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91.
D. F. Wozniak J. W. Olney L. Kettinger III M. Price J. P. Miller 《Psychopharmacology》1990,101(1):47-56
Several experiments were conducted to study the effects of the noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, MK-801, on learning and memory in the rat. Rats displayed impaired performance on several sensorimotor tests and appeared grossly intoxicated when treated IP with 0.2 mg/kg MK-801, but not when treated with lower doses (0.05 or 0.1 mg/kg). Postacquisition performance on two spatial learning tasks involving working memory protocols (reinforced alternation and radial arm maze) was impaired by MK-801 at intoxicating doses (0.2 mg/kg) but not at lower doses (0.05 or 0.1 mg/kg). Using a position habit reversal task, we found that rats could learn to reverse a position habit while under the influence of a nonintoxicating dose of MK-801 (0.1 mg/kg), but when tested on the following day performed as if they did not recall what they had learned. Thus, acute administration of a nonintoxicating dose of MK-801 disrupts the retention of new information learned under the influence of the drug but does not interfere with the performance of tasks that are well learned before the drug is administered. Whether the performance deficits on the spatial learning tasks observed only following intoxicating doses of MK-801 reflect an effect on memory is not clear. 相似文献
92.
Helmut Kreppel Franz -Xaver Reichl Ladislaus Szinicz Burckhard Fichtl Wolfgang Forth 《Archives of toxicology》1990,64(5):387-392
The efficacy ofdl-dimercaptopropanol (British Anti-Lewisite, BAL),dl-dimercaptopropanesulfonate (DMPS), and meso-dimercaptosuccinic acid (DMS A) was compared in reducing the acute As2O3 toxicity in mice. Mice were treated with a single equimolar dose of a dithiol compound (0.7 mmol/kg i.p.) 0.5 or 30 min after the s.c. injection of various doses of As2O3. Both DMPS and DMSA were significantly (p<0.05) more effective in mice treated 0.5 min after the poisoning if compared to BAL on an equimolar level. The highest potency ratio (PR) (LD50 with treatment/LD5o without treatment) was found in animals injected with DMSA (PR=8.6). The corresponding value for DMPS was 4.2, and for BAL 2.1, respectively. In animals treated 30 min after poisoning the efficacy of DMPS (PR = 2.6) was similar to the efficacy of DMSA 2.4, both being only slightly superior to BAL 2.O. DMPS and DMSA were found to be much less toxic than BAL. The LD50 of arsenic was 0.057 mmol/kg. The efficacy of BAL, DMPS, and DMSA in reducing the tissue content of arsenic following acute As2O3 poisoning was investigated in mice (n=6/group) and guinea pigs (n=3-4/group). The animals were injected s.c. with 0.043 mmol/kg As2O3 (containing a tracer dose of74As(III)). Thirty minutes later the antidotes were administered A were more effective in reducing the arsenic content of tissues than BAL. Moreover, BAL caused accumulation of the toxicant in the brain. It is concluded that the recommendation of BAL as drug of choice in acute arsenic poisoning needs to be carefully re-evaluated. 相似文献
93.
94.
Donald R. Miller Raymond J. Martineau Kathryn A. Hull François Vallée Marc LeBel 《Journal canadien d'anesthésie》1994,41(9):782-793
A randomized, double-blind study was undertaken to determine the dose requirements, recovery characteristics, and pharmacokinetic variables of midazolam given by continuous infusion for sedation in patients following abdominal aortic surgery. Thirty subjects, 50–75 yr, scheduled to undergo aortic reconstructive surgery, entered the study. Following a nitrous oxide-isoflurane-opioid anaesthetic technique, patients were randomly allocated to receive one of three loading doses (0.03, 0.06 or 0.1 mg · kg?1) and initial infusion rates (0.5, 1.0 or 1.5 μg · kg?1 · min?1) of midazolam, corresponding to groups low (L), moderate (M) and high (H). The infusion of midazolam was adjusted to maintain sedation levels of “3, 4 or 5,“ which permitted eye opening in response to either verbal command or a light shoulder tap, using a seven-point scale ranging from “0” (awake, agitated) to “6” (asleep, non-responsive). Additionally, morphine was given in increments of 2.0 mg iv prn for analgesia. On the morning after surgery, midazolam was discontinued, and the tracheas were extubated when patients were awake. Blood samples were taken during, and at increasing intervals for 48 hr following discontinuation of the infusion, and analyzed by gas chromatography. The desired level of sedation was maintained during more than 94% of the infusion period in all three groups, with a maximum of three dose adjustments per patient, for treatment which lasted 16.3 ± 0.6 hr. There was, however, an increase in both the infusion rates and mean plasma concentrations from Group L to Group H (P < 0.05), which corresponded to an inverse relationship of morphine requirements during the period of sedation (P < 0.05, Group H vs Group L). Optimal midazolam infusion rates and resulting plasma concentrations at the times the infusions were discontinued (in parentheses) were as follows — Group L: 0.60 ± 0.18 μg · kg?1 min?1 (76 ± 32 ng · mL?1), Group M: 0.90 ± 0.52 μg · kg?1 · min?1 (133 ± 71 ng · mL?1), and Group H: 1.34 ± 0.69 μg · kg?1 · min?1 (206 ± 106 ng · mL?1). Times to awakening were longer in Group H: 3.1 ± 3.4 hr, than in Group L: 1.1 ± 0.8 h, P < 0.05. Pharmacokinetic variables were found to be dose- independent over the range of infusion rates. Mean values were t1/2β = 4.4 ± 1.5 hr, CL = 5.94 ± 1.69 mL · min?1 · kg?1, Vd = 3.13 ± 1.07 L · kg?1. It is concluded that midazolam, infused between 0.6–0.9 μg · kg?1 · min?1, provides a stable level of sedation, when administered in conjunction with intermittent iv morphine following AAS. This sedation technique, which costs $1.65 ± 0.73 hr?1 ($Can), is associated with rapid recovery and minimal side effects. 相似文献
95.
Shuzo Oshita Yoshiki Fujiwara Hisashi Tamura Takefumi Sakabe Hiroshi Takeshita 《Journal canadien d'anesthésie》1994,41(6):534-541
To gain a better understanding of the direct actions of halothane on myocardial function in ischaemia, we studied the effects
of increasing extracellular potassium concentration and decreasing extracellular pH (acidosis), alone or in combination with
halothane, on the contractile force and resting tension in isolated atria. Guinea pig left atria were superfused with Tyrode’s
solution and stimulated at 1 Hz. Isometric contractile force and resting tension were measured using a force displacement
transducer. Perfusate potassium concentrations were increased from 5.4 mmol · L−1 to either 8.1 mmol · L−1 or 10.8 mmol · L−1 by adding KCl to the standard Tyrode’s solution, and its pH was decreased from 7.4 to either 7.0 or 6.5 by decreasing bicarbonate.
In standard Tyrode’s solution (potassium 5.4 mmol · L−1, pH 7.4), halothane 0.5–2% reduced contractile force in a dose-dependent manner (P < 0.05); the effective concentration of
halothane for 50% inhibition of contractile force (IC50) was 1.3%. Both increasing extracellular potassium and decreasing extracellular pH decreased the contractile force in a potassium-or
pH-dependent fashion. The negative inotropism of halothane (1%) was not altered by increasing potassium concentrations, whereas
1% halothane caused a greater decrease in contractile force at pH 6.5 than at pH 7.4. Halothane (1%) enhanced the acidosis
(pH 6.5)-induced increases in resting tension. Arrhythmias were produced in one of eight preparations during acidosis, while
four of eight preparations demonstrated arrhythmias during acidosis in the presence of halothane. These data suggest that
acidosis and halothane may have a synergistic interaction on the contractile force and resting tension of the atria. The increase
in resting tension observed during acidosis/ halothane conditions suggests than an increase in cytosolic calcium is associated
with these synergistic interactions between acidosis and halothane.
Pour mieux comprendre l’action direct de l’halothane sur la fonction myocardique pendant l’ischémie, nous avons étudié les
effets de l’augmentation du potassium extracellulaire et de la diminution du pH extracellulaire (acidose), seuls ou en association
avec l’halothane, sur la force contractile et la tension de repos d’oreillettes isolées. Des oreillettes gauches de cobaye
furent perfusées avec une solution de Tyrode et stimulées à 1 Hz. La force contractile isométrique et la tension de repos
ont été mesurées avec un transducteur de force de déplacement. Les concentrations de potassium perfusées ont été augmentées
de 5,4 mmol · L−1 à 8,1 mmol · L−1 ou à 10,8 mmol · L−1 par l’ajout de KCl à la solution standard de Tyrode, et son pH abaissé de 7,4 à 7,0 ou 6,5 par baisse des bicarbonates. Avec
la solution standard de Tyrode (potassium 5,4 mmol · L−1, pH 7,4), l’halothane (0.5–2%) diminue la force contractile proportionnellement à la dose (P < 0,05); la concentration efficace
d’halothane requise pour produire une inhibition de 50% de la force contractile (IC5O) a été de 1,3%. L’augmentation du potassium extracellulaire et la diminution du pH extracellulaire réduisent toutes les deux
la force contractile proportionnellement au potassium ou au pH. L’inotropisme négatif de l’halothane (1%) n’est pas modifié
par l’augmentation de la concentration de potassium alors que l’halothane produit une diminution plus importante de la force
contractile à un pH de 6,5 que de 7,4. L’halothane (1%) exagère l’augmentation de la tension de repos induite par l’acidose
(pH 6,5). Des arrythmies sont apparues sur une des huit préparations pendant l’acidose en présence d’halothane. Ces données
suggèrent que l’acidose et l’halothane pourraient avoir une activité synergique sur le force contractile et la tension de
repos des oreillettes. L’augmentation de la tension de repos observée pendant l’acidose combinée à l’halothane suggère l’association
d’une augmentation du calcium cytosolique avec des interactions synergiques entre l’acidose et l’halothane. 相似文献
96.
A case is presented of an eight-year-old child with a mediastinal tumour, who had developed acute renal failure following the institution of steroid therapy. Intrapleural analgesia was successfully used for the insertion of a peritoneal dialysis catheter so that the considerable risks of general anaesthesia were avoided. Subsequent dialysis allowed chemotherapy to commence and, as a result of the shrinkage in tumour size, general anaesthesia was administered safely two days later. The purpose of this report is to highlight the use of intrapleural analgesia in children as an alternative to general anaesthesia, when the latter is contraindicated. The mechanism of action of intra-pleural analgesia and the risks of anaesthesia in the presence of a mediastinal tumour are discussed. 相似文献
97.
Jonathan P. Purday 《Journal canadien d'anesthésie》1994,41(9):818-844
Monitoring of paediatric anaesthesia has become increasingly more complex in recent years and this is particulary true of
cardiac anaesthesia. The purpose of this review is to give a comprehensive update of published material related to both routine
and specialized cardiac monitoring. Routine monitoring can be particularly affected by the alterations of cardiac rhythm,
blood flow, cardiac output and oxygenation which result from the congenital heart abnormalities themselves, the type of surgery
undertaken and the effects of cardiopulmonary bypass. The use of specialized monitoring is becoming more widespread, particularly
in the areas of cerebral function, mixed venous oxygenation, cardiac output measurement and coagulation. In the last five
years, with the development of smaller probes, a great deal has been published on transoesophageal echocardiography. The use
of the current monitors of cerebral function still remains controversial despite the need for a monitor of adequate brain
perfusion, reflecting the need for a great deal of further research in this area. This review will concentrate on particular
areas which have seen the most profound changes and on monitoring that may form the standards of tomorrow. Finally, amongst
all the technology, it should not be forgotten that the most important clinical monitor is the bedside clinical monitoring
of the physicians themselves.
Depuis quelques années, le monitorage de l’anesthésie pédiatrique devient déplus en plus complexe et tout particulièrement
en anesthésie cardiaque. L’objectif de ce travail consiste à passer en revue la littérature actuelle qui traite du monitorage
usuel et spécialisé. Le monitorage usuel peut être influencé par les modifications de la fréquence cardiaque, du courant sanguin,
du débit cardiaque et de l’oxygénation provoqués par les anomalies cardiaques congénitales, du type de chirurgie et des retentissements
de la circulation extracorporelle. L’utilisation du monitorage spécialisé est de plus en plus répandu et concerne particulièrement
la circulation cérébrale, l’oxygénation du sang veineux mêlé, la mesure du débit cardiaque et la coagulation. Au cours des
cinq dernières années, le développement de sondes plus petites a généré de nombreuses publications sur l’échocardiographie
transoesophagienne. L’utilisation des moniteurs actuels de la fonction cérébrale demeure sujet à controverse bien qu ’un moniteur
de perfusion cérébrale adéquat demeure toujours aussi essentiel, confirmant ainsi le besoin de recherches supplémentaires
sur ce sujet. Ce survol se portera spécialement sur les champs d’activités qui ont connu les changements les plus profonds
et sur le monitorage qui établira les standards du futur. Finalement, au milieu de cette technologie, il ne faut jamais oublier
que le moniteur clinique le plus important se trouve au chevet du malade en la personne du médecin. 相似文献
98.
The treatment of cerebral arteriovenous malformations (AVM) or vascular anomalies are challenging neurosurgical procedures for an anaesthetist. Large AVMs are uncommon in children. Only 18% of AVMs become symptomatic before the age of 15 yr. This series reviews the experience at this institution during the period of 1982 to 1992. The symptoms at the time of presentation are varied and include haemorrhage (50%), seizures and hydrocephalus (36%) or congestive cardiac failure (18%). Symptoms of congestive heart failure predominate in the new-born whilst neurological symptoms, such as stroke, seizures or hydrocephalus occur more commonly in infants and older children. Approximately one third of AVMs in childhood present acutely. Radiological investigations, e.g., CT scan, MRI and cerebral angiography are essential to identify the precise location of the lesion. Therapeutic intervention in the acute presentation may involve craniotomy for evacuation of haematoma and treatment of increased intracranial pressure (ICP). Control of seizures and congestive heart failure may take priority and allow time to plan the elective procedures of embolization and surgical excision of the AVM. Operative intervention is hazardous and peroperative complications can be expected in more than 50% of patients. The morbidity and mortality associated with cerebral AVM are high, especially in infants who present in the neonatal period with congestive cardiac failure. The overall mortality in this series was 20%. Children presenting with intracranial arteriovenous malformations require a multidisciplinary approach. The successful management of anaesthesia either for embolization or surgical resection necessitates an understanding of the disciplines of paediatric and neuroanaesthesia. Special care and specific attention to detail may contribute to reduce the high morbidity and mortality encountered in these compromised children. 相似文献
99.
This study was conducted to assess the effect of sevoflurane on lung resistance and compliance, and its responsiveness to
histamine. We studied eight dogs to compare the effect of sevoflurane, isoflurane, enflurane, and halothane on bronchoconstriction
caused by histamine. Baseline values of pulmonary resistance (RL) and dynamic pulmonary compliance (Cdyn) were measured prior to administration of histamine. Histamine (2, 4, and 8 μg · kg−1) were administered iv, and the values of RL and Cdyn at the time of peak effect were recorded. Under 1 or 2 MAC anaesthesia, sevoflurane as well as the other three anaesthetics
had no bronchoactive effects. The four anaesthetics, including sevoflurane, demonstrated inhibitory effect on increases in
RL and decreases in Cdyn caused by histamine. At 1 MAC anaesthesia, % changes in RL caused by 2, 4, or 8 μg · kg−1 of histamine were 38 ± 11, 85 ± 21, or 132 ± 24% (mean ± SE) for halothane, and 65 ± 11, 132 ± 15, or 172 ± 19% for sevoflurane,
respectively. Sevoflurane was less effective than halothane in preventing increases in RL. In preventing decreases in Cdyn, sevoflurane was less effective than halothane only at 8 μg · kg−1 of histamine under 1 and 2 MAC anaesthesia. There was no difference in attenuating effect on changes in RL and Cdyn between sevoflurane and isoflurane or enflurane. We concluded that sevoflurane was less potent than halothane in attenuating
changes in RL and Cdyn in response to iv histamine.
Cette étude a été réalisée dans le but d’évaluer les effets du sévoflurane sur la résistance et la compliance pulmonaires
en réponse à l’histamine. Les effets du sévoflurane, de l’isoflurane, de l’enflurane et de l’halothane sur la bronchoconstriction
induite par l’histamine sont comparés sur huit chiens. Avant l’administration d’histamine, on mesure les valeurs initiales
de la résistance (RL) et de la compliance dynamique (Cdyn) pulmonaires. L’histamine (2, 4, 8 μg · kg−1) est administrée par la voie veineuse et les valeurs maximales de la RL et de la Cdyn sont enregistrées. Les quatre anesthésiques, dont le sévoflurane inhibent l’augmentation de la RL et la diminution de la Cdyn provoquées par l’histamine. A MAC 1 d’anesthésie, les pourcentages de changement de RL produits par 2, 4, ou 8 μg · kg−1 d’histamine sont respectivement de 38 ± 11, 85 ± 21, ou 132 ± 24% (moyenne + SD) pour l’halothane, et de 65 ± 11, 132 ± 15,
ou 172 ± 19% pour le sévoflurane. Le sévoflurane est moins efficace que l’halothane pour prévenir les augmentations de RL. Le sévoflurane est moins efficace pour prevenir la diminution de Cdyn mais seulement à 8 μg · kg−1 d’histamine sous anesthésie à MAC 1 et 2. Le sévoflurane, l’halothane et l’isoflurane ne sont pas de différents pour amortir
les changements de RL et Cdyn. Nous concluons que le sévoflurane est moins puissant que l’halothane pour diminuer la réponse à l’histamine de la RL et de la Cdyn. 相似文献
100.
A 13-yr-old boy was scheduled for emergency appendicectomy because of abdominal pain. His preoperative medical history was complicated by a recent hospital admission for management of asthma. He had presented to hospital seven days earlier because of dyspnoea, tachypnoea and oxygen desaturation to 77% on room air. Following admission, he required intensive non-ventilatory management of his asthma, including intravenous salbutamol, methylprednisolone, and aminophylline, as well as use of an ipratroprium bromide inhaler and 100% oxygen by mask. He was discharged to the ward, and continued on prednisone (deltacortisone), beclomethasone inhaler, ipratroprium inhaler, and salbutamol inhaler. During his ICU stay, he complained of nonspecific abdominal pain, interpreted as gastro-oesophageal reflux. After four days, he was discharged to the ward. On his sixth hospital day, he began to experience right-sided lower abdominal pain and right shoulder pain. A surgeon was consulted, and the patient was found to have a very tender right lower quadrant with guarding and rebound pain. He was therefore scheduled for appendicectomy; antibiotic therapy with ampicillin, gentamicin, and metronidazole was initiated. 相似文献