全文获取类型
收费全文 | 22667篇 |
免费 | 1540篇 |
国内免费 | 115篇 |
专业分类
耳鼻咽喉 | 242篇 |
儿科学 | 606篇 |
妇产科学 | 517篇 |
基础医学 | 3524篇 |
口腔科学 | 560篇 |
临床医学 | 2162篇 |
内科学 | 5046篇 |
皮肤病学 | 541篇 |
神经病学 | 2595篇 |
特种医学 | 683篇 |
外科学 | 2036篇 |
综合类 | 130篇 |
一般理论 | 13篇 |
预防医学 | 1939篇 |
眼科学 | 436篇 |
药学 | 1403篇 |
中国医学 | 78篇 |
肿瘤学 | 1811篇 |
出版年
2024年 | 36篇 |
2023年 | 215篇 |
2022年 | 424篇 |
2021年 | 728篇 |
2020年 | 479篇 |
2019年 | 683篇 |
2018年 | 737篇 |
2017年 | 568篇 |
2016年 | 654篇 |
2015年 | 787篇 |
2014年 | 937篇 |
2013年 | 1164篇 |
2012年 | 1869篇 |
2011年 | 1966篇 |
2010年 | 1062篇 |
2009年 | 963篇 |
2008年 | 1570篇 |
2007年 | 1556篇 |
2006年 | 1462篇 |
2005年 | 1402篇 |
2004年 | 1276篇 |
2003年 | 1143篇 |
2002年 | 1001篇 |
2001年 | 151篇 |
2000年 | 110篇 |
1999年 | 154篇 |
1998年 | 201篇 |
1997年 | 159篇 |
1996年 | 123篇 |
1995年 | 98篇 |
1994年 | 78篇 |
1993年 | 57篇 |
1992年 | 54篇 |
1991年 | 35篇 |
1990年 | 52篇 |
1989年 | 38篇 |
1988年 | 31篇 |
1987年 | 36篇 |
1986年 | 24篇 |
1985年 | 28篇 |
1984年 | 19篇 |
1983年 | 21篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 14篇 |
1975年 | 9篇 |
1974年 | 12篇 |
1973年 | 16篇 |
1970年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
Joachim H?chel D?rte Lehmann Claudia Fehrenberg Volker Unger David A Groneberg Christian Grosse-Siestrup 《Nephrology, dialysis, transplantation》2003,18(9):1748-1754
BACKGROUND: The isolated perfused canine kidney has been established as a valid model for conducting both renal physiology and transplantation research. This model is of particular importance for developing new strategies to improve graft function after renal transplantation. In the present study, a newly developed method using isolated haemoperfused porcine kidneys was adapted for use in canine kidneys. In contrast to haemoperfusion, synthetic perfusion media can be standardized and can prevent the initiation of blood-mediated reperfusion reactions. Thus, an additional aim was to determine whether blood could be replaced by synthetic cell-free perfusion solutions. METHODS: Canine kidneys (n = 30) were harvested from donors euthanized in veterinary practices for causes unrelated to the present study. The kidneys were isolated and perfused with autologous blood or cell-free synthetic electrolyte buffer (Tyrode solution). During perfusion, we monitored renal perfusate flow (RPF), glomerular filtration rate (GFR), electrolyte and glucose reabsorption, oxygen consumption and urine concentration. RESULTS: Changes in perfusion medium did not affect the RPF. In contrast, GFR, urine concentration and oxygen consumption were significantly higher, whereas fractional excretion of sodium and glucose were significantly lower in blood- than in Tyrode-perfused kidneys. CONCLUSIONS: This system offers a simple model for studying whole-organ functional alterations after acute renal ischaemia. Renal function indicators were below values reported during in vivo physiological conditions. These functions were better conserved when kidneys were perfused with autologous blood than with Tyrode. 相似文献
82.
Magdolna Hornyak Hans-Peter Hundemer Deborah Quail Dieter Riemann Ulrich Voderholzer Claudia Trenkwalder 《Clinical neurophysiology》2007,118(7):1532-1537
OBJECTIVE: To evaluate the relationship of the severity of restless legs syndrome (RLS) as assessed by a subjective, patient-rated scale (International RLS Study Group Rating Scale, IRLS), and of periodic leg movements in sleep (PLMS) as an objective parameter, in two different patient populations. METHODS: Data of 200 unmedicated patients with idiopathic RLS were evaluated. Group 1 (n=100) consisted of selected patients participating in the Pergolide European Australian RLS (PEARLS) study. Group 2 (n=100) represented an outpatient RLS population investigated in a Sleep Disorders Center. Additionally, Group 1 was also evaluated after a 6 week double-blind treatment period, where 47 patients received pergolide and 53 patients placebo. RESULTS: In unmedicated patients, IRLS scores correlated with the PLMS-arousal index (r=0.22, p=0.033) but not with the PLMS index in Group 1 while no correlation was found in Group 2. The change of the IRLS score under treatment in Group 1 correlated significantly both with the change of the PLMS index (r=0.42, p<0.001) and the change of the PLMS-arousal index (r=0.38, p<0.001). CONCLUSIONS: The IRLS adequately reflects treatment changes of PLMS indices. In unmedicated patients, the IRLS correlates with PLMS indices probably only in selected RLS populations with predefined PSG criteria and high PLM activity. SIGNIFICANCE: The IRLS is an appropriate subjective rating scale for measuring treatment effects in RLS. 相似文献
83.
84.
Claudia KY Lai 《BMC nursing》2007,6(1):5
Background
To date, the literature has provided an abundance of evidence on the adverse outcomes of restraint use on patients. Reportedly, nurses are often the personnel who initiate restraint use and attribute its use to ensuring the safety of the restrained and the others. A clinical trial using staff education and administrative input as the key components of a restraint reduction program was conducted in a rehabilitation setting to examine whether there were any significant differences in the prevalence of restraint use pre- and post-intervention. Subsequent to the implementation of the intervention program, focus group interviews were conducted to determine the perspective of the nursing staff on the use of restraints and their opinions of appropriate means to reduce their use. 相似文献85.
Bela Szabo Liselotte Hedler Claudia Schurr Klaus Starke 《Naunyn-Schmiedeberg's archives of pharmacology》1988,338(4):368-372
Summary The effects of ACTH on the release of noradrenaline and the increase of heart rate produced by sympathetic nerve stimulation (1 Hz) were studied in isolated perfused rabbit hearts. ACTH-(1–24) 0.1–100 nmol/l increased the stimulation-evoked overflow of noradrenaline concentration-dependently, reversibly and up to two-fold. The basal outflow of noradrenaline, the basal heart rate and the stimulation-evoked increase in heart rate were not changed. Human ACTH-(1–39) also increased the evoked overflow of noradrenaline. The effect of ACTH-(1–24) 0.3 nmol/l persisted after blockade of -adrenoceptors with propranolol and blockade of neuronal catecholamine uptake by cocaine. ACTH-(1–24) 3 nmol/l did not change the removal of noradrenaline from the perfusion fluid, when hearts were perfused with medium containing 59 nmol/l noradrenaline. The results show that ACTH increases the action potential-evoked release of noradrenaline from cardiac postganglionic sympathetic neurones, probably by activating specific presynaptic ACTH receptors. The high potency of ACTH suggests that these presynaptic receptors may be activated in vivo by circulating ACTH under certain pathophysiological conditions.Send offprint requests to B. Szabo at the above address 相似文献
86.
Claudia Ladner Gerhard Ehninger K. Fred Gey Michael R. Clemens 《Cancer chemotherapy and pharmacology》1989,25(3):210-212
Summary A total of 13 patients receiving bone marrow transplants (BMT) for treatment of different haematological diseases were investigated. Conditioning therapy preceding BMT consisted of fractionated total-body irradiation (12 Gy) and high-dose chemotherapy with cyclophosphamide (2±60 mg/kg). Patients stratified to be at high risk for relapse (6/13) were additionally treated with etoposide (30 mg/kg). Plasma concentrations of absolute and lipid-standardized antioxidants (-tocopherol and -carotene) decreased following conditioning therapy, presumably as the result of an enhanced breakdown of these antioxidants. Etoposide treatment did not amplify the loss of essential anti-oxidants but significantly increased lipid hydroperoxide concentrations in serum. We suggest that the abnormal generation of lipid hydroperoxides is the result of free radical formation. 相似文献
87.
Faravelli C Abrardi L Bartolozzi D Cecchi C Cosci F D'Adamo D Lo Iacono B Ravaldi C Scarpato MA Truglia E Rossi Prodi PM Rosi S 《Psychotherapy and psychosomatics》2004,73(4):226-234
BACKGROUND: It has been argued that lay interviewers' use of fully-structured interviews could lead to a diagnostic pattern different to that by treating physicians. Clinical interviewers in community samples should probably identify cases that are closer to those seen in clinical settings. The greatest advantage of using clinical interviewers consists of the immediate assessment of a possible psychopathology, i.e. the evaluation of current disorders. METHODS: Two thousand three hundred and sixty-three citizens from the community of Sesto Fiorentino, Italy, were interviewed by their own general practitioners using the Mini International Neuropsychiatric Interview (MINI). Positive cases for any lifetime psychiatric disorder as well as a random sample of the negative cases were re-interviewed by psychiatrists or trained residents in psychiatry using the Florence Psychiatric Interview (FPI). RESULTS: The point prevalence for any current disorder was 8.7%; the two disorders with the highest prevalence were generalised anxiety disorder (2.9%) and major depressive episode (2.7%). The figures increase about 50% when the sub-threshold sequelae of previous disorders are considered. Current comorbidity was generally high. The one-year prevalence of any disorder was 10.6%. Ninety-two percent of the cases sought help, 82% were being treated at the moment of interview. Social impairment was considerable. CONCLUSIONS: The period prevalence rates for most of the disorders considered were generally comparable with the range defined by previous studies conducted in other Western countries, despite using different methodologies. Conversely, the use of health facilities, the treatment received and the social impairment were much higher than those reported by the other studies, suggesting a greater similarity with the clinical samples. 相似文献
88.
Ezio Martuscelli Clara Silvestre Maurizio Canetti Claudia de Lalla Anna Bonfatti Alberto Seves 《Macromolecular chemistry and physics.》1989,190(10):2615-2625
The crystallization and the thermal behaviour of thin films of isotactic polypropylene/hydrogenated oligo(cyclopentadiene) of low molecular weight (iPP/HOCP) are studied using optical microscopy and differential scanning calorimetry (DSC). The spherulite growth rate, the overall crystallization rate and the equilibrium melting temperature of iPP are decreased by the addition of HOCP to iPP. This leads to the hypothesis that iPP and HOCP form a miscible blend in the amorphous phase. This hypothesis is also supported by the detection of a single blend-composition-dependent glass transition temperature of each blend as determined by DSC. 相似文献
89.
Palermo B Garbelli S Mantovani S Scoccia E Da Prada GA Bernabei P Avanzini MA Brazzelli V Borroni G Giachino C 《European journal of immunology》2005,35(11):3153-3162
Vitiligo is a skin disorder characterized by depigmented macules secondary to melanocyte loss. An unusual facet is its relation to melanoma: cytotoxic T lymphocytes directed to melanocyte antigens are found in both conditions and imply a breakdown of tolerance, yet the resulting immune reaction is the opposite. The mechanisms at the basis of these opposite effects are not known. Here, we performed a direct comparison of whole melanocyte-specific T cell populations in the two diseases. We demonstrate that neither precursor frequencies of Melan-A/MART-1-specific T lymphocytes nor their status of activation differ significantly. However, by using a tetramer-based T cell receptor down-regulation assay, we documented a higher affinity of vitiligo T cells. We calculated that the peptide concentration required for 50% of maximal receptor down-regulation differed by 6.5-fold between the two diseases. Moreover, only vitiligo T cells were capable of efficient receptor down-regulation and IFN-gamma production in response to HLA-matched melanoma cells, suggesting that this difference in receptor affinity is physiologically relevant. The differences in receptor affinity and tumor reactivity were confirmed by analyzing Melan-A/MART-1-specific clones established from the two diseases. Our results suggest that the quality, and not the quantity, of the melanocyte-specific cytotoxic responses differs between the two pathologies. 相似文献
90.
Casas KA Mononen TK Mikail CN Hassed SJ Li S Mulvihill JJ Lin HJ Falk RE 《American journal of medical genetics. Part A》2004,(4):331-339
We report a new patient with terminal deletion of chromosome 2 with breakpoint at 2q36 and five additional new patients with 2q terminal deletion with breakpoint at 2q37. Hemidiaphragmatic hernia is a novel finding in one patient with a breakpoint at 2q37.1. In comparing these patients to 60 previously reported individuals with 2q terminal deletions, certain physical abnormalities are loosely associated with positions of breakpoint. For example, facial features (e.g., prominent forehead, depressed nasal bridge, and dysmorphic ears and nose), short stature, and short hands and feet were frequent in patients with breakpoints at or proximal to 2q37.3. Reports of horseshoe kidney and Wilms tumor were limited to patients with a breakpoint at 2q37.1, and structural brain anomalies and tracheal anomalies were reported only in patients with breakpoints at or proximal to 2q37.1. Cleft palate was reported only in patients with the most proximal breakpoints (2q36 or 2q35). Neurological effects including developmental delay, mental retardation, autistic-like behavior, and hypotonia were typical in this patient population but did not stratify in severity according to breakpoint. Terminal deletion of the long arm of chromosome 2 should be considered in the infant with marked hypotonia, poor feeding, gastroesophageal reflux, and growth delay, and the older child with developmental delay, autistic behavior, and the characteristic facial and integumentary features described herein. Assignment of clinical features to specific breakpoints and refinement of predictive value may be useful in counseling. 相似文献