全文获取类型
收费全文 | 59718篇 |
免费 | 5079篇 |
国内免费 | 119篇 |
专业分类
耳鼻咽喉 | 515篇 |
儿科学 | 2445篇 |
妇产科学 | 1694篇 |
基础医学 | 7965篇 |
口腔科学 | 777篇 |
临床医学 | 7182篇 |
内科学 | 11181篇 |
皮肤病学 | 970篇 |
神经病学 | 6259篇 |
特种医学 | 1589篇 |
外国民族医学 | 1篇 |
外科学 | 6528篇 |
综合类 | 869篇 |
现状与发展 | 1篇 |
一般理论 | 85篇 |
预防医学 | 7425篇 |
眼科学 | 1444篇 |
药学 | 3971篇 |
中国医学 | 54篇 |
肿瘤学 | 3961篇 |
出版年
2023年 | 674篇 |
2022年 | 909篇 |
2021年 | 2307篇 |
2020年 | 1367篇 |
2019年 | 2043篇 |
2018年 | 2319篇 |
2017年 | 1593篇 |
2016年 | 1780篇 |
2015年 | 1920篇 |
2014年 | 2528篇 |
2013年 | 3247篇 |
2012年 | 4740篇 |
2011年 | 4642篇 |
2010年 | 2385篇 |
2009年 | 2137篇 |
2008年 | 3381篇 |
2007年 | 3526篇 |
2006年 | 3126篇 |
2005年 | 2868篇 |
2004年 | 2635篇 |
2003年 | 2290篇 |
2002年 | 2125篇 |
2001年 | 688篇 |
2000年 | 680篇 |
1999年 | 686篇 |
1998年 | 468篇 |
1997年 | 363篇 |
1996年 | 302篇 |
1995年 | 321篇 |
1994年 | 298篇 |
1993年 | 290篇 |
1992年 | 454篇 |
1991年 | 460篇 |
1990年 | 430篇 |
1989年 | 409篇 |
1988年 | 352篇 |
1987年 | 341篇 |
1986年 | 353篇 |
1985年 | 342篇 |
1984年 | 271篇 |
1983年 | 217篇 |
1982年 | 179篇 |
1981年 | 160篇 |
1980年 | 164篇 |
1979年 | 198篇 |
1978年 | 157篇 |
1977年 | 150篇 |
1974年 | 142篇 |
1973年 | 142篇 |
1971年 | 125篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Diane C. Mitchell Author Vitae Frank R. LawrenceAuthor Vitae Terryl J. HartmanAuthor Vitae Julianne M. CurranAuthor Vitae 《Journal of the American Dietetic Association》2009,109(5):909-913
The US Department of Agriculture's MyPyramid guidelines introduced a near doubling of the dietary recommendations for vegetables. These recommendations target specific subgroups of vegetables, including dry beans and peas. Dry beans and peas provide an array of nutrients and phytochemicals that have been shown to have beneficial health effects, yet consumption levels in the United States are quite low. Few studies have examined the influence of legume consumption on nutrient intakes. Therefore, the purpose of this study was to assess nutrient and food group intakes of dry bean and pea consumers compared to nonconsumers. Dietary intake data from the 1999-2002 National Health and Nutrition Examination Survey for adults aged ≥19 years was used. Results show that on any given day only 7.9% of adults are consuming dry beans and peas; Mexican Americans or other Hispanics are more likely to be consumers than nonconsumers. Consuming approximately ½ c dry beans or peas resulted in higher intakes of fiber, protein, folate, zinc, iron, and magnesium with lower intakes of saturated fat and total fat. These data support the specific recommendation for dry beans and peas as part of the overall vegetable recommendation. Increased consumption of dry beans and peas—economical and nutrient-rich foods—could improve the diet quality of Americans. 相似文献
63.
64.
65.
Safety and efficacy of bariatric surgery: Longitudinal Assessment of Bariatric Surgery 总被引:3,自引:0,他引:3
Steven H. Belle Ph.D. M.Sc.Hyg. Paul D. Berk M.D. Anita P. Courcoulas M.D. M.P.H. F.A.C.S. David R. Flum M.D. M.P.H. F.A.C.S. Carolyn W. Miles Ph.D. James E. Mitchell M.D. Walter J. Pories M.D. F.A.C.S. Bruce M. Wolfe M.D. F.A.C.S. Susan Z. Yanovski M.D. Longitudinal Assessment of Bariatric Surgery Consortium Writing Group 《Surgery for obesity and related diseases》2007,3(2):116-126
66.
Sarah J Buckley 《British medical journal》2005,331(7518):698-699
67.
R G O'Donnell L León Vintró G J Duffy P I Mitchell 《Applied radiation and isotopes》2004,60(2-4):539-542
The levels of residual radioactivity induced in Havar foils at the entrance of a high-pressure 18O-enriched water target used for the production of 18F- in a medical cyclotron with 16 MeV protons have been determined using high-resolution gamma-ray spectrometry. Whole body and skin dose rates arising from exposure to these foils during their periodic replacement have been estimated. The results indicate that irradiated foils do not represent a significant radiological hazard for the cyclotron operating staff and that no waste disposal difficulties should be encountered after an appropriate 'cooling' period of 2 years. 相似文献
68.
Amit Badhwar Thomas L Forbes Marge B Lovell Alison A Dungey Sarah D McCarter Jeffrey R Scott Guy DeRose Kenneth A Harris Richard F Potter 《Canadian journal of surgery》2004,47(5):352-358
BACKGROUND: Ischemic preconditioning (IPC) has been found in animals to have a protective effect against future ischemic injury to muscle tissue. Such injury is unavoidable during some surgical procedures. To determine whether chronic ischemia in the lower extremities would imitate IPC and reduce ischemic injury during vascular surgery, we designed a controlled clinical study. PATIENTS AND METHODS: Two groups of patients at a university-affiliated medical centre with chronic lower-extremity ischemia served as models of IPC: 6 patients awaiting femoral distal bypass (FDB) and 4 scheduled for aortobifemoral (ABF) bypass grafting for aortoiliac occlusive disease. Seven patients undergoing elective open repair of an infrarenal abdominal aortic aneurysm (AAA) were chosen as non-IPC controls. Three hematologic indicators of skeletal-muscle injury, lactate dehydrogenase (LDH), creatine kinase (CK) and myoglobin, were measured before placement of the proximal clamp, during surgical ischemia, immediately upon reperfusion, 15 minutes after and 1 hour after reperfusion, and during the first, second and third postoperative days. RESULTS: Baseline markers of skeletal-muscle injury were similar in all groups. In postreperfusion samples, concentrations of muscle-injury markers were significantly lower in the 2 PC groups than in the control group. For example, at day 2, LDH levels were increased by about 30% over baseline measures in the elective AAA (control) group, whereas levels in the FDB and ABF groups remained statistically unchanged from baseline. Myoglobin in controls had increased by 977%, but only by 160% in the FDB and 528% in the ABF groups. CK levels, in a similar trend, were 1432% higher in the control group and only 111% (FDB) and 1029% (ABF) in the study groups. Taken together, these data represent a significant level of protection. CONCLUSIONS: Patients with chronic lower-extremity ischemia suffered less severe ischemic injury after a period of acute ischemia than those with acute ischemia alone. Ischemic preconditioning is one proposed mechanism to help explain this protective effect. 相似文献
69.
70.