全文获取类型
收费全文 | 1337篇 |
免费 | 123篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 52篇 |
妇产科学 | 22篇 |
基础医学 | 192篇 |
口腔科学 | 17篇 |
临床医学 | 183篇 |
内科学 | 257篇 |
皮肤病学 | 25篇 |
神经病学 | 101篇 |
特种医学 | 169篇 |
外科学 | 124篇 |
综合类 | 29篇 |
一般理论 | 3篇 |
预防医学 | 133篇 |
眼科学 | 3篇 |
药学 | 152篇 |
肿瘤学 | 65篇 |
出版年
2021年 | 21篇 |
2019年 | 12篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 26篇 |
2015年 | 18篇 |
2014年 | 29篇 |
2013年 | 39篇 |
2012年 | 40篇 |
2011年 | 39篇 |
2010年 | 43篇 |
2009年 | 38篇 |
2008年 | 49篇 |
2007年 | 95篇 |
2006年 | 49篇 |
2005年 | 51篇 |
2004年 | 42篇 |
2003年 | 42篇 |
2002年 | 43篇 |
2001年 | 25篇 |
2000年 | 34篇 |
1999年 | 33篇 |
1998年 | 33篇 |
1997年 | 43篇 |
1996年 | 35篇 |
1995年 | 31篇 |
1994年 | 34篇 |
1993年 | 26篇 |
1992年 | 26篇 |
1991年 | 35篇 |
1990年 | 29篇 |
1989年 | 37篇 |
1988年 | 38篇 |
1987年 | 29篇 |
1986年 | 22篇 |
1985年 | 27篇 |
1984年 | 14篇 |
1983年 | 18篇 |
1982年 | 15篇 |
1980年 | 18篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 21篇 |
1976年 | 15篇 |
1975年 | 16篇 |
1973年 | 17篇 |
1972年 | 15篇 |
1971年 | 10篇 |
1970年 | 10篇 |
1968年 | 15篇 |
排序方式: 共有1529条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
J Dow M A Petty J M Grisar E R Wagner K D Haegele 《Drug metabolism and disposition》1991,19(6):1040-1045
MDL74270 (6-acetyloxy-3,4-dihydro-N,N,N,2,5,7, 8-heptamethyl-2H-1-benzopyran-2-ethanaminium, 4-methylbenzenesulfonate) is a quaternary amine analogue of alpha-tocopherol with free radical scavenger properties. Rats were injected iv with [14C]MDL74270 (0.91 mg/kg), and whole blood and heart tissue were sampled. Five min after drug, the heart tissue/blood ratio (T/B) of radioactivity was 3.5, whereas at 1 hr it was 20.1 and remained at this value up to at least 6 hr. After iv administration the t 1/2 of radioactivity in blood was 6.3 hr, but po blood levels could not be quantified. The 0- to 96-hr urinary elimination of radioactivity was 39.9 +/- 5.7% of the dose after iv and only 1.2 +/- 0.4% after po administration, conversely, 44.7 +/- 5.2% was excreted in feces after iv and 79.1 +/- 17.4% after po administration. These results confirmed poor oral absorption of the compound. Tissue distribution of [14C]MDL74270 was compared with that of its tertiary amine analogue [14C]MDL74366 in rat heart, skeletal muscle, brain, and whole blood, after iv administration (1 mg/kg). The heart T/B was above 20, 1-6 hr after [14C]MDL74270, whereas it was less than 2 after [14C]MDL74366. Over the 1- to 6-hr time interval, skeletal muscle T/B varied from 1.8 to 5 compared with 1.5 to 0.6 for [14C] MDL74366. Brain T/B was higher after the tertiary amine compound. Results showed marked cardioselectivity of radioactivity after [14C] MDL74270. Differential centrifugation of heart homogenates showed that radioactivity was equally distributed between the major subcellular fractions studied.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
8.
AR Jones BSC AJP Sandison FRCS WJ Owen MS FRCS 《International journal of clinical practice》1997,51(5):294-295
Pre-clerking of all patients undergoing elective general surgical operations was introduced at our hospital in an attempt to reduce an unacceptably high operation cancellation rate. A prospective audit has been performed on the effect of this policy on the cancellation rate. Before the introduction of pre-clerking there was a marked seasonal variation in the number of patients who failed to attend for surgery, which could be explained by absence on holiday. This seasonal variation disappeared after the start of pre-clerking clinics, but there has been no reduction in the number of cancellations for medical reasons. 相似文献
9.
Narrative and procedural discourse in temporal lobe epilepsy. 总被引:2,自引:0,他引:2
Brian Bell Christian Dow E Ryann Watson Austin Woodard Bruce Hermann Michael Seidenberg 《Journal of the International Neuropsychological Society》2003,9(5):733-739
It is well established that some individuals with temporal lobe epilepsy (TLE) demonstrate language deficits at the single word level. However, discourse production rarely has been examined quantitatively within this group. This study compared adult TLE patients with an early seizure onset (< or = age 14 years, n = 27) to a control group (n = 28) on narrative and procedural discourse tasks. As a group, the TLE patients performed normally on the procedural discourse task, but differed significantly from the controls on several narrative discourse variables. At the individual level, 30% of the TLE patients versus 4% of the controls demonstrated impaired discourse ability (p and 0.01). Within this early onset TLE group, discourse performance was not associated with demographic or seizure history variables. Considering the cognitive domain, discourse performance correlated significantly with working memory. In summary, mild discourse dysfunction was present in a significant minority of early onset TLE patients, but this deficit was not closely associated with other language measures. Discourse ability and its neuropsychological, neuroanatomical and conversational speech correlates deserve further study in TLE patients. 相似文献
10.
Berbaum KS; el-Khoury GY; Franken EA Jr; Kathol M; Montgomery WJ; Hesson W 《Radiology》1988,168(2):507-511
The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information. 相似文献