全文获取类型
收费全文 | 222528篇 |
免费 | 1577篇 |
国内免费 | 87篇 |
专业分类
耳鼻咽喉 | 1731篇 |
儿科学 | 7749篇 |
妇产科学 | 4056篇 |
基础医学 | 24858篇 |
口腔科学 | 2012篇 |
临床医学 | 14947篇 |
内科学 | 39835篇 |
皮肤病学 | 1204篇 |
神经病学 | 19748篇 |
特种医学 | 10697篇 |
外科学 | 38337篇 |
综合类 | 2889篇 |
一般理论 | 11篇 |
预防医学 | 21089篇 |
眼科学 | 3264篇 |
药学 | 11992篇 |
中国医学 | 644篇 |
肿瘤学 | 19129篇 |
出版年
2022年 | 130篇 |
2021年 | 296篇 |
2020年 | 173篇 |
2019年 | 256篇 |
2018年 | 24529篇 |
2017年 | 19702篇 |
2016年 | 22988篇 |
2015年 | 1315篇 |
2014年 | 1262篇 |
2013年 | 1385篇 |
2012年 | 8186篇 |
2011年 | 23886篇 |
2010年 | 20774篇 |
2009年 | 13367篇 |
2008年 | 23579篇 |
2007年 | 27404篇 |
2006年 | 1442篇 |
2005年 | 3941篇 |
2004年 | 5548篇 |
2003年 | 7375篇 |
2002年 | 4936篇 |
2001年 | 778篇 |
2000年 | 1089篇 |
1999年 | 541篇 |
1998年 | 469篇 |
1997年 | 531篇 |
1996年 | 359篇 |
1995年 | 338篇 |
1994年 | 355篇 |
1993年 | 314篇 |
1992年 | 349篇 |
1991年 | 330篇 |
1990年 | 361篇 |
1989年 | 349篇 |
1988年 | 297篇 |
1987年 | 315篇 |
1986年 | 251篇 |
1985年 | 294篇 |
1984年 | 221篇 |
1983年 | 224篇 |
1982年 | 216篇 |
1981年 | 158篇 |
1980年 | 265篇 |
1979年 | 233篇 |
1978年 | 178篇 |
1977年 | 137篇 |
1976年 | 162篇 |
1974年 | 105篇 |
1938年 | 99篇 |
1932年 | 111篇 |
排序方式: 共有10000条查询结果,搜索用时 134 毫秒
11.
12.
We report a case of intestinal obstruction in a 73-year-old woman caused by ileocolic intussusception. The underlying cause was a giant submucosal ulcerating lipoma (6?×?3.3?×?3.8 cm) extending from the superior mucosal lip of Bauhin’s valve. Abdominal ultrasonography showed a pathognomonic target-like mass appearing as multiple concentric rings. CT scan confirmed the diagnosis. Because of apparent obstruction, a laparotomy with right hemicolectomy and ileocolic anastomosis was performed. Lipomas most frequently occur in the cecum and ascending colon where they represent the most common submucosal mesenchymal tumor. They typically occur in elderly women with an incidence that varies from 0.15 to 0.56 %. Pain, rectal bleeding, and obstruction are typical symptoms. When faced with an intussusception in children, reduction with air per rectum can be performed. In adults, however, malignant cell spreading and seeding is of big concern. Since approximately 20–50 % of all underlying causes are malignant, explorative surgery is favored in adults. 相似文献
13.
14.
Henry Havel Gregory Finch Pamela Strode Marc Wolfgang Stephen Zale Iulian Bobe Hagop Youssoufian Matthew Peterson Maggie Liu 《The AAPS journal》2016,18(6):1373-1378
Advancing nanomedicines from concept to clinic requires integration of new science with traditional pharmaceutical development. The medical and commercial success of nanomedicines is greatly facilitated when those charged with developing nanomedicines are cognizant of the unique opportunities and technical challenges that these products present. These individuals must also be knowledgeable about the processes of clinical and product development, including regulatory considerations, to maximize the odds for successful product registration. This article outlines these topics with a goal to accelerate the combination of academic innovation with collaborative industrial scientists who understand pharmaceutical development and regulatory approval requirements—only together can they realize the full potential of nanomedicines for patients. 相似文献
15.
16.
M. Alexandra Friedman Charlotte M. Niznik Janelle R. Bolden Lynn M. Yee 《Journal of community health》2016,41(2):354-358
While peer support has been investigated in multiple clinical contexts, its application to the postpartum setting is unknown. The aim was to assess acceptability of a postpartum peer support program for women with diabetes. Observational survey-based needs assessment of forty low-income women with diabetes, receiving care at a major medical institution. Mean age and gravidity were 30.7 years and 3.15 ± 1.67 respectively. 45 % expressed interest in a “buddy.” There was no significant difference between groups desiring and not desiring this program. A majority of respondents desired telephone, text messaging, and in-person contacts (79.2, 72.1, 83.8 %), with 72.5 % of patients desiring diabetes-related activities during clinic waiting time. Many women desire a postpartum diabetes reciprocal peer program for support outside of clinician visits. Patients are receptive to educational services during their wait and outside of clinic time, a potentially valuable opportunity to share important health information. 相似文献
17.
18.
I. D. Petrova V. S. Petrov S. V. Seregin E. M. Malkova 《Molecular Genetics, Microbiology and Virology》2015,30(4):186-191
This paper presents an analysis of samples from 75 patients for the presence of rubella virus, viral RNA, and specific antibodies. For all samples, RNA detection was higher than virus isolation. It was found that it was not possible to isolate rubella virus in every sixth clinical sample containing the viral RNA. Primary structures of the site (from the 8072nd to 8291st nucleotide) of the rubella virus genome from 14 samples were determined. This paper shows that all the samples of rubella virus belong to the first genotype, subgroups 1h, and very likely to subgroups 1a and 1F. For the first time, the circulation of rubella virus of the genotype has been shown both prior to the start of mass vaccination in Western Siberia and after. 相似文献
19.
Konrad Matyja Anna Małachowska-Jutsz Anna K. Mazur Kazimierz Grabas 《Ecotoxicology (London, England)》2016,25(5):924-939
Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (TMDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and TMDTE are more appropriate than EC50 and IC50 for toxicity assessments, except for long exposure times. 相似文献
20.