全文获取类型
收费全文 | 15223篇 |
免费 | 999篇 |
国内免费 | 254篇 |
专业分类
耳鼻咽喉 | 218篇 |
儿科学 | 332篇 |
妇产科学 | 733篇 |
基础医学 | 1939篇 |
口腔科学 | 267篇 |
临床医学 | 1628篇 |
内科学 | 3223篇 |
皮肤病学 | 372篇 |
神经病学 | 936篇 |
特种医学 | 476篇 |
外科学 | 2326篇 |
综合类 | 443篇 |
现状与发展 | 2篇 |
一般理论 | 3篇 |
预防医学 | 763篇 |
眼科学 | 286篇 |
药学 | 1139篇 |
中国医学 | 102篇 |
肿瘤学 | 1288篇 |
出版年
2023年 | 79篇 |
2022年 | 237篇 |
2021年 | 435篇 |
2020年 | 220篇 |
2019年 | 330篇 |
2018年 | 420篇 |
2017年 | 290篇 |
2016年 | 296篇 |
2015年 | 460篇 |
2014年 | 586篇 |
2013年 | 734篇 |
2012年 | 1106篇 |
2011年 | 1091篇 |
2010年 | 703篇 |
2009年 | 575篇 |
2008年 | 876篇 |
2007年 | 928篇 |
2006年 | 806篇 |
2005年 | 838篇 |
2004年 | 701篇 |
2003年 | 578篇 |
2002年 | 540篇 |
2001年 | 481篇 |
2000年 | 422篇 |
1999年 | 355篇 |
1998年 | 134篇 |
1997年 | 116篇 |
1996年 | 101篇 |
1995年 | 78篇 |
1994年 | 72篇 |
1993年 | 52篇 |
1992年 | 182篇 |
1991年 | 170篇 |
1990年 | 145篇 |
1989年 | 125篇 |
1988年 | 109篇 |
1987年 | 122篇 |
1986年 | 101篇 |
1985年 | 84篇 |
1984年 | 75篇 |
1983年 | 58篇 |
1980年 | 38篇 |
1979年 | 58篇 |
1978年 | 49篇 |
1977年 | 42篇 |
1976年 | 39篇 |
1975年 | 38篇 |
1974年 | 47篇 |
1972年 | 59篇 |
1971年 | 35篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Propionic acidemia is a rare hereditary disease which is an autosomal recessive disorder. Defect of propionyl CoA carboxylase results in abnormal accumulation of propionate and its metabolites which interfere the pathway of glycine cleavage and the urea cycle. This organic acidemia is characterized by a wide spectrum of clinical and biochemical findings, including recurrent vomiting, difficult feeding, lethargy, hypotonia, metabolic ketoacidosis, hyperglycinemia and hyperammonemia during the acute episodes. We present a male newborn infant who sustained this disorder and was managed successfully with blood exchange transfusion, peritoneal dialysis, supplemented with sodium benzoate and sodium bicarbonate therapy. Urine gas chromatography disclosed significant elevation of propionate and its metabolites which subsided 2 days after peritoneal dialysis. Special designed formula was then given with restriction of protein intake and supplement with sodium benzoate and sodium carbonate. Prenatal genetic counseling is necessary in further pregnancy. Diagnosis can be obtained when propionyl CoA carboxylase activity is low in cultured amniotic fluid cells or chorion villi sample or when there is abnormally high methylcitrate level in amniotic fluid. 相似文献
12.
Ming-I. Hsu Paul Kolm John Leete Ke Wen Dong Suheil Muasher Sergio Oehninger 《Journal of assisted reproduction and genetics》1998,15(8):496-503
Purpose:
Our purpose was to examine implantation of singleton pregnancies achieved following various assisted reproductive technologies (ARTs) through the appearance and rising titers of serum human chorionic gonadotropin (hCG) levels.
Methods:
A total of 114 singleton pregnancies resulting from in vitro fertilization and intrauterine insemination was analyzed. Patients were divided into five groups according to the type of ovarian stimulation protocol [gonadotropin stimulation with/without the use of gonadotropin-releasing hormone agonist (GnRHa), long protocol, or flare-up technique] and to the day of embryo transfer (day 2 or day 3 after oocyte retrieval). Serial serum hCG levels were measured between 10 and 25 days after fertilization and log-transformed. Linear regression analyses were performed and extrapolated to hCG = 10 mIU/ml (hCG
10
), which was used as an estimate of detectable implantation. The slopes of the regression lines were used to estimate the rising speed of hCG.
Results:
There were no significant differences in the days of hCG in maternal serum to reach 10 mIU/ml (implantation) or in the slopes of the regression lines for all five studied groups.
Conclusions:
The appearance of hCG in maternal serum was used to assess the time of clinically detectable implantation. Furthermore, because hCG production is a marker of trophoblastic activity, its serum doubling time was used as an indicator of embryo quality. Results showed that in various ART protocols with and without GnRHa, there were no significant differences in implantation time or embryo quality. Embryo development in early pregnancy follows a preprogrammed-timing schedule and depends mainly on the embryonic age of the health, successfully implanted conceptus. 相似文献
13.
Philip Harber Laura Pea Paul Hsu Elizabeth Billet Deborah Greer Katty Kim 《American journal of industrial medicine》1994,25(4):519-526
Back pain among nurses is a common problem. Prior studies of this problem have been based on cross-sectional or retrospective data. This 18-month prospective study involving nurses newly graduated from nursing school investigated personal, worksite, and training factors associated with future risk of back pain. Each nurse underwent a preliminary interview and periodic follow-ups to identify those with back injuries. Contingency tables and logistic regression analyses demonstrated that prior significant back pain episodes (evidenced by previous job changes because of back pain, frequent medication use, etc.) were associated with increased future risk. Training at nursing school or on the job did not have a protective effect. This pilot study therefore suggests factors useful in placement and counseling of new nurses and indicates the need for further implementation of mechanical lift assist device use. © 1994 Wiley-Liss, Inc. 相似文献
14.
We present two case studies, one of generalized chorea and one of hemichorea, both after severe hypoglycemia episodes. Both cases showed hyperperfusion in their SPECT scans. The MRI and SPECT findings serve as clues regarding the role of basal ganglion dysfunction associated with chorea. 相似文献
15.
16.
A new diterpene antitumor antibiotic, myrocin C, has been isolated from the culture filtrate of a soil fungus, Myrothecium verrucaria strain No. 55. The antibiotic was effective against Gram-positive bacteria, fungi and yeasts, and prolonged the life span of mice bearing Ehrlich ascites carcinoma. 相似文献
17.
18.
Primary megaureter presents a spectrum of findings ranging from mild, clinically unimportant, stable ureterectasis to severe, progressive obstructive hydroureteronephrosis. We report a patient with a double uterus and ipsilateral renal dystrophy. A previous imaging study had revealed a double uterus and obstructed left hemivagina, into which a single vaginal ectopic ureter inserted. On follow-up intravenous urography 8 years later, the left kidney was non-functioning, and there was segmental dilation of the distal right ureter. Transvaginal sonography with real-time scanning and Doppler were useful in exploring the morphological and functional status of this dilated distal ureter. 相似文献
19.
20.
The significance of a rapid cold hemagglutination test for detecting mycoplasma infections in children with asthma exacerbation. 总被引:5,自引:0,他引:5
Ya Ting Chang Yao Hsu Yang Bor Luen Chiang 《Journal of microbiology, immunology, and infection》2006,39(1):28-32
BACKGROUND AND PURPOSE: Mycoplasma pneumoniae infection is a frequent cause of community-acquired respiratory infections in children and adults. However, standardized, rapid, specific methods for its diagnosis are lacking. The relationship between M. pneumoniae infection and asthma exacerbation has been recently discussed in the literature. We investigated the accuracy of rapid detection of mycoplasma infection by cold hemagglutination test compared to conventional enzyme immunoassays. The clinical characteristics of mycoplasma infection seen during emergent visits in asthmatic children were reviewed. METHODS: We retrospectively reviewed medical records of patients with asthma exacerbation visiting the Department of Pediatric Emergency, National Taiwan University Hospital, over a 12-month period. Subjects 2-18 years of age diagnosed with asthma at our outpatient clinic were included in this study. Patients with immunodeficiency, congenital anomalies, neurological diseases and irregular follow-up were excluded. RESULTS: A total of 269 children (174 males and 95 females) with a mean (+/- standard deviation) age of 6.15 +/- 3.08 years were included. The prevalence of asthma exacerbation in regular follow-up patients was 13.4%, and as many as 19.6% of cases (74/378 person-times) required hospitalization. Asthma attacks were most prevalent during December. 126 patients had both rapid cold hemagglutination testing and mycoplasma immunoglobulin M titers determined using acute blood samples drawn in the emergency room; 46 (36.5%) of these patients demonstrated mycoplasma infection. Sensitivity and specificity of the rapid cold hemagglutination test was 78.3% and 41.3%, respectively. The positive predictive value was 43.4%. Comparison of patients with or without mycoplasma infection revealed no differences in gender, age, chest X-ray findings, and most symptoms/signs and laboratory data, except that more signs of fever and auscultatory rales were seen in the non-mycoplasma infection group. CONCLUSIONS: Mycoplasma infections could be an exacerbating factor for asthma, and the rapid cold hemagglutination test should not be a guideline for prescribing macrolides in the emergency room. 相似文献