全文获取类型
收费全文 | 7887篇 |
免费 | 430篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 93篇 |
儿科学 | 277篇 |
妇产科学 | 226篇 |
基础医学 | 1120篇 |
口腔科学 | 384篇 |
临床医学 | 749篇 |
内科学 | 1535篇 |
皮肤病学 | 276篇 |
神经病学 | 762篇 |
特种医学 | 414篇 |
外科学 | 1097篇 |
综合类 | 124篇 |
一般理论 | 10篇 |
预防医学 | 421篇 |
眼科学 | 56篇 |
药学 | 413篇 |
中国医学 | 9篇 |
肿瘤学 | 384篇 |
出版年
2021年 | 100篇 |
2020年 | 71篇 |
2019年 | 75篇 |
2018年 | 105篇 |
2017年 | 90篇 |
2016年 | 114篇 |
2015年 | 121篇 |
2014年 | 164篇 |
2013年 | 266篇 |
2012年 | 335篇 |
2011年 | 340篇 |
2010年 | 221篇 |
2009年 | 221篇 |
2008年 | 317篇 |
2007年 | 361篇 |
2006年 | 310篇 |
2005年 | 324篇 |
2004年 | 280篇 |
2003年 | 273篇 |
2002年 | 303篇 |
2001年 | 273篇 |
2000年 | 234篇 |
1999年 | 217篇 |
1998年 | 132篇 |
1997年 | 118篇 |
1996年 | 103篇 |
1995年 | 82篇 |
1994年 | 88篇 |
1993年 | 88篇 |
1992年 | 122篇 |
1991年 | 108篇 |
1990年 | 117篇 |
1989年 | 146篇 |
1988年 | 117篇 |
1987年 | 143篇 |
1986年 | 117篇 |
1985年 | 95篇 |
1984年 | 86篇 |
1983年 | 79篇 |
1982年 | 61篇 |
1981年 | 53篇 |
1978年 | 59篇 |
1977年 | 56篇 |
1976年 | 68篇 |
1975年 | 51篇 |
1973年 | 59篇 |
1971年 | 50篇 |
1969年 | 53篇 |
1968年 | 49篇 |
1966年 | 55篇 |
排序方式: 共有8350条查询结果,搜索用时 15 毫秒
1.
Alexandra B. Morshed Rachel G. Tabak Cynthia D. Schwarz Debra Haire-Joshu 《Journal of nutrition education and behavior》2019,51(2):237-244
Objective
To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.Methods
This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.Results
Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).Conclusions and Implications
Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program. 相似文献2.
3.
4.
Bernhard L mmle Mauro Berrettini Hans Peter Schwarz Mary Jo Heeb John B. Griffin 《Thrombosis research》1986,41(6):747-759
The immunoblotting technique was applied to the study of Factor XII (F.XII) in plasma. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole plasma followed by electroblotting of the electropherograms to nitrocellulose (NC) membranes and immunologic detection by a double antibody technique was used. 125-F.XII was transferred to the NC membrane in amounts proportional to the amount applied to the gel provided that a constant amount of carrier protein was present. Based on this, a quantitative assay was developed using either normal plasma or F.XII dilutions in F.XII-deficient plasma as standards. The measurement of F.XII antigen by immunoblotting was reproducible and gave values similar to those obtained by radial immunodiffusion. Two normal plasma pools contained 26 and 29 μ/ml of F.XII according to the immunoblotting assay. Compared to other immunoassays, immunoblotting has the advantage of directly estimating the apparent molecular weight (MW) of the protein of interest. Thus, we could confirm the normal apparent MW (80,000) of a F.XII-like molecule previously isolated from a cross reacting material (CRM)-positive F.XII-deficient plasma. None of eight CRM-negative F.XII-deficient plasmas showed an 80,000 MW immunoreactive molecule. However, five of these eight plasmas had a faint autoradiographic band at 115,000 MW that was similarly seen in only three out of 43 individual normal plasmas. The nature of this 115,000 MW band remains to be defined. 相似文献
5.
Cholangiocarcinomas (CC) frequently demonstrate lymphatic spread. We investigated lymph node (LN) counts after resection of
extrahepatic CC and survival based on the SEER 1973–2004 database. Out of 20,068 CC patients, 1,518 individuals were selected
based on M0 stage and at least one LN examined. Primary cancer sites included gallbladder (29%), extrahepatic bile ducts (26%),
and intrapancreatic/ampullary bile ducts (45%); 42% of patients were LN-positive. The median number of LNs examined was four
(range 1–39). Median survival was 37 months for LN-negative and 16 months for LN-positive cancers. Multivariate prognostic
variables were the number of positive LNs, primary site, age (all at p < 0.0001), gender (p = 0.002), size (p = 0.005), T category (p = 0.009), and total LN count (or number of negative LNs obtained, p = 0.01). The impact of total LN counts was seen in LN-negative (median survival, 1 vs 10 or more LNs examined: 27 vs 51 months,
p = 0.002) and LN-positive disease (10 vs 22 months, p < 0.0001). Survival prediction of extrahepatic CCs is strongly influenced by total LN counts and numbers of negative LNs
obtained. Although the resulting incremental benefit is small, dissection and examination of 10 or more LNs should be considered
for curative intent resections. 相似文献
6.
7.
8.
F Keller C Rehbein A Schwarz M Fleck A Hayasaka D Schuppan G Offermann E G Hahn 《Nephron》1988,50(4):332-337
Measurements of elevated procollagen III peptide (PIIIP) levels are used to monitor fibrosing activity in hepatic and various other diseases. Elevated PIIIP levels have also been reported in renal failure patients without such diseases. Therefore, the serum levels and renal clearance of PIIIP were investigated in 17 healthy volunteers and 100 patients with different types of acute (n = 15) and chronic (n = 85) kidney disease. PIIIP was measured by conventional and Fab radioimmunoassays. Median PIIIP levels in serum (18, range 5-55 ng/ml) and urine (34, range 1-110 micrograms/day) were significantly higher in kidney patients than serum (9, range 6-14 ng/ml) and urine levels (17, range 6-24 micrograms/day) in normal volunteers (p = 0.01). No significant differences (Kruskal-Wallis H test) were found, however, within the different kidney disease groups (acute, chronic/glomerulonephritis, interstitial nephritis). Median renal clearance of PIIIP-related peptides in kidney patients (1.5, range 0.5-2.4 ml/min) did not differ significantly (Wilcoxon U test) from that in normal volunteers (1.3, range 0.4-2.2 ml/min). These findings indicate that PIIIP elimination does not depend on renal function. PIIIP-related peptides in serum and urine, however, increase with renal failure irrespective of the activity or type of renal disease. This can be explained most probably by enhanced turnover of collagen type III by the affected kidney itself. 相似文献
9.
E. D. Chan L. S. Terada M. I. Schwarz 《Journal of the National Medical Association》1995,87(11):826-828
Although the leading causes of fever and pulmonary infiltrates in sickle cell patients are acute bacterial pneumonia and the acute chest syndrome, the former is usually responsive to antibiotics and not protracted, and the clinical course of the latter is short and self-limited. A patient with sickle cell anemia presented with fever and pulmonary infiltrates of several weeks duration that were unresponsive to antibiotics. Gross endobronchial abnormalities were noted on bronchoscopy, and the biopsies were consistent with sarcoidosis. The diagnosis of sarcoidosis can be difficult to establish in a patient with sickle cell anemia and protracted fever since both disorders are associated with chronic interstitial changes on the chest radiograph as well as restrictive physiology. 相似文献
10.