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Neural correlates of behavioral gap detection in the inferior colliculus of the young CBA mouse 总被引:6,自引:0,他引:6
J. P. Walton R. D. Frisina J. R. Ison W. E. O'Neill 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,181(2):161-176
The gap detection paradigm is frequently used in psychoacoustics to characterize the temporal acuity of the auditory system.
Neural responses to silent gaps embedded in white-noise carriers, were obtained from mouse inferior colliculus (IC) neurons
and the results compared to behavioral estimates of gap detection. Neural correlates of gap detection were obtained from 78
single neurons located in the central nucleus of the IC. Minimal gap thresholds (MGTs) were computed from single-unit gap
functions and were found to be comparable, 1–2 ms, to the behavioral gap threshold (2 ms). There was no difference in MGTs
for units in which both carrier intensities were collected. Single unit responses were classified based on temporal discharge
patterns to steady-state noise bursts. Onset and primary-like units had the shortest mean MGTs (2.0 ms), followed by sustained
units (4.0 ms) and phasic-off units (4.2 ms). The longest MGTs were obtained for inhibitory neurons (xˉ = 14 ms). Finally,
the time-course of behavioral and neurophysiological gap functions were found to be in good agreement. The results of the
present study indicate the neural code necessary for behavioral gap detection is present in the temporal discharge patterns
of the majority of IC neurons.
Accepted: 6 February 1997 相似文献
3.
ObjectiveThe purpose of this work is to evaluate the impact of optimization of magnification on performance parameters of the variable resolution X-ray (VRX) CT scanner.MethodsA realistic model based on an actual VRX CT scanner was implemented in the GATE Monte Carlo simulation platform. To evaluate the influence of system magnification, spatial resolution, field-of-view (FOV) and scatter-to-primary ratio of the scanner were estimated for both fixed and optimum object magnification at each detector rotation angle. Comparison and inference between these performance parameters were performed angle by angle to determine appropriate object position at each opening half angle.ResultsOptimization of magnification resulted in a trade-off between spatial resolution and FOV of the scanner at opening half angles of 90°–12°, where the spatial resolution increased up to 50% and the scatter-to-primary ratio decreased from 4.8% to 3.8% at a detector angle of about 90° for the same FOV and X-ray energy spectrum. The disadvantage of magnification optimization at these angles is the significant reduction of the FOV (up to 50%). Moreover, magnification optimization was definitely beneficial for opening half angles below 12° improving the spatial resolution from 7.5 cy/mm to 20 cy/mm. Meanwhile, the FOV increased by more than 50% at these angles.ConclusionIt can be concluded that optimization of magnification is essential for opening half angles below 12°. For opening half angles between 90° and 12°, the VRX CT scanner magnification should be set according to the desired spatial resolution and FOV. 相似文献
4.
Yihe Lu Bojie Fu Liding Chen Zhiyun Ouyang Jianying Xu 《Biodiversity and Conservation》2006,15(8):2813-2827
Resolving the conflicts between biodiversity conservation and socioeconomic development is a global pursuit for the long-run
prospects of the human species. Based on Wenchuan County, a typical county in southwestern China, a group of 20 indicators
quantifying regional biodiversity and socioeconomic development was established to classify and evaluate the county area spatially.
A fuzzy c-means clustering (FCM) algorithm was used as the classification method. Three indices including BD, DL and DR characterizing
the value of biodiversity, the level and rate of socioeconomic development of the delineated regions were formulated. The
results indicated that Wenchuan County was optimally classified into 4 types of regions (region I to IV). The area percentages
of the regions vary widely from 4.3 to 65.7%. The sequences of the regions on biodiversity, socioeconomic development level,
and socioeconomic development rate were, respectively, IV > II > III > I, I > III > II > IV and III >I >II >IV. The spatial
strategy on coordinating biodiversity conservation and regional development is to develop mainly from the east(I, II, III)
and to conserve mainly in the west(IV). Eco-industry, such as eco-tourism and eco-agriculture, need to be emphasized in the
process of regional development. The quantitative methods used here may have a wide applicability. 相似文献
5.
Athenolide A,a New Steroidal Lactone from the Leaves of Athenaea martiana (Solanaceae) Determined by Means of HPLC‐HR‐MS‐SPE‐NMR Analysis 下载免费PDF全文
《化学与生物多样性》2018,15(1)
Athenaea (Solanaceae) is an endemic genus belonging to the Brazilian Atlantic Rainforest. Recently, botanical investigations suggested the re‐evaluation of the generic status of the genus Athenaea as a synonym of Aureliana. In this study, the first investigation of the Athenaea genus performed on Athenaea martiana by means of HPLC‐HR‐MS‐SPE‐NMR combined with high‐resolution radical scavenging profile led to identification of several phenolic acids as radical scavengers: protocatechuic acid ( 1 ), 4‐hydroxybenzoic acid ( 2 ), caffeic acid ( 3 ), vanillic acid ( 4 ), and ferulic acid ( 6 ). Additional analysis revealed a new steroidal lactone, named athenolide A ( 9 ). Their structures were elucidated by extensive use of NMR spectroscopy as well as HR‐MS. Chemotaxonomic considerations based on these results supported the chemical relationships between the Athenaea and Aureliana genera, in agreement with the recent botanical findings. 相似文献
6.
《Current biology : CB》2022,32(3):645-653.e8
Download : Download video (10MB) 相似文献
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ContextModerate-grained data may not always represent landscape structure in adequate detail which could cause misleading results. Certain metrics have been shown to be predictable with changes in scale; however, no studies have verified such predictions using independent fine-grained data.ObjectivesOur objective was to use independently derived land cover datasets to assess relationships between metrics based on fine- and moderate-grained data for a range of analysis extents. We focus on metrics that previous literature has shown to have predictable relationships across scales.MethodsThe study area was located in eastern Connecticut. We compared a 1 m land cover dataset to a 30 m resampled dataset, derived from the 1 m data, as well as two Landsat-based datasets. We examined 11 metrics which included cover areas and patch metrics. Metrics were analyzed using analysis extents ranging from 100 to 1400 m in radius.ResultsThe resampled data had very strong linear relationships to the 1 m data, from which it was derived, for all metrics regardless of the analysis extent size. Landsat-based data had strong correlations for most cover area metrics but had little or no correlation for patch metrics. Increasing analysis areas improved correlations.ConclusionsRelationships between coarse- and fine-grained data tend to be much weaker when comparing independent land cover datasets. Thus, trends across scales that are found by resampling land cover are likely to be unsuitable for predicting the effects of finer-scale elements in the landscape. Nevertheless, coarser data shows promise in predicting fine-grained for cover area metrics provided the analysis area used is sufficiently large. 相似文献
9.
Won Jae Choi 《Applied microbiology and biotechnology》2009,84(2):239-247
Enantiopure epoxides are high value-added synthons for the production of pharmaceuticals, agrochemicals, as well as versatile
fine chemicals and have broad scope of market demand for their applications. A major challenge in conventional organic synthesis
is to generate such compounds in high enantiopurity with reasonable yield. Among possible chemical and biological technologies
for enantiopure epoxide preparation, enzymatic kinetic resolution has been paid much attention with respect to its high enantioselectivity.
Epoxide hydrolase (EH) has shown promising characteristics for the preparation of enantiopure epoxides and vicinal diols during
enantioselective hydrolysis of racemic epoxides. EH is readily available from microbial resources thus it is being employed
for biohydrolysis of a variety of epoxides. Recent technical progress in EH-catalyzed enantioselective hydrolysis is summarized
in terms of exploration of novel EH, its functional improvement, high throughput assay, and preparative scale resolution process. 相似文献
10.