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   15083篇
  免费   906篇
  国内免费   83篇
耳鼻咽喉   192篇
儿科学   390篇
妇产科学   298篇
基础医学   1663篇
口腔科学   511篇
临床医学   1171篇
内科学   3433篇
皮肤病学   328篇
神经病学   878篇
特种医学   458篇
外国民族医学   5篇
外科学   2669篇
综合类   308篇
一般理论   14篇
预防医学   1084篇
眼科学   348篇
药学   1108篇
中国医学   100篇
肿瘤学   1114篇
  2023年   179篇
  2022年   473篇
  2021年   779篇
  2020年   422篇
  2019年   548篇
  2018年   700篇
  2017年   426篇
  2016年   433篇
  2015年   536篇
  2014年   685篇
  2013年   753篇
  2012年   1229篇
  2011年   1255篇
  2010年   739篇
  2009年   582篇
  2008年   892篇
  2007年   816篇
  2006年   775篇
  2005年   734篇
  2004年   636篇
  2003年   587篇
  2002年   477篇
  2001年   132篇
  2000年   98篇
  1999年   97篇
  1998年   85篇
  1997年   60篇
  1996年   73篇
  1995年   45篇
  1994年   47篇
  1993年   41篇
  1992年   50篇
  1991年   54篇
  1990年   36篇
  1989年   43篇
  1988年   40篇
  1987年   39篇
  1986年   28篇
  1985年   39篇
  1984年   36篇
  1983年   36篇
  1982年   45篇
  1981年   27篇
  1980年   31篇
  1979年   25篇
  1978年   31篇
  1977年   19篇
  1975年   21篇
  1974年   25篇
  1973年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Smith R  Davis N  Bouamra O  Lecky F 《Injury》2005,36(9):1034-8; discussion 1039
Intraosseous lines are a reliable and rapid tool for obtaining vascular access in emergency situations, particularly in children. Their use is recommended when intravenous access cannot be easily secured and there is a need for fluid or pharmacological resuscitation. Training in this technique is included in the Advanced Trauma Life Support (ATLS) and Advanced Paediatric Life Support course (APLS) provider courses. The objective of this study is to analyse the national use of intraosseous lines in paediatric trauma in England and Wales. Data has been collected from the Trauma Audit and Research Network (TARN) group longitudinally over 14 years from 1988 to 2002. From 23,489 paediatric trauma cases, intraosseous lines were used in only 129 patients. Compared with the remainder of the paediatric data, we found that these were the younger (1-6 years), more severely injured patients (higher ISS, lower GCS, higher head, thorax, and abdominal AIS). The mortality of these patients was high at 64% compared with 4% overall. IO line use was greater in general than in Paediatric hospitals, perhaps due to good intravenous access skills in paediatric centres. We recommend that intraosseous line use should be a skill available to everybody involved in paediatric trauma resuscitation, particularly those who may not have refined paediatric intravenous cannulation skills.  相似文献   
102.
OBJECTIVE: Ischemic heart failure is an increasingly prevalent global health concern with major morbidity and mortality. Currently, therapies are limited, and novel revascularization methods might have a role. This study examined enhancing endogenous myocardial revascularization by expanding bone marrow-derived endothelial progenitor cells with the marrow stimulant granulocyte-monocyte colony-stimulating factor and recruiting the endothelial progenitor cells with intramyocardial administration of the potent endothelial progenitor cell chemokine stromal cell-derived factor. METHODS: Ischemic cardiomyopathy was induced in Lewis rats (n = 40) through left anterior descending coronary artery ligation. After 3 weeks, animals were randomized into 4 groups: saline control, granulocyte-monocyte colony-stimulating factor only (GM-CSF only), stromal cell-derived factor only (SDF only), and combined stromal cell-derived factor/granulocyte-monocyte colony-stimulating factor (SDF/GM-CSF) (n = 10 each). After another 3 weeks, hearts were analyzed for endothelial progenitor cell density by endothelial progenitor cell marker colocalization immunohistochemistry, vasculogenesis by von Willebrand immunohistochemistry, ventricular geometry by hematoxylin-and-eosin microscopy, and in vivo myocardial function with an intracavitary pressure-volume conductance microcatheter. RESULTS: The saline control, GM-CSF only, and SDF only groups were equivalent. Compared with the saline control group, animals in the SDF/GM-CSF group exhibited increased endothelial progenitor cell density (21.7 +/- 3.2 vs 9.6 +/- 3.1 CD34 + /vascular endothelial growth factor receptor 2-positive cells per high-power field, P = .01). There was enhanced vascularity (44.1 +/- 5.5 versus 23.8 +/- 2.2 von Willebrand factor-positive vessels per high-power field, P = .007). SDF/GM-CSF group animals experienced less adverse ventricular remodeling, as manifested by less cavitary dilatation (9.8 +/- 0.1 mm vs 10.1 +/- 0.1 mm [control], P = .04) and increased border-zone wall thickness (1.78 +/- 0.19 vs 1.41 +/- 0.16 mm [control], P = .03). (SDF/GM-CSF group animals had improved cardiac function compared with animals in the saline control group (maximum pressure: 93.9 +/- 3.2 vs 71.7 +/- 3.1 mm Hg, P < .001; maximum dP/dt: 3513 +/- 303 vs 2602 +/- 201 mm Hg/s, P < .05; cardiac output: 21.3 +/- 2.7 vs 13.3 +/- 1.3 mL/min, P < .01; end-systolic pressure-volume relationship slope: 1.7 +/- 0.4 vs 0.5 +/- 0.2 mm Hg/microL, P < .01.) CONCLUSION: This novel revascularization strategy of bone marrow stimulation and intramyocardial delivery of the endothelial progenitor cell chemokine stromal cell-derived factor yielded significantly enhanced myocardial endothelial progenitor cell density, vasculogenesis, geometric preservation, and contractility in a model of ischemic cardiomyopathy.  相似文献   
103.
Congenital macrodactyly is a rare congenital malformation characterised by progressive enlargement of all mesenchymal elements of a digit. The present study is an attempt to draw the attention towards the similarities and differences between macrodactyly of the hand and foot. Radiographical, operative findings and histopathological examination of five cases are included in the present study. Emphasis was given to know the possible basic lesion. Radiographic findings, which differentiate this entity from other forms of local gigantism, were also analysed. The most characteristic finding noted was excessive overgrowth of fibro-fatty tissue with unusually large fatty lobules, apparently fixed by a mesh of dense fibrous tissue. Hypertrophy and tortuosity of the digital nerve, a striking feature in macrodactyly of the hand, was notably absent in cases affecting the foot. None of the patients had any other associated congenital anomalies. Neither the patients nor any of their family members had any stigmata of neurofibromatosis. Chromosomal study was normal in all of them. We conclude that in macrodactyly of the foot, excessive proliferation and accumulation of adipose tissue was the basic lesion, whereas involvement of the nerve might be the fundamental lesion in gigantism of the hand. Furthermore, whatever be the basic lesion, the final pathway must be either the local deficiency of a growth inhibiting factor or local expression of a basic intrinsic factor, leading to excessive growth of all elements of the digit.  相似文献   
104.
Genetic factors are important in the pathogenesis of osteoporosis, but little is known about the genetic determinants of treatment response. Previous studies have shown that polymorphisms of the LRP5 gene are associated with bone mineral density (BMD), but the relationship between LRP5 polymorphisms and response to bisphosphonate treatment in osteoporosis has not been studied. In this study we investigated LRP5 polymorphisms in relation to treatment response in a group of 249 osteoporotic or osteopenic men who participated in a 24-month randomized double blind placebo-controlled trial of risedronate treatment. BMD and biochemical markers of bone turnover were measured at baseline and after 6, 12, and 24 months of follow-up. We analyzed two coding polymorphisms of LRP5, which have previously been associated with BMD, V667M (rs4988321) and A1330V (rs3736228), and found a significant association between the A1330V polymorphism and hip BMD at baseline. Subjects with the 1330 Val/Val genotype had 8.4% higher total-hip BMD compared with the other genotype groups (P = 0.009), and similar associations were observed at the femoral neck (P = 0.01) and trochanter (P = 0.002). There was no association between A1330V and spine BMD, however, or between the V667M polymorphism and BMD at any site. The difference in hip BMD between A1330V genotype groups remained significant throughout the study, but there was no evidence of a genotype–treatment interaction in either risedronate- or placebo-treated patients. In conclusion, the LRP5 A1330V polymorphism is associated with hip BMD in osteoporotic men, but allelic variations in LRP5 do not appear to be associated with response to bisphosphonate treatment.  相似文献   
105.

Background:

Epiphrenic diverticula are rare outpouchings of the distal esophagus that infrequently require surgical intervention for the treatment of symptoms. In cases where surgical therapy is indicated, the traditional approach is through a thoracotomy. Advances in minimally invasive techniques have led to thoracoscopic and more recently laparoscopic management of epiphrenic diverticula. The purpose of this article is to review the literature on minimally invasive surgery for epiphrenic diverticula with particular attention to the operative approach and technique, surgical mortality and morbidity, and symptomatic outcomes.

Methods:

A review of the literature limited to studies in the English language and performed on humans was conducted on PubMed using the following key words: “esophageal diverticula” and “epiphrenic”. Articles retrieved by the PubMed search were reviewed.

Conclusions:

A minimally invasive approach to epiphrenic diverticula offers reduced operative mortality, decreased length of stay, and similar symptom relief compared with open surgery in the hands of experienced laparoscopic surgeons.  相似文献   
106.

Background

Comprehensive preoperative appraisal of potential living renal donors is the key for selecting a proper donor and a suitable kidney.

Objective

To prospectively assess the diagnostic value of 16-slice multidetector computed tomography (MDCT) in preoperative appraisal of vascular anatomy in potential living renal donors.

Materials and methods

Preoperative angiography using a 16-slice MDCT scanner was performed in 68 consecutive potential living renal donors. The MDCT angiography included unenhanced and contrast-enhanced multiphasic scans. The MDCT images were reviewed for the number and branching pattern of the renal arteries and for the number and presence of major or minor variants of the renal veins. The results were compared with the actual anatomy at the open donor nephrectomy as the diagnostic standard of reference.

Results

The sensitivity and the specificity of MDCT angiography for the detection of various anatomic variants of renal arteries as well as renal venous anomalies were 100%. The anatomic variants of renal arteries included accessory arteries (n = 7) and early arterial branching (n = 10). Whereas, the detected venous anomalies were of major category of the circumaortic left renal vein anomaly (n = 2). No minor renal venous anomaly was identified in any subject.

Conclusion

16-Slice MDCT angiography is highly accurate for preoperative assessment of diverse anomalies of the renal vascular anatomy in potential living renal donors; in consequence, it markedly affects the surgical planning.  相似文献   
107.
OBJECT: Ibuprofen is an antiinflammatory drug that disrupts leukocyte-endothelial cell interactions by limiting expression of endothelial adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1), also known as CD54. The authors hypothesized that ibuprofen could reduce the size of the infarct associated with transient focal ischemia by inhibition of ICAM-1 expression, and they evaluated its effects in rats treated with middle cerebral artery (MCA) occlusion. Ibuprofen treatment was compared with mild systemic hypothermia, which is known to be neuroprotective and is commonly used during neurosurgical procedures. METHODS: The maximum ibuprofen dose (240 mg/kg/day) that could be tolerated with no systemic toxicity was established in the initial experiments. In the efficacy experiment, rats were pretreated with vehicle, ibuprofen, or hypothermia (33 degrees C) prior to 2 hours of MCA occlusion; then their brains were harvested at 24 hours of reperfusion for histological studies. End-ischemic cerebral blood flow (CBF) was evaluated using [14C]iodoantipyrine autoradiography in additional cohorts. Expression of ICAM-1 within ischemic compared with nonischemic caudate nucleus and putamen (striatum) or cortex was evaluated using immunohistochemical studies. Compared with vehicle treatment, ibuprofen produced a 46.2% reduction (p = 0.01) in striatal infarcts, which was comparable to hypothermia (48.7% reduction, p = 0.02). Ibuprofen did not alter end-ischemic CBF in any region studied, and the ibuprofen treatment group had the lowest proportion of animals with marked ICAM-1 staining. CONCLUSIONS: Ibuprofen given in maximum tolerated doses reduces the striatal infarct size after focal cerebral ischemia. The neuroprotective mechanism does not work through preservation of intraischemic CBF and is consistent with inhibition of ICAM-1 expression; however, at the doses used in this study, other effects of ibuprofen on platelet and endothelial function are possible.  相似文献   
108.
Disease status assessment of neuroblastoma patients requires computed tomography (or magnetic resonance imaging), bone scan, metaiodobenzylguanidine (MIBG) scan, bone marrow tests, and urine catecholamine measurements. There is no clinical experience concerning the evaluation of these patients by means of technetium-99m (99mTc)-somatostatin analog scintigraphy. Furthermore, these radiopharmaceuticals are promising imaging agents owing to their lower cost, availability, dosimetry, and ease of preparation. An 8-year-old boy already diagnosed with stage-IV neuroblastoma received chemotherapy. In the follow-up, after obtaining the parents’ informed consent, iodin 131 (131I)-MIBG and 99mTc-6-hydrazinopyridine-3-carboxylic acid (HYNIC)-octreotide scans were done on separate days to evaluate tumor extension. Even as the 131I-IBG scan showed mild diffuse uptake in the projection of both lung hili, the 99mTc-HYNIC-octreotide scan showed multiple axial and appendicular bone uptakes and paravertebral, abdominal, mediastinal, and supraclavicular ganglionar uptakes. The 99mTc-HYNIC-octreotide showed much more lesion extension than the 131I-MIBG. Therefore, 99mTc-HYNIC-octreotide may be a promising radiopharmaceutical for the evaluation of neuroblastoma patients. This finding justifies the pre liminary evaluation of this tracer in the context of a clinical trial.  相似文献   
109.
The Harmonic Scalpel (HS) is frequently used for hepatic resection. Yet, no current study addresses its utility compared to conventional methods. We reviewed our experience with this device to determine if it decreased perioperative complications when compared to the traditional clamp crushing technique. One hundred forty-nine anatomic hepatic resections were performed at our institution from September 1992 to February 2002. Patients were divided into two groups based on the technique of resection: HS [53% (n = 79)] versus clamp crushing [47% (n = 70)]. Use of the HS was associated with a shorter mean operative time (357 +/- 15.0 vs. 404 +/- 19.1 min; p = 0.05) and a trend toward decreased blood loss (1211 +/- 125.5 vs. 1411 +/- 180.7 mL; P = NS) and transfusion requirements (2.6 +/- 0.5 vs. 1.7 +/- 0.3 units; P = 0.10). However, use of the HS was associated with a significant increase in biliary fistulas [24% (n = 19) vs. 7% (n = 5); P = 0.01]. Use of the Harmonic Scalpel was associated with decreased operative time and a trend toward decreased blood loss and transfusion requirements. Its use was also associated with a significant increase in the incidence of postoperative bile leaks, and, therefore, surgeons must be vigilant during liver parenchymal transection when using this device.  相似文献   
110.
Clinical outcome of fractures of the talar body   总被引:1,自引:0,他引:1       下载免费PDF全文
Fractures of the talar body present a great challenge to surgeons due to their rarity and high incidence of sequelae. This study reports the medium-term results of displaced fractures of the talar body treated by internal fixation. Nineteen patients (13 M, 6 F, mean age 31) with talar body fractures were studied retrospectively to assess outcome after operative treatment. The fractures were classified as coronal (11), sagittal (6) and crush fractures (2). Six patients sustained open fractures and two had associated talar neck fractures. Average follow-up was 26 months (range: 18-43). Clinical outcome based on American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scoring was excellent function in four patients, good in six, fair in four and poor in five. Early complications included two superficial wound infections, one partial wound dehiscence, one instance of skin necrosis and one deep infection. Other complications included delayed union in one, avascular necrosis in seven and malunion in one patient. Talar injuries are serious because they can compromise motion of the foot and ankle and result in severe disability. Crush fractures of the talar body and those associated with open injuries and talar neck fractures are associated with a less favourable outcome.  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