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   1278篇
  免费   100篇
  国内免费   15篇
耳鼻咽喉   32篇
儿科学   38篇
妇产科学   25篇
基础医学   96篇
口腔科学   51篇
临床医学   143篇
内科学   223篇
皮肤病学   37篇
神经病学   51篇
特种医学   66篇
外国民族医学   1篇
外科学   187篇
综合类   78篇
预防医学   85篇
眼科学   38篇
药学   127篇
  1篇
中国医学   28篇
肿瘤学   86篇
  2023年   13篇
  2022年   27篇
  2021年   44篇
  2020年   35篇
  2019年   34篇
  2018年   43篇
  2017年   28篇
  2016年   45篇
  2015年   30篇
  2014年   39篇
  2013年   67篇
  2012年   60篇
  2011年   78篇
  2010年   45篇
  2009年   34篇
  2008年   47篇
  2007年   65篇
  2006年   83篇
  2005年   68篇
  2004年   62篇
  2003年   53篇
  2002年   59篇
  2001年   47篇
  2000年   44篇
  1999年   49篇
  1998年   15篇
  1997年   19篇
  1996年   18篇
  1995年   11篇
  1994年   8篇
  1993年   8篇
  1992年   13篇
  1991年   5篇
  1990年   11篇
  1989年   5篇
  1988年   5篇
  1987年   5篇
  1986年   5篇
  1985年   5篇
  1984年   9篇
  1983年   4篇
  1980年   4篇
  1978年   4篇
  1975年   2篇
  1974年   3篇
  1973年   2篇
  1972年   3篇
  1971年   2篇
  1969年   8篇
  1967年   3篇
排序方式: 共有1393条查询结果,搜索用时 31 毫秒
91.
BACKGROUND: Hematopoietic growth factors (HGFs) have been used to reduce the neutropenic complications of cytotoxic chemotherapy so that higher doses may be given. The authors have previously shown that endogenous serum granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) levels at night (p.m.) were significantly higher than those in the morning (a.m.). METHODS: Twenty-four patients with soft tissue or bone sarcoma who were treated with high dose ifosfamide-based chemotherapy were enrolled in this study. Patients were randomized to either a.m. or p.m. treatment. GM-CSF was administered at a dose of 5 microg/kg/day at 10 a.m. or 10 p.m., beginning 36-48 hours after the last chemotherapy dose. GM-CSF therapy was continued until the neutrophil count exceeded 1,000/mm3 for 2 consecutive days. Leukocyte, neutrophil, monocyte, and platelet counts were measured immediately before GM-CSF administration and exactly 12 hours after the first dose of GM-CSF, and every 24 hours until 3 days after the cessation of GM-CSF. RESULTS: The mean duration of Grade 3-4 neutropenia was 5.3 +/- 0.4 days for the a.m. treatment arm and 6.5 +/- 0.3 days for the p.m. treatment arm (P = 0.017). Although the duration of neutropenia in the a.m. arm was significantly shorter than in the p.m. arm, there were no differences related to the number of febrile neutropenic episodes or the duration of antibiotic administration. Also, there were no differences in the side effects observed in the a.m. and p.m. arms. CONCLUSIONS: The finding of 1.2 days' difference in the duration of Grade 3-4 neutropenia warrants further study of chronotherapy with HGFs.  相似文献   
92.
Mitomycin C prevents strictures in caustic esophageal burns in rats   总被引:2,自引:0,他引:2  
BACKGROUND: Caustic esophageal injuries lead to stricture formation. Although a number of agents have been tried experimentally to prevent strictures, few have gained clinical application. The purpose of this study was to investigate the effectiveness of Mitomycin C (MMC), which inhibits fibroblastic proliferation in preventing caustic esophageal strictures. MATERIAL AND METHODS: Fifty-six rats were allocated into four groups. Caustic esophageal burns were created as described by Gehanno. Group A was instilled only with saline. Group B was injured and untreated. Groups C and D were injured and received topical MMC at 0.02 and 0.04% concentrations, respectively. At 28 days, stenosis index (SI), collagen deposition, and hydroxyproline content (HP) were determined in distal esophageal segments. Statistical analyses were done. RESULTS: Mean SI in Group B was significantly higher than others (P < 0.05). Mean SI was statistically higher in Group C than A and D and similar between groups A and D. The greatest accumulation of collagen was found in Group B, followed by Group C, D, and A, respectively. Collagen deposition in Group D was statistically lower than Group B (P < 0.01) and similar to Group C. Mean HP in Group B was statistically higher than others (P < 0.05), significantly higher in Group C than Group D (P = 0.047), and similar between Groups A and D (P = 0.73). CONCLUSION: MMC was effective in preventing strictures following experimental caustic esophageal injury, in a dose-dependent manner. We consider that it can gain clinical utilization with the establishment of effective mode, dose, and timing of therapy.  相似文献   
93.
94.
Summary Background To investigate dietary habits and evaluate these with regard to cardiovascular risk status in Turkish adolescents aged 12–19 years. Methods A total of 300 adolescents, 135 males and 165 females aged between 12 and 19, were included in the study. Dietary intake was determined by using 3–day food records (including 1 weekend day). Adolescents smoking habits and familial chronic diseases were recorded. The values obtained for energy and nutrient intakes were compared with RDA and DRI and recommendations given by AHA. Results The mean energy intakes of male and female subjects were 1964 ± 723 kcal and 1804 ± 486 kcal respectively. According to NHANES III, age–standardized (CDC: Centers for Disease Control and Prevention) prevalence of overweight indicated that 20.7% among male and 17.5% among female adolescents were at risk for becoming overweight. The prevalence of premature CHD family history was found to be 9.6% for males and 11.5 % for females. The prevalence of current smoking was found to be 22.2 % for males and 18.2 % for females. In addition, 29.6% of the males and 37.6% of the females were physically inactive (p < 0.05); however, male adolescents (48.2%) were significantly more likely than female adolescents (52.1 %) to report sufficient moderate physical activity (p < 0.05). The dietary fiber intake was slightly below the recommended intake of 10 g per 1000 kcal. Compared to the AHA averages, these adolescents had significantly higher intake of total fat, saturated fat, sodium and dietary cholesterol and lower intake of polyunsaturated fat, monounsaturated fat and dietary fiber. The Turkish adolescents also had higher amounts of energy from fat. The mean percentage of energy from fat was 34.2 ± 6% TE for males and 35.2 ± 6.8 % TE for females; saturated fat was 11.8 ± 6.8 % TE for males and 12.1 ± 8.9 for females. The intake of fat and saturated fat was higher than the AHA recommendations. The polyunsaturated to saturated fat ratio was 0.4 ± 0.2 and reflected a high saturated fat (12.0 ± 7.7% TE) and low polyunsaturated fat (5.5 ± 3.9 % TE) diet. In addition, the percentage of adolescents who did not meet 66% of RDA for vitamin E, B6, and folates and the recommendation for RDA dietary fiber is presented. Approximately, 80% of adolescents failed to meet the dietary recommendation of the AHA for polyunsaturated fatty acids, and about 26.7% reported a cholesterol intake higher than 100 mg/1000 kcal. Conclusion It can be said that fiber, total fat, saturated fatty acid, cholesterol and sodium intake of Turkish adolescents are found to be high; however, their vitamin E, vitamin B6 and folate intake are found to be low compared to AHA recommendations. Turkish adolescents fruit and vegetable intake are also found to be low.  相似文献   
95.
Three cases of cerebral salt wasting complicating tuberculous meningitis are described. Diagnosis was based on hyponatraemia associated with high urinary sodium excretion and inappropriately high urine output in the presence of dehydration. Treatment with fludrocortisone resulted in sodium and fluid homeostasis.  相似文献   
96.
BACKGROUND AND AIM: The biliary tract has been referred to as the "Achilles heel" of liver transplantation. The aim of this study was to document the frequency, clinical presentation and management of biliary complications after liver transplantation in the King Faisal Specialist Hospital and Research Center (KFSH&RC), Riyadh, Saudi Arabia. METHODS: The liver transplant clinic at KFSH&RC has registered and followed 220 patients (150 male and 70 female patients; age 40.6 +/- 18.6 years; pediatric 33, adult 187) during the period from 1987 to June 2003. A total of 235 transplants were carried out on these patients. Cadaveric liver transplants had been carried out on 202 patients, non-heart beating liver transplant in three patients, live donor liver transplants in 11 and split transplant in four. Biliary reconstruction was duct-to-duct anastomosis in 147 patients and Roux-en-Y in 73. Biliary complications were suspected on clinical and biochemical parameters and confirmed using imaging techniques. RESULTS: Forty patients (18.2%) developed 53 biliary complications. These included bile leak in 16, strictures in 25, calculi in eight, and sphincter of Oddi dysfunction and possible recurrence of primary sclerosing cholangitis in the donor duct in two patients each. Bile leaks were observed in the early postoperative period (median period 30 days, range 1-150 days, 95% confidence interval [CI] 8-51). Leakage occurred at the anastomotic site in 13 patients. Patients presented with bilious drainage (n = 6), abdominal pain at T-tube removal (n = 3), fever (n = 2), sepsis (n = 1), dyspnea (n = 1) and abnormal liver tests (n = 3). Eleven patients had intra-abdominal bilious collections. Two patients were treated conservatively, eight patients had ultrasound-guided aspiration of biloma, five had biliary stenting at endoscopic retrograde cholangiopancreatography and two patients needed surgery. There were four deaths, two of which were related to bile leak, one patient was left with permanent external biliary drainage and four patients had biliary strictures in the follow-up period. Biliary strictures occurred at a median period of 360 days (range 4-2900 days; 95% CI 50-670) after the transplant. Hepatic artery thrombosis caused biliary strictures in three, while 21 strictures were localized to the anastomotic site. Biliary strictures presented with elevated liver tests in five patients, progressive cholestasis in five, cholangitis (with septicemia in five) in 11, abdominal pain in two and acute pancreatitis in three patients. Repeat sessions of endoscopic or percutaneous dilatation and stenting (mean sessions 4.4/patient, range 3-7) were attempted in 20 patients to relieve strictures, with success in only nine patients. Seven patients had surgery. Four patients with biliary strictures died. Biliary calculi developed late in the follow-up period and had the appearance of biliary casts in five and sludge in three patients. Eleven (27.5%) patients with biliary disease died compared with 35 (19.4%) patients without biliary disease. CONCLUSIONS: Biliary complications occurred in 18.2% of patients after liver transplantation and included biliary leak and biliary strictures with or without calculi. Management involved a combination of endoscopic, radiologic and operative procedures. Biliary complications caused considerable morbidity and mortality in liver transplant patients.  相似文献   
97.
Preoperative hookwire localization of breast lesions is a well established technique to aid surgeons in localizing breast tumors. We describe the innovative use of a standard hookwire with CT guidance to localize an intraperitoneal inclusion cyst.  相似文献   
98.
Summary One of the mechanisms of injury in varicocele has been proposed to be elevated nitric oxide (NO). We aimed to determine the association between the elevation of NO and lipid oxidation in varicocele compared with peripheral venous levels of these two substances as it has not been studied before. The study group consisted of 13 adolescents with left idiopathic varicocele of grades II-III. Blood specimens were obtained from dilated spermatic and peripheral veins simultaneously. Peripheral samples were also collected from 13 healthy children as controls. Nitrite/nitrate levels (NO(x)) and levels of malonedialdehyde (MDA) were determined using Griess reaction and thiobarbituric acid test, respectively. Results were compared with Kruskal-Wallis and Mann-Whitney tests. Peripheral NO(x) and MDA were the same in the study and control groups (p = 0.069 and p = 0.27, respectively). Spermatic vein NO(x) and MDA levels were elevated significantly compared with the peripheral levels in the study group (p = 0.005 and p = 0.048, respectively). Increased NO(x) levels with lipid oxidation occur locally in adolescent varicocele, implying that these events could be reversed by early treatment.  相似文献   
99.
Purpose This work was carried out to follow up the healing of full-thickness incision wounds opened on the back skin of rabbits in order to gain insight into the periodical correlation among such factors as ascorbic acid, collagen (hydroxyproline), the zinc content, and tensile strength of wound tissue. The need to provide vitamin C or zinc supplements after such wound incisions is also discussed.Methods Full-thickness incision wounds and the ascorbic acid and hydroxyproline levels were measured in 24 rabbits by spectrophotometric methods on day 0 and on the 3rd, 5th, 7th, and 15th days after operation. The tensile strength was measured by a polygraph using a force displacement transducer. The zinc levels of the wounds were measured by atomic absorption spectrophotometry.Results The zinc and hydroxyproline levels reached the peak levels on the 5th day, but the tensile strength of wound increased sharply on the 7th day after wounding while the zinc levels did not change. These results indicated that in the first 7 days of wound healing, high levels of ascorbic acid, hydroxyproline, and zinc cumulation occurred in the wound tissue, and the tensile strength reached its highest level on the 15th day without any supplementation.Conclusion The supplementation of zinc and/or ascorbic acid should therefore be given just at the beginning of the wounding period, especially if there is deficiency of these nutrients.  相似文献   
100.
In this study, catalase enzyme was immobilized by entrapping in alginate beads in the presence of gelatin. In the optimization studies of the bioactive layer immobilized some parameters such as enzyme amount, alginate, gelatin, and crosslinking agent glutaraldehyde amount were determined as 700 U/mL, 2.0%, 18 mg/mL, and 5.0%, respectively. Effects of pH and temperature on the immobilization were also investigated. In the characterization studies of the immobilized enzyme storage and thermal stability experiments were done. The immobilized enzyme was used for the decomposition of hydrogen peroxide in milk samples and also by using a catalase biosensor prepared by the decomposition level of hydrogen peroxide was detected.  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