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   332篇
  免费   9篇
  国内免费   2篇
儿科学   2篇
妇产科学   1篇
基础医学   19篇
口腔科学   3篇
临床医学   22篇
内科学   74篇
神经病学   92篇
特种医学   11篇
外科学   52篇
综合类   10篇
预防医学   15篇
眼科学   1篇
药学   27篇
中国医学   1篇
肿瘤学   13篇
  2019年   2篇
  2016年   2篇
  2014年   3篇
  2013年   6篇
  2012年   8篇
  2011年   17篇
  2010年   9篇
  2009年   6篇
  2008年   9篇
  2007年   13篇
  2006年   15篇
  2005年   16篇
  2004年   12篇
  2003年   12篇
  2002年   6篇
  2001年   6篇
  2000年   8篇
  1999年   5篇
  1998年   4篇
  1997年   4篇
  1996年   3篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1992年   7篇
  1991年   11篇
  1990年   9篇
  1989年   13篇
  1988年   18篇
  1987年   4篇
  1986年   12篇
  1985年   4篇
  1984年   5篇
  1983年   6篇
  1982年   5篇
  1981年   5篇
  1980年   7篇
  1979年   7篇
  1978年   5篇
  1977年   7篇
  1976年   7篇
  1975年   8篇
  1974年   11篇
  1973年   3篇
  1972年   2篇
  1971年   1篇
  1970年   5篇
  1969年   3篇
  1968年   1篇
  1967年   1篇
排序方式: 共有343条查询结果,搜索用时 15 毫秒
1.
A prospective longitudinal study was performed to evaluate the vertebral body replacement system Synex associated with posterior fixation in unstable burst fractures of the lumbar and thoracic spine. Within 24 months, we treated 28 patients (average age, 41 years; range, 22–64 years; 14 women, 14 men) with acute unstable burst fractures without osteoporosis of the thoracolumbar region (n=16) and the thoracic (n=3) as well as the lumbar (n=9) spine in two stages (primary dorsal transpedicular stabilization and secondary vertebral body replacement). The complications were analyzed and the postoperative follow-up result was evaluated regarding stability, bone fusion, correction loss, pain and neurological status. One patient showed a transient irritation of the lumbosacral plexus and one patient had a superficial wound infection (complication rate, 7.1%). At the follow-up examination (mean follow-up, 13 months) only in two cases a minimal loss of correction (<5°) was measured. Radiologically, 27 patients showed secure bone fusions and all patients had stability of the osteosynthesis. Most of the patients stated no or just slight pain at follow-up. Only two patients with pain to a medium degree had to take painkillers. The vertebral body replacement system Synex seems to be a good alternative for vertebral body replacement in unstable burst fractures of the thoracic and lumbar spine since at present follow-up it shows a high rate of bone fusion and minimal loss of correction.  相似文献   
2.
Barnett  MJ; Zussman  WV 《Radiology》1986,160(1):223-225
Granulocytic sarcoma (chloroma), a rare tumor usually associated with myelogenous leukemia, is capable of invading the meninges or brain parenchyma. Radiologic findings in a case of granulocytic sarcoma of the brain, as well as those in 11 previously reported cases of intracranial leukemic masses, are interpreted. On computed tomographic scans, the lesions can appear isodense or hyperdense, edema and necrosis are variable, and there is uniform enhancement following intravenous administration of contrast material. There may be some affinity for the posterior fossa.  相似文献   
3.
Limited efficacy of chemotherapy in most solid tumors has revived interest in immunotherapeutic approaches for cancer. One novel form of immunotherapy is the use of cancer vaccines consisting of tumor cells genetically engineered to secrete cytokines. The rationale for this immunization strategy is based on the existence of tumor-specific antigens, on the importance of the cellular arm of the immune system in mediating an effective antitumor response, and on the role of cytokines in regulating the cellular immune response. Such tumor vaccines showed considerable promise in various animal models and induced potent antitumor immunity in the host, which led to regression of established tumors and, moreover, produced immunological memory protecting animals from a subsequent tumor challenge at a distant site. Translated to the human patient, this implies that genetically modified tumor vaccines may be able to eradicate or reduce existing tumor deposits to subclinical levels as well as provide long-term protection from regrowth of tumor cells. This report will review and discuss the concept and rationale for the use of cytokine-secreting tumor vaccines for the treatment of human malignancies.  相似文献   
4.
Using the peroxidase-antiperoxidase (PAP) technique it could be established that a variety of nerve cells of human Pons and Medulla oblongata contain proctolin-like material. These neurons belong to the Nuc. olivaris caudalis, Nuc. originis n. hypoglossi, Nuc. raphes dorsalis and the Nuc. ambiguus. Furthermore, proctolin immunoreactive peptide was found to be contained in certain fiber systems (Lemniscus medialis and fiber tracts near the Raphe).  相似文献   
5.
G Wagner  B Voigt  H Vieweg 《Die Pharmazie》1984,39(4):226-230
The headline compounds were prepared from purified cyanophenylalanines after presenting arylsulfonylglycyl residues, activation of the carboxyl group by formation of the p- nitrophenylester followed by aminolysis and transfer of a cyano in an amidine function. Besides some esters and an acid were synthetized with the basic structure mentioned in the headline . The p-compounds with a cycloaliphatic amide component proved as "tight binding inhibitors". The greatest antithrombin effect shows N alpha-(2- naphthylsulphonylglycyl )-4- amidinophenylalaninpiperidi d with a Ki-value of 6 X 10(-9) mol/l using S-2238 as a substrate.  相似文献   
6.
Vieweg U  Meyer B  Schramm J 《Surgical neurology》2000,54(3):203-10; discussion 210-1
BACKGROUND: A single-institution series of injuries of the upper cervical spine are analyzed retrospectively and the literature relevant to the topic is reviewed. METHODS: Seventy patients (34 female, 36 male, mean age 47 years) were admitted during a 5-year period for injuries of the upper cervical spine. Sixty-five were followed for a mean time of 18 months. Three isolated ligamentous instabilities, 6 isolated C1 fractures, 3 complex C2 fractures, 10 combined C1/C2, and 48 C2 fractures (17 hangman's, 31 odontoid) were diagnosed. Twenty-nine patients were treated conservatively and for 41 patients surgery was the primary treatment. Twenty-three ventral odontoid screw fixations, 8 ventral platings and 10 dorsal stabilizations were performed. Stability was evaluated using flexion-extension radiography. Pain levels and neurological outcome were assessed. RESULTS: Operative mortality and neurological morbidity were 0%. Two wound infections and 3 instabilities (17%) in odontoid Type II fractures primarily treated with ventral odontoid screw fixation needed dorsal restabilization. During follow-up examinations the neurological status of three patients was improved. In 62 patients preoperative status was attained. Six patients evaluated their pain as severe, two as disabling. CONCLUSIONS: Candidates for surgery as the primary treatment include those with isolated ligamentous instabilities, Type III hangman's fractures and Type II odontoid fractures with dislocation more than 5 mm. In combined C1/C2 fractures the axis fracture dictates the treatment strategy. Patients who undergo dorsal procedures and have involvement of C1 have a greater chance of developing persistent pain.  相似文献   
7.
BACKGROUND/AIM: Gastroesophageal reflux disease (GERD) is a prevalent disease associated with a high symptom burden and a reduced quality of life. This multicenter, randomized, double-blind study compared relief from key GERD symptoms (heartburn, acid eructation, and pain on swallowing) and from other gastrointestinal symptoms (epigastric pain, vomiting, nausea, flatulence, retching, and retrosternal feeling of tightness) and safety profiles of the proton pump inhibitor pantoprazole and the H2 antagonist ranitidine in patients suffering from symptomatic GERD. METHODS: The patients [338 intention-to-treat (ITT) population; 284 per-protocol (PP) population] received 20 mg pantoprazole (once daily in the morning) plus ranitidine placebo (once daily in the evening; ITT n = 167, PP n = 136) or pantoprazole placebo (once daily in the morning) plus 300 mg ranitidine (once daily in the evening; ITT n = 171, PP n = 148) for 28 days. The primary efficacy criterion (ITT and PP populations) was relief from key GERD symptoms (heartburn, acid eructation, and pain on swallowing) after 28 days of treatment. Secondary criteria (PP) included relief from key GERD symptoms on day 14, relief from all gastrointestinal symptoms on days 14 and 28, and relief from key GERD symptoms on days 14 and 28. Safety evaluations included adverse events and laboratory assessments. RESULTS: Significantly more pantoprazole-treated patients were free from key GERD symptoms at day 28 (68.3%, n = 114) as compared with ranitidine-treated patients (43.3%, n = 74; 95% confidence interval for odds ratio 1.84-4.51). Pantoprazole was also significantly more efficacious in controlling all gastrointestinal symptoms of GERD. By day 28, 51.5% (n = 70) of the pantoprazole-treated patients were completely symptom free versus 31.1% (n = 46) of the ranitidine-treated patients (95% confidence interval for odds ratio 1.45-3.83). Both treatments were well tolerated. CONCLUSION: Pantoprazole is significantly superior to ranitidine in the treatment of key and associated gastrointestinal symptoms of GERD and is well tolerated.  相似文献   
8.
The distribution and severity of coronary artery disease and left ventricular dysfunction were evaluated in 103 patients with single coronary artery disease and angina pectoris. The coronary arterial patterns were separated into right (76), mixed (18), and left (9) systems depending upon the blood supply to the inferior surface of the left ventricle. The following relationships were noted: (1) In patients with single coronary artery disease and angina pectoris, coronary arterial lesions are similar among right, mixed, and left systems. (2) In order of frequency, single coronary artery disease occurred most commonly in the left anterior descending coronary artery (55), next most commonly in the right coronary artery (36), and least commonly in the circumflex/obtuse marginal coronary artery (12). (3) Left ventricular wall motion abnormalities were seen in descending order of frequency: patients with right coronary artery (50%), left anterior descending coronary artery (36%), and circumflex/obtuse marginal coronary artery (25%) disease.  相似文献   
9.
Bone strength, a key determinant of fracture risk, has been shown to display clear sexual dimorphism after puberty. We sought to determine whether sex differences in bone mass and hip bone geometry as an index of strength exist in school‐age prepubertal children and the degree to which the differences are independent of body size and lean mass. We studied 3514 children whose whole‐body and hip scans were measured using the same densitometer (GE‐Lunar iDXA) at a mean age of 6.2 years. Hip dual‐energy X‐ray absorptiometry (DXA) scans underwent hip structural analyses (HSA) with derivation of bone strength indices. Sex differences in these parameters were assessed by regression models adjusted for age, height, ethnicity, weight, and lean mass fraction (LMF). Whole‐body bone mineral density (BMD) and bone mineral content (BMC) levels were 1.3% and 4.3% higher in girls after adjustment by LMF. Independent of LMF, boys had 1.5% shorter femurs, 1.9% and 2.2% narrower shaft and femoral neck with 1.6% to 3.4% thicker cortices than girls. Consequent with this geometry configuration, girls observed 6.6% higher stresses in the medial femoral neck than boys. When considering LMF, the sexual differences on the derived bone strength indices were attenuated, suggesting that differences in muscle loads may reflect an innate disadvantage in bone strength in girls, as consequence of their lower muscular acquisition. In summary, we show that bone sexual dimorphism is already present at 6 years of age, with boys having stronger bones than girls, the relation of which is influenced by body composition and likely attributable to differential adaptation to mechanical loading. Our results support the view that early life interventions (ie, increased physical activity) targeted during the pre‐ and peripubertal stages may be of high importance, particularly in girls, because before puberty onset, muscle mass is strongly associated with bone density and geometry in children. © 2015 American Society for Bone and Mineral Research.  相似文献   
10.
OBJECTIVE: Obesity is a major health problem among children and adolescents which is potentially affected by socioeconomic status (SES). The high risk group (HRG) comprises those youths with a body mass index (BMI) between the 85th and 95th percentile (at risk for overweight) and > or = 95th percentile (overweight). We sought a potential link between the HRG and SES. METHODS: Public schools in Chesterfield County, Virginia measured BMI among students in kindergarten and third, seventh, and tenth grades. We assessed SES based on eligibility for the National School Lunch Program and the percentage of the school-age population living in poverty based on per capita income from the 2000 Census. RESULTS: From 28 to 38% of children and adolescents were in the high risk group. Low SES had robust and highly significant correlations with HRG status with r-values ranging from 0.565 to 0.842, P < 0.0001. CONCLUSIONS: Low SES appears to be an important factor in childhood and adolescent obesity.  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