全文获取类型
收费全文 | 3258308篇 |
免费 | 226036篇 |
国内免费 | 8441篇 |
专业分类
耳鼻咽喉 | 44809篇 |
儿科学 | 107925篇 |
妇产科学 | 90280篇 |
基础医学 | 458321篇 |
口腔科学 | 89593篇 |
临床医学 | 296241篇 |
内科学 | 633505篇 |
皮肤病学 | 78031篇 |
神经病学 | 263620篇 |
特种医学 | 125664篇 |
外国民族医学 | 918篇 |
外科学 | 485991篇 |
综合类 | 65440篇 |
现状与发展 | 6篇 |
一般理论 | 1175篇 |
预防医学 | 246006篇 |
眼科学 | 73744篇 |
药学 | 243400篇 |
13篇 | |
中国医学 | 7089篇 |
肿瘤学 | 181014篇 |
出版年
2019年 | 25497篇 |
2018年 | 36035篇 |
2017年 | 27891篇 |
2016年 | 32224篇 |
2015年 | 36161篇 |
2014年 | 49638篇 |
2013年 | 74244篇 |
2012年 | 99049篇 |
2011年 | 104718篇 |
2010年 | 63006篇 |
2009年 | 60175篇 |
2008年 | 97599篇 |
2007年 | 103839篇 |
2006年 | 105704篇 |
2005年 | 101322篇 |
2004年 | 97355篇 |
2003年 | 93915篇 |
2002年 | 90684篇 |
2001年 | 159347篇 |
2000年 | 163401篇 |
1999年 | 137515篇 |
1998年 | 38864篇 |
1997年 | 34494篇 |
1996年 | 34689篇 |
1995年 | 33512篇 |
1994年 | 30534篇 |
1993年 | 28642篇 |
1992年 | 106378篇 |
1991年 | 102417篇 |
1990年 | 99590篇 |
1989年 | 96347篇 |
1988年 | 88010篇 |
1987年 | 85998篇 |
1986年 | 80894篇 |
1985年 | 76970篇 |
1984年 | 57115篇 |
1983年 | 48133篇 |
1982年 | 28291篇 |
1981年 | 25074篇 |
1979年 | 50564篇 |
1978年 | 35263篇 |
1977年 | 30597篇 |
1976年 | 27779篇 |
1975年 | 30124篇 |
1974年 | 35366篇 |
1973年 | 33748篇 |
1972年 | 31863篇 |
1971年 | 29628篇 |
1970年 | 27242篇 |
1969年 | 26231篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Upper gastrointestinal (GI) bleeding remains a significant cause of mortality and morbidity among renal transplant recipients. We retrospectively analyzed the records of patients who received renal transplantations between January 2001 and July 2007 using mycophenolate mofetil (MMF) in their immunosuppressive regimens. The following data were recorded for those subjects with upper GI bleeding during the first month after transplantation (group B, cases): age, sex, acute rejection episodes, pretransplant upper GI endoscopic findings, Helicobacter positivity, and cytomegalovirus (CMV) seropositivity. The same parameters were studied among a group of patients, who did not have a history of upper GI bleeding (group A, controls). A statistical analysis was performed to ascertain potential risk factors. Among 523 patients (311 females, 212 males) of age range 7 to 58 years, 27 (5.2%) had upper GI bleeding: 13 males and 14 females of mean age 44 ± 12 years. The most frequent endoscopic finding was erosive gastritis (n = 13; 48.1%) followed by duodenal ulcers. Binary logistic regression analysis comparing the 2 groups showed that acute rejection episodes (P = .015) and active CMV infection (P = .046) were the most prominent risk factors for upper GI bleeding during the first month after renal transplantation. 相似文献
992.
993.
R. Pezzilli A.M. Morselli-Labate D. Campana R. Casadei E. Brocchi R. Corinaldesi 《Pancreatology》2009,9(4):375-382
Aims: To explore the quality of life in patients treated medically during the acute phase of pancreatitis as well as at 2 and 12 months after discharge from the hospital. Patients: 40 patients were studied. The etiology of the pancreatitis was biliary causes in 31 patients and non-biliary causes in 9; mild disease was present in 29 patients and severe disease in 11. 30 patients completed the two surveys at 2 and 12 months after hospital discharge. Methods: The SF-12 and EORTC QLQ-C30 questionnaires were used for the purpose of the study. Results: The two physical and mental component summaries of SF-12, all the domains of EORTC QLQ-C30 (except for physical functioning and cognitive functioning) and some symptom scales of EORTC QLQ-C30 (fatigue, nausea/ vomiting, pain, and constipation) were significantly impaired during the acute phase of pancreatitis. There was a significant improvement in the SF-12 physical component summary, and global health, role functioning, social functioning, nausea/vomiting, pain, dyspnea, and financial difficulties (EORTC QLQ-C30) at 2 months after discharge as compared to the basal evaluation. Similar results were found after 12 months except for the mental component score at 12-month evaluation, which was significantly impaired in acute pancreatitis patients in comparison to the norms. The physical functioning of the EORTC QLQ-C30 at basal evaluation was significantly impaired in patients with severe pancreatitis in comparison to patients with mild pancreatitis. Conclusions: Two different patterns can be recognized in the quality of life of patients with acute pancreatitis: physical impairment is immediately present followed by mental impairment which appears progressively in the follow-up period. 相似文献
994.
995.
996.
M. F. O'Rourke 《Internal medicine journal》2009,39(5):344-345
997.
998.
999.
Rebecca P. Ang Robert M. Klassen Wan Har Chong Vivien S. Huan Isabella Y.F. Wong Lay See Yeo Lindsey L. Krawchuk 《Journal of adolescence》2009,32(5):1225-1237
We provide further evidence for the two-factor structure of the 9-item Academic Expectations Stress Inventory (AESI) using confirmatory factor analysis on a sample of 289 Canadian adolescents and 310 Singaporean adolescents. Examination of measurement invariance tests the assumption that the model underlying a set of scores is directly comparable across groups. This study also examined the cross-cultural validity of the AESI using multigroup confirmatory factor analysis across both the Canadian and Singaporean adolescent samples. The results suggested cross-cultural invariance of form, factor loadings, and factor variances and covariances of the AESI across both samples. Evidence of AESI's convergent and discriminant validity was also reported. Findings from t-tests revealed that Singaporean adolescents reported a significantly higher level of academic stress arising from self expectations, other expectations, and overall academic stress, compared to Canadian adolescents. Also, a larger cross-cultural effect was associated with academic stress arising from other expectations compared with academic stress arising from self expectations. 相似文献
1000.
The recent development of brain atlases with computer graphics templates, and of huge databases of neurohistochemical data on the internet, has forced a systematic re-examination of errors associated with comparing histological features between adjacent sections of the same brain, between brains treated in the same way, and between brains from groups treated in different ways. The long-term goal is to compare as accurately as possible a broad array of data from experimental brains within the framework of reference atlases. Main sources of error, each of which ideally should be measured and minimized, include intrinsic biological variation, linear and nonlinear distortion of histological sections, plane of section differences between each brain, section alignment problems, and sampling errors. These variables are discussed, along with approaches to error estimation and minimization in terms of a specific example—the distribution of neuroendocrine neurons in the rat paraventricular nucleus. Based on the strategy developed here, the main conclusion is that the best long-term solution is a high-resolution 3D computer graphics model of the brain that can be sliced in any plane and used as the framework for quantitative neuroanatomy, databases, knowledge management systems, and structure–function modeling. However, any approach to the automatic annotation of neuroanatomical data—relating its spatial distribution to a reference atlas—should deal systematically with these sources of error, which reduce localization reliability. 相似文献