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The proportion of spermatozoa exhibiting the vigorous motilitybehaviour termed ’hyperactivation‘ (HA) has beenshown to be increased following removal of seminal plasma andstimulation with chemical agents such as pentoxifylline. Theaim of this study was to examine the relationship between theproportion of HA in cryopreserved semen samples from sperm donorsand the corresponding pregnancy rates achieved by donor insemination.Cryopreserved samples from 20 men were incubated in the presenceor absence of 3 mM pentoxifylline for 1 h and the %HA determinedin each sample. The relationship between pregnancy rate, theproportion of HA spermatozoa in control and pentoxifyllinetreatedgroups and the change in %HA following pentoxifylline treatment(HA) as well as the mean semen characteristics for each donor[sperm count, motility (%), motility index, normal morphology(%), post-thaw motility (%) and post-thaw motility index] wereexamined by logistic regression of the occurrence of clinicalpregnancy with each insemination. Both HA and mean post-thawmotility index were significantly related to pregnancy ratesand together accounted for 64% of the observed variation inpregnancy rates.  相似文献   
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The effect of the nitric oxide synthase inhibitor N-nitro- -arginine methyl ester (L-NAME) on the basal and stimulation-evoked release of dopamine (DA) and acetylcholine (ACh) was investigated in rat striatum. The experiments were carried out in isolated superfused striatal slices, loaded with either [3H]-dopamine or [3H]-choline.We have found that L-NAME reduced the elecrical field stimulation-evoked release of DA, while its enantiomer N-nitro-D-arginine methyl ester (D-NAME) was ineffective. In the presence of the nitric oxide (NO) precursor -arginine L-NAME failed to influence DA release. Furthermore, treatment with the N-methyl- -aspartate (NMDA) receptor antagonist MK-801 completely reversed the effect of L-NAME on striatal DA release. In contrast, L-NAME had no effect on either the basal or the stimulation-evoked ACh release in any experimental conditions studied.Our data indicate that endogenously produced NO is involved in the modulation of striatal DA, but not in ACh release. Furthermore, it seems likely that the modulatory effect of NO is linked to activation of presynaptic NMDA receptors located on the striatal dopaminergic nerve terminals.  相似文献   
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Electroconvulsive therapy (ECT), which is among the oldest and most controversial treatments in the field of psychiatry, has its 80th birthday this year. In this brief historical overview, the discovery of the therapeutic effects of convulsive therapy by Laszló Meduna, and the circumstances that motivated Ugo Cerletti and Lucio Bini to use electricity as a means of seizure induction are described. Meduna’s original theory about the antagonism between epilepsy and schizophrenia has been replaced by hypotheses on the mechanism of action of ECT. The position of ECT in modern psychiatry is also discussed with special attention to its most important clinical indications, including catatonia, and pre- and postpartum affective and psychotic states that are responsive to ECT and in which ECT may even be lifesaving. Adverse effects and comparison of ECT with recently developed brain stimulation methods are also reviewed. The negative media portrayal of ECT and its earlier misuse may have contributed to its negative professional and public perceptions indicated repeatedly in attitude surveys. This negative attitude has played an important role in the decreasing use of ECT in the developed world and a reduction in access to ECT, which constitutes a violation of psychiatric patients’ right to an effective treatment.  相似文献   
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Background: The long‐term success rates achieved in dental implantology suggest that flexibility might well exist within the various implant systems to a degree that an altered protocol (ie, one‐stage surgery and immediate or early loading) can be performed under controlled conditions. However, before variations of the protocol can be considered for general use, they must be subjected to critical analysis, particularly with respect to the predictability of osseointegration, alteration of soft tissue barrier, and relative change in bone height around the implants. Purpose: The aim of this prospective multicenter study was to evaluate implant survival and periimplant conditions around endosseous implants placed in a one‐stage surgical procedure and early loading. Materials and Methods: A total of 170 implants were placed in 40 patients with mandibular edentulism and were functionally loaded within 6 weeks with overdentures (n = 30) or fixed prostheses (n = 10). All patients and prosthetic constructions were evaluated according to a standardized protocol during 3 years of follow‐up. Cumulative implant survival rates were calculated, and implant loss in relation to implant size and bone quality and quantity were evaluated. Furthermore, the protocol included assessment of clinical (plaque and bleeding scores, prosthesis stability) and radiographic parameters. Results: Over a period of 3 years, the implant survival rate was 93% for both implants and prostheses (fixed or removable). No implants were lost after the first year of loading. The periimplant tissues were in a healthy condition. Mean marginal bone resorption from the time of loading to the 3‐year follow‐up was 0.41 mm (SD 0.52). Conclusions: From this study it may be concluded that early loading results in good implant survival and proper periimplant health in edentulous mandibles.  相似文献   
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The variable regions of the heavy and light chains of the protective murine monoclonal antibody (MAb) 2H1 (m2H1) were expressed with the human constant region genes for immunoglobulin G2 (IgG2) and kappa, respectively, to construct a chimeric antibody (ch2H1). ch2H1 retains the specificity of the parent MAb, exhibits biological activity, and lacks the toxicity of the parent murine IgG1 in chronically infected mice.  相似文献   
69.
Cervical spinal lesions at C6 result in paralysis of the triceps brachii while leaving deltoid and elbow flexor function intact. We examined the spatial–temporal characteristics of goal-directed aiming movements performed by C6 tetraplegics who had undergone musculotendinous transfer surgery in which the posterior deltoid replaces the triceps as the elbow extensor. On some trials, liquid crystal goggles were used to eliminate vision of the limb and target upon movement initiation. Although tetraplegic participants achieved the same degree of movement accuracy/consistency as control participants, their movement times were longer regardless of whether the movements were made away from (elbow extension) or towards the body (elbow flexion). Longer movement times were related to lower peak velocities, and not the symmetry of the aiming profiles. The tetraplegic participants were no more dependent on visual feedback for limb regulation than control participants. Although the characteristics of the movement trajectories were surprisingly similar, in both vision conditions, tetraplegics required more real and proportional time to reduce spatial variability in the limb’s trajectory for elbow extensions. Our results indicate that the sensorimotor system is adaptable and that the representations governing limb control are not muscle specific.  相似文献   
70.

Background  

Although training and education have long been accepted as integral to disaster preparedness, many currently taught practices are neither evidence-based nor standardized. The need for effective evidence-based disaster training of healthcare staff at all levels, including the development of standards and guidelines for training in the multi-disciplinary health response to major events, has been designated by the disaster response community as a high priority. We describe the application of systematic evidence-based consensus building methods to derive educational competencies and objectives in criteria-based preparedness and response relevant to all hospital healthcare workers.  相似文献   
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