全文获取类型
收费全文 | 15424篇 |
免费 | 1222篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 297篇 |
儿科学 | 321篇 |
妇产科学 | 210篇 |
基础医学 | 1962篇 |
口腔科学 | 528篇 |
临床医学 | 1483篇 |
内科学 | 3115篇 |
皮肤病学 | 201篇 |
神经病学 | 1724篇 |
特种医学 | 561篇 |
外科学 | 2165篇 |
综合类 | 242篇 |
一般理论 | 10篇 |
预防医学 | 1423篇 |
眼科学 | 265篇 |
药学 | 1042篇 |
1篇 | |
中国医学 | 9篇 |
肿瘤学 | 1124篇 |
出版年
2023年 | 89篇 |
2022年 | 145篇 |
2021年 | 272篇 |
2020年 | 198篇 |
2019年 | 227篇 |
2018年 | 296篇 |
2017年 | 231篇 |
2016年 | 241篇 |
2015年 | 239篇 |
2014年 | 388篇 |
2013年 | 662篇 |
2012年 | 866篇 |
2011年 | 946篇 |
2010年 | 550篇 |
2009年 | 544篇 |
2008年 | 949篇 |
2007年 | 985篇 |
2006年 | 1033篇 |
2005年 | 980篇 |
2004年 | 962篇 |
2003年 | 971篇 |
2002年 | 955篇 |
2001年 | 165篇 |
2000年 | 109篇 |
1999年 | 146篇 |
1998年 | 214篇 |
1997年 | 197篇 |
1996年 | 195篇 |
1995年 | 162篇 |
1994年 | 140篇 |
1993年 | 107篇 |
1992年 | 113篇 |
1991年 | 108篇 |
1990年 | 101篇 |
1989年 | 75篇 |
1988年 | 93篇 |
1987年 | 79篇 |
1986年 | 90篇 |
1985年 | 95篇 |
1984年 | 125篇 |
1983年 | 136篇 |
1982年 | 161篇 |
1981年 | 140篇 |
1980年 | 153篇 |
1979年 | 72篇 |
1978年 | 114篇 |
1977年 | 91篇 |
1976年 | 96篇 |
1974年 | 72篇 |
1972年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
181.
Jack V. Tu Michael J. Schull Lorraine E. Ferris Janet E. Hux Donald A. Redelmeier 《Canadian Medical Association journal》2001,164(12):1709-1712
HEALTH CARE REPORT CARDS INVOLVE COMPARISONS of health care systems, hospitals or clinicians on performance measures. They are going to be an important feature of medical care in Canada in the new millennium as patients demand more information about their medical care. Although many clinicians are aware of this growing trend, they may not be prepared for all of its implications. In this article, we provide some historical background on health care report cards and describe a number of strategies to help clinicians survive and thrive in the report card era. We offer a number of tips ranging from knowing your outcomes first to proactively getting involved in developing report cards. 相似文献
182.
183.
Jack Feehan Moustapha Kassem Robert J Pignolo Gustavo Duque 《Journal of bone and mineral research》2021,36(1):12-23
Circulating osteogenic progenitor (COP) cells are a population of cells in the peripheral blood with the capacity for bone formation, as well as broader differentiation into mesoderm-like cells in vitro. Although some of their biological characteristics are documented in vitro, their role in diseases of the musculoskeletal system remains yet to be fully evaluated. In this review, we provide an overview of the role of COP cells in a number of physiological and pathological conditions, as well as identify areas for future research. In addition, we suggest possible areas for clinical utilization in the management of musculoskeletal diseases. © 2020 American Society for Bone and Mineral Research (ASBMR). 相似文献
184.
185.
Amalia S. Magaret Jack Salerno Jason F. Deen Margaret Kloster Nicole Mayer-Hamblett Bonnie W. Ramsey Dave P. Nichols 《Journal of cystic fibrosis》2021,20(2):e16-e18
Chronic Azithromycin (AZM) is a common treatment for lung infection. Among adults at risk of cardiac events, AZM use has been associated with cardiovascular harm. We assessed cardiovascular safety of AZM among children with CF, as a secondary analysis of a placebo-controlled, clinical trial, in which study drug was taken thrice-weekly for a planned 18 months. Safety assessments using electrocardiogram (ECG) occurred at study enrollment, and then after 3 weeks and 18 months of participation. Among 221 study participants with a median of 18 months follow-up, increased corrected QT interval (QTc) of ≥30 msec was rare, at 3.4 occurrences per 100 person-years; and incidence of QTc prolongation was no higher in the AZM arm than the placebo arm (1.8 versus 5.4 per 100 person-years). No persons experienced QTc intervals above 500 msec. Long-term chronic AZM use was not associated with increased QT prolongation. 相似文献
186.
Dayana A. Delgado Meytal Chernoff Lei Huang Lin Tong Lin Chen Farzana Jasmine Justin Shinkle Shelley A. Cole Karin Haack Jack Kent Jason Umans Lyle G. Best Heather Nelson Donald Vander Griend Joseph Graziano Muhammad G. Kibriya Ana Navas-Acien Margaret R. Karagas Habibul Ahsan Brandon L. Pierce 《Environmental health perspectives》2021,129(5)
187.
Value-adding partnerships have emerged as a preferred strategy of private health care providers to achieve high-quality, low-cost provider status. This same strategy can be applied by public sector providers through the creation of public-private partnership organizations (3POs). Strategies to build 3POs between local governments and their medical communities currently under development are outlined. The conceptual and practical aspects of implementing 3POs are presented. 相似文献
188.
Endocrine-metabolic response to abdominal aortic surgery: A randomized trial of general anesthesia versus general plus epidural anesthesia 总被引:4,自引:0,他引:4
Harm J. Smeets M.D. Job Kievit M.D. Frans T. Dulfer B.Sc Jack W. van Kleef M.D. 《World journal of surgery》1993,17(5):601-606
The influence of epidural anesthesia on the endocrine-metabolic response following abdominal aortic reconstruction was studied in a prospective randomized trial. Cortisol and catecholamine responses and nitrogen balance were measured in two groups of five patients receiving general anesthesia only (group 1) or general anesthesia combined with epidural bupivacaine (group 2). The study lasted from preoperatively until the first postoperative day. At 2100 hours on the day of surgery serum cortisol concentrations were higher in group 1 than in group 2 (1.41 versus 0.82 mol/L; p<0.01). Likewise the total perioperative hypercortisolemia, expressed as the area under the curve, was significantly higher in group 1 (11.7 versus 5.7 mol/L/hr, p<0.01). Intraoperative urinary excretion of epinephrine and postoperative norepinephrine excretion were significantly higher in group 1 than in group 2. Urinary excretion of free cortisol and cumulative nitrogen balance were not different between the groups. Although the number of patients was limited and the sensory nerve block level was not measured perioperatively, this study suggests that epidural anesthesia attenuates the stress response to aortic surgery.
Resumen Se diseñó un ensayo clínico prospectivo y randomizado con el fin de estudiar el efecto de la anestesia epidural sobre la respuesta endocrino-metabolica luego de una reconstrucción aórtica abdominal. Se determinaron la respuesta de cortisol y catecolaminas y el balance de nitrógeno en dos grupos de 5 pacientes que recibieron anestesia general solamente (Grupo 1) o anestesia general combinada con bupivacaína epidural (Grupo 2). El estudio se realizó en el periodo comprendido entre la fase preoperatoria hasta el primer día postoperatorio. A las 21:00 horas del mismo día de la cirugía las concentraciones séricas de cortisol resultaron más altas en el Grupo 1 que en el Grupo 2 (1.41 versus 0.82 micromol/l, p<0.01). Igualmente, la hipercortisolemia total perioperatoria apareció más alta en el Grupo 1 (11.7 versus 5.7 micromol/l* hora, p<0.01). La excreción urinaria intraoperatoria de epinefrina y la excreción postoperatoria de norepinefrina aparecieron significativamente más altas en el Grupo 1 que en el Grupo 2. No se registraron diferencias en la excreción urinaria de cortisol libre ni en el balance acumulado de nitrógeno. Aunque el número de pacientes fue limitado y el nivel del bloqueo sensorial no fue determinado perioperatoriamente, el presente estudio sugiere que la anestesia epidural atenúa la respuesta de estrés en la cirugia aórtica.
Résumé Dans une étude prospective et randomisée, l'influence de l'anesthésie péridurale sur la résponse métabolique endocrinienne a été étudiée dans la période préopératoire immédiate jusqu'au premier jour postopératoire après la chirurgie de l'aorte abdominale. On a mesuré les résponses en catécholamines et l'équilibre azoté chez cinq patients ayant eu une anesthésie générale seule (groupe 1) et cinq patients ayant une anesthésie générale combinée avec une anesthésie péridurale par la bupivacaïne (groupe 2). A 21H00 le jour de l'intervention,. la concentration en cortisol était plus haute dans le groupe 1 par rapport au groupe 2 (1.41 vs 0.82 micromol/l, p<0.01). De même, l'hypercortisolémie périopératoire totale, exprimée par la surface sous la courbe, était significativement plus élevée dans le groupe 1 (11.7 vs 5.7 micromol/l heure, p<0.01). L'excrétion urinaire peropératoire d'épinéphrine et l'excrétion postopératoire de la norépinéphrine étaient significativement plus élevées dans le groupe 1 par rapport au groupe 2. L'excrétion urinaire du cortisol libre et l'équilibre azoté tout au long de l'étude n'étaient pas très différents. Bien que le nombre de patients était limité et que le niveau supérieur de l'anesthésie n'ait pas été mesuré en périopératoire, les résultats de cette étude suggèrent que l'anesthésie péridurale atténue la réponse au stress dans la chirurgie de l'aorte abdominale.相似文献
189.
Davy C. H. Cheng Frances Chung Kenneth R. Chapman Jack Romanelli 《Journal canadien d'anesthésie》1990,37(5):521-527
This randomized double-blind study compared the effects of: (1) saline infusion (C); (2) sufentanil alone (1.0 micrograms.kg-1) (S); and (3) low-dose sufentanil (0.5 micrograms.kg-1) in combination with lidocaine (1.5 mg.kg-1) (LS): on the cardiovascular responses to tracheal intubation and on postoperative ventilation as monitored by respiratory inductive plethysmography in day-care surgical procedures of approximately 60 min duration. Thirty healthy, unpremedicated patients were studied. Thiopentone requirements were reduced by 40 and 28 per cent in the S and LS groups respectively compared with control (P less than 0.001). Both treatments suppressed HR and BP responses (P less than 0.005) to intubation. Postoperatively, PaCO2 was elevated (P less than 0.05) in group S. Dose-related respiratory depression was observed. The incidence of postoperative apnoea was significantly higher in both S and LS groups than compared with control (P less than 0.05). However, only patients in group S showed higher apnoea index and mean apnoea duration over the initial 10-20 min after surgery compared with control (P less than 0.005). In addition, group S showed slower respiratory frequency and prolonged expiratory time (P less than 0.005). In conclusion, an induction dose of sufentanil (1 microgram.kg-1) used in balanced anaesthesia of less than 70 min duration was associated with significant respiratory depression, particularly during the initial 10-20 min after surgery, whereas low-dose sufentanil (0.5 micrograms.kg-1) with lidocaine (1.5 mg.kg-1) had minimal postoperative respiratory depression and comparable attenuation of pressor responses to intubation. 相似文献
190.
Aversion instead of preference learning indicated by nicotine place conditioning in rats 总被引:5,自引:5,他引:0
Douglas E. Jorenby Rhea E. Steinpreis Jack E. Sherman Timothy B. Baker 《Psychopharmacology》1990,101(4):533-538
Although nicotine is a drug of abuse for millions of smokers, it has been difficult to demonstrate clearly the motivational properties of nicotine with rats using the conditioned place preference (CPP) paradigm. The first experiment attempted to replicate CPPs reported by other researchers using nicotine doses of 0.4, 0.8, and 1.2 mg/kg. There was a trend for all three doses to produce aversions, but it was significant only for the 0.8 mg/kg dose. Exposures to the CS alone extinguished aversions, but a priming dose (0.2 mg/kg) of nicotine given after extinction produced aversions only in animals exposed to 1.2 mg/kg. Experiment 2 tested whether preexposure to morphine or nicotine would sensitize animals to nicotine's reinforcing effects. In this experiment, rats were exposed to either six nicotine (0.6 mg/kg) or morphine (1.0 mg/kg) dosings prior to preference conditioning. Neither preferences nor aversions were observed in any group following subsequent conditioning with 0.6 mg/kg nicotine. The results suggest that previous observations of preference effects may have been due to specific procedural factors or may have depended on negative reinforcement due to stress reduction. 相似文献