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   15088篇
  免费   708篇
  国内免费   22篇
耳鼻咽喉   513篇
儿科学   1274篇
妇产科学   514篇
基础医学   982篇
口腔科学   925篇
临床医学   1047篇
内科学   2764篇
皮肤病学   403篇
神经病学   955篇
特种医学   654篇
外科学   3385篇
综合类   104篇
一般理论   7篇
预防医学   464篇
眼科学   479篇
药学   798篇
中国医学   56篇
肿瘤学   494篇
  2024年   14篇
  2023年   186篇
  2022年   126篇
  2021年   286篇
  2020年   221篇
  2019年   288篇
  2018年   509篇
  2017年   423篇
  2016年   494篇
  2015年   381篇
  2014年   534篇
  2013年   784篇
  2012年   923篇
  2011年   1029篇
  2010年   553篇
  2009年   342篇
  2008年   913篇
  2007年   969篇
  2006年   982篇
  2005年   953篇
  2004年   955篇
  2003年   892篇
  2002年   876篇
  2001年   512篇
  2000年   592篇
  1999年   365篇
  1998年   104篇
  1997年   91篇
  1996年   80篇
  1995年   43篇
  1994年   38篇
  1993年   22篇
  1992年   29篇
  1991年   40篇
  1990年   26篇
  1989年   29篇
  1988年   24篇
  1987年   25篇
  1986年   23篇
  1985年   16篇
  1984年   15篇
  1983年   9篇
  1982年   5篇
  1981年   9篇
  1980年   8篇
  1979年   19篇
  1978年   12篇
  1977年   12篇
  1972年   9篇
  1970年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
It is well established that a condition of hypercoagulation due to deficiencies of antithrombin III, protein C and protein S may result in thrombo-embolism. To evaluate the possibility of hypercoagulation in acute mesenteric ischemia (AMI); clinical features, ECG changes, drug history, the length of intestine remaining after the resection and mortality of 15 consecutive patients were recorded and plasma levels of antithrombin III, Protein C and protein S were measured. Antihypertensive, antidiabetic and digitalis were the main drugs used by the patients. Atrial fibrillation was the main ECG finding (60%). AMI was attributed to thrombo-embolic phenomena because of atrial fibrillation in these patients. Levels of antithrombin III and protein S were lower in patients without atrial fibrillation compared to those with the condition (mean values 16.18 vs. 18.04 and 87.33 vs. 94.22 respectively) but the difference was not statistically significant. Levels of Protein C were lower and the length of intestine remaining after resection was shorter in patients without, compared to those with, atrial fibrillation (mean values 77.00 vs. 88.66, and 52.5 cm vs. 86.11 cm respectively). The difference was statistically significant (p < 0.05). Postoperative mortality rate was 33.3% (5 patients) and the length of intestine remaining after resection was the main determining factor in the prognosis of the patients. We conclude that a condition of hypercoagulation due to a deficiency of protein C has a significant role in the pathogenesis of AMI especially in patients without atrial fibrillation.  相似文献   
992.
Summary Osteomas of the paranasal sinuses are usually asymptomatic. When enlarged, they could give rise to intracranial manifestations and serious complications. Osteomas most commonly affect the fronto-ethmoid sinuses. They rarely show intra-orbital extension or cause intracranial complications such as CSF rhinorrhea, pneumocephalus and intracranial infection. We report two unusual cases of frontal osteomas complicated by rare manifestations such as intracranial mucocele, CSF leak, pneumocephalus and bacterial meningitis. We demonstrate the importance of these intracranial manifestations when these lesions are accompanied by neurological symptoms and signs with special emphasis on the importance of early treatment.  相似文献   
993.
The aim of this study was to evaluate the clinical effectiveness of distal forearm intravenous regional anaesthesia (IVRA) with the tourniquet applied 3 cm above the wrist. One hundred and twenty patients undergoing out-patient hand surgery were operated for 13 different hand problems under distal forearm IVRA, using 10 ml of a solution containing 1.5 mg/kg prilocaine. Sensory block onset time was 4.5 minutes (3.5-6.5 min.). Mean tourniquet time was 17.6 minutes (range, 7-27.5 min). Mean tourniquet pressure was 240 mmHg (range, 220-270 mm Hg). The mean VAS score for tourniquet pain was 3.8 (range, 2-10). No local or systemic side effects related to the IVRA were observed. The study showed that distal forearm IVRA using 10 ml of a solution containing 1.5 mg/kg prilocaine provides safe, rapid and effective anaesthesia for patients undergoing outpatient hand surgery.  相似文献   
994.
Kalayci M  Cağavi F  Gül S  Yenidünya S  Açikgöz B 《Acta neurochirurgica》2004,146(12):1347-54; discussion 1354
BACKGROUND: Intramedullary spinal cord metastases (ISCM) are rare but, with increasing use of magnetic resonance imaging (MRI) are being encountered with increasing frequency. Optimum treatment remains controversial. On the basis of a review of previous reports and experience with a patient with an ISCM from a large cell lung cancer, we propose practical diagnostic and therapeutic approaches. FINDINGS: We found 284 patients who had an Intramedullary spinal cord metastasis reported in English literature up to February 2004. 32 had been treated surgically. The mean survival in these patients was two times longer than in those treated by a conservative approach. Improvement and prolonged survival occurred in patient we treated by microsurgical dissection of the metastasis. CONCLUSION: Early diagnosis and early surgical resection can result in improvement in neurological deficits and in the quality of life of patients with a Intramedullary spinal cord metastasis.  相似文献   
995.

Background

Satisfactory neurologic outcome following aortic arch repair through right brachial artery perfusion is well established. However, how neurocognitive functions are affected following selective cerebral perfusion, still needs to be elucidated.

Methods

In a period between April 2002 and March 2003, 22 patients (19 male, 3 female, with a mean age of 46.8 ± 12; range: 26 to 70 years old), underwent aortic arch repair using right brachial artery low flow (8 to 10 mL · kg−1 · min−1) selective antegrade cerebral perfusion under moderate hypothermia (26°C). There were 6 Stanford type-A dissections and 16 ascending aortic aneurysms. All patients were evaluated preoperatively and postoperatively (at seventh day and second month) for neurocognitive functions.

Results

There was no operative mortality. The average cardiopulmonary bypass time was 115.0 ± 24.2 minutes and the average antegrade cerebral perfusion time was 29.8 ± 7.1 minutes (19 to 38 minutes). No major neurologic deficit was observed in the postoperative period. In terms of neurocognitive test results, between the preoperative and postoperative assessments for both hemispheric cognitive functions no deterioration was detected.

Conclusions

The low-flow selective antegrade cerebral perfusion technique through the right brachial artery may safely be used for the great majority of patients undergoing aortic arch repair without causing deteriorations in neurocognitive functions.  相似文献   
996.
The objective of the present study was to describe the relationship between some reproductive parameters, hormonal levels, and some biochemical properties of blood serum in rams under the Afyon province conditions. The total protein and globulin were positively (P < 0.01) correlated with sperm motility and sperm concentration in all of rams. Total lipid was negatively (P < 0.05) correlated with sperm motility and concentration in Daglic, and it was positively (P < 0.01) correlated with percentage of abnormal spermatozoa in Chios rams. Total lipid and cholesterol was positively (P < 0.01) correlated with triiodothyronine in all of rams and was negatively (P < 0.05) correlated with testosterone in Daglic rams. Percentage of abnormal spermatozoa were negatively (P < 0.01) correlated with alanine amino transaminase (ALT) level, but were positively (P < 0.01) associated with aspartate amino transaminase (AST) level and AST/ALT ratio in all of rams.  相似文献   
997.
Radiation injury attributable to radiotherapy is a topic that has attracted ample attention in the literature, especially in a vast number of publications in plastic surgery. However, the literature is clearly devoid of compilations regarding the effects of ionized radiation accidents. A case of a radiation accident is presented. It is nearly impossible to anticipate the extent of effects of external irradiation of the skin and subcutaneous tissues. The initially healed area should be expected to show late recurrent necrosis. Patients exposed to ionized external irradiation are no longer radioactive and can be treated as ordinary patients. However, these patients should be followed closely for years, keeping in mind the onset of late radiation effects like skin necrosis in various parts of the body, skin and other organ cancers, leukemia, infertility, hypothyroidism, and cataracts.  相似文献   
998.
Treatment for testicular tumours has progress in such a manner in the last years that high cure percentages can at present be achieved. After chemotherapy, in most cases, residual mass can appear. In this cases surgery is considered a viable therapeutic option although it implies an advanced surgical training since it is a complex technique and implies serious implications. We submit the case of a patient who presented a large residual mass from a testicular germ cell tumour after being treated with orquiectomía and chemotherapy. Surgery was performed resulting in total and radical extirpation of residual mass.  相似文献   
999.
Stab wound of the cervical spinal cord with ipsilateral vertebral artery injury is rare. We report a case of a penetrating injury by scissors to the cervical spinal cord and right vertebral artery. The management is discussed and literature reviewed.  相似文献   
1000.
Several urinary markers for transitional cell carcinoma have been investigated, including urine cytology, bladder tumor antigen, autocrine motility factor receptor and fibrin degradation products. Unfortunately, they have poor overall sensitivity. The United States Food and Drug Administration have recently approved nuclear matrix protein (NMP 22) for the detection of occult or rapidly recurring disease after transurethral resection of bladder tumor. The objective of the current study was to assess the sensitivity of NMP 22 for the detection of bladder carcinoma, as well as to correlate the NMP 22 values with multiplicity of tumor, tumor size, configuration, stage and grade respectively. A total of 78 patients (38 with bladder cancer) provided a urine sample which was divided into appropriate aliquots for each of urine cytology and NMP 22. Comparative results demonstrate a clear superiority of NMP 22 in bladder cancer detection (52.6% vs 31.6% sensitivity), while specificity was in favor of urine cytology (100% vs 82.5%). For superficial tumors, sensitivity was 78.5% for NMP 22 and 41.6% for cytology and for invasive cancers, sensitivity was 90% for NMP 22 and 60% for cytology. Urinary NMP 22 levels were significantly correlated with tumor grade and were significantly higher in large tumors than small tumors. NMP 22 test results showed sufficient sensitivity in comparison with urine cytology for the detection of transitional cell carcinoma. However, we do not think that it is a useful tool as a substitute for endoscopic examination for the detection and surveillance in bladder cancer.  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