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   22640篇
  免费   1336篇
  国内免费   158篇
耳鼻咽喉   184篇
儿科学   529篇
妇产科学   382篇
基础医学   3202篇
口腔科学   629篇
临床医学   2234篇
内科学   4950篇
皮肤病学   429篇
神经病学   2600篇
特种医学   1486篇
外科学   3333篇
综合类   135篇
一般理论   9篇
预防医学   814篇
眼科学   469篇
药学   1218篇
中国医学   19篇
肿瘤学   1512篇
  2023年   161篇
  2022年   324篇
  2021年   582篇
  2020年   384篇
  2019年   451篇
  2018年   546篇
  2017年   476篇
  2016年   603篇
  2015年   693篇
  2014年   866篇
  2013年   1015篇
  2012年   1606篇
  2011年   1591篇
  2010年   1037篇
  2009年   965篇
  2008年   1464篇
  2007年   1568篇
  2006年   1345篇
  2005年   1368篇
  2004年   1273篇
  2003年   1181篇
  2002年   1102篇
  2001年   307篇
  2000年   259篇
  1999年   261篇
  1998年   209篇
  1997年   164篇
  1996年   141篇
  1995年   97篇
  1994年   101篇
  1993年   97篇
  1992年   151篇
  1991年   119篇
  1990年   101篇
  1989年   107篇
  1988年   104篇
  1987年   85篇
  1986年   75篇
  1985年   70篇
  1984年   46篇
  1983年   48篇
  1979年   70篇
  1978年   51篇
  1977年   44篇
  1974年   39篇
  1973年   46篇
  1972年   54篇
  1968年   33篇
  1935年   32篇
  1934年   33篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Five cases of unilateral vocal cord paralysis/paresis were diagnosed following extracorporeal membrane oxygenation for newborn respiratory failure. All were right sided and transient in nature. None of the five patients had other findings commonly associated with vocal cord palsy. The extracorporeal membrane oxygenation procedure requires surgical dissection in the carotid sheath on the right side of the neck, an area immediately adjacent to both the vagus and recurrent laryngeal nerve. It is speculated that vocal cord paralysis in these infants was acquired as a result of the extracorporeal membrane oxygenation cannulation. Although the vocal cord paralysis resolved in all cases, two patients had difficult courses after extracorporeal membrane oxygenation. Therefore, laryngoscopic examination should be considered for patients after extracorporeal membrane oxygenation.  相似文献   
22.
Painful calcinosis appeared at the wrist of an eight-year-old girl with lead poisoning. Careful history revealed that calcification occurred at the site of previous extravasation of calcium disodium edetate (EDTA) used in chelation therapy. Light microscopic, ultrastructural, electron activation, and X-ray diffraction studies demonstrated apatites with some suggestion of an admixture of octacalcium phosphate.  相似文献   
23.
In an in vitro study, 10 gallbladders of adult pigs and 6 gallbladders of lambs, all removed immediately after slaughtering, were stimulated in a water bath by electric means to induce active contraction. Gallbladder emptying was followed by ultrasonography employing five measurement procedures: (1) gallbladder width, (2) longitudinal planimetry, (3) transverse planimetry, (4) ellipsoid method, and (5) sum of cylinders method. In an in vivo investigation, gallbladder emptying of 30 volunteers (12 healthy subjects, 18 diabetics) was evaluated in the same way after ingestion of a fatty meal. Gallbladder width was found to be unsuitable to estimate the decrease in gallbladder volume due to a nonlinear relation of the parameters. Longitudinal planimetry tended to be less valid than transverse planimetry in assessing gallbladder volume reduction. The most valid estimation of gallbladder volume decreases was obtained by the two three-dimensional procedures. However, in neither in vitro nor in vivo could a significant difference between the sum of cylinders method and the ellipsoid method in determining relative volume reduction be established. We conclude that a three-dimensional measurement procedure should be used for valid assessments of gallbladder motility. However, according to our data there is no advantage in using the time-consuming sum of cylinders method compared to the simple ellipsoid method.  相似文献   
24.
Background and aims Since the introduction of endovascular aortic aneurysm repair (EVAR) for aortic aneurysms, the number of juxtarenal aortic aneurysms (JRA) has been growing steadily due to selection bias (neck morphology for EVAR). This case-match study compares the perioperative outcome and midterm results of suprarenally clamped JRA with infrarenal aortic aneurysms (AAA). Methods From 1997 to 2004, patients who received open surgery with suprarenal clamping for JRA were included in the study and compared to matched patients with infrarenal clamping (AAA). Measurements analyzed were the in-hospital mortality and morbidity. Midterm results were obtained through clinical investigation and magnetic resonance angiography imaging. Results Thirty-five patients (mean age, 68.4 years; 30 male and 5 female) received suprarenal cross-clamping for JRA. The overall in-hospital mortality for JRA and for the controls (AAA) with elective aortic repair was 4.5% (6.1% JRA; 3% AAA, p = 0.058). The morbidity of JRA was elevated according to the rate of pulmonary complications (p = 0.021) and the need for re-operation (p = 0.019). The mean follow-up time was 2.3 years (range, 8–96 months). At follow-up, 28 patients (80%) from the JRA group and 29 patients from the AAA group (82.9%) were alive. Conclusion Open aortic surgery for JRA with the need for suprarenal cross-clamping shows a slightly elevated in-hospital mortality rate without statistical significance and equal midterm mortality results in comparison with infrarenally clamped aortic aneurysms.  相似文献   
25.
BACKGROUND AND PURPOSE: The efficacy of radiation treatment (RT) for plantar heel pain has been reported repeatedly. Yet, the results referring to the pain relief rate, to long-term effects and prognostic factors are not consistent. In this paper, the effectiveness (pain relief rate and long-term results) and prognostic factors of RT for plantar heel pain have been investigated. PATIENTS AND METHODS: From January 2000 to October 2000, 62 patients (73 heels) with painful plantar heel spurs and a minimum pain history of 3 months were treated and evaluated in a prospective study. Mean age was 54 years (range 28-84 years). All patients were treated with a total dose of 5 Gy in seven fractions (= one series), given twice a week at a single-dose sequence of 0.25-0.25-0.5-1.0-1.0-1.0-1.0 Gy (10-MV photons, source-skin distance [SSD] 100 cm, direct portal, field size 12 x 17 cm). The mean duration of heel pain before RT was 26 weeks (= 6.5 months; range 3-120 months). By means of a visual analog scale (VAS) the patients had to self-assess the quantity of their heel pain once before, three times during and four times after RT at a longterm median follow-up of 28 and 40 months. Additionally, the patients had to assess their mechanical heel stress extent during RT. Effectiveness was estimated according to the patients' judgment of pain reduction. RESULTS: A significant reduction of heel pain extent measured by VAS has been observed already during the RT series (before RT: 6.3 +/- 1.5 vs. 3.8 +/- 2.1 at the end of RT; p < 0.001). 6 weeks after RT (FU 1) pain reduction (> 20%) was achieved in 60 heels (82.3%; n = 73), in 64 heels (91.4%; n = 70) after a mean follow-up of 28 months (FU 2), and in 61 heels (89.7%; n = 68) after a mean follow-up of 40 months (FU 3), respectively. Sufficient pain relief (> 80% compared to initial extent) was observed in 18/73 heels (24.6%) at FU 1 (FU 2: 42/70; 60.0%; FU 3: 37/68; 54.4%), including 13/73 heels (17.8%) with complete pain relief (FU 2: 39/70; 55.7%; FU 3: 36/68; 52.9%). Partial improvement (50-80% pain reduction) was observed in 27/73 heels (37.0%) at FU 1 (FU 2: 14/70; 20.0%; FU 3: 15/68; 22.1%), and minor partial improvement (20-50% pain reduction) in 15/73 heels (20.5%) at FU 1 (FU 2: 8/70; 11.4%; FU 3: 9/68; 13.2%), respectively. No change was seen in 13/73 heels (17.8%) at FU 1 (FU 2: 6/70; 8.6%; FU 3: 7/68; 10.3%). Older patients (p = 0.04) and patients who avoided heel stress during the period of RT (p < 0.01) demonstrated a better short-term response (FU 1); both effects were lost 28 and 40 months after RT. Moreover, significant differences in the extent of heel pain reduction by RT were observed in dependence on previous pain duration (at FU 2-3). CONCLUSION: The results confirm the high efficacy of RT in painful plantar spur and add new aspects to formerly published data concerning the time course of changes in heel pain reduction. Pain relief can be expected during and shortly after RT. In addition, the initial success can be transformed into effective long-term results > 2 years after RT; however, further improvement is not to be expected. As a new prognostic factor, the reduction of mechanical heel stress during RT may ameliorate the short-term results, whereas short heel pain history improves the long-term results. Especially for older patients, RT should be taken into consideration as primary treatment.  相似文献   
26.
Abstract Background: Primary shoulder hemiarthroplasty is an established treatment modality for complex fractures of the proximal humerus. Long-term functional outcome is often disappointing. However, little is known about social implications particularly in the elderly. Methods: A single-institution case series of consecutive geriatric patients (age > 70 years) treated with shoulder hemiarthroplasty for complex fractures of the proximal humerus between 1994 and 1997 was analysed. Postoperative morbidity, long-term function, radiological outcome and social implications were evaluated. Results: Seventy-seven patients fulfilled the study criteria. Median age at the time of operation was 80 years (range 70–93 years). Systemic and local postoperative complications were observed in 8% including 2 patients (3%) with revision surgery. Postoperative mortality was 1%. Forty-eight patients (62%) were available for follow-up (median 49 months, range 25–80 months), 22 (29%) died from causes unrelated to hemiarthroplasty before follow-up and 7 patients (9%) did not attend follow-up examination. Median Constant-Murley score was 41 points (range 17–77 points). Long-term results concerning pain were satisfying. The Oxford shoulder score ranged from 14 to 40 (median 30). Forty-one patients (85%) still lived in their original environment and managed their daily life independently despite poor shoulder function. Four patients (8%) lived in a retirement home and 3 (6%) in a nursery home. Eighty percent of our patients were still able to use public transportation, do the daily shopping and wash their whole body by themselves. Conclusion: Most patients managed their daily life independently despite poor shoulder function.  相似文献   
27.
OBJECTIVES: to report our experience with hybrid vascular procedures in patients with pararenal and thoracoabdominal aortic pathologies. METHODS: 68 patients were treated for thoracoabdominal aortic pathologies between October 1999 and February 2004; 19 patients (16 men; mean age 68, range 40-79) with high risk for open thoracoabdominal repair were considered to be candidates for combined endovascular and open repair. Aortic pathologies included five thoracoabdominal Crawford I aneurysms, one postdissection expanding aneurysm, three symptomatic plaque ruptures (Crawford IV), five combined thoracic descending and infrarenal aneurysms with a healthy visceral segment, three juxtarenal or para-anastomotic aneurysms, and two patients with simultaneous open aortic arch replacement and a rendezvous maneuver for thoracic endografting. Commercially available endografts were implanted with standardized endovascular techniques after revascularization of visceral and renal arteries. RESULTS: Technical success was 95%. One patient developed a proximal type I endoleak after chronic expanding type B dissection and currently is waiting conversion. Nine patients underwent elective, five emergency and five urgent (within 24 h) repair. 17 operations were performed simultaneously, and 2 as a staged procedure. Postoperative complications include two retroperitoneal hemorrhages, and one patient required long-term ventilation with preexisting subglottic tracheal stenosis. Thirty-day mortality was 17% (one multiple organ failure, one secondary rupture after open aortic arch repair, one myocardial infarction). Paraplegia or acute renal failure were not observed. Total survival rate was to 83% with a mean follow-up of 30 months. CONCLUSIONS: Midterm results of combined endovascular and open procedures in the thoracoabdominal aorta are encouraging in selected high risk patients. Staged interventions may reduce morbidity.  相似文献   
28.
The purpose of the study was to determine the incidence, risk factors, treatment, and influence on survival of patients with de novo esophageal cancer after liver transplantation (LT). From 1988 to 2006, 1,926 patients underwent LT in our institution. A total of 9 patients (0.5%) developed a de novo esophageal cancer and 1 patient a cancer of the cardia (0.05%). A retrospective analysis was performed to reveal underlying diseases, timeframes between LT and appearance of cancer, predisposing factors, cancer therapy, complications, immunosuppressive regimens, and survival. Of our 10 patients, 7 (70%) suffered from esophageal squamous cell carcinoma (SCC) and 3 patients (30%) developed an adenocarcinoma, including the patient with cancer of the cardia. A total of 9 patients were transplanted due to alcoholic cirrhosis; 1 patient suffered from hepatocellular carcinoma in nonA-nonB hepatitis-related cirrhosis. Median time to tumor diagnosis was 51 months after transplantation. A total of 5 patients were treated conservatively with combined radiochemotherapy and 5 underwent surgical resection. Patients with radiochemotherapy showed a mean survival of 14.8 months vs. 24.8 months for the patients of the surgery group. No major postoperative complication has been observed. A total of 2 patients of the surgery group are still alive after a follow-up of 15 and 89 months. In conclusion, de novo esophageal and cancer of the cardia after LT is a rare event. In spite of immunosuppression, no increased complication rate has been observed. Patients may have a survival benefit from surgical resection.  相似文献   
29.
Background: Neuraxial blockade is used as primary anesthetic technique in one third of surgical procedures. The authors tested whether bisoprolol would protect patients at risk for cardiovascular complications undergoing surgery with spinal block.

Methods: The authors performed a double-blinded, placebo-controlled, multicenter trial to compare the effect of bisoprolol with that of placebo on 1-yr composite outcome including cardiovascular mortality, nonfatal myocardial infarction, unstable angina, congestive heart failure, and cerebrovascular insult. Bisoprolol was given orally before and after surgery for a maximum of 10 days. Adrenergic receptor polymorphisms and safety outcome measures of bisoprolol therapy were also determined.

Results: A total of 224 patients were enrolled. Spinal block could not be established in 5 patients. One hundred ten patients were assigned to the bisoprolol group, and 109 patients were assigned to the placebo group. The mean duration of treatment was 4.9 days in the bisoprolol group and 5.1 days in the placebo group. Bisoprolol therapy reduced mean heart rate by 10 beats/min. The primary outcome was identical between treatment groups and occurred in 25 patients (22.7%) in the bisoprolol group and 24 patients (22.0%) in the placebo group during the 1-yr follow-up (hazard ratio, 0.97; 95% confidence interval, 0.55-1.69; P = 0.90). However, carriers of at least one Gly allele of the [beta]1-adrenergic receptor polymorphism Arg389Gly showed a higher number of adverse events than Arg homozygous (32.4% vs. 18.7%; hazard ratio, 1.87; 95% confidence interval, 1.04-3.35; P = 0.04).  相似文献   

30.
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