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42.
Carla Stecco Piero Pavan Paola Pachera Raffaele De Caro Arturo Natali 《Surgical and radiologic anatomy : SRA》2014,36(1):25-32
The mechanical properties of deep fasciae strongly affect muscular actions, development of pathologies, such as acute and chronic compartment syndromes, and the choice of the various fascial flaps. Actually, a clear knowledge of the mechanical characterization of these tissues still lacks. This study focuses attention on experimental tests of different regions of human crural fascia taken from an adult frozen donor. Tensile tests along proximal–distal and medial–lateral direction at a strain rate of 120 %/s were performed at the purpose of evaluating elastic properties. Viscous phenomena were investigated by applying incremental relaxation tests at total strain of 7, 9 and 11 % and observing stress decay for a time interval of 240 s. The elastic response showed that the fascia in the anterior compartment is stiffer than in the posterior compartment, both along the proximal–distal and medial–lateral directions. This result can explain why the compartment syndromes are more frequent in this compartment with respect to posterior one. Furthermore, the fascia is stiffer along the proximal–distal than along medial–lateral direction. This means that the crural fascia can adapt to the muscular variation of volume in a transversal direction, while along the main axis it could be considered as a structure that contributes to transmitting the muscular forces at a distance and connecting the different segments of the limb. The stress relaxation tests showed that the crural fascia needs 120 s to decrease stress of 40 %, suggesting a similar time also in the living so that the static stretching could have an effect on the fascia. 相似文献
43.
Cryptococcus neoformans is a facultative intracellular pathogen and the causative agent of cryptococcosis, a disease that is often fatal to those with compromised immune systems. C. neoformans has the capacity to escape phagocytic cells through a process known as nonlytic exocytosis whereby the cryptococcal cell is released from the macrophage into the extracellular environment, leaving both the host and pathogen alive. Little is known about the mechanism behind nonlytic exocytosis, but there is evidence that both the fungal and host cells contribute to the process. In this study, we used time-lapse movies of C. neoformans-infected macrophages to delineate the kinetics and quantitative aspects of nonlytic exocytosis. We analyzed approximately 800 macrophages containing intracellular C. neoformans and identified 163 nonlytic exocytosis events that were further characterized into three subcategories: type I (complete emptying of macrophage), type II (partial emptying of macrophage), and type III (cell-to-cell transfer). The majority of type I and II events occurred after several hours of intracellular residence, whereas type III events occurred significantly (P < 0.001) earlier in the course of macrophage infection. Our results show that nonlytic exocytosis is a morphologically and temporally diverse process that occurs relatively rapidly in the course of macrophage infection. 相似文献
44.
Elymir S Galvis-Garc a Sergio Sobrino-Coss o Arturo Reding-Bernal Yesica Contreras-Mar n Karina Sol rzano-Acevedo Patricia Gonz lez-Zavala Rosa M Quispe-Siccha 《World journal of gastroenterology : WJG》2020,26(34):5169-5180
BACKGROUND Endoscopic ultrasound(EUS) and endoscopic ultrasound elastography(EUS-E) simulation lessens the learning curve; however, models lack realism, diminishing competitiveness.AIM To standardize the mechanical properties of polyvinyl alcohol(PVA) hydrogel for simulating organs and digestive lesions.METHODS PVA hydrogel(Sigma Aldrich, degree of hydrolysis 99%) for simulating EUS/EUS-E lesions was investigated in Unidad de Investigación y Desarrollo Tecnológico at Hospital General de México "Dr. Eduardo Liceaga", Mexico City. We evaluated physical, contrast, elasticity and deformation coefficient characteristics in lesions, applying Kappa's concordance and satisfaction questionnaire(Likert 4-points).RESULTS PVA hydrogel showed stable mechanical properties. Density depended on molecular weight(MW) and concentration(C). PVA bblocks with the greatest density showed lowest tensile strength(r =-0.8, P = 0.01). Lesions were EUSgraphically visible. Homogeneous and heterogeneous examples were created from PVA blocks or PVA phantoms, exceeding(MW_2 = 146000-186000, C_9 = 15% and C_(10) = 20%) with a density under(MW_1 = 85000-124000, C_1 = 7% and C_2 = 9%). We calculated elasticity and deformation parameters of solid(blue) areas, contrasting with the norm(Kappa = 0.8; high degree of satisfaction).CONCLUSION PVA hydrogels were appropriate for simulating organs and digestive lesions using EUS/EUS-E, facilitating practice and reducing risk. Repetition amplified skills, while reducing the learning curve. 相似文献
45.
O'Hara GA Duncan CJ Ewer KJ Collins KA Elias SC Halstead FD Goodman AL Edwards NJ Reyes-Sandoval A Bird P Rowland R Sheehy SH Poulton ID Hutchings C Todryk S Andrews L Folgori A Berrie E Moyle S Nicosia A Colloca S Cortese R Siani L Lawrie AM Gilbert SC Hill AV 《The Journal of infectious diseases》2012,205(5):772-781
46.
Muscelli E Casolaro A Gastaldelli A Mari A Seghieri G Astiarraga B Chen Y Alba M Holst J Ferrannini E 《The Journal of clinical endocrinology and metabolism》2012,97(8):2818-2826
Context: Dipeptidyl peptidase IV (DPP-4) inhibitors improve glycemic control in patients with type 2 diabetes. The underlying mechanisms (incretin effect, β-cell function, endogenous glucose production) are not well known. Objective: The aim of the study was to examine mechanisms of the antihyperglycemic effect of DPP-4 inhibitors. Design, Setting, and Patients: We administered a mixed meal with glucose tracers ([6,6-(2)H(2)]-glucose infused, [1-(2)H]-glucose ingested), and on a separate day, a glucose infusion matched the glucose responses to the meal (isoglycemic test) in 50 type 2 diabetes patients (hemoglobin A(1c) = 7.4 ± 0.8%) and seven controls; 47 diabetic completers were restudied after 6 wk. Glucose fluxes were calculated, and β-cell function was assessed by mathematical modeling. The incretin effect was calculated as the ratio of oral to iv insulin secretion. Intervention: We conducted a 6-wk, double-blind, randomized treatment with sitagliptin (100 mg/d; n = 25) or placebo (n = 22). Results: Relative to placebo, meal-induced changes in fasting glucose and glucose area under the curve (AUC) were greater with sitagliptin, in parallel with a lower appearance of oral glucose [difference (post-pre) AUC = -353 ± 915 vs. +146 ± 601 μmol · kg(-1) · 5 h] and greater suppression of endogenous glucose production. Insulin sensitivity improved 10%, whereas total insulin secretion was unchanged. During the meal, β-cell glucose sensitivity improved (+19[29] vs. 5[21] pmol · min(-1) · m(-2) · mm(-1); median [interquartile range]) and glucagon AUC decreased (19.6 ± 7.5 to 17.3 ± 7.1 ng · ml(-1) · 5 h), whereas intact glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 AUC increased with sitagliptin vs. placebo. The incretin effect was unchanged because sitagliptin increased β-cell glucose sensitivity also during the isoglycemic test. Conclusions: Chronic sitagliptin treatment improves glycemic control by lowering the appearance of oral glucose, postprandial endogenous glucose release, and glucagon response, and by improving insulin sensitivity and β-cell glucose sensing in response to both oral and iv glucose. 相似文献
47.
48.
Gilbert R Fluke J O'Donnell M Gonzalez-Izquierdo A Brownell M Gulliver P Janson S Sidebotham P 《Lancet》2012,379(9817):758-772
We explored trends in six developed countries in three types of indicators of child maltreatment for children younger than 11 years, since the inception of modern child protection systems in the 1970s. Despite several policy initiatives for child protection, we recorded no consistent evidence for a decrease in all types of indicators of child maltreatment. We noted falling rates of violent death in a few age and country groups, but these decreases coincided with reductions in admissions to hospital for maltreatment-related injury only in Sweden and Manitoba (Canada). One or more child protection agency indicators increased in five of six countries, particularly in infants, possibly as a result of early intervention policies. Comparisons of mean rates between countries showed five-fold to ten-fold differences in rates of agency indicators, but less than two-fold variation in violent deaths or maltreatment-related injury, apart from high rates of violent child death in the USA. These analyses draw attention to the need for robust research to establish whether the high and rising rates of agency contacts and out-of-home care in some settings are effectively reducing child maltreatment. 相似文献
49.
Ewing Duque Arturo Mangas Pablo Salinas Zaida Díaz-Cabiale José Angel Narváez Rafael Coveñas 《Brain structure & function》2013,218(1):131-149
We have studied the distribution of alpha-neo-endorphin- or neurokinin B-immunoreactive fibres and cell bodies in the adult human brainstem with no prior history of neurological or psychiatric disease. A low density of alpha-neo-endorphin-immunoreactive cell bodies was only observed in the medullary central gray matter and in the spinal trigeminal nucleus (gelatinosa part). Alpha-neo-endorphin-immunoreactive fibres were moderately distributed throughout the human brainstem. A high density of alpha-neo-endorphin-immunoreactive fibres was found only in the solitary nucleus (caudal part), in the spinal trigeminal nucleus (caudal part), and in the gelatinosa part of the latter nucleus. Neurokinin B-immunoreactive cell bodies (low density) were found in the periventricular central gray matter, the reticular formation of the pons and in the superior colliculus. The distribution of the neurokinin-immunoreactive fibres was restricted. In general, for both neuropeptides the density of the immunoreactive fibres was low. In the human brainstem, the proenkephalin system was more widely distributed than the prodynorphin system, and the preprotachykinin A system (neurokinin A) was more widely distributed than the preprotachykinin B system (neurokinin B). 相似文献
50.
Kent R. Van Sickle Hanuma Reddy Nanda Kumar Amit Parikh Arturo A. Ayon Stephen M. Cohn 《The Journal of surgical research》2013