全文获取类型
收费全文 | 2360284篇 |
免费 | 175856篇 |
国内免费 | 5086篇 |
专业分类
耳鼻咽喉 | 32312篇 |
儿科学 | 74662篇 |
妇产科学 | 65735篇 |
基础医学 | 337156篇 |
口腔科学 | 69569篇 |
临床医学 | 210361篇 |
内科学 | 455439篇 |
皮肤病学 | 51930篇 |
神经病学 | 184741篇 |
特种医学 | 90559篇 |
外国民族医学 | 406篇 |
外科学 | 360962篇 |
综合类 | 58580篇 |
现状与发展 | 6篇 |
一般理论 | 752篇 |
预防医学 | 178607篇 |
眼科学 | 56603篇 |
药学 | 174660篇 |
7篇 | |
中国医学 | 5573篇 |
肿瘤学 | 132606篇 |
出版年
2018年 | 25121篇 |
2017年 | 19301篇 |
2016年 | 21374篇 |
2015年 | 24510篇 |
2014年 | 34404篇 |
2013年 | 50868篇 |
2012年 | 69764篇 |
2011年 | 73512篇 |
2010年 | 43337篇 |
2009年 | 40571篇 |
2008年 | 68657篇 |
2007年 | 73542篇 |
2006年 | 73852篇 |
2005年 | 71147篇 |
2004年 | 68967篇 |
2003年 | 65807篇 |
2002年 | 63527篇 |
2001年 | 114664篇 |
2000年 | 117276篇 |
1999年 | 97711篇 |
1998年 | 26773篇 |
1997年 | 23714篇 |
1996年 | 23641篇 |
1995年 | 22599篇 |
1994年 | 20980篇 |
1993年 | 19562篇 |
1992年 | 76284篇 |
1991年 | 73954篇 |
1990年 | 71611篇 |
1989年 | 68921篇 |
1988年 | 63501篇 |
1987年 | 62180篇 |
1986年 | 58696篇 |
1985年 | 56128篇 |
1984年 | 42055篇 |
1983年 | 35870篇 |
1982年 | 21043篇 |
1981年 | 19038篇 |
1979年 | 39022篇 |
1978年 | 27437篇 |
1977年 | 23258篇 |
1976年 | 21576篇 |
1975年 | 23014篇 |
1974年 | 28115篇 |
1973年 | 27104篇 |
1972年 | 25510篇 |
1971年 | 23682篇 |
1970年 | 22249篇 |
1969年 | 21056篇 |
1968年 | 19410篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Steven V Koenen Anjoke J M Huisjes Jules Dings Yolanda van der Graaf Gerard H A Visser Hein W Bruinse 《The journal of maternal-fetal & neonatal medicine》2006,19(2):93-99
OBJECTIVE: To determine if there is a diurnal pattern in the clinical symptoms of HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) syndrome. STUDY DESIGN: A retrospective study was performed in 134 pregnancies complicated by HELLP syndrome. The medical records were reviewed to describe each HELLP episode. Time of day was divided into three periods, day, evening, and night. The following parameters were categorized according to the time of day: onset of symptoms, consultation by the doctor, initial blood sampling, diagnosis and decrease of symptoms. Biochemical parameters at clinical presentation and consecutive changes within 24 h were recorded. RESULTS: In 65 pregnancies 77 HELLP episodes were well documented. Times of onset of symptoms and consultation by the doctor were significantly higher during the evening and night (p < 0.001), whereas times of diagnosis and decrease of symptoms occurred significantly more during the day (p < 0.001). In only 49.3% of the cases were diagnostic laboratory criteria met at clinical presentation. This was mainly due to platelet values in excess of 100 x 10(9)/l. Several hours later (median 8 h, range 2-23) the decrease in platelets occurred. CONCLUSIONS: A diurnal pattern exists in the clinical symptoms of HELLP syndrome that is characterized by an exacerbation during the night and recovery during the day. There is a considerable delay between the onset of symptoms and the fulfillment of diagnostic laboratory criteria. 相似文献
23.
A Kotsiou M Tsamouri S Anagnostopoulou M Tzivras E Vairactaris C Tesseromatis 《European journal of drug metabolism and pharmacokinetics》2006,31(2):97-101
Liver disease alters the pharmacokinetic and pharmacodynamic properties of hepatically eliminated drugs. The main factors influenced are plasma albumin levels, enzyme balance (induction & inhibition) and drug binding to tissue proteins. The influence of lidocaine on serum, heart and liver propranolol levels in Wistar rats after liver injury induced by carbon tetrachloride CCl4 0.4 ml/kg x 2/wkl, was investigated. 40 male Wistar rats were divided into four groups (I, II, III, IV; n=10), Group I animals received only propranolol (labelled + cold substance) 40 mg/kg/12 h p.o., group II propranolol plus lidocaine in a single dose of 4mg/kg s.c., group III was treated with CCl4 for 6 weeks and received propranolol x2 at the same dosage as group I, while group VI was treated with CCl4 and the same drug dosage as group II. The simultaneous administration of H3-propranolol and lidocaine increased propranolol levels in the serum and tissues. The liver in damaged animals showed an increase of propranolol level under lidocaine co-administration, probably due to CCl4 induced liver enzyme activity, resulting in a rapid propranolol metabolism or to competition between both drug protein binding sites. The increased propranolol levels in the heart after lidocaine administration were probably due to attributed to its high affinity for heart tissue. Consequently, as regards the therapeutic approach for patients with liver disease receiving propranolol their propranolol dosage should be reduced when lidocaine is co-administered. 相似文献
24.
A-C Koschker M Fassnacht S Hahner D Weismann B Allolio 《Experimental and clinical endocrinology & diabetes》2006,114(2):45-51
BACKGROUND: Adrenocortical carcinoma (ACC) is a rare and highly malignant tumour with a poor prognosis. Patients present with signs of steroid hormone excess (e.g., Cushing's syndrome) or symptoms due to an abdominal mass. DIAGNOSIS: In case of an adrenal mass, hormonal workup before surgery is required for differential diagnosis, perioperative management, and for follow-up. The imaging of choice is CT or MRI with MRI being of additional use when invasion of big vessels is suspected. Apart from that, the use of 18-FDG-PET is becoming increasingly established. TREATMENT: Surgical resection is the therapeutic option of choice in stages 1 - 3. In stage 4, the adrenolytic compound mitotane is part of the first-line treatment, but often needs to be combined with cytotoxic chemotherapy. Most patients will eventually have a recurrence, so adjuvant treatment (mitotane/tumour bed radiation) has to be considered in high risk patients, even if randomized controlled trials on adjuvant treatment are still lacking. STRUCTURAL PROGRESS: Several national and European structures have recently been established in order to increase our knowledge of ACC, improve therapeutic options and diagnostic procedures, and promote research. GANIMED, as a Germany-wide network of experts on adrenal diseases, has been founded allowing for improved gathering of data and joint studies. ENSAT (European Network for the Study of Adrenal Tumours) has been brought to life, aiming at European standards for therapy, diagnosis and tumour banking. Since 2003, patients can be enrolled in the German ACC Registry. France and Italy have also developed a central registry to collect nationwide data from patients with ACC. For the first time, patients with metastatic/unresectable ACC can participate in a prospective controlled randomized trial comparing two different cytotoxic chemotherapy regimes (FIRM-ACT). 相似文献
25.
M Vitacca M Paneroni L Bianchi E Clini A Vianello P Ceriana L Barbano B Balbi S Nava 《The European respiratory journal》2006,27(2):343-349
The present study compared four different sites and conditions for the measurement of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) in 38 spontaneous breathing tracheotomised patients. Of the patients, 28 had chronic obstructive pulmonary disease (COPD). The four different conditions were: 1) through a cuff inflated cannula (condition A); 2) through the mouth with a deflated cannula (condition B); 3) through the mouth with a phonetic uncuffed cannula (condition C); and 4) through the mouth after stoma closure (condition D). Five trials in each condition were performed using a standardised method. The measurement of both MIP and MEP differed significantly depending on the condition of measurement. MIP taken in condition A was significantly higher when compared with conditions B, C and D. MEP in condition A was significantly higher when compared with condition B and D. In condition A the highest frequency of the best measurement of MIP and MEP was observed at the fourth and fifth effort, respectively. The same results were obtained after the selection of only COPD patients. In conclusion, respiratory muscle assessment differs significantly depending on measurement condition. Measurement through inflated cannula tracheotomy yields higher values of both maximal inspiratory and maximal expiratory pressure. 相似文献
26.
27.
In cystic fibrosis (CF), perturbations of total daily energy expenditure (TDEE) may be a major determinant of altered nutrition and growth. Measurement of TDEE is problematic, though the flex-heart rate method (FHRM) provides a close estimation of TDEE, as compared to the cost-prohibitive, gold standard, the double-labeled water method, and permits estimates of the energy cost of daily activities (ECA) above resting energy expenditure (REE). We hypothesize that alterations in ECA affects TDEE in CF. PURPOSE: To measure components of TDEE in adolescents with CF and normal lung function compared with controls, and to determine whether ECA can be improved by diet and exercise. METHODS: Clinically stable CF subjects (aged 9-13, n=12) and age- and gender-matched controls (n=13) had repeated measurements of TDEE by FHRM, REE, and maximal cardiopulmonary exercise testing (CPET) during a 6-week exercise and diet program. RESULTS: While the mean REE was similar in both groups, ECA was significantly lower in CF adolescents as compared to controls (p=0.02). During CPET, maximal exercise in CF was characterized by hyperventilation, which was unrelated to ventilation-perfusion mismatching. There were no changes in REE after dietary intervention. CONCLUSION: ECA in CF adolescents with normal lung function is lower when compared to healthy controls. These findings support the hypothesis that clinically stable patients with CF have inefficient energy metabolism or alternatively conserve energy during activities of daily living. 相似文献
28.
S. Spinty H. Rogozinski G. T. Lealman J. E. Wraith 《Journal of inherited metabolic disease》2003,25(8):697-698
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy. 相似文献
29.
30.