全文获取类型
收费全文 | 463篇 |
免费 | 66篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 20篇 |
妇产科学 | 13篇 |
基础医学 | 44篇 |
口腔科学 | 10篇 |
临床医学 | 51篇 |
内科学 | 77篇 |
皮肤病学 | 4篇 |
神经病学 | 26篇 |
特种医学 | 61篇 |
外科学 | 22篇 |
综合类 | 6篇 |
预防医学 | 31篇 |
眼科学 | 1篇 |
药学 | 145篇 |
中国医学 | 5篇 |
肿瘤学 | 12篇 |
出版年
2021年 | 4篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 19篇 |
2014年 | 25篇 |
2013年 | 16篇 |
2012年 | 16篇 |
2011年 | 18篇 |
2010年 | 25篇 |
2009年 | 7篇 |
2008年 | 17篇 |
2007年 | 20篇 |
2006年 | 18篇 |
2005年 | 17篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 7篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 17篇 |
1996年 | 11篇 |
1995年 | 13篇 |
1994年 | 18篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 7篇 |
1989年 | 18篇 |
1988年 | 23篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1984年 | 21篇 |
1983年 | 9篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1958年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有529条查询结果,搜索用时 15 毫秒
1.
Assessment of caffeine exposure: caffeine content of beverages, caffeine intake, and plasma concentrations of methylxanthines 总被引:4,自引:0,他引:4
The caffeine content of all tea or coffee beverages consumed by 17 healthy adults over 24 hours was measured. Plasma caffeine, theophylline, theobromine, and paraxanthine concentrations were determined over the same 24 hours. The average caffeine content per drink was 60.4 +/- 21.8 mg for instant coffee (14-fold range), 80.1 +/- 19.2 mg for brewed coffee (2.8-fold range), and 28.8 +/- 13.7 mg for tea (5.5-fold range). The number of drinks of coffee and tea consumed was a poor index of actual caffeine intake (r2 = 0.42). Caffeine intake correlated poorly with the 24-hour average caffeine concentration (r2 = 0.41), but there was a very good correlation between a single plasma caffeine concentration measured at 5 PM and the 24-hour average concentration (r2 = 0.94). The same was true for paraxanthine (r2 = 0.86). Paraxanthine accounted for 67.3% of the total dimethylxanthines in plasma, while theobromine and theophylline accounted for 24.4% and 8.3%, respectively. Mean caffeine clearance was 1.2 +/- 0.3 ml/min/kg. Plasma caffeine concentration before the first drink in the morning correlated very poorly with caffeine clearance (r2 = 0.07), even when adjusted for caffeine intake (r2 = 0.21). 相似文献
2.
WHAN KOOK CHUNG KYU YONG CHOI CHANG DON LEE JIN WU CHUNG HEE SIK SUN KYU WON CHUNG BOO SUNG KIM CHUNG SIK CHUN KYOO HONG CHO SEUNG JO KIM 《Journal of gastroenterology and hepatology》1987,2(1):13-17
Different doses of hepatitis B virus vaccine—prepared by Korea Green Cross Corporation, were given to healthy infants born to HBsAg-negative mothers at birth, 1 and 6 months of age. A dose of 2 μg was administered intradermally in Group A and, in the three other groups, the vaccine was given intramuscularly (i.m.). An adequate follow-up observation was possible for 9 months after birth in 22, 25, 23 and 21 infants in Groups A, B, C and D, respecvely.
Group C (5 μg, i.m.) produced seroconversion most rapidly, showing the highest rate (96%) at 9 months of age. The lowest seroconversion rate (5%) was found at the age of 1 month in Group A subjects, but the rate increased to 91% after a booster dose was given at 6 months of age.
While it can be concluded that a 5 μg i.m. dose of vaccine at 0, 1 and 6 months of age is optimum for the immunization of infants in efficacy and economy, a 2 μg intradermal dose can also be considered as an immunogenic and economical regimen, though the immune response is slower and a special technique is required for immunization. 相似文献
Group C (5 μg, i.m.) produced seroconversion most rapidly, showing the highest rate (96%) at 9 months of age. The lowest seroconversion rate (5%) was found at the age of 1 month in Group A subjects, but the rate increased to 91% after a booster dose was given at 6 months of age.
While it can be concluded that a 5 μg i.m. dose of vaccine at 0, 1 and 6 months of age is optimum for the immunization of infants in efficacy and economy, a 2 μg intradermal dose can also be considered as an immunogenic and economical regimen, though the immune response is slower and a special technique is required for immunization. 相似文献
3.
JO MANION RN MA CNAA 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1986,15(2):103-108
A documentation system that facilitates accurate and complete recording is needed by every obstetric/neonatal nursing service. Developing an individualized system is a major undertaking. However, specific steps can be taken to ease the process. These steps are described, beginning with the assessment phase and concluding with evaluation. 相似文献
4.
Determination of the parent of origin in nine cases of prenatally detected chromosome aberrations found after intracytoplasmic sperm injection 总被引:1,自引:17,他引:1
Van Opstal D; Los FJ; Ramlakhan S; Van Hemel JO; Van Den Ouweland AM; Brandenburg H; Pieters MH; Verhoeff A; Vermeer MC; Dhont M; In't Veld PA 《Human reproduction (Oxford, England)》1997,12(4):682-686
Prenatal cytogenetic analysis of 71 fetuses conceived by intracytoplasmic
sperm injection (ICSI) resulted in the detection of nine (12.7%) chromosome
aberrations including two cases of 47,XXY, four cases involving a 45,X cell
line and three autosomal trisomies. Molecular analysis of the parental
origin of the deleted or supernumerary chromosome was performed by using
polymorphic microsatellite markers. Six cases involving a sex chromosome
abnormality were found to be of paternal origin while the two trisomic
cases that could be analysed were of maternal origin. Two cases involved
the same infertile couple who had two consecutive ICSI pregnancies
terminated because of a chromosome abnormality. The replaced embryos in
both cases originated from a single batch of ICSI fertilized oocytes of
which part was used to initiate the first pregnancy and part was
cryopreserved and used to initiate the second pregnancy.
相似文献
5.
Winberg JO; Hammami-Hauasli N; Nilssen O; Anton-Lamprecht I; Naylor SL; Kerbacher K; Zimmermann M; Krajci P; Gedde-Dahl T Jr; Bruckner-Tuderman L 《Human molecular genetics》1997,6(7):1125-1135
Dystrophic epidermolysis bullosa (EBD) is a clinically heterogeneous skin
disorder, characterized by abnormal anchoring fibrils (AF) and loss of
dermal-epidermal adherence. EBD has been linked to the COL7A1 gene at
chromosome 3p21 which encodes collagen VII, the major component of the AF.
Here we investigated two unrelated EBD families with different clinical
phenotypes and novel combinations of recessive and dominant COL7A1
mutations. Both families shared the same recessive heterozygous 14 bp
deletion at the exon-intron 115 boundary of the COL7A1 gene. The deletion
caused in-frame skipping of exon 115 and the elimination of 29 amino acid
residues from the pro-alpha1(VII) polypeptide chain. As a result,
procollagen VII was not converted to collagen VII and the C-terminal NC-2
propeptide which is normally removed from the procollagen VII prior to
formation of the anchoring fibrils was retained in the skin. All affected
individuals also carried missense mutations in exon 73 of COL7A1 which lead
to different glycine- to-arginine substitutions in the triple-helical
domain of collagen VII. Combination of the deletion mutation with a G2009R
substitution resulted in a mild phenotype. In contrast, combination of the
deletion with a G2043R substitution led to a severe phenotype. The G2043R
substitution was a de novo mutation which alone caused a mild phenotype.
Thus, different combinations of dominant and recessive COL7A1 mutations can
modulate disease activity of EBD and alter the clinical presentation of the
patients.
相似文献
6.
Andrew N Stone Peter I Mackenzie Aleksandra Galetin J Brian Houston John O Miners 《Drug metabolism and disposition》2003,31(9):1086-1089
Morphine elimination involves UDP-glucuronosyltransferase (UGT) catalyzed conjugation with glucuronic acid to form morphine 3- and 6-glucuronides (M3G and M6G, respectively). It has been proposed that UGT2B7 is the major enzyme involved in these reactions, but there is evidence to suggest that other isoforms also catalyze morphine glucuronidation in man. Thus, we have characterized the selectivity and kinetics of M3G and M6G formation by recombinant human UGTs. UGT 1A1, 1A3, 1A6, 1A8, 1A9, 1A10, and 2B7 all catalyzed M3G formation, but only UGT2B7 formed M6G. The kinetics of M3G formation by the UGT1A family isoforms was consistent with a single enzyme Michaelis-Menten model, with apparent Km values ranging from 2.6 to 37.4 mM. In contrast, M3G and M6G formation by UGT2B7 exhibited atypical kinetics. The atypical kinetics may be described by a model with high- and low-affinity Km values (0.42 and 8.3 mM for M3G, and 0.97 and 7.4 mM for M6G) from fitting to a biphasic Michaelis-Menten model. However, a multisite model with an interaction between two identical binding sites in a negative cooperative manner provides a more realistic approach to modeling these data. According to this model, the respective binding affinities (Ks) for M3G and M6G were 1.76 and 1.41 mM, respectively. These data suggest that M6G formation may be used as a selective probe for UGT2B7 activity, and morphine glucuronidation by UGT2B7 appears to involve the simultaneous binding of two substrate molecules, highlighting the need for careful analysis of morphine glucuronidation kinetics in vitro. 相似文献
7.
8.
NUNO DIAS FERREIRA M.D. DANIEL CAEIRO M.D. LUÍS ADÃO M.D. MARCO OLIVEIRA M.D. HELENA GONÇALVES M.D. JOSÉ RIBEIRO M.D. MADALENA TEIXEIRA M.D. ANÍBAL ALBUQUERQUE M.D. JOÃO PRIMO M.D. PEDRO BRAGA M.D. LINO SIMÕES M.D. VASCO GAMA RIBEIRO M.D. 《Pacing and clinical electrophysiology : PACE》2010,33(11):1364-1372
Background: Previous reports have suggested the occurrence of cardiac conduction disorders and permanent pacemaker (PPM) requirement after transcatheter aortic valve implantation (TAVI). Based on a single‐center experience, we aim to assess the incidence of postprocedural conduction disorders, need for PPM, and its determinants after TAVI with a self‐expanding bioprosthesis. Methods: From August 2007 to October 2009, 32 consecutive patients underwent TAVI with the Medtronic CoreValve (MCV) System (Medtronic Inc., Minneapolis, MN, USA). Three patients paced at baseline and two cases of procedure‐related mortality were excluded. We analyzed the 12‐lead electrocardiogram at baseline, immediately after procedure and at discharge. Requirements for PPM were documented and potential clinical, electrophysiological, echocardiographic, and procedural predictors of PPM requirement were studied. Results: After TAVI, eight patients (29.6%) required PPM implantation due to high‐grade atrioventricular (AV) block. The prevalence of left bundle branch block increased from 13.8% to 57.7% directly after implantation (P = 0.001). Need for PPM was correlated to the depth of prosthesis implantation (r = 0.590; P = 0.001). At a cutoff point of 10.1 mm, the likelihood of pacemaker could be predicted with 87.5% sensitivity and 74% specificity and a receiver operator characteristic curve area of 0.86 ± 0.07 (P = 0.003). Of the seven patients with preexisting right bundle branch block (RBBB), four (57.1%) required PPM implantation after TAVI. Conclusions: High‐grade AV block requiring PPM implantation is a common complication following TAVI and could be predicted by a deeper implantation of the prosthesis. Patients with preexisting RBBB also seem to be at risk for the development of high‐grade AV block and subsequent pacemaker implantation. (PACE 2010; 1364–1372) 相似文献
9.
YENN‐JIANG LIN M.D. SHIH‐LIN CHANG M.D. LI‐WEI LO M.D. YU‐FENG HU M.D. KAZUYOSHI SUENARI M.D. CHENG‐HUNG LI M.D. TZE‐FAN CHAO M.D. FA‐PO CHUNG M.D. JO‐NAN LIAO M.D. BENY HARTONO M.D. HAN‐WEN TSO Ph.D. HSUAN‐MING TSAO M.D. JIN‐LONG HUANG M.D. TSAIR KAO Ph.D. SHIH‐ANN CHEN M.D. 《Journal of cardiovascular electrophysiology》2012,23(11):1155-1162
Modified Pulmonary Vein Isolation in AF Ablation. Introduction: Pulmonary vein isolation (PVI) is the primary ablation therapy in patients with atrial fibrillation (AF). We hypothesized that high dominant frequency (DF) sites (AF nests during sinus rhythm [SR]) adjacent to the PV ostia are associated with the atrial substrate that maintains AF, and PVI incorporating the high‐frequency AF nests may have a higher efficacy. Methods and Results: In a prospective and randomized comparison, 126 symptomatic paroxysmal AF patients that underwent PVI were enrolled. We compared the efficacy of a modified PVI (ablation line: 1.0–1.5 cm from the PV ostium with encircling the AF nests [spectral analysis with DF >70 Hz during SR, Group II]) versus the anatomy‐guided conventional PVI (Group I). In Group II, the DF value along the PV ostium was lower than 70 Hz after the PVI. The primary endpoint was the freedom from symptomatic atrial arrhythmias after a single procedure. We also followed the autonomic function by a time‐domain analysis of the heart rate variability. In both groups, AF nests were observed and electric isolation was successfully obtained in all patients. With a mean duration of 16 ± 6.1 months of follow‐up, Group II had a higher single procedure efficacy without drugs (78.7% vs 66.1%, log‐rank test: P = 0.02), and fewer repeat procedures (6.6% vs 23%; P = 0.04), as compared to Group I. Conclusion: PVI incorporating the high frequency AF nests adjacent to the PV ostia had a better single procedure efficacy. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1155–1162, November 2012) 相似文献
10.
Martin NK Vickerman P Miners A Foster GR Hutchinson SJ Goldberg DJ Hickman M 《Hepatology (Baltimore, Md.)》2012,55(1):49-57
Injecting drug use is the main risk of hepatitis C virus (HCV) transmission in most developed countries. HCV antiviral treatment (peginterferon-α + ribavirin) has been shown to be cost-effective for patients with no reinfection risk. We examined the cost-effectiveness of providing antiviral treatment for injecting drug users (IDUs) as compared with treating ex/non-IDUs or no treatment. A dynamic model of HCV transmission and disease progression was developed, incorporating: a fixed number of antiviral treatments allocated at the mild HCV stage over 10 years, no retreatment after treatment failure, potential reinfection, and three baseline IDU HCV chronic prevalence scenarios (20%, 40%, and 60%). We performed a probabilistic cost-utility analysis estimating long-term costs and outcomes measured in quality adjusted life years (QALYs) and calculating the incremental cost-effectiveness ratio (ICER) comparing treating IDUs, ex/non-IDUs, or no treatment. Antiviral treatment for IDUs is the most cost-effective option in the 20% and 40% baseline chronic prevalence settings, with ICERs compared with no treatment of £ 521 and £ 2,539 per QALY saved, respectively. Treatment of ex/non-IDUs is dominated in these scenarios. At 60% baseline prevalence, treating ex/non-IDUs is slightly more likely to be the more cost-effective option (with an ICER compared with no treatment of £ 6,803), and treating IDUs dominated due to high reinfection. A sensitivity analysis indicates these rankings hold even when IDU sustained viral response rates as compared with ex/non-IDUs are halved. CONCLUSION: Despite the possibility of reinfection, the model suggests providing antiviral treatment to IDUs is the most cost-effective policy option in chronic prevalence scenarios less than 60%. Further research on how HCV treatment for injectors can be scaled up and its impact on prevalence is warranted. 相似文献