全文获取类型
收费全文 | 8181篇 |
免费 | 615篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 417篇 |
妇产科学 | 318篇 |
基础医学 | 1008篇 |
口腔科学 | 78篇 |
临床医学 | 1176篇 |
内科学 | 1548篇 |
皮肤病学 | 365篇 |
神经病学 | 717篇 |
特种医学 | 178篇 |
外科学 | 578篇 |
综合类 | 111篇 |
一般理论 | 6篇 |
预防医学 | 1246篇 |
眼科学 | 56篇 |
药学 | 586篇 |
中国医学 | 6篇 |
肿瘤学 | 363篇 |
出版年
2023年 | 56篇 |
2022年 | 55篇 |
2021年 | 131篇 |
2020年 | 99篇 |
2019年 | 142篇 |
2018年 | 168篇 |
2017年 | 149篇 |
2016年 | 156篇 |
2015年 | 160篇 |
2014年 | 220篇 |
2013年 | 369篇 |
2012年 | 489篇 |
2011年 | 520篇 |
2010年 | 270篇 |
2009年 | 239篇 |
2008年 | 503篇 |
2007年 | 455篇 |
2006年 | 487篇 |
2005年 | 528篇 |
2004年 | 517篇 |
2003年 | 447篇 |
2002年 | 420篇 |
2001年 | 131篇 |
2000年 | 122篇 |
1999年 | 136篇 |
1998年 | 100篇 |
1997年 | 81篇 |
1996年 | 75篇 |
1995年 | 73篇 |
1994年 | 60篇 |
1993年 | 47篇 |
1992年 | 80篇 |
1991年 | 86篇 |
1990年 | 77篇 |
1989年 | 79篇 |
1988年 | 91篇 |
1987年 | 83篇 |
1986年 | 65篇 |
1985年 | 84篇 |
1984年 | 76篇 |
1983年 | 74篇 |
1982年 | 53篇 |
1981年 | 65篇 |
1980年 | 48篇 |
1979年 | 42篇 |
1978年 | 40篇 |
1977年 | 25篇 |
1974年 | 40篇 |
1973年 | 32篇 |
1972年 | 28篇 |
排序方式: 共有8802条查询结果,搜索用时 15 毫秒
71.
Hoffman J Salzman C Garbaccio C Burns SP Crane D Bombardier C 《The journal of spinal cord medicine》2011,34(4):404-409
Background/objective
Persons with chronic spinal cord injury (SCI) have a high lifetime need for ongoing patient education to reduce the risk of serious and costly medical conditions. We have addressed this need through monthly in-person public education programs called SCI Forums. More recently, we began videotaping these programs for streaming on our website to reach a geographically diverse audience of patients, caregivers, and providers.Design/methods
We compared information from the in-person forums to that of the same forums shown streaming on our website during a 1-year period.Results
Both the in-person and Internet versions of the forums received high overall ratings from individuals who completed evaluation forms. Eighty-eight percent of online evaluators and 96% of in-person evaluators reported that they gained new information from the forum; 52 and 64% said they changed their attitude, and 61 and 68% said they would probably change their behavior or take some kind of action based on information they learned. Ninety-one percent of online evaluators reported that video is better than text for presenting this kind of information.Conclusion
Online video is an accessible, effective, and well-accepted way to present ongoing SCI education and can reach a wider geographical audience than in-person presentations. 相似文献72.
Anna Porter Michael J. Fischer Xuelei Wang Deborah Brooks Marino Bruce Jeanne Charleston William H. Cleveland Donna Dowie Marquetta Faulkner Jennifer Gassman Leena Hiremath Cindy Kendrick John W. Kusek Keith C. Norris Denyse Thornley-Brown Tom Greene James P. Lash 《Journal of the American Society of Nephrology : JASN》2014,25(8):1849-1855
Low health-related quality of life (HRQOL) has been associated with increased risk for hospitalization and death in ESRD. However, the relationship of HRQOL with outcomes in predialysis CKD is not well understood. We evaluated the association between HRQOL and renal and cardiovascular (CV) outcomes in 1091 African Americans with hypertensive CKD enrolled in the African American Study of Kidney Disease and Hypertension (AASK) trial and cohort studies. Outcomes included CKD progression (doubling of serum creatinine/ESRD), CV events/CV death, and a composite of CKD progression or death from any cause (CKD progression/death). We assessed HRQOL, including mental health composite (MHC) and physical health composite (PHC), using the Short Form-36 survey. Cox regression analyses were used to assess the relationship between outcomes and five-point decrements in MHC and PHC scores using measurements at baseline, at the most recent annual visit (time-varying), or averaged from baseline to the most recent visit (cumulative). During approximately 10 years of follow-up, lower mean PHC score was associated with increased risk of CV events/CV death and CKD progression/death across all analytic approaches, but only time-varying and cumulative decrements were associated with CKD progression. Similarly, lower mean MHC score was associated with increased risk of CV events/CV death regardless of analytic approach, while only time-varying and cumulative decrements in mean MHC score was associated with CKD progression and CKD progression or death. In conclusion, lower HRQOL is associated with a range of adverse outcomes in African Americans with hypertensive CKD. 相似文献
73.
74.
75.
Varicocele represents the most common cause of male infertility, and most reports indicate that varicocelectomy has a beneficial effect on male fertility and pregnancy outcome. Assisted reproductive technologies (ARTs) are an alternative to varicocelectomy for the management of couples with a varicocele. The age of the female partner is important in the decision-making process; however, the true influence of female age on pregnancy outcome following varicocelectomy or ART in these couples is unknown. We evaluated the outcomes of 2 cohorts of infertile men with a varicocele and a female partner 35 years of age or older; one group selected varicocelectomy and the other a nonsurgical approach. We reviewed a group of consecutive infertile men who underwent microsurgical varicocelectomy and whose partners are 35 years of age or older (n = 110). We also reviewed a consecutive group of men with varicoceles who elected not to have surgery and whose partners are 35 years of age or older (n = 94). The outcome measures included changes in semen parameters, pregnancy rates (assisted and unassisted), and use of ART. The surgical and nonsurgical groups had comparable semen parameters and female ages. Mean sperm concentration and motility increased significantly after varicocelectomy (P < .05). At a mean of 30 months follow-up, 35% of couples in the surgical group achieved a spontaneous pregnancy and an additional 6% achieved a pregnancy via ART (20% of this group attempted ART). In the nonsurgical group, 25% achieved a spontaneous pregnancy and an additional 16% achieved a pregnancy with ART (40% of this group attempted ART). This study on the natural history of infertile men with varicocele and advanced female age suggests that the surgical and nonsurgical approaches offer comparable pregnancy outcome (combined assisted and unassisted pregnancy rates are about 40%). Overall, these data suggest that varicocelectomy is an acceptable option for couples with advanced female age, but other female factors must be considered in the decision-making process. 相似文献
76.
Edgerton JR Herbert MA Jones KK Prince SL Acuff T Carter D Dewey T Magee M Mack M 《The heart surgery forum》2004,7(1):8-15
Abstract Background: Cardiac surgery has expanded the available approaches to aortocoronary artery bypass grafting to include approaches from minimally invasive surgery to full sternotomy. The heart can be arrested, left beating, or assisted with a right ventricular assist device or cardiopulmonary bypass pump. We have examined the 4 surgical modes that we use routinely in our large multisurgeon practice to determine our selection biases and the outcomes of the different techniques. Methods: Of the 4733 coronary artery bypass grafting (CABG) patients we studied from January 2000 through December 2002, 2332 (49.3%) operations were done on-pump on the arrested heart, 1908 (40.3%) were performed off-pump, 364 (7.7%) were performed on-pump on the beating heart, and 129 (2.7%) were performed with right heart assist. The preoperative risk factors, operative variables, and postoperative outcomes of the groups were analyzed. Results: Patients selected for on-pump beating heart procedures tended to be sicker with the highest predicted risk of death. We also selected patients who were in cardiogenic shock, in resuscitation, in emergent or salvage status, on dialysis, and with preoperative intra-aortic balloon pump (IABP) use for on-pump beating heart procedures at higher than expected rates. Patients with renal failure with or without dialysis, and those having a history of cerebrovascular accident tended not to be chosen for on-pump arrested heart procedures. Off-pump beating heart procedures were avoided for patients with cardiogenic shock or resuscitation, in emergent or salvage status, and with preoperative IABP use. The mortality rate in these patients was slightly worse in the on-pump beating heart group (4.4%) than in the on-pump arrested heart (3.5%) and off-pump (2.3%) groups (analysis of variance [ANOVA], P =.04). Atrial fibrillation occurred more frequently in both the on-pump beating heart (20.1%) and on-pump arrested heart (23.8%) groups (ANOVA, P <.001). The on-pump groups had higher rates of blood product use and reoperation for bleeding and a prolonged ventilation rate, compared with the other procedures. On-pump patients had a statistically longer length of stay than either off-pump or right heart-assisted patients ( P <.05) and required longer times on the ventilator and in the intensive care unit. Conclusions: Normothermic cardiopulmonary bypass with a beating heart is safe and efficacious and may be the method of choice for patients in cardiogenic shock, requiring resuscitation, or with previous CABG surgery, recent myocardial infarction, a low ejection fraction, or unstable arrhythmias. 相似文献
77.
78.
The subcellular sites of synthesis of phosphatidylinositol and phosphatidylglycerol in type II pneumonocytes isolated from
lungs of adult rats were investigated. Microsomes contained approximately 34% of the total cellular activity of CDP-diacylglycerol:
inositol 3-phosphatidyltransferase (EC 2.7.8.11) but less than 10% of the total activity of CDP-diacylglycerol: glycerol 3-phosphate
phosphatidyltransferase (EC 2.7.8.5) and the latter activity could be attributed to mitochondrial contamination of the microsomal
fraction. A crude mitochondrial fraction contained approximately 90% of the total cellular activity of CDP-diacylglycerol:
glycerol 3-phosphate phosphatidyltransferase and also contained more than 50% of the total CDP-diacylglycerol: inositol 3-phosphatidyltransferase
activity. When the crude mitochondrial fraction was subfractionated by use of discontinuous density gradient centrifugation,
the distribution of CDP-diacylglycerol: inositol 3-phosphatidyltransferase activity was similar to that of NADPH: cytochromec reductase activity but dissimilar to the distribution of CDP-diacylglycerol: glycerol 3-phosphate phosphatidyltransferase
activity which resembled that of succinate dehydrogenase. Electron microscopy of subcellular fractions revealed that fractions
rich in CDP-diacylglycerol: inositol 3-phosphatidyltransferase activity contained numerous smooth membrane vesicles, whereas
fractions rich in CDP-diacylglycerol: glycerol 3-phosphate phosphatidyltransferase activity contained mainly mitochondria.
We conclude that the subcellular sites of synthesis of phosphatidylinositol and phosphatidylglycerol in type II pneumonocytes
are most likely the endoplasmic reticulum and mitochondria, respectively.
The results of this investigation were presented, in part, at the 73rd annual meeting of the American Society of Biological
Chemists 相似文献
79.
Blair JA Patzkowski JC Schoenfeld AJ Cross Rivera JD Grenier ES Lehman RA Hsu JR;Skeletal Trauma Research Consortium 《The spine journal》2012,12(9):824-829
Background contextThe severity and prognosis of combat-related injuries to the spine and spine injuries sustained unrelated to direct combat have not been previously compared. Differences may have implications on tactics, treatment strategies, and directions for future research.PurposeCompare the severity and prognosis of battle and nonbattle injuries to the spine.Study designRetrospective study.Patient sampleAmerican military personnel who were injured in a combat zone and whose medical data were abstracted in the Joint Theater Trauma Registry (JTTR).MethodsThe JTTR was queried using International Statistical Classification of Diseases, Ninth Revision codes to identify all individuals who sustained battle and nonbattle injuries to the neck, back, spinal column, or spinal cord in Operation Iraqi Freedom or Operation Enduring Freedom from October 2001 to December 2009. Medical records of all identified servicemembers were individually reviewed. Demographic information, including sex, age, military rank, date of injury, and final disposition, was obtained for all patients. Spinal injuries were categorized according to anatomic location, associated neurologic involvement, precipitating mechanism of injury (MOI), and concomitant wounds. These data points were compared for the groups battle spine injuries (BSIs) and nonbattle spine injuries (NBSIs).ResultsFive hundred two servicemembers sustained a total of 1,834 battle injuries to the spinal column, including 1,687 fractures (92%), compared with 92 servicemembers sustaining 267 nonbattle spinal column injuries, with 241 (90%) fractures. Ninety-one BSI servicemembers (18% of patients) sustained spinal cord injuries (SCIs) with 41 (45%) complete SCIs, compared with 13 (14% of patients) nonbattle SCIs with six (46.2%) complete injuries (p=.92). The reported MOI for 335 BSI servicemembers (66.7%) was an explosion compared with one NBSI explosive injury. Eighty-four patients (17%) sustained gunshot wounds (GSWs) in battle compared with five (5.2%) nonbattle GSWs. Fifteen patients (3.0%) sustained a battle-related fall compared with 29 (30%) nonbattle-related falls. Battle spine injury servicemembers underwent significantly higher rates of surgical interventions (p<.0001), were injured by high-energy injury mechanisms at a significantly greater rate (p<.0001), and demonstrated a trend toward lower neurologic recovery rates after SCI (p=.16).ConclusionsBattle spine injury and NBSI are separate entities that may ultimately have disparate long-term prognoses. Nonbattle spine injury patients, although having similar MOIs compared with civilian spinal trauma, maintain a different patient demographic. Further research must be directed at accurately quantifying the long-term disabilities of all spine injuries sustained in a combat theater, whether they are the result of battle or not. 相似文献
80.
Laura Teeter Julie Gassaway Sally Taylor Jacqueline LaBarbera Shari McDowell Deborah Backus Jeanne M. Zanca Audrey Natale Jordan Cabrera Randall J. Smout Scott E. D. Kreider Gale Whiteneck 《The journal of spinal cord medicine》2012,35(6):503-526