全文获取类型
收费全文 | 18856篇 |
免费 | 1177篇 |
国内免费 | 84篇 |
专业分类
耳鼻咽喉 | 182篇 |
儿科学 | 600篇 |
妇产科学 | 416篇 |
基础医学 | 2484篇 |
口腔科学 | 371篇 |
临床医学 | 2190篇 |
内科学 | 4458篇 |
皮肤病学 | 527篇 |
神经病学 | 1892篇 |
特种医学 | 413篇 |
外科学 | 1448篇 |
综合类 | 103篇 |
一般理论 | 8篇 |
预防医学 | 1945篇 |
眼科学 | 305篇 |
药学 | 1279篇 |
中国医学 | 69篇 |
肿瘤学 | 1427篇 |
出版年
2024年 | 12篇 |
2023年 | 167篇 |
2022年 | 327篇 |
2021年 | 544篇 |
2020年 | 329篇 |
2019年 | 525篇 |
2018年 | 643篇 |
2017年 | 403篇 |
2016年 | 483篇 |
2015年 | 549篇 |
2014年 | 768篇 |
2013年 | 993篇 |
2012年 | 1562篇 |
2011年 | 1586篇 |
2010年 | 820篇 |
2009年 | 784篇 |
2008年 | 1292篇 |
2007年 | 1273篇 |
2006年 | 1237篇 |
2005年 | 1230篇 |
2004年 | 1057篇 |
2003年 | 1020篇 |
2002年 | 930篇 |
2001年 | 89篇 |
2000年 | 78篇 |
1999年 | 131篇 |
1998年 | 160篇 |
1997年 | 146篇 |
1996年 | 138篇 |
1995年 | 107篇 |
1994年 | 79篇 |
1993年 | 91篇 |
1992年 | 61篇 |
1991年 | 38篇 |
1990年 | 39篇 |
1989年 | 42篇 |
1988年 | 26篇 |
1987年 | 22篇 |
1986年 | 34篇 |
1985年 | 35篇 |
1984年 | 31篇 |
1983年 | 29篇 |
1982年 | 30篇 |
1981年 | 33篇 |
1980年 | 34篇 |
1979年 | 17篇 |
1978年 | 15篇 |
1976年 | 12篇 |
1974年 | 11篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
41.
42.
Periodic lateralized epileptiform discharges: etiology, clinical aspects, seizures, and evolution in 130 patients. 总被引:4,自引:0,他引:4
Irene García-Morales M Teresa García Lucia Galán-Dávila Carlos Gómez-Escalonilla Rosana Saiz-Díaz Antonio Martínez-Salio Pilar de la Pe?a Julian A Tejerina 《Journal of clinical neurophysiology》2002,19(2):172-177
The purpose of this study was to analyze the clinical aspects in 130 patients presenting periodic lateralized epileptiform discharges (PLEDs) in their EEG and to compare these results with those found in the literature. Etiology, neurologic deficit, seizure occurrence, and evolution were studied in each patient by historical review. The recordings were obtained on 8- or 16-channel EEGs with electrode placement according to the International 10-20 System. Recordings containing PLEDs were selected. PLEDs were defined as repetitive periodic, focal, or hemispheric epileptiform discharges (spikes, spike and waves, polyspikes, sharp waves) usually recurring every 1 to 2 seconds. The statistical study was carried out via the chi(2) test using the computer program SPSS. The main etiology found in this group of patients was stroke (61 of 130 patients). Other processes found were brain infections, tumors, hematomas, and several other entities grouped together as miscellaneous (anoxic encephalopathy, subarachnoid hemorrhage, craniocerebral trauma, Creutzfeldt-Jacob disease, migraine, multiple sclerosis, and aminophylline intoxication). Half of these patients (65 of 130) developed seizures, mostly partial motor seizures. No significant relation between etiology and seizures was found (chi(2) = 2.81, P = 0.4222). Seizures recurred in 14 of 130 patients during a follow-up of 14.5 months. PLEDs were not recorded in any EEG at the time of seizure recurrence. PLEDs constitute a distinctive but uncommon EEG phenomenon of repetitive, periodic, and stereotyped lateralized complexes. In agreement with the literature, PLEDs were associated with an acute process and occurred early during the course of the illness in all patients studied and were usually associated with structural lesions, with stroke being the main etiology. Traditionally, seizures occur with PLEDs but it is also accepted that they can exist in patients who never develop epileptic activity, either clinically or electrically, as demonstrated in 50% of the patients studied. No significant association between seizures and any etiology could be found. It was not demonstrated that the occurrence of seizures may influence the outcome in any way. 相似文献
43.
Pulmonary effects of closure of patent ductus arteriosus in premature infants with severe respiratory distress syndrome 总被引:1,自引:0,他引:1
The pulmonary effects of closure of a patent ductus arteriosus (PDA) were investigated in 11 premature infants with severe respiratory distress syndrome. Successful closure of a PDA did not improve the short-term severity of pulmonary disease (24 and 48 h after treatment) as judged by the arterial/alveolar oxygen tension ratio or the amount of ventilatory support. Also, pulmonary mechanics measured 24 h before, 24 and 48 h after treatment, were not statistically different.Conclusion Infants with severe respiratory disease requiring high ventilation pressure and high oxygen concentration, where structural changes in the lungs are already established, will rarely show short-term improvement in pulmonary disease as a result of closure of a PDA. The overall clinical condition may, however, improve as a result of reduced cardiovascular strain. Earlier treatment of a PDA could reduce the ventilation period and the possible risk of developing chronic lung disease. 相似文献
44.
Ruprecht Nitschke Charles Pratt Michael Harris Jeffrey Krischer Teresa J. Vietti Holcombe Grier Willem Kamps Stuart Toledano 《Investigational new drugs》1992,10(2):93-96
CHIP (325 mg/M2), a second generation cisplatin derivative, was administered intravenously every 3 weeks to 85 pediatric patients with recurrent sarcomas (19), osteosarcomas (20), neuroblastoma (23), germ cell tumors (10), and other malignant tumors (7). Thirty-eight of them had been previously exposed to cisplatin. Partial remissions were only observed in 3 of 23 (13% SE=7%) patients having neuroblastoma. Severe thrombocytopenia (65%) and neutropenia (35%) were the dose limiting factors. 相似文献
45.
Silvia Helena de Bortoli Cassiani RN MN Doctoral student Assistant Professor Maria Lúcia Zanetti RN MN Doctoral student Assistant Professor Nilza Teresa Rotter Pelá RN DNS Head of the 《Journal of advanced nursing》1992,17(5):576-581
Studies have shown that students and the general population have little knowledge about nursing schools and the nursing profession. This study investigates the extent to which a sample of the population of Brazil is aware of the existence of nursing schools, and how they have obtained this information. Data were collected by telephone interviews. The sample consisted of 326 subjects whose telephone numbers were taken from the telephone book. Analysis showed that 73% of the subjects were aware of the existence of two nursing schools in the city; however, 65.03% did not know the names of these schools. Direct communication with friends and family, as well as indirect communication by television and advertising, were the sources of information mentioned by those questioned. 相似文献
46.
Shirley Kobar Coni C Francis Samantha MaWhinney Teresa Sharp 《Nutrition in clinical practice》2003,18(5):417-421
BACKGROUND: Development of an acclimation protocol for use when measuring resting energy expenditure (REE) would simplify and standardize data collection. The purpose of this study was to determine if our 2 metabolic carts could be used interchangeably and to determine if excluding the first 3 or 5 minutes of data collected as an acclimation period would significantly improve the coefficients of variation (CVs) for oxygen consumed (VO(2)) and carbon dioxide produced (VCO(2)) when performing REE assessments with our metabolic cart systems. METHODS: Thirteen healthy, nonsmoking adults ranging in age from 32 to 45 years, with activity levels ranging from sedentary to highly active, participated. Indirect calorimetry was performed twice in the morning after 30 minutes of supine resting. Subjects had fasted for 12 hours, and did not exercise within the last 24 hours. The system order for testing was randomized for the first measurement. When the first measurement was completed, subjects were crossed over for measurement using a second metabolic cart. RESULTS: The CVs for VO(2) and VCO(2) were significantly lower when excluding the first 3 (VO(2), p = .0005), (VCO(2), p = .0024) or 5 minutes (VO(2), p = .0001, VCO(2), p = .0021) of data compared with no exclusions. No significant differences in CVs between the 3- and 5-minute exclusions were found for VO(2) (p = .3224) or VCO(2) (p = .2255). CONCLUSIONS: Clearly, our machines cannot be used interchangeably within a study. An acclimation period improves CVs of VO(2) and VCO(2.) The similarities in CVs led us to adopt a 3-minute acclimation period for measuring REE. 相似文献
47.
Teresa Pelissier Carlos Paeile Rub n Soto-Moyano Hern n Saavedra Alejandro Hern ndez 《European journal of pharmacology》1990,190(3):287-293
The antinociceptive activity of the selective k opioid agonist U-50,488H, given intrathecally (i.t.) against chemically induced cutaneous pain in rats, was assessed from cumulative dose-response experiments and the formalin test. Three successive i.t. doses of 5, 10 and 35 nmol of U-50,488H produced a gradual reduction of pain scores which was statistically significant at all observation periods. This effect was antagonized significantly by 3 mg/kg i.p. of the opiate antagonists, naloxone and WIN 44,441-3. The analgesia profile showed a clear dose-response relationship. A dose producing 50% ‘maximum posible analgesia’ of 6.20 nmol (95% confidence interval: 3.05–12.59 nmol) was calculated. The results indicated that cutaneous pain of a chemical/inflammatory nature is highly sensitive to activation of k receptors of the spinal cord dorsal horn. 相似文献
48.
Ana María Fortuna Marco Balleza Núria Calaf Mercedes González Teresa Feixas Pere Casan 《Archivos de bronconeumologia》2009,45(3):143-147
Nitric oxide (NO) production has been described using a 2-compartment model for the synthesis and movement of NO in both the alveoli and the airways. The alveolar concentration of NO (CaNO), an indirect marker of the inflammatory state of the distal portions of the lung, can be deduced through exhalation at multiple flow rates. Our objective was to determine reference values for CaNO. The fraction of exhaled NO (FeNO) was measured in 33 healthy individuals at a rate of 50 mL/s; the subjects then exhaled at 10, 30, 100, and 200 mL/s to calculate CaNO. A chemiluminescence analyzer (NIOX Aerocrine) was used to perform the measurements. The mean (SD) FeNO was 15 (6) ppb. The mean CaNO was 3.04 (1.30) ppb. These values of CaNO measured in healthy individuals will allow us to analyze alveolar inflammatory behavior in respiratory and systemic processes. 相似文献
49.
Radiation therapy has been a major treatment option for patients with prostate cancer with documented efficacy over the last 30 years. Recent research has shown a correlation between improved local control, disease-free survival, and overall survival and dose delivered. Excessive dose to the rectum is one of the leading causes of morbidity in the treatment of prostate cancer. The RTOG and others have suggested dose limitations based on various treatment parameters. Intensity-modulated radiation therapy (IMRT) is becoming more widely used, with the goal of improving dose coverage while limiting morbidity. In an effort to evaluate our inverse-planning technique relative to our forward-planned technique based on rectal dose, 2 plans were generated on 10 patients. One plan was generated with 9-field forward planning, using 2 posterior obliques to decrease dose to the rectum. The other plan utilized inverse IMRTplanning. To evaluate dose to the rectum, we compared the dose gradient from the posterior edge of the prostate across the anterior third of the rectal wall. This gradient, which is not part of the IMRT planning objectives, proved useful in assessing plan differences, and led to new dose objectives for certain IMRT plans. 相似文献
50.
Anna Gasinska Jan Skolyszewski Tadeusz Popiela Piotr Richter Zbigniew Darasz Krystyna Nowak Joanna Niemiec Beata Biesaga Agnieszka Adamczyk Krzysztof Bucki Krzysztof Malecki Marian Reinfuss Teresa Kowalska 《Journal of gastrointestinal surgery》2007,11(4):520-528
Purpose Assessment of tumor proliferation rate using Bromodeoxyuridine labeling index (BrdUrdLI) as a possible predictor of rectal
cancer response to preoperative radiotherapy (RT).
Methods and material Ninety-two patients were qualified either to short RT (5 Gy/fraction/5 days) and surgery about 1 week after RT (schedule I),
or to short RT and 4–5 weeks interval before surgery (schedule II). Tumor samples were taken twice from each patient: before
RT and at the time of surgery. The samples were incubated with BrdUrd for 1 h at 37°C, and the BrdUrdLI was calculated as
a percentage of BrdUrd-labeled cells.
Results Thirty-eight patients were treated according to schedule I and 54 patients according to schedule II. Mean BrdUrdLI before
RT was 8.5% and its value did not differ between the patients in the two compared groups. After RT tumors showed statistically
significant growth inhibition (reduction of BrdUrdLI). As the pretreatment BrdUrd LI was not predictive for early clinical
and pathologic tumor response, prognostic role of the ratio of BrdUrdLI after to BrdUrdLI before RT was considered. The ratios
were calculated separately for fast (BrdUrd LI > 8.5%) and slowly (BrdUrd LI ≤ 8.5%) proliferating tumors and correlated with
overall treatment time (OTT, i.e., time from the first day of RT to surgery). One month after RT, accelerated proliferation
was observed only in slowly proliferating tumors.
Conclusions Pretreatment BrdUrdLI was not predictive for early clinical and pathologic tumor response. The ratio after/before RT BrdUrdLI
was correlated to inhibition of proliferation in responsive tumors.
The paper was presented at ECCO 13, October 30 to November 03, 2005 in Paris, France 相似文献