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121.
James Courtney Parker Adel Sakla Francis M. Donovan David Beam Annu Chekuri Mohammad Al-Khatib Charles R. Hamm Fabien G. Eyal 《Medical & biological engineering & computing》2009,47(9):931-939
A prototype time cycled, constant volume, closed circuit perfluorocarbon (PFC) total liquid ventilator system is described.
The system utilizes microcontroller-driven display and master control boards, gear motor pumps, and three-way solenoid valves
to direct flow. A constant tidal volume and functional residual capacity (FRC) are maintained with feedback control using
end-expiratory and end-inspiratory stop-flow pressures. The system can also provide a unique continuous perfusion (bias flow,
tracheal insufflation) through one lumen of a double-lumen endotracheal catheter to increase washout of dead space liquid.
FRC and arterial blood gases were maintained during ventilation with Rimar 101 PFC over 2–3 h in normal piglets and piglets
with simulated pulmonary edema induced by instillation of albumin solution. Addition of tracheal insufflation flow significantly
improved the blood gases and enhanced clearance of instilled albumin solution during simulated edema. 相似文献
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124.
U Schauseil-Zipf W Hamm S Mandl-Kramer E Gladtke A Bolte 《Monatsschrift für Kinderheilkunde》1985,133(2):93-98
58 small-for-date (SFD) aged 6 to 12 years, born between 1970 and 1975 were followed-up. Retardation of motor skills and speech during early infancy was found in 20-30%. At 6 to 12 years of age one third still had deficits in body weight und height. Neurological abnormalities in 17 children were usually mild, most often affecting fine motor function. Significant impairment of visuomotor perception on psychological testing was seen in 21 children, and EEG abnormalities in 20 cases. The results in neurological, psychological and EEG investigations for 23 children (group I) were normal. 24 patients (group II) showed one or two abnormal findings. In 9 children (group III) results of all three examinations were abnormal. The follow-up results were influenced by socioeconomic factors. Small-for-date babies showed on the whole encouraging results on follow-up during later childhood, with 40% of the children being normal, and mostly mild abnormalities in the remaining patients. Prognosis may be further improved by preterm delivery, i.e. early termination of intrauterine growth retardation. 相似文献
125.
DeFord SM Wilson MS Rice AC Clausen T Rice LK Barabnova A Bullock R Hamm RJ 《Journal of neurotrauma》2002,19(4):427-438
Experimental investigations of single mild brain injury (SMI) show relatively little resultant cognitive impairment. However, repeated mild brain injuries (RMI), as those sustained by athletes (e.g., football, hockey, and soccer players) may have cumulative effects on cognitive performance and neuropathology. Numerous clinical studies show persistent, latent, and long-term consequences of RMI, unlike the episodic nature of SMI. The nature of repeated traumatic brain injury (TBI) introduces confounding factors in invasive and even semiinvasive animal models of brain injury (e.g., scar formation). Thus, the present study characterizes SMI and RMI in a noninvasive mouse weight drop model and the cumulative effects of RMI on cognitive performance. Investigation of drop masses and drop distances revealed masses of 50, 100, and 150 g dropped from 40 cm resulted in 0% mortality, no skull fracture, and no difference in acute neurological assessment following sham injury, SMI, or RMI. Cumulative effects of RMI were examined following four mild brain injuries 24 h apart induced by 50-, 100-, or 150-g masses dropped from 40 cm through histological measures, mean arterial pressure, and measures of complex/spatial learning. RMI produced no overt cell death within the cortex or hippocampus, no evidence of blood-brain barrier compromise, and no significant change in mean arterial pressure. Following testing in the Morris water maze (MWM) on days 7-11 after initial injury, mice in the RMI 100-g and RMI 150-g groups had significantly longer MWM goal latencies compared to sham, SMI 150-g, and RMI 50-groups. Additionally, the evident cognitive deficit manifested in the absence of observed cell death. This is the first study to show complex/spatial learning deficits following RMI, similar to the visual/spatial perception and planning deficits observed in clinical studies. 相似文献
126.
127.
Wolburg H Wolburg-Buchholz K Kraus J Rascher-Eggstein G Liebner S Hamm S Duffner F Grote EH Risau W Engelhardt B 《Acta neuropathologica》2003,105(6):586-592
In the central nervous system (CNS) complex endothelial tight junctions (TJs) form a restrictive paracellular diffusion barrier, the blood-brain barrier (BBB). During inflammation, BBB properties are frequently lost, resulting in brain edema. To investigate whether BBB leakiness correlates with molecular changes at BBB TJs, we performed immunofluorescence stainings for TJ molecules in a mouse model of experimental autoimmune encephalomyelitis (EAE) and in human tissue with glioblastoma multiforme (GBM). In TJs of healthy CNS vessels in both mouse and man we detected occludin, ZO-1, claudin-5 and claudin-3. In EAE brain and spinal cord sections we observed the selective loss of claudin-3 immunostaining from TJs of venules surrounded by inflammatory cuffs, whereas the localization of the other TJ proteins remained unchanged. In addition, selective loss of claudin-3 immunostaining was also observed in altered cerebral microvessels of human GBM. Our data demonstrate the selective loss of claudin-3 from BBB TJs under pathological conditions such as EAE or GBM when the integrity of the BBB is compromised, and therefore suggest that claudin-3 is a central component determining the integrity of BBB TJs in vivo. 相似文献
128.
Cabrera-Vera TM Vanhauwe J Thomas TO Medkova M Preininger A Mazzoni MR Hamm HE 《Endocrine reviews》2003,24(6):765-781
In multicellular organisms from Caenorhabditis elegans to Homo sapiens, the maintenance of homeostasis is dependent on the continual flow and processing of information through a complex network of cells. Moreover, in order for the organism to respond to an ever-changing environment, intercellular signals must be transduced, amplified, and ultimately converted to the appropriate physiological response. The resolution of the molecular events underlying signal response and integration forms the basis of the signal transduction field of research. An evolutionarily highly conserved group of molecules known as heterotrimeric guanine nucleotide-binding proteins (G proteins) are key determinants of the specificity and temporal characteristics of many signaling processes and are the topic of this review. Numerous hormones, neurotransmitters, chemokines, local mediators, and sensory stimuli exert their effects on cells by binding to heptahelical membrane receptors coupled to heterotrimeric G proteins. These highly specialized transducers can modulate the activity of multiple signaling pathways leading to diverse biological responses. In vivo, specific combinations of G alpha- and G beta gamma-subunits are likely required for connecting individual receptors to signaling pathways. The structural determinants of receptor-G protein-effector specificity are not completely understood and, in addition to involving interaction domains of these primary acting proteins, also require the participation of scaffolding and regulatory proteins. 相似文献
129.
After reading the series of articles on a new approach to controlling chemicals, an initiative targeted especially on small and medium-sized businesses, in the Annals of Occupational Hygiene (1998; 42: 355-411), German specialists for health and safety at work realized that problems in this area are very similar in the UK and Germany. Also, in Germany different institutions have developed an array of solutions to help small and medium-sized enterprises during recent years. In this paper, we present these activities and hope to promote an international discussion about practical support for work with chemical substances. 相似文献
130.
RATIONALE AND OBJECTIVES: Preclinical in-vivo characterization of a newly developed MR contrast medium consisting of very small superparamagnetic iron oxide particles (VSOP) coated with citrate (VSOP-C184). METHODS: VSOP-C184 (core diameter: 4 nm; total diameter: 8.6 nm; relaxivities in water at 0.94 T (T1) 20.1 and (T2) 37.1 l/[mmol*sec]) was investigated to determine its pharmacokinetics, efficacy, acute single dose toxicity, repeated dose toxicity, and genotoxicity. RESULTS: The plasma elimination half-life at 0.045 mmol Fe/kg was 21.3 +/- 5.5 minutes in rats and 36.1 +/- 4.2 minutes in pigs, resulting in a T1-relaxation time of plasma of < 100 milliseconds for 30 minutes in pigs. The particles are mainly cleared via the phagocytosing system of the liver. MR angiography at a dose of 0.045 mmol Fe/kg shows an excellent depiction of the thoracic and abdominal vasculature in rats and of the coronary arteries in pigs. The LD50 in mice is > 17.9 mmol Fe/kg. A good tolerance and safety profile was found. CONCLUSIONS: The experiments indicate, that VSOP-C184 may be a well tolerated and safe contrast medium for MR imaging that can be effectively used for MR angiography including visualization of the coronary arteries. 相似文献