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71.
Cindy Johnston Stephan Eliez Jennifer Dyer‐Friedman David Hessl Bronwyn Glaser Christine Blasey Annette Taylor Allan Reiss 《American journal of medical genetics. Part A》2001,103(4):314-319
There have been contradictory findings in the fragile X (fraX) literature about possible neurocognitive and psychological symptoms due to the fraX premutation (pM). The purpose of the present study was to investigate the relationship between CGG repeat length and neurobehavioral functioning in carriers of the fraX pM. Eighty‐five female carriers of the pM with allele sizes ranging from 59–166 were administered a comprehensive IQ test (WAIS‐III) and completed a questionnaire designed to measure psychopathology (Symptom Checklist (SCL)‐90‐R). No relationship between allele size and cognition was identified. A significant negative relationship between allele size and age was found, as well as a positive relationship between allele size and depression. Follow‐up analyses separating small and large allele sizes (below and above 100 CGG repeats) indicated that individuals with larger allele sizes scored significantly higher on the Interpersonal Sensitivity and Depression subscales of the SCL‐90‐R. Despite the limitation of few individuals with high CGG repeat lengths, our findings suggest that females with larger premutated alleles (≥ 100 repeats) display some clinical manifestations of fraX syndrome. © 2001 Wiley‐Liss, Inc. 相似文献
72.
73.
D. V. Beard PhD B. M. Hemminger K. M. Denelsbeck R. E. Johnston 《Journal of digital imaging》1994,7(2):69-76
A considerable number of prototype and commerical workstations have been developed during the last 10 years for electronic display of computed tomographic (CT) images during clinical interpretation. These CT workstations have varied widely in the number and size of monitors available for the display of the medical images ranging from a single 1,024×1,204-pixel monitor, to eight 2,500×2,000-pixel monitors. Image display times also have varied considerably, ranging from as fast as. 11 seconds, to as slow as 26 seconds to fill a single monitor. No consensus has formed in the workstation community with regard to display area and response time requirements. To address this issue, we have constructed a time-motion model of CT interpretation. Model accuracy is experimentally verified with three workstations as well as with the film alternator. In general, CT interpretations with an electronic workstation become faster as display area increases and display time decreases. Results can be used by workstation designers and purchasers to roughly estimate differences in interpretation speeds among contending CT workstation designs. 相似文献
74.
Summary The whole cell lipid and sterol content of the drug resistant strains cyh1, cyh3 and cyh4 was compared with that of wild type by thin layer and gas liquid chromatography and by UV spectrophotometric analysis. The cyh3 and cyh4 strains had a decreased content of the unsaturated 18:1 fatty acid oleic acid, a decreased content of ergosterol and an increased content of 24,28 dehydroergosterol with respect to wild type. The cyh1 strain, however, only showed a decreased content of ergosterol and an increased content of 24,28 dehydro-ergosterol when compared to wild type. 相似文献
75.
Contrast Limited Adaptive Histogram Equalization image processing to improve the detection of simulated spiculations in dense mammograms 总被引:1,自引:0,他引:1
Pisano Etta D. Zong Shuquan Hemminger Bradley M. DeLuca Marla Johnston R. Eugene Muller Keith Braeuning M. Patricia Pizer Stephen M. 《Journal of digital imaging》1998,11(4):193-200
The purpose of this project was to determine whether Contrast Limited Adaptive Histogram Equalization (CLAHE) improves detection of simulated spiculations in dense mammograms. Lines simulating the appearance of spiculations, a common marker of malignancy when visualized with masses, were embedded in dense mammograms digitized at 50 micron pixels, 12 bits deep. Film images with no CLAHE applied were compared to film images with nine different combinations of clip levels and region sizes applied. A simulated spiculation was embedded in a background of dense breast tissue, with the orientation of the spiculation varied. The key variables involved in each trial included the orientation of the spiculation, contrast level of the spiculation and the CLAHE settings applied to the image. Combining the 10 CLAHE conditions, 4 contrast levels and 4 orientations gave 160 combinations. The trials were constructed by pairing 160 combinations of key variables with 40 backgrounds. Twenty student observers were asked to detect the orientation of the spiculation in the image. There was a statistically significant improvement in detection performance for spiculations with CLAHE over unenhanced images when the region size was set at 32 with a clip level of 2, and when the region size was set at 32 with a clip level of 4. The selected CLAHE settings should be tested in the clinic with digital mammograms to determine whether detection of spiculations associated with masses detected at mammography can be improved.Key Words: mammography, image processing, contrast limited adaptive histogram equalization, observer studies, breast cancer, spiculations 相似文献
76.
M. B. Dutia Alexander R. Johnston 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1998,118(2):148-154
The postnatal maturation of medial vestibular nucleus (MVN) neurones was examined in slices of the dorsal brainstem prepared
from balb/c mice at specific stages during the first postnatal month. Using spike-shape averaging to analyse the intracellularly recorded
action potentials and after-hyperpolarisations (AHPs) in each cell, all the MVN neurones recorded in the young adult (postnatal
day 30; P30) mouse were shown to have either a single deep AHP (type A cells), or an early fast and a delayed slow AHP (type
B cells). The relative proportions of the two subtypes were similar to those in the young adult rat. At P5, all the MVN cells
recorded showed immature forms of either the type A or the type B action potential shape. Immature type A cells had broad
spontaneous spikes, and the characteristic single AHP was small in amplitude. Immature type B cells had somewhat narrower
spontaneous spikes that were followed by a delayed, apamin-sensitive AHP. The delayed AHP was separated from the repolarisation
phase of the spike by a period of isopotentiality. Over the period P10–P15, the mean resting potentials of the MVN cells became
more negative, their action potential fall-times became shorter, the single AHP in type A cells became deeper, and the early
fast AHP appeared in type B cells. Until P15 cells of varying degrees of electrophysiological maturity were found in the MVN
but by P30 all MVN cells recorded were typical adult type A or type B cells. Exposure to the selective blocker of SK-type
Ca-activated K channels, apamin (0.3 μM), induced depolarising plateaux and burst firing in immature type B cells at rest.
The duration of the apamin-induced bursts and the spike frequency during the bursts were reduced but not abolished after blockade
of Ca channels in Ca-free artificial cerebrospinal fluid containing Cd2+. By contrast, in mature type B cells at rest apamin selectively abolished the delayed slow AHP but did not induce bursting
activity. Apamin had no effect on the action potential shape of immature type A cells. These data show that the apamin-sensitive
I
AHP is one of the first ionic conductances to appear in type B cells, and that it plays an important role in regulating the intrinsic
rhythmicity and excitability of these cells.
Received: 19 November 1996 / Accepted: 30 June 1997 相似文献
77.
In postnatal day 7 rats, a unilateral intrastriatal injection of 12.5 nmol of N-methyl-D-aspartate (NMDA) reproducibly injures the ipsilateral striatum, adjacent hippocampus and overlying cortex. The severity of injury can be quantified by comparing cerebral hemisphere weights in animals sacrificed 5 days after the injection. Co-injection of NMDA and the glycine receptor antagonists kynurenic acid (KYN) or 7-chlorokynurenic acid (7-CKA) reduced the severity of NMDA-induced damage in a dose-dependent fashion. One hundred nmol of KYN with 12.5 nmol of NMDA reduced average % damage from 19.3 +/- 0.9% (n = 9) to 2.3 +/- 0.5% (n = 6), P less than 0.001, ANOVA. Co-injection of 40 nmol of 7-CKA with 12.5 nmol of NMDA (n = 6) reduced average % damage from 17.1 +/- 1.6% (n = 15) to 3.0 +/- 0.6%, P less than 0.001, ANOVA. Concurrent injection of 1000 nmol glycine with 5 nmol NMDA did not increase the extent of NMDA-induced damage. Our results demonstrate that glycine receptor antagonists attenuate NMDA-induced brain injury in vivo. 相似文献
78.
Luo Ling Xu Daniel W. McVicar Adit Ben-Baruch Douglas B. Kuhns James Johnston Joost J. Oppenheim Ji Ming Wang 《European journal of immunology》1995,25(9):2612-2617
The diversity of monocyte chemotactic protein (MCP)3 target cell types, as well as the capacity of MCP3 to desensitize leukocyte responses to other CC chemokines, suggested that MCP3 may interact with multiple CC chemokine receptors. The purpose of this study is to establish how MCP3 binds and activates monocytes and neutrophils. We show that human monocytes exhibit high-affinity binding for 125I-MCP3 with an estimated Kd of 1–3 nM and about 10000 binding sites/cell. The binding of 125I-MCP3 to monocytes was progressively less well competed by CC chemokines macrophage inflammatory protein (MIP)lα (Kd = 5–10 nM), RANTES (Kd = 5–10 nM), MCP1 (monocyte chemoattractant and activating factor, or MCAF) (Kd = 60 nM) and MIP1β (Kd > 100 nM). On the other hand, unlabeled MCP3 displaced the binding of radiolabeled MIP1α, RANTES, MCP1 and MIP1β as effectively as the isologous CC chemokines. In agreement with the binding data, pretreatment of monocytes with MCP3 completely desensitized the calcium flux in response to MIP1α and RANTES. However, MIP1α and RANTES failed to desensitize the response of monocytes to MCP3. MCP3 and MCP1 partially desensitized each other's effects on monocytes. These binding and cross-desensitization results suggest that MCP3 binds and signals through other binding sites in addition to those shared with MIP1α, RANTES and MCP1. The unidirectional competition for MIP1β binding and signaling by MCP3 suggests the existence of an as-yet unidentified site for MCP3 shared with MIP1β. The existence of another unique binding site(s) for MCP3 was further shown by the failure of any of the other CC chemokines to compete effectively for MCP3 binding on neutrophils. MCP3 in our study was also the only human CC chemokine that consistently chemoattracted neutrophils. These results suggest that MCP3 is a ligand that can bind and activate a broad range of target cells through receptors shared by other CC chemokines as well as its own receptor. 相似文献
79.
80.