全文获取类型
收费全文 | 1223篇 |
免费 | 68篇 |
国内免费 | 90篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 52篇 |
妇产科学 | 13篇 |
基础医学 | 140篇 |
口腔科学 | 19篇 |
临床医学 | 254篇 |
内科学 | 295篇 |
皮肤病学 | 77篇 |
神经病学 | 68篇 |
特种医学 | 85篇 |
外科学 | 93篇 |
综合类 | 71篇 |
预防医学 | 65篇 |
眼科学 | 8篇 |
药学 | 80篇 |
中国医学 | 3篇 |
肿瘤学 | 56篇 |
出版年
2021年 | 11篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 15篇 |
2014年 | 32篇 |
2013年 | 39篇 |
2012年 | 28篇 |
2011年 | 29篇 |
2010年 | 43篇 |
2009年 | 32篇 |
2008年 | 26篇 |
2007年 | 80篇 |
2006年 | 34篇 |
2005年 | 43篇 |
2004年 | 34篇 |
2003年 | 38篇 |
2002年 | 20篇 |
2001年 | 28篇 |
2000年 | 27篇 |
1999年 | 30篇 |
1998年 | 37篇 |
1997年 | 56篇 |
1996年 | 38篇 |
1995年 | 41篇 |
1994年 | 38篇 |
1993年 | 29篇 |
1992年 | 21篇 |
1991年 | 11篇 |
1990年 | 26篇 |
1989年 | 38篇 |
1988年 | 25篇 |
1987年 | 25篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1977年 | 11篇 |
1976年 | 13篇 |
1975年 | 8篇 |
1968年 | 8篇 |
1966年 | 9篇 |
1965年 | 12篇 |
1963年 | 11篇 |
1959年 | 13篇 |
1956年 | 8篇 |
排序方式: 共有1381条查询结果,搜索用时 60 毫秒
91.
国产沉香化学成分的研究——Ⅲ.异白木香醇的结构测定和低沸点成分的分离与鉴定 总被引:4,自引:0,他引:4
自国产沉香(Aquilaria sinensis)[瑞香科(Thymeleaceae)植物]的挥发油中,经硅胶柱层析和离心薄层层析分离得到一新的倍半萜,命名为异白木香醇(isobaimuxinol),根据光谱(IR,1HNMR,13CNMR,2 D-NMR和MS)分析确定其结构式为(Ⅰ)所示,并用X-光衍射晶体解析进一步确定了其立体化学。同时,也从该植物挥发油的低沸点部分分离得到四个已知化合物:苄基丙酮,对甲氧基苄基丙酮,茴香酸和β-沉香呋喃。这些化合物均为首次从该植物中得到。 相似文献
92.
ABSTRACT— Glafenine was associated with hepatic injury in 38 cases. The causal relationship was assessed on the basis of the temporal relationship with drug use, course and exclusion of other causes. In 27 cases a causal relationship was considered likely, i.e. ‘probable’ (12 cases) or ‘possible’ (15 cases), whereas in 11 cases it was either unlikely or unclassifiable. In both the ‘probable’ and ‘possible’ groups 60–70% of individuals were women. Jaundice was present in three-quarters of cases in both groups. Eosinophilia was more frequent in the group of ‘probable’ cases, and this group had the highest case-fatality rate (42%). Onset varied from 2 days (after a rechallenge) to 8 months, but most cases appeared between 2 weeks and 4 months after starting therapy. Histology in 22 cases showed a predominantly hepatocellular pattern, varying from spotty panlobular necrosis, centrilobular and (sub)massive necrosis (acute pattern) to fibrosis and cirrhosis (chronic pattern). The chemical structure of glafenine and the clinicopathological pattern it induces resemble that of cinchophen. The incidence is unknown. Either metabolic idiosyncrasy or an immunoallergic mechanism seems to be responsible. 相似文献
93.
94.
95.
96.
97.
98.
Surgery remains the treatment of choice for massive and recurrent hemoptysis. In some instances, however, immediate surgical intervention is contraindicated. In these situations, bronchial artery embolization (BAE) has proved to be a successful definitive treatment for non-surgical candidates and a palliative therapy in patients requiring hemodynamic stabilization prior to surgery. The most serious complication of BAE is spinal cord ischemia. This relates directly to the potential anastomotic connections between the bronchial circulation and the anterior spinal artery. Somatosensory evoked potentials (SSEPs) have been used in the past to monitor spinal cord ischemia during procedures that threaten the vascularity of the spinal cord. The authors report two cases in which SSEPs were employed to monitor spinal cord ischemia during bronchial artery embolization. 相似文献
99.
国产沉香化学成分的研究——Ⅲ.异白木香醇的结构测定和低沸点成分的分离与鉴定 总被引:3,自引:0,他引:3
自国产沉香(Aquilaria sinensis)[瑞香科(Thymeleaceae)植物]的挥发油中,经硅胶柱层析和离心薄层层析分离得到一新的倍半萜,命名为异白木香醇(isobaimuxinol),根据光谱(IR,~1HNMR,~(13)CNMR,2 D-NMR和MS)分析确定其结构式为(Ⅰ)所示,并用X-光衍射晶体解析进一步确定了其立体化学。同时,也从该植物挥发油的低沸点部分分离得到四个已知化合物:苄基丙酮,对甲氧基苄基丙酮,茴香酸和β-沉香呋喃。这些化合物均为首次从该植物中得到。 相似文献
100.
Improving house staff ordering of three common laboratory tests. Reductions in test ordering need not result in underutilization 总被引:3,自引:0,他引:3
K Kroenke J F Hanley J B Copley J I Matthews C E Davis C J Foulks J L Carpenter 《Medical care》1987,25(10):928-935
Most studies of modifying test ordering have focused on costs. Questions not addressed are whether programs to reduce testing lead to a higher proportion of clinically indicated tests and is underutilization an adverse outcome of such programs? To investigate this, we studied the house staff's ordering of three common laboratory tests at baseline and after educational and administrative interventions. Over a 2-year period, 3,603 urine cultures, sputum cultures, and admission urinalyses were reviewed. A lecture emphasizing the indications for these tests followed by chart audit and weekly feedback increased the proportion of clinically indicated tests. Subsequently, an administrative intervention requiring the intern to list the reason for ordering the test on the laboratory request form further improved test ordering. Underutilization, defined as a failure to order a potentially indicated test, was assessed during two representative periods. The "underutilization rate" (omitted tests per 100 patients) was no worse during maximal intervention than it was 9 months after the last intervention (7.7 vs. 11.1, NS). No immediate adverse consequences resulted from tests not ordered. Our findings indicate that it may be possible to selectively reduce the ordering of unnecessary tests without sacrificing quality of care. 相似文献