全文获取类型
收费全文 | 136540篇 |
免费 | 7606篇 |
国内免费 | 784篇 |
专业分类
耳鼻咽喉 | 1295篇 |
儿科学 | 4312篇 |
妇产科学 | 3028篇 |
基础医学 | 19527篇 |
口腔科学 | 4851篇 |
临床医学 | 12256篇 |
内科学 | 31091篇 |
皮肤病学 | 3429篇 |
神经病学 | 13275篇 |
特种医学 | 3504篇 |
外国民族医学 | 1篇 |
外科学 | 12728篇 |
综合类 | 465篇 |
一般理论 | 57篇 |
预防医学 | 12822篇 |
眼科学 | 2209篇 |
药学 | 9515篇 |
中国医学 | 507篇 |
肿瘤学 | 10058篇 |
出版年
2024年 | 148篇 |
2023年 | 1268篇 |
2022年 | 2751篇 |
2021年 | 4614篇 |
2020年 | 2862篇 |
2019年 | 3889篇 |
2018年 | 4424篇 |
2017年 | 3305篇 |
2016年 | 3876篇 |
2015年 | 4241篇 |
2014年 | 5635篇 |
2013年 | 7328篇 |
2012年 | 11143篇 |
2011年 | 11625篇 |
2010年 | 6271篇 |
2009年 | 5332篇 |
2008年 | 9127篇 |
2007年 | 9133篇 |
2006年 | 8383篇 |
2005年 | 7810篇 |
2004年 | 7020篇 |
2003年 | 6247篇 |
2002年 | 5641篇 |
2001年 | 1004篇 |
2000年 | 825篇 |
1999年 | 1051篇 |
1998年 | 1012篇 |
1997年 | 819篇 |
1996年 | 704篇 |
1995年 | 577篇 |
1994年 | 543篇 |
1993年 | 466篇 |
1992年 | 580篇 |
1991年 | 474篇 |
1990年 | 473篇 |
1989年 | 449篇 |
1988年 | 373篇 |
1987年 | 310篇 |
1986年 | 347篇 |
1985年 | 323篇 |
1984年 | 272篇 |
1983年 | 238篇 |
1982年 | 227篇 |
1981年 | 167篇 |
1980年 | 168篇 |
1979年 | 182篇 |
1978年 | 119篇 |
1977年 | 131篇 |
1976年 | 113篇 |
1974年 | 101篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Comparative in vivo evaluation of technetium and iodine labels on an anti-HER2 affibody for single-photon imaging of HER2 expression in tumors. 总被引:1,自引:0,他引:1
Anna Orlova Fredrik Y Nilsson Maria Wikman Charles Widstr?m Stefan St?hl J?rgen Carlsson Vladimir Tolmachev 《Journal of nuclear medicine》2006,47(3):512-519
In vivo diagnosis with cancer-specific targeting agents that have optimal characteristics for imaging is an important development in treatment planning for cancer patients. Overexpression of the HER2 antigen is high in several types of carcinomas and has predictive and prognostic value, especially for breast cancer. A new type of targeting agent, the Affibody molecule, was described recently. An Affibody dimer, His6-(ZHER2:4)2 (15.4 kDa), binds to HER2 with an affinity of 3 nmol/L and might be used for the imaging of HER2 expression. The use of 99mTc might improve the availability of the labeled conjugate, and Tc(I)-carbonyl chemistry enables the site-specific labeling of the histidine tag on the Affibody molecule. The goals of the present study were to prepare 99mTc-labeled His6-(ZHER2:4)2 and to evaluate its targeting properties compared with the targeting properties of 125I-4-iodobenzoate-His6-(ZHER2:4)2 [125I-His6-(ZHER2:4)2]. METHODS: The labeling of His6-(ZHER2:4)2 with 99mTc was performed with an IsoLink kit. The specificity of 99mTc-His6-(ZHER2:4)2 binding to HER2 was evaluated in vitro with SK-OV-3 ovarian carcinoma cells. The comparative biodistributions of 99mTc-His6-(ZHER2:4)2 and 125I-His6-(ZHER2:4)2 in tumor-bearing BALB/c nu/nu mice were determined. RESULTS: The labeling yield for 99mTc-His6-(ZHER2:4)2 was approximately 60% (50 degrees C), and the radiochemical purity was greater than 97%. The conjugate was stable during storage and under histidine and cysteine challenges and demonstrated receptor-specific binding. The biodistribution study demonstrated tumor-specific uptake levels (percentage injected activity per gram of tissue [%IA/g]) of 2.6 %IA/g for 99mTc-His6-(ZHER2:4)2 and 2.3 %IA/g for 125I-His6-(ZHER2:4)2 at 4 h after injection. Both conjugates provided clear imaging of SK-OV-3 xenografts at 6 h after injection. The tumor-to-nontumor ratios were much more favorable for the radioiodinated Affibody. CONCLUSION: The use of Tc(I)-carbonyl chemistry enabled us to prepare a stable, site-specifically labeled 99mTc-His6-(ZHER2:4)2 conjugate that was able to bind to HER2-expressing cells in vitro and in vivo. The indirectly radioiodinated conjugate provided better tumor-to-liver ratios. The labeling of Affibody molecules with 99mTc should be investigated further. 相似文献
102.
Dr Maria Theresia Kaltwasser 《Am J Cardiovasc Drugs》2005,5(5):319-324
OBJECTIVE: To examine the economic consequences of effective antihypertensive treatment using the novel vasodilating beta1-adrenoceptor antagonist nebivolol (Nebilet) from the perspective of the healthcare provider. METHODS: The evaluation was based on a postmarketing surveillance study in Germany involving 8682 moderately hypertensive patients. Using the Framingham Risk Model, the antihypertensive effectiveness of nebivolol after 6 weeks of treatment was extrapolated to estimate the reductions in 10-year risks of cardiovascular events. Data sources included direct costs for medical and invasive cardiovascular interventions in Germany, costs of therapy in the US and the UK, and estimates on the prevalence of cardiovascular events issued by the American Heart Association. RESULTS: Six-week antihypertensive treatment resulted in a DBP reduction of 13.7 mm Hg. The rate of responders, defined as those patients achieving DBP <90 mm Hg, was 70%. SBP was reduced by 26.1 mm Hg. According to the Framingham Risk Model, 313 deaths would be avoided. Coronary heart disease (CHD) could be reduced by 94 cases (from 1339 to 1245 events) and 150 strokes would be avoided (from 518 to 368 events) in a 10-year period. This reduction of 244 cardiovascular events among the 8682 patients investigated corresponded to cost savings of between Euro 250,000 and Euro 2.5 million, depending on the healthcare environment and the intervention applied. CONCLUSION: Treatment of moderately hypertensive patients with nebivolol can be considered cost effective. Nebivolol has the potential to decrease the overall long-term costs of medical care for patients with hypertension. 相似文献
103.
Grafts of porcine intestinal submucosa for repair of cervical and abdominal esophageal defects in the rat. 总被引:2,自引:0,他引:2
Maria Francelina Lopes António Cabrita José Ilharco Pedro Pessa Jo?o Patrício 《Journal of investigative surgery》2006,19(2):105-111
Porcine small intestinal submucosa (SIS) is a cell-free collagen matrix that has demonstrated its ability as scaffold material for constructive remodeling of damaged or missing tissue. The purpose of this study was to evaluate the morphology and function of esophagoplasty in rat using a porcine SIS scaffold for the repair of a semi-circumferential defect in the cervical or in the abdominal esophagus. Sixty-seven rats underwent surgical excision of the anterior wall either of the cervical or of the abdominal esophagus and subsequent repair of the defect with an SIS patch graft. Outcomes of weight gain, signs of dysphagia, hematological and serum chemistry parameters, and barium swallow studies were used to assess the progress of healing and function over a 150-day time period. The grafts were studied for gross changes and histology at predetermined time points. Ninety-four percent of the SIS-treated rats survived, showing no significant differences in survival rate between groups. The grafted animals did well, without signs of dysphagia, and gaining weight. Barium swallow studies showed no evidence of fistula, significant stenosis, or diverticula. No hematological or serum biochemistry abnormalities were found. By 150 days, the SIS graft was replaced with esophageal-derived tissues. Specimens were completely lined by keratinized stratified squamous epithelium and showed complete regeneration of muscle fibers and scarce immunoreactivity for nerve. In the rat model, a patch graft technique using porcine SIS appears to induce esophageal regrowth either in cervical and abdominal esophagus. The repair mechanism occurred through a regenerative healing process. 相似文献
104.
Maria José GaldOn Estrella Durá Yolanda Andreu Maite Ferrando Rafael Poveda José Vicente Bagán 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2006,102(1):40-46
OBJECTIVE: This study analyzes the differences in psychological variables and symptomatology between temporomandibular disorder diagnosis subgroups. STUDY DESIGN: The sample included 114 temporomandibular disorder patients that were evaluated in coping, distress, and temporomandibular characteristics. Diagnostic muscular (n = 58) and articular (n = 56) subgroups were compared in these variables through a MANCOVA. RESULTS: Muscular patients show a higher level of general distress, specifically in the anxiety and somatization subscales and a more active coping style, with a tendency of a minor use of humor and a higher number of parafunctional habits, specifically, biting nails, hangnails, and lips. CONCLUSION: We discuss the differences found in order to design the targets of the psychological intervention of temporomandibular patients. 相似文献
105.
Cristina Tassorelli Francesca Mancini Laura Balloni Claudio Pacchetti Giorgio Sandrini Giuseppe Nappi Emilia Martignoni 《Movement disorders》2006,21(12):2240-2243
Currently, the best treatment option for idiopathic cervical dystonia (ICD) is injection of botulinum toxin (BTX) into the affected muscles, whereas rehabilitative approaches have given disappointing results. We evaluated whether the association of an ad hoc rehabilitative program may improve the clinical efficacy of BTX treatment in a single-center, cross-over, controlled study. Forty patients with ICD were randomly assigned to two different treatment groups: (1) BTX type A (BTX-A) plus a specific program of physical therapy (BTX-PT) or (2) BTX-A alone (BTX-0). Patients in the BTX-PT group showed a longer duration of the clinical benefit (118.8 vs. 99.1 days) and needed a lower dose of BTX at reinjection (284.5 vs. 325.5 units). In addition, they showed more marked reductions in their disability in activities of daily living (-9.7 vs. -4.85 points) and subjective pain (-13.35 vs. 6.95 points) scores. Association of BTX-A therapy with a specific program of physical therapy may improve ICD treatment outcome. 相似文献
106.
Gabriele Masi Giulio Perugi Cristina Toni Stefania Millepiedi Maria Mucci Nicoletta Bertini Hagop S Akiskal 《Neuropsychopharmacology》2006,59(7):603-610
BACKGROUND: Recent research has addressed the issue of subtyping juvenile bipolar disorder (JBD). Accordingly, we set out to find out, in a naturalistic sample of bipolar children and adolescents with mania and mixed mania, whether the most useful subtyping should be based on clinical features (elated vs. irritable) or course (episodic vs. chronic). METHODS: We studied 136 patients, 81 male patients (59.6%) and 55 female patients (40.4%), mean age 13.5 +/- 2.9 years, meeting the DSM-IV diagnosis of bipolar disorder, assessed by a structured clinical interview (Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version [K-SADS-PL]). RESULTS: Regarding course, 77 patients (56.6%) had an episodic course and 59 patients (43.4%) had a chronic course. Patients with chronic course were significantly younger, had an earlier onset of JBD, and presented a more frequent comorbidity with disruptive behavior disorders. According to the prevalent mood disturbance, 75 patients (55.1%) showed an elated and 61 patients (44.9%) showed an irritable mood. Elated mood was more frequent in patients with episodic course, whereas irritable mood was more frequent in the patients with chronic course. CONCLUSIONS: These findings suggest that chronic versus episodic course may be a putative differential feature. Further validation of such a distinction would require prospective studies, temperament evaluation, gender and neurobiologic approaches, and differential psychopharmacologic assignment and response. 相似文献
107.
Jorge Polónia Jo?o Maldonado Rui Ramos Susana Bertoquini Mary Duro Cristina Almeida Jo?o Ferreira Loide Barbosa José Alberto Silva Luís Martins 《Revista portuguesa de cardiologia》2006,25(9):801-817
BACKGROUND: Portugal has one of the highest mortality rates from stroke, a high prevalence of hypertension and probably a high salt intake level. AIM: To evaluate Portuguese salt intake levels and their relationship to blood pressure and arterial stiffness in a sample of four different adult populations living in northern Portugal. METHODS: A cross-sectional study evaluating 24-hour urinary excretion of sodium (24 h UNa+), potassium and creatinine, blood pressure (BP), and pulse wave velocity (PWV) as an index of aortic stiffness in adult populations of sustained hypertensives (HT), relatives of patients with previous stroke (Fam), university students (US) and factory workers (FW), in the context of their usual dietary habits. RESULTS: We evaluated a total of 426 subjects, mean age 50 +/- 22 years, 56% female, BMI 27.9+/-5.1, BP 159/92 mmHg, PWV 10.4+/-2.2 m/s, who showed mean 24h UNa+ of 202 +/- 64 mmol/d, corresponding to a daily salt intake of 12.3 g (ranging from 5.2 to 24.8). The four groups were: HT: n = 245, 49 +/- 18 years, 92% of those selected, 69% treated, BP 163/94 mmHg, PWV 11.9 m/s, 24 h UNa+ 212 mmol/d, i.e. 12.4 g/d of salt); Fam: n = 38, 64 +/- 20 years, 57 % of those selected, BP 144/88 mmHg, PWV 10.5 m/s, 24 h UNa+ 194 mmol/d, i.e. 11.1 g/d of salt; US: n = 82, 22 +/- 3 years, 57% of those selected, BP 124/77 mmHg, PWV 8.7 m/s, 24h UNa+ 199 mmol/d, i.e. 11.3 g/d of salt; FW: n = 61, 39 9 years, 47% of those selected, BP 129/79 mmHg, PWV 9.5 m/s, 24 h UNa+ 221 mmol/d, i.e. 12.9 g/d of salt. The ratio of urinary sodium/potassium excretion (1.9 (0.4) was significantly higher in HT than the other three groups. In the 426 subjects, 24h UNa+ correlated significantly (p < 0.01) with systolic BP (r = 0.209) and with PWV (r=0.256) after adjustment for age and BP. Multivariate analysis showed that BP, age and 24h UNa+ correlated independently with PWV taken as a dependent variable. CONCLUSIONS: Four different Portuguese populations showed similarly high mean daily salt intake levels, almost double those recommended by the WHO. Overall, high urinary sodium excretion correlated consistently with high BP levels and appeared to be an independent determining factor of arterial stiffness. These findings suggest that Portugal in general has a high salt intake diet, and urgent measures are required to restrict salt consumption in order to prevent and treat hypertensive disease and to reduce overall cardiovascular risk and events. 相似文献
108.
Andr ia Kist Fernandes Felipe Mallmann Ana Maria Pasquali Steinhorst Fernando Lopes Nogueira Eduardo Mü ller vila Dumitriu Zunino Saucedo Francisco Juchem Machado Marcelo Greg rio Raymundi S rgio Saldanha Menna Barreto Paulo de Tarso Roth Dalcin 《The Journal of asthma》2003,40(6):683-690
Asthma patients that depend on emergency department (ED) services are generally considered to have extremely poor disease control and prognosis. It is important to identify characteristics related to poor disease control and frequent visits to the ED to apply appropriate clinical management. This study comprised a cross-sectional survey of consecutive patients with asthma exacerbation (age ≥12 years) presenting at the adult ED of a large, tertiary care, university-affiliated hospital over a 2-month period. The frequent visitors (FV) were defined by ≥3 visits to the ED in the preceding year, and the occasional visitors (OV) by ≤2 visits. Eighty-six patients (61 females and 25 males) were included in the study (mean age 38 ± 18 years). Of these patients, 51.2% were FV and 48.8% were OV. Sixty-nine percent had annual income lower than A$3000 and 66.3% had ≤8 years of the formal education. Only 18.6% had used inhaled corticosteroids, 79.1% identified the asthma attack severity, 70.9% increased or initiated inhaled β-agonist, 20.9% increased or initiated steroid therapy, and 55.8% had an asthma action plan for attack. The number of hospital admissions in past year (OR 4.3, P = .02), use of home nebulizer (OR 3.6, P = .05) and the lack of a written asthma action plan (OR 3.3, P = .03) were independently associated with frequent visits to the ED. We conclude that a substantial proportion of the patients that visit the ED are FV. These patients are more likely to have hospital admission in the past year, to use a home nebulizer, and to lack a written asthma action plan. They should be considered the most important target for asthma education. 相似文献
109.
Ana C Mendes M Madalena Caldeira Claudia Silva Shawn C Burgess Matthew E Merritt Filipe Gomes Cristina Barosa Teresa C Delgado Fatima Franco Pedro Monteiro Luis Providencia John G Jones 《Magnetic resonance in medicine》2006,56(5):1121-1125
Menthol glucuronide was isolated from the urine of a healthy 70-kg female subject following ingestion of 400 mg of peppermint oil and 6 g of 99% [U-(13)C]glucose. Glucuronide (13)C-excess enrichment levels were 4-6% and thus provided high signal-to-noise ratios (SNRs) for confident assignment of (13)C-(13)C spin-coupled multiplet components within each (13)C resonance by (13)C NMR. The [U-(13)C]glucuronide isotopomer derived via direct pathway conversion of [U-(13)C]glucose to [U-(13)C]UDP-glucose was resolved from [1,2,3-(13)C(3)]- and [1,2-(13)C(2)]glucuronide isotopomers derived via Cori cycle or indirect pathway metabolism of [U-(13)C]glucose. In a second study, a group of four overnight-fasted patients (63 +/- 10 kg) with severe heart failure were given peppermint oil and infused with [U-(13)C]glucose for 4 hr (14 mg/kg prime, 0.12 mg/kg/min constant infusion) resulting in a steady-state plasma [U-(13)C]glucose enrichment of 4.6% +/- 0.6%. Menthol glucuronide was harvested and glucuronide (13)C-isotopomers were analyzed by (13)C NMR. [U-(13)C]glucuronide enrichment was 0.6% +/- 0.1%, and the sum of [1,2,3-(13)C(3)] and [1,2-(13)C(2)]glucuronide enrichments was 0.9% +/- 0.2%. From these data, flux of plasma glucose to hepatic UDPG was estimated to be 15% +/- 4% that of endogenous glucose production (EGP), and the Cori cycle accounted for at least 32% +/- 10% of GP. 相似文献
110.
M. L. Garrè V. Capra E. Di Battista L. Giampietri P. Nozza A. Raso A. Pezzolo A. Rossi C. Milanaccio M. Pavanello A. Naselli 《Child's nervous system》2007,23(2):219-223
Objects Genetic syndromes associated with ependymoma are uncommon, with the exception of NF2. We describe two cases of ependymoma
presenting with Klinefelter’s Syndrome (KS) as co-morbid condition.
Materials and methods The first patient was diagnosed for KS during pregnancy; he also presented a thyroid agenesis and a deficit of methyltetrahydrofolate
reductase (MTHFR); at 30 months of age he was operated on for a grade II ependymoma of IV ventricle; after a multiple-stage
surgery, he underwent oral chemotherapy and stereotactic radiotherapy, but after 15 months he presented a local recurrence
and died. The second patient was diagnosed for KS at the age of 16 months; at 10 years of age, due to back pain, he underwent
an MRI, which showed a cauda equine tumor. He underwent surgery and radiotherapy. Histology was of mixopapillary ependymoma.
Conclusion In a review of literature, various neoplasms have been described in association with KS. To our knowledge, these are the first
two cases reported of ependymoma associated to KS. A retrospective study of 44 monoinstitutional ependymoma cases demonstrated
association with genetic syndromes in 22%. 相似文献