全文获取类型
收费全文 | 40903篇 |
免费 | 3094篇 |
国内免费 | 359篇 |
专业分类
耳鼻咽喉 | 706篇 |
儿科学 | 688篇 |
妇产科学 | 1031篇 |
基础医学 | 6259篇 |
口腔科学 | 1087篇 |
临床医学 | 4014篇 |
内科学 | 8490篇 |
皮肤病学 | 1212篇 |
神经病学 | 2992篇 |
特种医学 | 1994篇 |
外科学 | 5308篇 |
综合类 | 392篇 |
现状与发展 | 4篇 |
一般理论 | 9篇 |
预防医学 | 1750篇 |
眼科学 | 715篇 |
药学 | 3620篇 |
中国医学 | 535篇 |
肿瘤学 | 3550篇 |
出版年
2023年 | 308篇 |
2022年 | 984篇 |
2021年 | 1501篇 |
2020年 | 828篇 |
2019年 | 1227篇 |
2018年 | 1402篇 |
2017年 | 1115篇 |
2016年 | 1475篇 |
2015年 | 1959篇 |
2014年 | 2143篇 |
2013年 | 2574篇 |
2012年 | 3612篇 |
2011年 | 3423篇 |
2010年 | 2123篇 |
2009年 | 1728篇 |
2008年 | 2398篇 |
2007年 | 2154篇 |
2006年 | 1918篇 |
2005年 | 1822篇 |
2004年 | 1503篇 |
2003年 | 1310篇 |
2002年 | 1164篇 |
2001年 | 729篇 |
2000年 | 699篇 |
1999年 | 567篇 |
1998年 | 219篇 |
1997年 | 208篇 |
1996年 | 147篇 |
1995年 | 125篇 |
1994年 | 117篇 |
1993年 | 108篇 |
1992年 | 258篇 |
1991年 | 239篇 |
1990年 | 213篇 |
1989年 | 193篇 |
1988年 | 180篇 |
1987年 | 133篇 |
1986年 | 126篇 |
1985年 | 128篇 |
1984年 | 91篇 |
1983年 | 76篇 |
1981年 | 55篇 |
1979年 | 88篇 |
1978年 | 58篇 |
1977年 | 47篇 |
1975年 | 79篇 |
1973年 | 47篇 |
1972年 | 62篇 |
1971年 | 67篇 |
1970年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Kuo-Sheng Hung MD Phd Chung-Ling Liang MD Cheng-Haung Wang MD Hsueh-Wen Chang PhD Naeun Park MS Suh-Hang Hank Juo MD PhD 《Journal of clinical neuroscience》2004,11(8):849-853
Frontal intracerebral haemorrhage (ICH) is a common result of cranial trauma. Outcome differences between bilateral and unilateral frontal ICH are not well studied but would be valuable to predict prognosis in clinical practice. Two aims are proposed in this study: first to compare the risk of developing delayed ICH after bilateral or unilateral frontal ICH, and second to determine the variables helpful to predict outcome according to the Glasgow Outcome Scale (GOS). Between January 1993 and December 1997, 694 consecutive patients with traumatic ICH were admitted to the Chang Gung Medical Center within 24 h of the trauma. Patients with ICH in sites other than the frontal lobes were excluded. A total of 161 cases (mean age 46.3+/-20.3 years), including 57 bilateral (mean age 52.5+/-18.7 years) and 104 unilateral (mean age 42.9+/-20.5 years) traumatic frontal ICH were studied. Twenty-eight of 57 patients (49%) with bifrontal ICH versus 17 of 104 patients (16%) with unilateral frontal ICH had a further, delayed ICH. In 42 of 45 patients (93%) with delayed ICH, this occurred within 5 days of the initial trauma. Multivariate logistic regression was used to select significant predictors of outcome. We found that delayed ICH (p<0.001), age (p=0.004) and mechanism of injury (p=0.001) explained the worse outcome in patients with bifrontal ICH. The best-fitting logistic regression model included three variables: delayed ICH (p=0.011), initial GCS (p=0.023), and a sum score of clinical and radiological variables (p=0.003). Bifrontal ICH tended to occur in older patients after a fall and was associated with a higher risk of developing delayed ICH or brain stem compression compared to unilateral ICH damage. Using these three variables - delayed ICH, initial GCS, and the sum score - in a logistical regression model is useful to predict outcome in patients with traumatic frontal ICH and may aid patient management. 相似文献
22.
23.
24.
As an ongoing effort to elucidate the mechanisms involved in the calcium-dependent fertility regulation process, the viscoelastic properties of the mucus obtained from lamb cervix and human semen, as well as their water and total protein contents after exposure to EDTA, a chelating agent, or Nonoxynol-9 (N-9), a spermicidal agent, were examined. The viscosity was measured using a Cone Plate Digital Viscometer, while the water and total protein contents were determined by the lyophilization process and the Lowry method, respectively. The significant changes in the rheological properties of mucus, such as its viscosity and the water content, upon exposure to EDTA were demonstrated. The viscosity of cervical mucus and human semen were significantly increased by EDTA treatment (as compared to the controls): lamb cervical mucus (2.9 ± 0.3 vs. 2.2 ± 0.3 cps) and human semen (5.0 ± 0.3 vs. 4.3 ± 0.3 cps), respectively. The hydration rate was decreased by EDTA treatment as compared with the control (93.6 ± 0.7 vs. 96.8 ± 0.8%). Among tested samples, the reduction in the percentage of sperm penetration through the cervical mucus was the highest in the mucus containing EDTA, which had the lowest water content (93.6 ± 0.7%), indicating that there is a positive relationship between the hydration rate of the cervical mucus and its ability to permit the penetration of spermatozoa. This result indicates that spermicidal activity exerted by high concentrations of EDTA is in part due to its effect on the rheological properties of cervical mucus or semen. 相似文献
25.
26.
C Metzner W Hartig R Matkowitz H J Graubaum K Jung C Wagenknecht R Ritter 《Infusionstherapie und klinische Ern?hrung》1987,14(6):256-260
A reproducible liver lesion was caused in 28 pigs by intermittent, intraperitoneal administration of thioacetamide. The morphological degree of the liver lesion was checked by histological investigations (material drawn from the liver by biopsy). During a 3-day infusion period a so-called liver solution (Aminofusin hepar) was given to one group of animals, a normal solution (Infesol) to a second group, and only an electrolyte infusion solution under oral nutrition ad libitum to a third one. The solutions were labelled with (15N) glycine. The amounts of total N, total 15N, 15N with single non-protein fractions, a number of enzymes of 15N incorporated into the liver protein were measured in urine, and the following points were established: 1. The catabolic situation of metabolism is eliminated both by the so-called normal solution and the specific amino acid solution. The two mixtures of L-amino acids thus have a nutritive effect. 2. The toxic liver lesion is an indication for parenteral nutrition. Oral nutrition alone is not sufficient. 3. The so-called liver solution influences the liver metabolism of the protracted liver lesion more than the so-called normal solution does, and considerably more than an electrolyte infusion solution under oral nutrition ad libitum. 相似文献
27.
BACKGROUND AND PURPOSE: There are limited data on the pattern of cancer distribution among adolescents in Taiwan. This study evaluated the characteristics of these rare cancers in a medical center. METHODS: Analyses of the characteristics of malignant neoplasms for patients aged 14 to 17 years at diagnosis were performed for all cases recorded in the tumor registry of Chang Gung Memorial Hospital (CGMH) at Linkou for the period 1995 to 2001. All eligible tumors were categorized in 1 of 12 diagnostic groups according to the scheme of the International Classification of Childhood Cancer (ICCC). Relative frequencies, age, and gender variations and the characteristics of tumor types were analyzed. RESULTS: Cancer was diagnosed in 320 adolescents during the study period. The male/female ratio was 1.17. Leukemia was the leading diagnostic group. The frequency of carcinomas increased with age and was highest among 17-year-olds. In this age group, non-rhabdomyosarcoma soft tissue sarcoma/primitive neuroectodermal tumor (non-RMS STS/PNET), thyroid carcinoma (CA) and ovarian germ cell tumor (GCT) were the 3 most common solid tumors; the embryonal malignancies were rare. Tumors with the greatest male predominance were intracranial GCT (91%), nasopharyngeal CA (87.5%), osteosarcoma (84.6%), and colorectal CA (75%). Tumors with the greatest female predominance were thyroid CA (78.3%), gonadal GCT (75%), and non-RMS/PNET (56.5%). Hepatocellular CA comprised 9.4% of all carcinomas. CONCLUSIONS: The relative frequency and the distribution of histology subtypes among adolescents were between those of childhood and adult cancers. There were marked variations in tumor occurrence between genders and among different ages. 相似文献
28.
29.
30.
Chang Hyun Lee Jung-Gi Im Jin Mo Goo Hyun Ju Lee Sung-Tae Hong Cheng Hua Shen Doo Hyun Chung Kyu Ri Son Jung Min Chang Hong Eo 《Korean journal of radiology》2007,8(5):372-381
OBJECTIVE: To investigate the serial CT findings of Paragonimus westermani infected dogs and the microscopic structures of the worm cysts using Micro-CT. MATERIALS AND METHODS: This study was approved by the committee on animal research at our institution. Fifteen dogs infected with P. westermani underwent serial contrast-enhanced CT scans at pre-infection, after 10 days of infection, and monthly thereafter until six months for determining the radiologic-pathologic correlation. Three dogs (one dog each time) were sacrificed at 1, 3 and 6 months, respectively. After fixation of the lungs, both multi-detector CT and Micro-CT were performed for examining the worm cysts. RESULTS: The initial findings were pleural effusion and/or subpleural ground-glass opacities or linear opacities at day 10. At day 30, subpleural and peribronchial nodules appeared with hydropneumothorax and abdominal or chest wall air bubbles. Cavitary change and bronchial dilatation began to be seen on CT scan at day 30 and this was mostly seen together with mediastinal lymphadenopathy at day 60. Thereafter, subpleural ground-glass opacities and nodules with or without cavitary changes were persistently observed until day 180. After cavitary change of the nodules, the migratory features of the subpleural or peribronchial nodules were seen on all the serial CT scans. Micro-CT showed that the cyst wall contained dilated interconnected tubular structures, which had communications with the cavity and the adjacent distal bronchus. CONCLUSION: The CT findings of paragonimiasis depend on the migratory stage of the worms. The worm cyst can have numerous interconnected tubular channels within its own wall and these channels have connections with the cavity and the adjacent distal bronchus. 相似文献