全文获取类型
收费全文 | 575篇 |
免费 | 41篇 |
国内免费 | 22篇 |
专业分类
儿科学 | 37篇 |
妇产科学 | 3篇 |
基础医学 | 57篇 |
口腔科学 | 8篇 |
临床医学 | 75篇 |
内科学 | 109篇 |
皮肤病学 | 4篇 |
神经病学 | 7篇 |
特种医学 | 176篇 |
外科学 | 41篇 |
综合类 | 15篇 |
预防医学 | 44篇 |
眼科学 | 6篇 |
药学 | 41篇 |
肿瘤学 | 15篇 |
出版年
2020年 | 3篇 |
2018年 | 3篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 15篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2007年 | 14篇 |
2006年 | 4篇 |
2005年 | 11篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 32篇 |
1997年 | 29篇 |
1996年 | 40篇 |
1995年 | 23篇 |
1994年 | 19篇 |
1993年 | 28篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 15篇 |
1989年 | 29篇 |
1988年 | 26篇 |
1987年 | 32篇 |
1986年 | 17篇 |
1985年 | 27篇 |
1984年 | 14篇 |
1983年 | 15篇 |
1982年 | 23篇 |
1981年 | 15篇 |
1980年 | 13篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 9篇 |
1976年 | 20篇 |
1975年 | 7篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1971年 | 6篇 |
1969年 | 10篇 |
1968年 | 7篇 |
1967年 | 3篇 |
1966年 | 4篇 |
1957年 | 2篇 |
排序方式: 共有638条查询结果,搜索用时 15 毫秒
611.
612.
613.
Tan XQ Chen HS Liu RH Tan CH Xu CL Xuan WD Zhang WD 《第二军医大学学报》2006,27(5):513-513
Seven lignans having a diarylhydroxybutyrolactone skeleton were isolated from the leaves and stems of Trachelospermum jasminoides (Lindl.) Lem. Their structures were elucidated to be nortrachelogenin 8'-O-beta-D-glucopyranoside (1), nortrachelogenin 5 '- C- beta-D-glucopyranoside (2), trachelogenin amide (3), nortracheloside, trachelogenin, tracheloside, and trachelogenin 4'- O- beta-gentiobioside, respectively, on the basis of spectroscopic analyses. 相似文献
614.
615.
616.
mdx muscle pathology is independent of nNOS perturbation 总被引:2,自引:0,他引:2
Crosbie RH; Straub V; Yun HY; Lee JC; Rafael JA; Chamberlain JS; Dawson VL; Dawson TM; Campbell KP 《Human molecular genetics》1998,7(5):823-829
In skeletal muscle, neuronal nitric oxide synthase (nNOS) is anchored to
the sarcolemma via the dystrophin-glycoprotein complex. When dystrophin is
absent, as in Duchenne muscular dystrophy patients and in mdx mice, nNOS is
mislocalized to the interior of the muscle fiber where it continues to
produce nitric oxide. This has led to the hypothesis that free radical
toxicity from mislocalized nNOS may contribute to mdx muscle pathology. To
test this hypothesis directly, we generated mice devoid of both nNOS and
dystrophin. Overall, the nNOS- dystrophin null mice maintained the
dystrophic characteristics of mdx mice. We evaluated the mice for several
features of the dystrophic phenotype, including membrane damage and muscle
morphology. Removal of nNOS did not alter the extent of sarcolemma damage,
which is a hallmark of the dystrophic phenotype. Furthermore, muscle from
nNOS-dystrophin null mice maintain the histological features of mdx
pathology. Our results demonstrate that relocalization of nNOS to the
cytosol does not contribute significantly to mdx pathogenesis.
相似文献
617.
Nuclear genes of human complex I of the mitochondrial electron transport chain: state of the art 总被引:4,自引:3,他引:4
Smeitink JA; Loeffen JL; Triepels RH; Smeets RJ; Trijbels JM; van den Heuvel LP 《Human molecular genetics》1998,7(10):1573-1579
The mitochondrial electron transport chain (mtETC) consists of four
multi-subunit enzyme complexes. Complex I or NADH:ubiquinone
oxidoreductase, the largest mtETC multisubunit complex, consists of
approximately 41 subunits. Seven of these subunits are encoded by the
mitochondrial genome, the remainder by the nuclear genome. Among the
mitochondriocytopathies, complex I deficiencies are encountered frequently.
Although some complex I deficiencies have been associated with
mitochondrial DNA mutations, the genetic defect has not been elucidated in
the majority of complex I-deficient patients. It is expected that many of
these patients have mutations in the nuclear- encoded subunits of this
complex, so vital for cellular energy production. After a brief summary of
the current knowledge of complex I from cow, bacteria and fungi, this
review presents the state of the art of the knowledge of the human
nuclear-encoded complex I genes which, in the last 18 months, has made
enormous progress. At present, the complete gene structure of four subunits
and the cDNA structure of 18 of the 34 complex I nuclear-encoded subunits
are known. Mapping of these subunits shows a random distribution over the
chromosomes. The chromosomal localization is known for 14 complex I genes.
Recently, the first mutation, a 5 bp duplication in the 18 kDa (AQDQ)
subunit, has been reported. We expect that within 1 year all human
nuclear-encoded complex I subunits will be cloned. Mutational analysis of
these subunits is warranted in complex I-deficient patients and will not
only be important for genetic counselling but will also extend the
knowledge regarding the functional properties of the individual human
complex I subunits.
相似文献
618.
According to a recent hypothesis the therapeutic effects of antidepressants might be related to acute or cumulative suppression of NREM sleep intensity. This intensity has been proposed to be expressed in the EEG power density in NREM sleep. In the present study the relationship was examined between the changes of EEG power density in NREM sleep and the changes in clinical state in 16 depressed patients during treatment with citalopram, a highly specific serotonin uptake inhibitor. A one-week wash-out period was followed by 1 week of placebo administration, a medication period of 5 weeks, and a one-week placebo period. In order to minimize systematic influences of sleep duration and NREM-REM sleep alterations, EEG power was measured over the longest common amount of NREM sleep stages 2, 3 and 4 (91.5 min). During the last treatment week and the week after withdrawal, a significant decrease of EEG power as compared to baseline was found in the 8-9 Hz frequency range. No clear-cut change, however, was observed in the EEG power of the delta frequency range (1-4 Hz), which is considered to be the principle manifestation of NREMS intensity. Furthermore, no relationship between changes in EEG power density and changes in clinical state could be demonstrated. 相似文献
619.
The intake of nutrients over a five day period was studied in 23 children whose atopic eczema was being treated by the avoidance of multiple foods. The results were compared with those from 23 healthy control children not on a diet. Significantly low intakes of calcium were discovered in 13 patients but not in controls. Avoidance of multiple foods is potentially hazardous and requires continued paediatric and dietetic supervision. 相似文献
620.
Lower esophageal sphincter pressures and serum gastrin levels after cholinergic stimulation 总被引:2,自引:0,他引:2
Higgs RH; Humphries TJ; Castell DO; McGuigan JE 《The American journal of physiology》1976,231(4):1250-1253