. This study provides the immunological framework for the development of a specific, peptide-based immunodiagnostic test for leprosy. 相似文献
179.
Ar A Tazawa H 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》1999,124(4):250-500
Bird embryos may be regarded as developing in their thermo-neutral zone, at rest, and stay in the egg for a fixed period of time until hatching. It is therefore interesting to investigate if they follow the same 'rule' set for adult homeotherms, which states that, within a taxonomically or functionally defined category such as mammals or birds, the number of heart beats throughout the life span (sL) is more or less constant. This rule stems from the allometric relationships between heart rate (fH) and body mass (mB) and between sL and mB. As a step towards understanding the general allometric nature of avian embryonic physiology we analyzed the fH values of avian embryos in relation to their incubation span (sI). Data from 30 species were selected from the scientific literature for the analyses. Values obtained from invasive methods which were judged to grossly alter natural incubation conditions, or from undefined or unmatched temperature conditions were not used. These include most values obtained below the first 30% of the incubation. Also, data obtained after internal pipping were discarded since hatching activity influences them. Values for sI and egg mass (mE) as representatives of embryonic mass were also collected. Embryonic fH was normalized to 70.1-80% sI. At 20.1-30% sI it was only 85% of the value at 70.1-80% sI and increased to a plateau at about 50.1-60% sI. It was almost constant among species between 50.1 and 60% sI and pre-internal pipping (PIP) time and thus, the mean fH value between 50.1 and 60% sI and between 90.1 and 100% excluding pipped eggs (fH) was taken as a representative value for each given species. The fH (min-1) and the corresponding sI (days) values for the 30 species, scaled with mE (g) as follows: fH = 371.1.mE-0.112 and: sI = 12.29.mE+0.209. Both powers were significantly different from 0. The product of fH and sI (fH.sI), representing the total number of heartbeats throughout the incubation, scaled with mE for the entire data set as follows: fH.sI = 6.565 x 10(+6).mE+0.096, where the +0.096 power is significantly different from 0. Values for fH.sI from embryos of altricial birds tended to concentrate at the low mE end of the plot while those of the precocial ones tended towards the high end. Separate analyses showed that the mE power for the combined altricial and semi-altricial species (ASA), and the combined precocial and semi precocial species (PSP), of log fH.sI against log mE regressions, were both insignificantly different from 0. Thus, means of fH.sI for ASA and PSP were calculated. The mean ASA value of 7.27 x 10(+6) heartbeats for fH.sI, was significantly different from the mean PSP value of 10.93 x 10(+6). The difference of 3.66 x 10(-6) (33.5%) heartbeats can be attributed to either the more advanced stage of the PSP hatchlings at hatch, to the larger mE values of these hatchlings, to the difference in water fraction of the hatchlings or all. The result of a linear regression of fH.sI against the rate of sI completion (the inverse of incubation span, fI; day-1) was: fH.10(-6) = 0.205 + 3.940.sI-1. Thus, the faster is the average rate of development accomplished per day (shorter incubation) the higher is daily heart rate. Data tended to cluster such that large eggs, mostly of the PSP type with relatively low fH, complete 2-4% of their incubation per day, while small, ASA type eggs with relatively high fH, complete 6-8% of their incubation time per day. We conclude that, at this stage of knowledge, the data is insufficient to resolve whether the different modes of hatch stage alone can explain differences in the total number of heartbeats throughout embryonic life among all bird species, or egg mass and water content differences contribute variability. This should be investigated on a larger sample of species in more depth. 相似文献
180.
Quindós G Abarca L Carrillo-Muñoz AJ Arévalo MP Bornay FJ Casals JB Hernández-Molina JM Iglesias I Linares MJ Martín-Mazuelos E Pereiro Ferreirós M Rezusta A Rubio MC Salesa R San Millán R Torres-Rodríguez JM 《Revista iberoamericana de micología》1999,16(2):97-100
Twelve Spanish laboratories collected 325 yeast clinical isolates during a 30 day's period, among them 224 Candida albicans, 30 Candida glabrata, and 27 Candida parapsilosis. In vitro antifungal susceptibility to amphotericin B, ketoconazole, fluconazole and itraconazole was determined by an agar diffusion test (Neo-Sensitabs, Rosco, Denmark). All the isolates tested were susceptible in vitroto amphotericin B and nearly all (97.2%) to itraconazole. In vitrosusceptibility to fluconazole and ketoconazole was high (90.2% and 91.4% of isolates, respectively) but showed variations depending on the species tested. Resistance to fluconazole and ketoconazole was low in C. albicans (4% and 3%, respectively), but 30% of Candida guilliermondii and 36% of C. glabrata isolates were resistant to fluconazole. Ketoconazole resistance was observed in 40% of C. glabrata, and 17% of Candida tropicalis. Resistance to antifungal drugs is very low in Spain and it is related to non-C. albicans isolates. 相似文献