全文获取类型
收费全文 | 17172篇 |
免费 | 1163篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 187篇 |
儿科学 | 434篇 |
妇产科学 | 364篇 |
基础医学 | 2560篇 |
口腔科学 | 461篇 |
临床医学 | 1748篇 |
内科学 | 3393篇 |
皮肤病学 | 257篇 |
神经病学 | 1715篇 |
特种医学 | 502篇 |
外国民族医学 | 1篇 |
外科学 | 1793篇 |
综合类 | 243篇 |
一般理论 | 22篇 |
预防医学 | 1852篇 |
眼科学 | 238篇 |
药学 | 1400篇 |
中国医学 | 64篇 |
肿瘤学 | 1180篇 |
出版年
2023年 | 116篇 |
2022年 | 275篇 |
2021年 | 485篇 |
2020年 | 297篇 |
2019年 | 407篇 |
2018年 | 464篇 |
2017年 | 331篇 |
2016年 | 349篇 |
2015年 | 403篇 |
2014年 | 615篇 |
2013年 | 782篇 |
2012年 | 1191篇 |
2011年 | 1246篇 |
2010年 | 634篇 |
2009年 | 565篇 |
2008年 | 937篇 |
2007年 | 1001篇 |
2006年 | 861篇 |
2005年 | 857篇 |
2004年 | 831篇 |
2003年 | 691篇 |
2002年 | 705篇 |
2001年 | 288篇 |
2000年 | 283篇 |
1999年 | 254篇 |
1998年 | 176篇 |
1997年 | 153篇 |
1996年 | 123篇 |
1995年 | 118篇 |
1994年 | 117篇 |
1993年 | 97篇 |
1992年 | 219篇 |
1991年 | 196篇 |
1990年 | 188篇 |
1989年 | 136篇 |
1988年 | 154篇 |
1987年 | 154篇 |
1986年 | 173篇 |
1985年 | 140篇 |
1984年 | 111篇 |
1983年 | 88篇 |
1982年 | 81篇 |
1981年 | 58篇 |
1979年 | 82篇 |
1976年 | 59篇 |
1974年 | 58篇 |
1973年 | 74篇 |
1971年 | 63篇 |
1969年 | 70篇 |
1968年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Paul R. Finley R. Jane Williams Carla Fletcher 《Journal of clinical laboratory analysis》1988,2(4):249-255
We have devised assays to detect both circulating alloantibodies to platelets (indirect assay) and platelet-association IgG and IgM (direct assay) using a flow cytometric technique. A variety of patients with immune thrombocytopenia were studied. Employment of a confocal lens in the flow cytometer increased the discrimination power of the instrument. Patients with autoimmune thrombocytopenia (idiopathic thrombocytic purpura [ITP], systemic lupus erythematosus (SLE), lymphoma, leukemia, and drug-induced thrombocytopenia showed a significant increase in platelet-associated antibody. Circulating antibodies to platelets (alloantibodies) were demonstrated in cases of platelet refractoriness and neonatal isoimmune purpura. Day-today precision of the assays ranged from 3% to 6% (coefficient of variation). No interference was shown in the presence of hemoglobin (5 g/L), triglycerides (10 g/L), or polyclonal and monoclonal immunoglobulinemia (50 g/L: IgG, IgA, IgM). The sensitivity of the direct assay was 500 attograms of IgG or IgM platelet. 相似文献
22.
Luiz H Castro Luiz K Ferreira Leandro R Teles Carmen L Jorge Paula R Arantes Carla R Ono Carla C Adda Rosa F Valerio 《Seizure》2007,16(1):50-58
PURPOSE: Hypothalamic hamartoma (HH) related epilepsy presents with gelastic seizures (GS), other seizure types and cognitive deterioration. Although seizure origin in GS has been well established, non-GS are poorly characterized. Their relationship with the HH and cognitive deterioration remains poorly understood. We analyzed seizure type, spread pattern in non-GS and their relationship with the epileptic syndrome in HH. METHODS: We documented all current seizure types in six adult patients with HH-epilepsy with video-EEG monitoring, characterized clinical-electrographic features of gelastic and non-gelastic seizures and correlated these findings with cognitive profile, as well as MRI and ictal SPECT data. RESULTS: Only four seizure types were seen: GS, complex partial (CPS), tonic seizures (TS) and secondarily generalized tonic-clonic seizures (sGTC). An individual patient presented either CPS or TS, but not both. GS progressed to CPS or TS, but not both. Ictal patterns in GS/TS and in GS/CPS overlapped, suggesting ictal spread from the HH to other cortical regions. Ictal SPECT patterns also showed GS/TS overlap. Patients with GS-CPS presented a more benign profile with preserved cognition and clinical-EEG features of temporal lobe epilepsy. Patients with GS-TS had clinical-EEG features of symptomatic generalized epilepsy, including mental deterioration. CONCLUSIONS: Video-EEG and ictal SPECT findings suggest that all seizures in HH-related epilepsy originate in the HH, with two clinical epilepsy syndromes: one resembling temporal lobe epilepsy and a more catastrophic syndrome, with features of a symptomatic generalized epilepsy. The epilepsy syndrome may be determined by HH size or by seizure spread pattern. 相似文献
23.
Marcelo Biscegli Jatene Estela Azeka Edmar Atik Arlindo Riso Carla Tanamati Miguel Barbero Marcial Sergio Almeida de Oliveira 《The Journal of heart and lung transplantation》2005,24(5):638-641
A 28-month-old boy, weighing 11 kg, with severe dilated cardiomyopathy, was transplanted on December 1995. Hypertension and supraventricular tachycardia were detected in the immediate post-operative period, with favorable outcome. After 5 months of clinically asymptomatic follow-up, a dilation in the ascending aorta was observed on routine echocardiogram. Nuclear magnetic resonance imaging (NMRI) confirmed an ascending aortic aneurysm, with a diameter of 38 mm. An operation was performed, a bovine pericardium patch was sutured with reconstruction of the aortic wall, excluding the aneurysm. Good recovery was obtained and the child was discharged on Day 7 postoperatively. A post-operative echocardiogram showed absence of the aortic aneurysm and good surgical results. Another NMRI was done 5 months later, showing an intact ascending aorta. After 64 months, the patients clinical condition was confirmed as normal by echocardiogram. Surgical treatment was successful and the positive results have been maintained. 相似文献
24.
Joana Correia Fátima Franco Silva Carla Roque Henrique Vieira Luís Augusto Providéncia 《Revista portuguesa de cardiologia》2007,26(4):335-343
BACKGROUND: High rates of morbidity and mortality are observed in patients with advanced heart failure (AHF). AHF is now considered the most costly syndrome in cardiology owing to the substantial economic burden associated with hospitalizations for acute decompensation. A management program that involves specialized follow-up by a multidisciplinary team has been suggested as a desirable strategy for improving outcomes for these patients. ObjectivE: To evaluate the impact of a specialized outpatient heart failure (HF) follow-up program for patients with AHF on frequency and duration of hospitalization for HF and functional status. METHODS: We retrospectively studied 167 consecutive patients with AHF who were referred to the outpatient HF follow-up program in our institution between January and November 2002, of whom 147 followed for > or =30 days were included in the analysis. In addition to demographic and baseline clinical characteristics, HF medication and NYHA functional class, the number and duration of hospitalizations for HF during the previous 12 months were recorded and compared at the time of referral and after a follow-up period of 6.5+/-3 months. RESULTS: Of the 147 patients analyzed (aged 60.8+/-13 years; 79% male; left ventricular ejection fraction 27+/-11%), 67% were in NYHA functional class III, 20% in class II and 13% in class IV at the time of referral. There was a significant improvement in functional class during the mean follow-up period: 55% of the patients were in class III, 37% in class II, 5% in class I and 3% in class IV (p<0.0001). The proportion of patients on beta-blockers or spironolactone increased from 33% and 51% at the time of referral to 69% and 71% respectively after referral (p<0.0001). In the 12 months before referral, 39% of the patients had been hospitalized for acute decompensation of HF (87 hospitalizations - mean 7.2/month) versus 13% of the patients during the mean follow-up period (25 hospitalizations - 3.8/month, p<0.0001). No significant differences were found in the proportion of patients on angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, digoxin or diuretics, or in the mean duration of hospitalization before and after referral. ConclusioN: The specialized follow-up of patients with AHF by a team with expertise in HF resulted in significant therapeutic optimization. Increased use of beta-blockers and spironolactone was associated with significant improvement in functional capacity and significant reduction in hospitalizations. 相似文献
25.
26.
Steven N Singh X Charlene Tang Bramah N Singh Paul Dorian Domenic J Reda Crystal L Harris Ross D Fletcher Satish C Sharma J Edwin Atwood Alan K Jacobson H Daniel Lewis Becky Lopez Dennis W Raisch Michael D Ezekowitz 《Journal of the American College of Cardiology》2006,48(4):721-730
OBJECTIVES: The purpose of this study was to determine quality of life (QOL) and exercise performance (EP) in patients with persistent atrial fibrillation (AF) converted to sinus rhythm (SR) compared with those remaining in or reverting to AF. BACKGROUND: Restoration of SR in patients with AF improving QOL and EP remains controversial. METHODS: Patients with persistent AF were randomized double-blind to amiodarone, sotalol, or placebo. Those not achieving SR at day 28 were cardioverted and classified into SR or AF groups at 8 weeks (n = 624) and 1 year (n = 556). The QOL (SF-36), symptom checklist (SCL), specific activity scale (SAS), AF severity scale (AFSS), and EP were assessed. RESULTS: Favorable changes were seen in SR patients at 8 weeks in physical functioning (p < 0.001), physical role limitations (p = 0.03), general health (p = 0.002), and vitality (p < 0.001), and at 1 year in general health (p = 0.007) and social functioning (p = 0.02). Changes in the scores for SCL severity (p = 0.01), functional capacity (p = 0.003), and AFSS symptom burden (p < 0.001) at 8 weeks and in SCL severity (p < 0.01) and AF symptom burden (p < 0.001) at 1 year showed significant improvements in SR versus AF. Symptomatic patients were more likely to have improvement. The EP in SR versus AF was greater from baseline to 8 weeks (p = 0.01) and to 1 year (p = 0.02). The EP correlated with physical functioning and functional capacity except in the AF group at 1 year. CONCLUSIONS: In patients with persistent AF, restoration and maintenance of SR was associated with improvements in QOL measures and EP. There was a strong correlation between QOL measures and EP. 相似文献
27.
Carla Santos Araújo Roberto Roncon Albuquerque Mónica Moreira Rodrigues Benedita Sampaio Maia Adelino F Leite Moreira Manuel Pestana 《Revista portuguesa de cardiologia》2006,25(4):419-427
INTRODUCTION: The biological activity of the natriuretic peptide (NP) system is dependent on the balance between NP tissue levels and the local expression of their receptors. In the kidney, the natriuretic peptide receptor type A (NPR-A) is the principal receptor mediating NP activity and is mainly expressed in the renal medulla. An increase in circulating NP levels is well documented in chronic renal failure (CRF); however, the renal expression of NPR-A has not been evaluated in this condition. METHODS: Wistar-Han rats were submitted to right nephrectomy plus ablation of both poles of the left kidney (3/4nx; n=27) or were sham operated (Sham; n=22) and followed for up to 26 weeks post surgery. Blood pressure measurements were performed weekly. Two, 10 and 26 weeks after surgery, renal sodium and creatinine excretion were evaluated and the kidneys removed for NPR-A mRNA quantification by real-time PCR. The results of mRNA quantification are expressed in arbitrary units (AU) set as the mean value of the Sham group (Sham=1 AU), after normalization for GAPDH (p<0.05). weeks after surgery) and in elevated fractional sodium excretion (+270%, 26 weeks after surgery). Although sodium intake was similar in 3/4nx and Sham rats, blood pressure was higher in 3/4nx rats and increased progressively throughout the study. This was accompanied by a marked decrease in NPR-A mRNA levels in the renal medulla from 3/4nx animals at 2, 10 and 26 weeks post surgery. Conclusion: In 3/4nx rats, the expression of NPR-A in the renal medulla of the remnant kidney is markedly reduced from 2 weeks up to 26 weeks post surgery. It is suggested that this may contribute to the progressive increase in blood pressure, as well as to the renal fibrosis observed in 3/4nx rats. 相似文献
28.
The effect of low dose lofepramine in depressed elderly patients in general medical wards. 下载免费PDF全文
R S Tan R J Barlow C Abel S Reddy A J Palmer A E Fletcher C G Nicholl B M Pitt C J Bulpitt 《British journal of clinical pharmacology》1994,37(4):321-324
A double-blind randomised controlled trial of the effect of low dose lofepramine (70 mg once daily) against placebo was carried out on depressed elderly inpatients on general medical wards for the elderly, comparing measures of depression and side-effects between the randomised groups. Patients were identified for the study using the Geriatric Depression Scale (GDS) and the Brief Assessment Schedule Depression Cards (BASDEC). Sixty-three subjects were randomised: 46 patients completed the entire trial of 28 days treatment. BASDEC and GDS were administered on day 8 post-admission, and depressed patients were randomised double-blind to either low dose lofepramine (70 mg daily) (n = 23) or placebo (n = 23). Assessment of changes in depressive states were made using the Montgomery Asberg Depression Rating Scale (MADRS) on days 8, 18 and 36 post-admission. Both groups improved by a similar amount during the trial. Lofepramine tended to be more effective than placebo in those patients who were more depressed (GDS > or = 18). On the other hand, subjects who were less depressed (i.e. GDS < 18) improved more on placebo than lofepramine. Low dose lofepramine may prove useful in moderately or severely depressed patients treated for only 4 weeks. However, low dose lofepramine is not indicated for mild (GDS 15-18) depression. 相似文献
29.
Salvatore Serra Giuliana Brunetti Giovanni Vacca Carla Lobina Mauro A M Carai Gian Luigi Gessa Giancarlo Colombo 《Alcohol》2003,29(2):101-108
Results of a recent study have demonstrated that exposure to multiple ethanol concentrations and repeated ethanol deprivation periods in Indiana ethanol-preferring (P) rats resulted in the development of an alcohol deprivation effect (ADE; the temporary increase in voluntary ethanol intake after a period of deprivation from ethanol) characterized by consumption of intoxicating amounts of ethanol. The current study was designed to possibly extend these results to Sardinian alcohol-preferring (sP) rats, generated with the same selective program previously used for P rats. To this aim, ethanol-naive sP rats were exposed initially to the home cage four-bottle choice [10%, 20%, and 30% (vol./vol.) ethanol solutions and water] for eight consecutive weeks. Subsequently, rats were divided into two groups: The first group had continuous access to the four-bottle regimen (nondeprived rats), and the second group was exposed to five cycles of 14-day periods of deprivation from ethanol and 14-day periods of reexposure to the four-bottle regimen. An ADE developed after each deprivation period. However, the extra intake of ethanol was limited to the first hour of each reaccess period. Magnitude of ADE did not change with repeated periods of deprivation. However, a shift in preference toward the two highest concentrations of ethanol solutions was evident from the first reexposure to ethanol and was maintained throughout the study. These results provide further evidence on the heterogeneity of ethanol-drinking behavior among rat lines selectively bred for high ethanol preference and consumption. 相似文献
30.
Conjunctivitis and pterygium associated with the American Indian type of polymorphous light eruption 总被引:1,自引:0,他引:1
D C Fletcher K G Romanchuk P R Lane 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》1988,23(1):30-33
We describe three patients with the American Indian type of polymorphous light eruption (actinic prurigo), two Cree Indian sisters and a Cree Indian boy, who had eye symptoms similar to those seen in limbal-type vernal catarrh. 相似文献