首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11009篇
  免费   552篇
  国内免费   59篇
耳鼻咽喉   103篇
儿科学   584篇
妇产科学   153篇
基础医学   1260篇
口腔科学   223篇
临床医学   843篇
内科学   2262篇
皮肤病学   294篇
神经病学   720篇
特种医学   275篇
外科学   1753篇
综合类   294篇
一般理论   3篇
预防医学   555篇
眼科学   394篇
药学   1046篇
  2篇
中国医学   76篇
肿瘤学   780篇
  2023年   68篇
  2022年   188篇
  2021年   389篇
  2020年   199篇
  2019年   265篇
  2018年   310篇
  2017年   228篇
  2016年   295篇
  2015年   344篇
  2014年   471篇
  2013年   620篇
  2012年   868篇
  2011年   836篇
  2010年   487篇
  2009年   412篇
  2008年   663篇
  2007年   633篇
  2006年   638篇
  2005年   553篇
  2004年   503篇
  2003年   408篇
  2002年   355篇
  2001年   168篇
  2000年   177篇
  1999年   148篇
  1998年   86篇
  1997年   67篇
  1996年   46篇
  1995年   43篇
  1994年   40篇
  1993年   37篇
  1992年   95篇
  1991年   84篇
  1990年   82篇
  1989年   80篇
  1988年   71篇
  1987年   63篇
  1986年   61篇
  1985年   61篇
  1984年   43篇
  1983年   24篇
  1982年   26篇
  1979年   39篇
  1977年   31篇
  1975年   33篇
  1974年   29篇
  1973年   25篇
  1972年   32篇
  1971年   25篇
  1968年   21篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
BACKGROUND: Erectile dysfunction is a common and potentially treatable problem. Other than psychological, anatomical and metabolic factors, vasculogenic causes also play an important role in erectile dysfunction. Among the various diagnostic tools available for the diagnosis of vasculogenic causes, colour Doppler sonography is noninvasive, simple and promising. METHODS: This preliminary prospective study was conducted on 40 patients with erectile dysfunction, coming from a rural background to a hospital situated in a semi-urban setting. RESULTS: It was found that a cut-off value of 10 cm/second for peak systolic velocity in flaccid penis had the best accuracy among three chosen cut-off values, i.e. 5, 10, 15 cm/second, for detecting arterial insufficiency with sensitivity of 94.1%, specificity of 93.6%, negative predictive value of 98% and positive predictive value of 80%. CONCLUSION: Doppler sonography may be used as a good predictor of clinical response to intracavernosal injection of a vasodilating pharmacological agent.  相似文献   
92.
Background The presence of biliary obstruction in patients with gallbladder cancer (GBC) is generally viewed as an indicator of advanced disease, inoperability and poor prognosis. Methods Data was collected from patients with GBC with obstructive jaundice who underwent resection during the period January 2001 to October 2003. Systematic analysis of prospective data was undertaken; patients were analyzed for resectability, post-operative morbidity, mortality and disease-free survival. Results During this period 14 patients with GBC with biliary obstruction underwent resection with curative intent. In these jaundiced patients, the resectability rate was 27.45% (14 of 51). In the jaundiced group the mortality was 7.14% the morbidity rate 50%, the mean disease free survival was 23.46 months (median 26 months and range of 2 to 62 months). Seven patients (50%) survived more than two years. Conclusion Biliary obstruction in gall bladder cancer is not sine qua non of inoperability and resection results in meaningful prolongation of survival.  相似文献   
93.
Anesthesia care for the patients undergoing ophthalmologic surgical procedures during local/regional anesthesia balances goals of patient comfort with safety and an optimal outcome in a highly cost-conscious environment. This article discusses current practices and trends in anesthesia care with respect to sedation for eye surgery during local/regional anesthesia. Although there is no evidence that one local/regional anesthesia technique or sedation analgesia regimen is superior to the others, this review highlights important differences between these varied approaches. The type of block used for the ophthalmologic surgery alters the sedation requirements. Changes in surgical techniques have increased the popularity of topical anesthesia, which reduces the need for sedation analgesia and may lessen the need for an anesthesia practitioner. The involvement of an anesthesia practitioner in eye surgery varies from facility to facility based on costs, anesthesiologist availability, and local standards. Anesthesia care choices are often made based on surgeon skill and anesthesiologist comfort, as well as the expectations and needs of the patient.  相似文献   
94.
BACKGROUND: The clinical effectiveness of carotid endarterectomy (CEA) is well established. But the economic impact of CEA and carotid artery stenting (CAS) is still uncertain. The objective of this study was to compare hospital costs and reimbursement for CAS and CEA. STUDY DESIGN: We performed a retrospective database analysis on pair-matched patients who underwent CEA (n = 31) and CAS (n = 31) at the Richard M Ross Heart Hospital in Columbus, OH. The hospital's clinical and financial databases were used to obtain patient-specific information and procedural charges. Cost data were generated by applying the hospital's ratio of cost to charges for all DRG charges. The Wilcoxon signed-rank test was used to examine the differences between costs of these procedures. RESULTS: Data are reported as mean +/- SD. The mean age of patients in CAS group was 70.14 years (+/- 1.60 years) versus 68.64 years (+/- 1.75 years) for CEA patients (p < 0.05). The total direct cost associated with CEA ($3,765.12+/-$2,170.82) was significantly lower than the CAS cost ($8,219.71+/-$2,958.55, p < 0.001). The mean procedural cost for CAS ($7,543.61+/-$2,886.54) was significantly higher than that for CEA ($2,720.00+/-$926.38, p < 0.001). The hospital experienced cost savings of $9,690.87 for CEA versus $4,804.79 for CAS from private insurance. Similarly, savings obtained by Medicare-enrolled CEA patients were higher than those for CAS patients ($1,497.79). CONCLUSIONS: CAS is significantly more expensive than CEA, with a major portion of cost attributed to the total procedural cost. The hospital experienced significant savings from CEA procedures compared with CAS under all DRG classifications and insurers. Hospitals must develop new financial strategies and improve the efficiency of infrastructure to make CAS financially viable.  相似文献   
95.
96.
97.

Background

Despite significant pain relief following total hip arthroplasty (THA) in patients with ankylosing spondylitis, a small subset of patients presenting with extra-articular extension contracture of hips remains unsatisfied.

Methods

We retrospectively evaluated the patients with ankylosing spondylitis who underwent simultaneous bilateral THA and had extensor tightness of both hips preoperatively. They were managed with modified Z-plasty of iliotibial band. Patients with windswept deformity, commonly seen in bilateral hip arthritis caused by ankylosing spondylitis, were excluded.

Results

Between July 2011 and June 2015, out of 148 patients with bilateral hip involvement, 10 patients (20 hips) had extension contracture of both hips that was addressed during surgery. All patients were followed up for a minimum of 2 years. They could sit comfortably on a chair of height 18 inches with hips and knees flexed to at least 90°. The mean postoperative sum range of motion was 144.6° with an average hip flexion of 95° (range, 90°-105°). None of them had recurrence of extension contracture. There was significant improvement in range of motion and hence ambulation and function. No radiolucent lines exceeding 2 mm were seen in any of the zones around either of the components as evaluated in latest X-rays.

Conclusion

Extension contracture of hip although rare is a noticeable problem and needs to be addressed during THA. Modified Z-plasty technique of iliotibial band is a reliable method in managing these patients.  相似文献   
98.
Abstracts     
Abstract

The efficacies of four bowel care regimens (bisacodyl suppositories, glycerin suppositories, mineral oil enemas and docusate sodium mini-enemas) were compared in seven subjects with traumatic spinal cord injury. Efficacy was assessed in terms of colonic transit time, bowel evacuation time and subjective responses to a questionnaire. Both docusate sodium mini-enemas and mineral oil enemas decreased total and left-sided colonic transit time. However, docusate sodium mini-enemas were superior to mineral oil enemas in terms of the decrease in bowel evacuation time and symptom reduction. Results in this small group of subjects suggest that docusate sodium mini-enemas may have advantages in the management of bowel evacuation in individuals with spinal cord injury. (J Spinal Cord Med 1998;21 -24)  相似文献   
99.
BACKGROUND CONTEXT: Administration of analgesic medication, before the actual onset of painful stimulus, is more effective than that after the onset of painful stimulus. This is the principle of preemptive analgesia. Although it is often considered superior to other forms of analgesia, its role in postoperative pain relief after lumbosacral spinal surgery has not been fully investigated. PURPOSE: To analyze the efficacy of preemptive analgesia with a single caudal epidural injection for patients undergoing surgeries on the lumbosacral spine by the posterior approach. STUDY DESIGN/SETTING: Randomized, double-blinded and controlled clinical trial. PATIENT SAMPLE: Eighty-two patients who underwent discectomy in the lumbosacral spine by the posterior approach, with or without instrumentation, were randomized to the control group (n=40) and to the study group (n=42). METHODS: Patients in control group received a single caudal epidural injection of 20 ml of normal saline. Patients in study group received a single caudal epidural injection of 20 ml containing bupivacaine and tramadol as the active agents. The time interval between this injection and the surgical incision was never less than 20 minutes in either of the groups. This facilitated enough time for the drug to get fixed to the nerve roots, leading to effective preemptive analgesia. OUTCOME MEASURES: Patients were monitored for postoperative pain immediately after surgery when they had completely recovered and regained consciousness from general anesthesia, and subsequently 4, 8, 12 and 24 hours thereafter. Pain was quantified using the visual analog scale (VAS) and the verbal rating scale (VRS). The time at which supplemental analgesic medication was first demanded in the postoperative period by the patient was also noted. RESULTS: The two groups were comparable for age, sex, body weight and the type of surgery they underwent. Because the data did not have a normal Gaussian distribution, the one-tailed Mann-Whitney test, being a nonparametric test, was adopted for statistical analysis. Accordingly, VAS and VRS values at all time intervals were significantly lower (p<.0001) in the study group as compared with the control group. This indicated significantly better pain relief in the study group. There was also a significant delay (p=.0041) in the first demand for supplemental analgesic medication in the postoperative period in the study group. No complication specific to the procedure was noted except for the development of postoperative urinary retention, which was transient and appropriately managed with urinary catheterization. CONCLUSIONS: Preemptive analgesia with a single caudal epidural injection of bupivacaine and tramadol is a safe, simple and effective method for postoperative pain relief.  相似文献   
100.
BACKGROUND: Systemic oxygen consumption is not routinely measured during cardiopulmonary bypass, despite its potential benefits. We aimed to develop a noninvasive method to continuously measure oxygen consumption using respiratory mass spectrometry during hypothermic cardiopulmonary bypass in pigs. METHODS: Nine pigs weighing 18.5 (1.6) kg underwent hypothermic (32 degrees C) cardiopulmonary bypass for 180 minutes with 120 minutes of aortic cross clamping. An AMIS 2000 mass spectrometer (Innovision A/S, Odense, Denmark) was adapted for the on-line measurement of oxygen consumption by sampling the inlet and outlet gases of the membrane oxygenator together with measurement of the "expired" gas volume. RESULTS: Active cooling for 60 minutes reduced the venous blood temperature by 2.9 (0.8) degrees C and VO(2) by 0.70 (0.33) mL/kg/min. The 40-minute active rewarming restored the venous blood temperature by 4.4 (0.4) degrees C and oxygen consumption increased by 1.36 (0.33) mL/kg/min. There was wide interanimal variability, however, particularly at higher venous blood temperatures. Immediately after the release of aortic cross clamp, there was a noticeably acute increase in oxygen consumption in all the pigs (0.64 [0.21] mL/kg/min). CONCLUSIONS: A simple and safe adaptation of mass spectrometry allows continuous measurement of oxygen consumption during hypothermic cardiopulmonary bypass. The wide interindividual variations observed in this pilot study underscore the need to more accurately describe changes in oxygen consumption and how they are affected by temperature, oxygen delivery, and other interventions during cardiopulmonary bypass. As such, the technique may have an important role in clinical research and management of oxygen transport in patients undergoing cardiac surgery.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号