全文获取类型
收费全文 | 16928篇 |
免费 | 769篇 |
国内免费 | 137篇 |
专业分类
耳鼻咽喉 | 169篇 |
儿科学 | 375篇 |
妇产科学 | 123篇 |
基础医学 | 2144篇 |
口腔科学 | 305篇 |
临床医学 | 1076篇 |
内科学 | 4519篇 |
皮肤病学 | 447篇 |
神经病学 | 1387篇 |
特种医学 | 538篇 |
外科学 | 2707篇 |
综合类 | 46篇 |
一般理论 | 4篇 |
预防医学 | 371篇 |
眼科学 | 618篇 |
药学 | 1125篇 |
中国医学 | 28篇 |
肿瘤学 | 1852篇 |
出版年
2023年 | 94篇 |
2022年 | 205篇 |
2021年 | 445篇 |
2020年 | 215篇 |
2019年 | 271篇 |
2018年 | 345篇 |
2017年 | 272篇 |
2016年 | 370篇 |
2015年 | 414篇 |
2014年 | 503篇 |
2013年 | 611篇 |
2012年 | 1092篇 |
2011年 | 1148篇 |
2010年 | 683篇 |
2009年 | 578篇 |
2008年 | 1001篇 |
2007年 | 1147篇 |
2006年 | 1077篇 |
2005年 | 1213篇 |
2004年 | 1196篇 |
2003年 | 1057篇 |
2002年 | 1098篇 |
2001年 | 188篇 |
2000年 | 136篇 |
1999年 | 220篇 |
1998年 | 291篇 |
1997年 | 216篇 |
1996年 | 220篇 |
1995年 | 195篇 |
1994年 | 167篇 |
1993年 | 176篇 |
1992年 | 99篇 |
1991年 | 88篇 |
1990年 | 91篇 |
1989年 | 82篇 |
1988年 | 58篇 |
1987年 | 43篇 |
1986年 | 44篇 |
1985年 | 41篇 |
1984年 | 43篇 |
1983年 | 36篇 |
1982年 | 42篇 |
1981年 | 40篇 |
1980年 | 33篇 |
1979年 | 31篇 |
1978年 | 35篇 |
1977年 | 25篇 |
1976年 | 12篇 |
1975年 | 12篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 656 毫秒
41.
Masamitsu Endo Kouichirou Kobayashi Makoto Tsubota Masahiro Seki Hideo Sato Tasuku Noto Takashi Iwa 《Surgery today》1996,26(1):1-4
This study was conducted to compare the midline incision right retroperitoneal approach for repairing abdominal aortic aneurysms (AAA) with the transperitoneal approach. The intra- and postoperative course of 15 patients who underwent AAA repair using the transperitoneal approach between 1987 and 1991 and another 15 patients who underwent AAA repair using the retroperitoneal approach between 1991 and 1994 were evaluated. The incidence of postoperative wound complications was also assessed. There was no operative or hospital death in either group. Although a significantly longer interval was required from the incision to the aortic clamp using the extraperitoneal method, there were no statistical differences in the aortic clamping time, total operation time, or blood loss between the two groups. On the other hand, there was a statistically significant improvement in bowel function and a significant reduction in the length of postoperative hospitalization following the extraperitoneal procedure. Furthermore, no wound complications such as those associated with the left flank incision developed after the extraperitoneal procedure. Thus, we recommend the midline incision right retroperitoneal approach for AAA as it does not involve muscle division and is associated with fewer complications. 相似文献
42.
Yuka Sakazume Makoto Tanaka Itsuo Isobe Rika Tominaga Eiji Nanba Koichi Okamoto 《Clinical neurology》2004,44(8):541-544
We reported a patient with middle-aged onset sialidosis type I. A 52-year-old Japanese man was referred to our hospital because of dysarthria, involuntary movement of his extremities and gait disturbance since the age of 46 years. On admission, neurological examination revealed scanning speech, action myoclonus, cerebellar ataxia and cherry-red spots. Vacuolated lymphocytes were found in peripheral blood. Brain 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) showed decreased glucose metabolism in the cerebellum. Enzymological analysis using his skin fibroblasts revealed primary deficiency of sialidase activity. Sialidase gene analysis identified compound heterozygotes for base substitusions of 239T-to-C and 649G-to-A, which resulted in amino acid alterations of P80L and V217M, respectively. These mutations have been reported in Japanese sialidosis type II (P80L) and I (V217M). Further studies are required to reveal effects of gene mutations on residual enzyme activities and phenotypes. 相似文献
43.
44.
45.
MASAHIKO NAKASONO MITSUYOSHI HIROKAWA NAOKI MUGURUMA SEISUKE OKAMURA SUSUMU ITO AKIKO IGA SATOSHI WADA MICHIYO OKAZAKI TAKAHIRO HORIE TAMOTSU FUKUDA TOSHIAKI SANO 《Journal of gastroenterology and hepatology》2006,21(1):65-70
Background: Colonic pseudolipomatosis is rare and the pathogenesis is controversial. The purpose of the present paper was to clarify endoscopic and histological characteristics of colonic pseudolipomatosis and to discuss the etiology. Methods: A total of 15 lesions from 14 patients was reviewed. They were able to be histologically classified into two groups on the basis of variety in size of the vacuoles: Group A, the ratio of largest vacuole to smallest vacuole in size is less than three, Group B, the ratio is more than four. Results: Four of 15 lesions were group A, and were endoscopically polypoid or flat lesions covered with normal‐looking mucosa. They were microscopically characterized by (i) predominant location in the upper portion of the lamina propria; (ii) no submucosal involvement; (iii) less variation in vacuolar size; and (iv) no association with lymph follicles. The vacuoles of group A contained proteinaceous materials in two of four lesions. Group B (11 lesions) had small elevated mucosa with normal‐looking surface or non‐elevated reddish mucosa. Microscopically, the lesions were mainly located in the lower portion of the lamina propria, occasionally also in the submucosa, had variable‐sized vacuoles, and were related to lymph follicles. Conclusion: It is suggested that the vacuoles in group A contain fluid, and may indicate an abnormal stagnation of interstitial fluid. Microscopic appearance of group B is essentially similar to that of pneumatosis coli. It is thought that group B probably results from penetration of gas from the crypts into the mucosa during colonoscopy. It is unclear why group B had a preference for ileocecal valve and an association with lymph follicles. 相似文献
46.
Newborn infant with maternal anti-SSA antibody-induced complete heart block accompanying cardiomyopathy. 总被引:2,自引:0,他引:2
Newborn case of maternal anti-SSA antibody-induced congenital complete heart block (CCHB) accompanying cardiomyopathy is presented. Unexpectedly, she died of ventricular tachycardia, not bradycardia, 6 days after birth. Autopsy revealed left ventricular cardiomyopathy with endocardial fibroelastosis. Thus, when evaluating fetal cardiac performance in cases of maternal anti-SSA antibody-induced CCHB, it is necessary to pay attention to myocardial attributes such as endocardial hyperplasia. 相似文献
47.
The threshold beta-ray energy for Cerenkov photon production can be reduced to about 0.07 MeV by using a transparent ceramic with a high refractive index. This makes it possible to measure the low-energy beta-emitters 14C and 45Ca by Cerenkov counting with efficiencies of 1.5% and 2.3%, respectively. 相似文献
48.
Health-related quality of life among persons living in Japan with a permanent colostomy. 总被引:2,自引:0,他引:2
Naomi Ito Makoto Tanaka Keiko Kazuma 《Journal of wound, ostomy, and continence nursing》2005,32(3):178-83; quiz 184-5
OBJECTIVE: To compare the health-related quality of life (HRQOL) of persons with a permanent colostomy to that of the general Japanese population and explore the factors influencing HRQOL. DESIGN: A cross-sectional survey. SETTING AND SUBJECTS: A total of 255 persons with an ostomy who attended a meeting of the Japan Ostomy Association in the Kanto region of Japan. INSTRUMENTS: The HRQOL was assessed using Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), Japanese version 1.2. Factors potentially influencing the HRQOL were age, sex, marital status, employment status, number of people in the household, time since colostomy, and diagnosis. METHODS: Questionnaires were distributed to the subjects and SF-36 scores were determined and compared with the corresponding national-norm data by Wilcoxon signed rank sum test. A logistic regression analysis was used to explore the influencing factors. RESULTS: The questionnaire response rate was 66.7%. Subjects with a urostomy or an ileostomy and those with missing data were excluded. Data from 102 subjects with a permanent colostomy were analyzed. The subjects' scores were significantly lower than the national-norm scores in the role-physical and social functioning scales. Being employed was associated with significantly lower scores or associated with a tendency toward lower scores. CONCLUSIONS: Scores in two scales in these subjects were lower than those of national-norm scores. Being employed had a negative impact on the HRQOL of subjects with a permanent colostomy. The results of this study provide reference data for future research and underscore the importance of support for persons with a colostomy. 相似文献
49.
Dose-Related Effects of the Hepatocarcinogen, Wy-14,643, on Peroxisomes and Cell Replication 总被引:3,自引:3,他引:0
Dose-Related Effects of the Hepatocarcinogen, Wy-14,643, onPeroxisomes and Cell Replication. WADA, N., MARSMAN, D. S.,AND POPP, J. A. (1992). Fundam. Appl. Toxicol. 18, 149154. The dose and time dependency of peroxisome proliferation andhepatocyte replication was evaluated in the liver of rats fedthe peroxisome proliferator and hepatocarcinogen, Wy-14,643.Male F344 rats were fed NIH07 diet blended with Wy-14,643 at0, 5, 10, 50, 100, or 1000 ppm for 1, 3, 6, or 13 weeks. Hepatomegalywas induced by Wy-14,643 at all doses and at all time points.Peroxisome proliferation was present in rats fed 5 ppm Wy-14,643as early as 1 week, as determined by the peroxisome-specificNAD+ reduction of palmitoyl CoA (PCO) and the peroxisome-associatedactivity of carnitine acetyltransferase (CAT) (5-and 11-foldover control, respectively). The elevations of PCO and CAT weredose-dependent from 5 to 50 ppm and then plateaued from 50 to1000 ppm throughout the treatment period. Hepatocellular replication,evaluated by nuclear histoautoradiography ([3H]thymidine labeling,6-day infusion), was increased in all Wy-14,643 dose groupsafter 1 week of treatment (5 ppm, 4-fold; 10 ppm, 5-fold; 50ppm, 13-fold; 100 ppm, 12-fold; and 1000 ppm, 13-fold over controls).However, in 5 and 10 ppm groups this cell replication returnedto control levels by 3 weeks. In contrast, 50, 100, and 1000ppm groups had sustained increases in cell replication up to13 weeks (13 weeks: 6-, 7-, and 9-fold over controls, respectively).We have demonstrated that Wy-14,643 can induce peroxisome proliferationat 5 ppm, a dose 200 times lower than the dose shown to be highlyhepatocarcinogenic in rats (100% incidence by 60 weeks). Incontrast, 50 ppm was identified as the minimal dose which inducedsustained cell replication in rat liver. These data show thatperoxisome proliferation can be dissected from sustained cellreplication for correlating either peroxisome induction or cellreplication with tumor formation. These results provide importantinformation that can be used to design carcinogenicity experimentsto test if peroxisome proliferation and/or chronic enhancementof cell replication predictive risk factors for hepatocarcinogenieity. 相似文献
50.
Heat Flow and Distribution during Epidural Anesthesia 总被引:43,自引:0,他引:43