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31.
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) is an important
metabolite of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-
(3-pyridyl)-1-butanone (NNK). Using the chiral derivatizing agent, (R)-
(+)-alpha-methylbenzyl isocyanate [(R)-(+)-MBIC], previous work has shown
that the enantiomeric ratio of metabolically formed NNAL and its
glucuronide derivative may be species dependent. However, the absolute
configuration of such NNAL has not been previously reported. Synthetically
prepared racemic NNAL was converted to diastereomeric esters by reaction
with (R)-(+)- and (S)-(-)-alpha-methoxy-alpha-
(trifluoromethyl)phenylacetic acid (MTPA) chloride (Mosher's reagent) and
the products were characterized by 1H-NMR. Based on chemical shift data,
the absolute configuration of NNAL in each diastereomeric ester was
assigned. Hydrolysis of (R)-NNAL-(R)-MTPA gave (R)-NNAL. This was converted
to the corresponding carbamate by reaction with (R)-(+)-alpha- MBIC and the
absolute configurations of the diastereomeric carbamates formed by reaction
of (R)- and (S)-NNAL with (R)-(+)-MBIC were thereby assigned. Conversion of
metabolically produced NNAL to the same carbamates allowed us to assign the
NNAL formed from NNK by rat liver microsomes as (R)-NNAL. The major and
minor NNAL-glucuronide diastereomers found in the urine of patas monkeys
and humans exposed to NNK were similarly assigned; they were formed from
(R)-NNAL and (S)- NNAL, respectively.
相似文献
32.
33.
Gomez R Harvey J Quick C Scharer I Harris G 《Journal of child psychology and psychiatry, and allied disciplines》1999,40(2):265-274
Based on parent and teacher ratings of primary school children on a scale comprising the 18 DSM-IV AD/HD symptoms, this study used confirmatory factor analysis to compare three models: all items in one factor; inattention in one and hyperactivity and impulsivity items in a separate factor; and inattention, hyperactivity, and impulsivity items in three separate factors. It also examined the prevalence rates of the three AD/HD Types, and gender and age differences. Results supported both the two- and three-factor models, with the three-factor model only slightly better than the two-factor model. Based on parent-teacher agreement, the prevalence rates were 1.6, 0.2 and 0.6% for the Inattentive, Hyperactive-Impulsive, and Combined Types, respectively. Overall, the male to female ratio was 5: 1, and boys were rated higher than girls by both parents and teachers. Age differences were minimal. The implications of the findings in relation to some of the assumptions made in DSM-IV for AD/HD are discussed. 相似文献
34.
35.
MAGNOLOL REDUCES INFARCT SIZE AND SUPPRESSES VENTRICULAR ARRHYTHMIA IN RATS SUBJECTED TO CORONARY LIGATION 总被引:7,自引:0,他引:7
1. Magnolol is an active component of Magnolia officinalis. It is 1000-times more potent than α-tocopherol in inhibiting lipid peroxidation in rat heart mitochondira. In the present study, the in vivo antiarrhythmic and anti-ischaemic effects of magnolol in coronary ligated rats were investigated. 2. Male Sprague-Dawley rats were anaesthetized with urethane. Magnolol, at dosages of 10?7, 10?8 and 10?9 g/kg, was adminstered intravenously 15 min before ligation of the coronary artery. 3. The incidence and duration of ventricular tachycardia and ventricular fibrillation during 30 min coronary ligation were significantly reduced by magnolol. Ventricular arrhythmias during 10 min reperfusion after the relief of coronary ligation were also reduced. 4. In rats subjected to 4h coronary ligation, 10?7 and 10?8 g/kg magnolol significantly reduced infarct size. 5. We conclude that magnolol may protect the myocardium against ischaemic injury and suppress ventricular arrhythmia during ischaemia and reperfusion. 相似文献
36.
37.
Wuhl E.; Fusch Ch.; Scharer K.; Mehls O.; Schaefer F. 《Nephrology, dialysis, transplantation》1996,11(1):75-80
BACKGROUND: Various anthropometric techniques are used to assess total bodywater in children on dialysis; however, their predictive accuracyand precision has not been validated. METHODS: We compared total body water measurements obtained by deuteriumoxide (D2O) dilution with predictions of total body water from(1) height and weight, (2) skinfold measurements, and (3) bioelectricalimpedance analysis, using previously published formulae forhealthy children. Measurements were performed in 14 patientson peritoneal and in nine patients on haemodialysis, aged 422years. RESULTS: In the total population of dialysed patients, weight was thestrongest single predictor of total body water (R2=0.93) followedby the resistance index (RI=height2/impedance; R2=0.85) andheight (R2=0.93). A prediction formula based on height and weightpredicted total body water with a residual mean square error(RMSE) of 1.97 l (coefficient of variation (CV)=10.0%) and witha systematic overestimation of true total body water by 0.4%.A prediction equation based on skinfold measurements yieldeda total body water estimate with an RMSE of 2.15 1 (CV=10.5%)and overpredicted true total body water by an average of 2.2%.Using three published prediction equations incorporating RI,RMSEs of 2.78 1 (CV=14.1%) with a mean under- or overestimationof true total body water by 6.9, 7.1, and 0.8% respectively,were achieved. The prediction of total body water was optimizedby linear combinations of RI or the log-transformed sum of fourskinfolds (logsum) with weight by the following equations: total body water (1) = 9.973.13xlogsum +0.59xweight (kg) (1) (R2 = 0.951; RMSE=1.67 1; CV = 8.17%). total body water (1) = 1.99 + 0.144 x RI (Ohm/cm2) + 0.40 x weight (kg) (2) (R2 = 0.949; RMSE = 1.671; CV = 8.53%). The fit of these prediction formulae, which were derived fromthe total population, did not differ significantly between haemo-and peritoneal dialysis patients or between boys and girls. CONCLUSIONS: Both skinfold measurements and bioelectrical impedance analysiscan be used to improve the height- and weight- based predictionof total body water in children on dialysis. 相似文献
38.
MM Harjai DC Agarwal P Dave SS Jog P Arora SM VSM 《Medical Journal Armed Forces India》2005,61(2):143-147
Background
The sudden increase in incidence and magnitude of mine blast injuries prompted us to highlight the problem and its management.Methods
The cases of mine blast injuries occurring during mining and demining in a particular geographical area were analysed. Total 27 cases of mine blast injuries occurred during mining or demining operations in a period of 13 months.Results
Various body regions were involved in the mine blast injuries but the main brunt was borne by feet and legs followed by multiple body regions due to splinters. 14 patients underwent below knee (BK) amputation while 4 patients required through knee (TK) amputations. The effect of blast was so severe that most of the cases required 2 to 5 times wound debridements. The initial aggressive debridement / open stump amputation saved the limb and life of all patients.Conclusion
A mine blast causes extensive injuries and psychological trauma. Management is needed urgently, surgery is difficult, and amputation is often inevitable. Maximum lives and limbs can be saved with aggressive debridement, repeated inspections and dressings under anaesthesia and definitive closure at optimum time.Key Words: Amputation, Antipersonnel mine, Crush syndrome, Debridements, Mine blast injury, Secondary missiles, Shrapenels 相似文献39.
Tu'meh SS; Tracy DA; Wynne J; Konstam MA; Kozlowski JF; Neumann AL; Holman BL 《Radiology》1982,145(2):463-466
The authors describe a simple technique for diagnosis of tricuspid regurgitation. Red blood cells were labeled in vivo with 99mTc and 22 patients were studied with ECG-gated blood-pool imaging of the liver. A single region of interest was manually drawn around the liver and a time-activity curve obtained. The per cent change in liver counts during the cardiac cycle was found to be significantly higher in the 12 patients with tricuspid regurgitation (Group I) (mean, 4.04 +/- 1.6%; range, 1.3-21.4%) compared with the 10 controls (Group II) (mean, 0.35 +/- 0.16%; range, 0.013-1.3%) (p less than 0.05). Using a 1% change in liver counts as the criterion of a positive study, all 12 cases in Group I were diagnosed correctly, but there was one false positive in Group II; thus the sensitivity was 100% and the specificity 90%. 相似文献