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1.
To investigate pain that occurs in the absence of painful stimulation, normal subjects were connected to a sham stimulator and were told that a headache could occur as a result of the electrical current they would receive. Half of the subjects who received this suggestion reported pain. The frequency and intensity of pain reports in a group which was given prior pain experience as a reference point in reporting pain and in a group which was exposed to a manipulation designed to reduce intentional deception were not significantly different from the pain reports of a group not exposed to these manipulations. The frequency of pain reports in subjects not connected to the sham stimulator but still asked to report pain was 25% which was significantly less than the frequency for subjects who were told there would be stimulation to the head. Pain ratings increased as the settings of the sham stimulator were increased. Subjects who reported pain had significantly fewer electrodermal responses to tones signaling them to prepare for a reaction time task. The results suggest that pain can be produced in the absence of peripheral stimulation. The pain does not appear to be due to intentional deception or the lack of a standard for comparison, but is strongly influenced by environmental cues. Psychophysiologically, pain responders were less attentive to signal stimuli. 相似文献
2.
Balloon dacryocystoplasty: indications and contraindications 总被引:3,自引:0,他引:3
3.
To assess its reliability as a marker of cardiomegaly in elderly patients, we compared a clinical assessment of heart size with that calculated from chest radiography. In 100 hospitalized subjects of median age 78 years, the apex beat was palpable in only 35% and its palpability declined with increasing age. Even when palpable, the apex beat had low specificity (74%) and sensitivity (69%) as a marker of cardiomegaly and its positive predictive value (69%) and negative predictive value (74%) were poor. The clinical assessment of heart size in elderly hospitalized patients should be interpreted with caution. 相似文献
4.
In recent years there has been considerable improvement in short-tandem repeat (STR) investigations of hair, which were previously
marred by small amounts of nuclear DNA and its degradation. This study examined the suitability of two STR kits with shortened
amplicons for the investigation of hairs from routine casework. The overall sucess rate was more than 20%. Furthermore, the
usefulness of quantification with real-time ploymerase chain reaction as a screening method was demonstrated. 相似文献
5.
6.
Joaquín Martí M.C. Santa-Cruz Shirley A. Bayer Bernardino Ghetti Jos P. Hervs 《International journal of developmental neuroscience》2007,25(5):299-307
Generation and survival of midbrain dopaminergic (DA) neurons were investigated using tyrosine hydroxylase (TH) immunocytochemistry combined with tritiated thymidine autoradiography at appropriate anatomical levels throughout the anteroposterior (A/P) axes of the substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA). The wild-type (+/+) and homozygous weaver (wv/wv) mice used here were the offspring of pregnant dams injected with the radioactive precursor when the mesencephalic neurons were being produced (gestational days 11-15). Data reveal that, at postnatal day 90, depletion of TH-stained cells in the wv/wv presented an A/P pattern of increasing severity and, therefore, the DA cells located in posterior parts of the SNc or the VTA appear to be more vulnerable than the settled anterior neurons. When the time of neuron origin is inferred for each level of these cell groups, it is found that the neurogenesis span is similar for both experimental groups, although significant deficits in the frequency of wv/wv late-generated neurons were observed in any level considered. On the other hand, it has been found that TH-positive neurons were settled along the extent of the SNc and the VTA following precise and differential neurogenetic gradients. Thus, the acute rostrocaudal increase in the proportion of late-generated neurons detected in both+/+DA-cell groups is disturbed in the weaver homozygotes due to the indicated A/P depletion. 相似文献
7.
Short-survival, sequential, and long-survival thymidine radiograms of rat embryos, fetuses, and young pups were analyzed in order to examine the time of origin, settling pattern, and neuroepithelial site of origin of the anterior thalamic nuclei--the lateral dorsal (lateral anterior), anterodorsal, anteroventral and anteromedial nuclei--and of two rostral midline structures--the anterior paraventricular and paratenial nuclei. The neurons of the lateral dorsal nucleus are generated over a 3-day period between days E14-E16 and their settling pattern displays a combined lateral-to-medial and dorsal-to-ventral neurogenetic gradient. The bulk of the neurons of the anteroventral nucleus are generated over a 3-day period between days E15-E17 and settle with an oblique lateral-to-medial and ventral-to-dorsal neurogenetic gradient. The bulk of the neurons of the anteromedial nucleus are generated over a 2-day period between days E16-E17 and show the same settling pattern as the anteroventral nucleus. The neurons of the anterodorsal nucleus are generated over a 3-day period between days E15-E17 and show a lateral-to-medial neurogenetic gradient. The bulk of the neurons of the central part and lateral part of the paraventricular nucleus are generated over a 2-day period (E16-E17 and E17-E18, respectively) and each part displays a ventral-to-dorsal neurogenetic gradient. Finally, the bulk of the neurons of the paratenial nucleus are generated over a 4-day period between days E15-E18 and settle with a lateral-to-medial neurogenetic gradient. Observations are presented that the anterior thalamic nuclei, constituting the distinct "limbic thalamus," derive from a discrete neuroepithelial source. This is the crescent-shaped germinal matrix lining the diencephalic (medial) wall of the hitherto unrecognized anterior transitional promontory, which we call the anterior thalamic neuroepithelial lobule. On day E16 three migratory streams leave the anterior neuroepithelial lobule and, on the basis of their labeling pattern in relation to the neurogenetic gradients of the anterior thalamic nuclei, they are identified, from dorsal to ventral, as the putative migratory streams of the anterodorsal, anteroventral, and lateral dorsal nuclei. On day E17 the putative migratory stream of the anteromedial nucleus appears to leave the same neuroepithelial region that on the previous days was the source of the anteroventral nucleus. Dorsally, two neuroepithelial patches persist after day E17 and these are identified as the putative cell lines of the anterior paraventricular and paratenial nuclei. 相似文献
8.
R. L. Kaufmann R. M. Bayer C. Harnasch 《Pflügers Archiv : European journal of physiology》1972,332(2):96-116
Summary An investigation was carried out on isolated cat's papillary muscle in order to study displacement effects upon the intensity and the time course of the contractile activity. Displacements occurring before or very early during a contractile cycle produce effects which can be entirely explained on the basis of the cardiac active length-tension relation. Displacements occurring later exhibit additional effects in so far as either stretches or releases induce a drop of contractile activation such that the course of the subsequent tension development is markedly below that of the same displacement applied earlier. In order to separate these effects from those based on the active length-tension correlation experiments were performed in which very short release-stretch or stretch-release operations were applied so that the muscle length was virtually the same at the beginning and at the end of the operation. The results obtained under these conditions can be summarized as follows.The extend to which contractile tension drops after a stretch-release or a release-stretch cycle has been applied depends upon (1) the stimulus intervention interval (2) the length change performed (3) the velocity of displacement during the intervention. It is not dependent on the initial muscle length. Increasing the extracellular Ca-concentration considerably reduces the displacement effects. The results are tentatively explained by assuming an internal feedback loop between a variable of the contractile machinary and the preceding mechanism of activation.This investigation was supported by the Deutsche Forschungsgemeinschaft (grant Ka 287, 1+3). 相似文献
9.
Duncan WC; Illingworth PJ; Young FM; Fraser HM 《Human reproduction (Oxford, England)》1998,13(9):2532-2540
The molecular mechanisms involved in luteolysis are still unclear in the
primate. This study aimed to investigate the effect of induced luteolysis
on the ovarian luteinizing hormone (LH) receptor and the steroidogenic
enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset
monkey. Luteolysis was induced in the mid-luteal phase either directly by
systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal
using systemic gonadotrophin releasing hormone antagonist (GnRHant)
treatment. The LH receptor was studied by isotopic mRNA in-situ
hybridization and in-situ ligand binding and 3beta-HSD expression was
studied using isotopic mRNA in-situ hybridization and immunohistochemistry.
Induced luteolysis was associated with a reduction in the expression of LH
receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a
reduction in the LH receptor (P < 0.05) and 3beta-HSD protein
concentrations within 24 h. There were no differences in the findings
whether luteolysis was induced with PGF2alpha or GnRHant. This study shows
that disparate mechanisms to induce luteolysis in the primate result in an
identical rapid loss of the LH receptor and 3beta-HSD. In conclusion,
induced luteolysis leads to rapid loss of the steroidogenic pathway in
luteal cells.
相似文献
10.