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排序方式: 共有10000条查询结果,搜索用时 187 毫秒
91.
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Torous DK Hall NE Illi-Love AH Diehl MS Cederbrant K Sandelin K Pontén I Bolcsfoldi G Ferguson LR Pearson A Majeska JB Tarca JP Hynes GM Lynch AM McNamee JP Bellier PV Parenteau M Blakey D Bayley J van der Leede BJ Vanparys P Harbach PR Zhao S Filipunas AL Johnson CW Tometsko CR Dertinger SD 《Environmental and molecular mutagenesis》2005,45(1):44-55
An interlaboratory study was performed to validate an anti-CD71/flow cytometry-based technique for enumerating micronucleated reticulocytes (MN-RETs) in mouse peripheral blood. These experiments were designed to address International Workshop on Genotoxicity Test Procedures validation criteria by evaluating the degree of correspondence between MN-RET measurements generated by flow cytometry (FCM) with those obtained using traditional microscopy-based methods. In addition to these cross-methods data, flow cytometric MN-RET measurements for each blood sample were performed at two separate sites in order to evaluate the reproducibility of data between laboratories. In these studies, groups of male CD-1 mice were treated with vehicle (saline or vegetable oil), a negative control (saline or vegetable oil), or four dose levels of five known genotoxicants (clastogens: cyclophosphamide, benzo[a]pyrene, 5-fluorouracil, methotrexate; aneugen: vincristine sulfate). Exposure occurred on 3 consecutive days via intraperitoneal injection, and blood samples were obtained approximately 24 hr after the final treatment. MN-RET frequencies were determined for each sample based on the analysis of 2,000 (microscopy) and 20,000 (FCM) reticulocytes. Regardless of the method utilized, each genotoxic agent was observed to cause statistically significant increases in the frequency of MN-RETs, and each response occurred in a dose-dependent manner. Spearman's correlation coefficient (rs) for FCM versus microscopy-based MN-RET measurements (nine experiments, 252 paired measurements) was 0.740, indicating a high degree of correspondence between methods. The rs value for all flow cytometric MN-RET measurements performed at the two independent sites was 0.857 (n = 248), suggesting that the automated method is highly transferable between laboratories. Additionally, the flow cytometric system offered advantages relative to microscopy-based scoring, including a greater number of cells analyzed, much faster analysis times, and a greater degree of objectivity. Collectively, data presented in this report suggest that the overall performance of mouse peripheral blood micronucleus tests is enhanced by the use of the flow cytometric scoring procedure. 相似文献
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95.
R. Shafiq Geoffrey W. Stuart Jennifer Sandbach Paul Maruff Jon Currie 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1998,118(2):221-229
Latencies of eye movements to peripheral targets are reduced when there is a short delay (typically 200 ms) between the offset
of a central visual fixation point and the target onset. This has been termed the gap effect. In addition, some subjects, usually with practice, exhibit a separate population of very short latency saccades, called express saccades. Both these phenomena have been attributed to disengagement of visual attention when the fixation point is extinguished. A
competing theory of the gap effect attributes it to disengagement of oculomotor fixation during the temporal gap. It is known
that auditory targets are effective in eliciting saccadic eye movements, and also that covert attention operates in the auditory
modality. If the gap effect and express saccades are due to disengagement of spatial attention, both should persist in the
auditory modality. However, fixation of gaze is largely under visual control. If the gap effect results from disengagement
of fixation, then at least a reduced effect should be seen in the auditory modality. Human subjects performed the gap task
and a control task in the dark, using auditory fixation points and saccadic targets, on five successive days. Despite this
practice, express saccades were not observed. There was a reliable gap effect, but the reduction in saccadic latency was only
17 ms, compared with 32 ms for the same subjects in the visual modality. This suggests that about half the gap effect is due
to disengagement of visual fixation. The remainder was not due to non-specific warning effects and could be attributed to
offset of the auditory fixation stimulus.
Received: 1 March 1996 / Accepted: 11 July 1997 相似文献
96.
97.
Fulvio Andruzzi Sukiman Suradi Geoffrey Pilcher 《Macromolecular chemistry and physics.》1982,183(9):2183-2190
The enthalpies of combustion of poly(ethylene oxide), ΔH(c)=-1178,7 ± 1,3 kJ . mol-1, and of a random copolymer of overall molar composition 0,41 (poly(ethylene oxide)) + 0,59 (poly(oxy-1,4-cyclohexylene)), ΔH(c)=-2566,4 ± 1,8 kJ . mol-1, were measured at 298,15 K by high-precision bomb calorimetry. The enthalpy of polymerisation of ethylene oxide was derived as ΔH (l → c) = -102,4 ± 1,6 kJ . mol-1. The enthalpy of copolymerisation of ethylene oxide and 7-oxabicyclo[2.2.1]heptane was ΔH (l → c) = -63,0 ± 2,1 kJ . mol-1, compared with -68,1 ± 1,6 kJ . mol-1 for producing the two homopolymers in the proportion in which the monomers were present in the copolymer. It is concluded that insertion of an ethylene oxide unit into a poly(oxy-1,4-cyclohexylene) chain does not affect the strain-energy by a significant amount. 相似文献
98.
Luby TM Cole G Baker L Kornher JS Ramstedt U Hedley ML 《Clinical immunology (Orlando, Fla.)》2004,112(1):45-53
Injection of microparticle-encapsulated DNA elicits immune responses to plasmid-encoded antigens in mice and humans. Cytochrome P450 CYP1B1 (CYP1B1) is a member of the CYP1 P450 enzyme family that is overexpressed in a variety of solid tumors. The work described herein was performed to study the kinetics of stimulating T cell responsiveness with an encapsulated DNA encoding CYP1B1 and provides support for the clinical development of this formulation. Immunization of HLA-A2/Kb transgenic mice with human CYP1B1 encoding plasmid DNA formulated in poly(lactide-co-glycolide) (PLG) microparticles elicits CD8+ T cells that respond to human CYP1B1-positive target cells. The duration of the immune response, the effect on the immune response of multiple injections, and the safety of repeated injections were studied. These results show that the PLG-encapsulated DNA therapeutic elicits durable immune responses to CYP1B1, the responses are dependent on repeat immunization, and that the formulation is well tolerated. 相似文献
99.
Practical aspects of functional MRI (NMR Task Group #8) 总被引:1,自引:0,他引:1
Price RR Allison J Massoth RJ Clarke GD Drost DJ;NMR Task Group # 《Medical physics》2002,29(8):1892-1912
100.
Neuropsychological Deficit and Academic Performance in Children and Adolescents Following Traumatic Brain Injury 总被引:1,自引:1,他引:1
Kinsella Glynda; Prior Margot; Sawyer Michael; Murtagh Douglas; Eisenmajer Richard; Anderson Vicki; Bryan Doug; Klug Geoffrey 《Journal of pediatric psychology》1995,20(6):753-767
Evaluated the utility of neuropsychological testing in predictingacademic outcome in children 1 year following traumatic braininjury (TBI). Fifty-one schoolage children who were admittedto hospital after TBI were assessed with a battery of neuropsychologicalmeasures at 3 months postinjury. Academic achievement was assessedat 3 and 12 months postinjury. The neuropsychological batteryincluded intelligence testing and measures of memory, learning,and speed of information processing. Academic outcome was assessedin terms of post-TBI changes in reading, spelling, and arithmetic;changes in teacher ratings of school performance; and changein school placement. According to logistic regression analysis,change in placement from regular to special education at 1-yearpost-TBI was predicted by injury severity and by neuropsychologicalperformance at 3 months post-TBI. Findings suggest that neuropsychologicaltesting is useful in identifying children with special educationalneeds subsequent to TBI. 相似文献