全文获取类型
收费全文 | 389篇 |
免费 | 20篇 |
国内免费 | 16篇 |
专业分类
儿科学 | 26篇 |
妇产科学 | 7篇 |
基础医学 | 48篇 |
口腔科学 | 23篇 |
临床医学 | 33篇 |
内科学 | 60篇 |
皮肤病学 | 14篇 |
神经病学 | 7篇 |
特种医学 | 77篇 |
外科学 | 34篇 |
综合类 | 15篇 |
预防医学 | 11篇 |
眼科学 | 18篇 |
药学 | 18篇 |
中国医学 | 2篇 |
肿瘤学 | 32篇 |
出版年
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 3篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 23篇 |
2013年 | 20篇 |
2012年 | 4篇 |
2011年 | 12篇 |
2010年 | 33篇 |
2009年 | 27篇 |
2008年 | 4篇 |
2007年 | 16篇 |
2006年 | 11篇 |
2005年 | 8篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 33篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 9篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1959年 | 1篇 |
1958年 | 2篇 |
1957年 | 1篇 |
1955年 | 1篇 |
1954年 | 2篇 |
1949年 | 2篇 |
排序方式: 共有425条查询结果,搜索用时 15 毫秒
1.
2.
3.
Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability 总被引:1,自引:15,他引:1
La Spada AR; Peterson KR; Meadows SA; McClain ME; Jeng G; Chmelar RS; Haugen HA; Chen K; Singer MJ; Moore D; Trask BJ; Fischbeck KH; Clegg CH; McKnight GS 《Human molecular genetics》1998,7(6):959-967
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG
repeat expansion in the first exon of the androgen receptor (AR) gene.
Disease-associated alleles (37-66 CAGs) change in length when transmitted
from parents to offspring, with a significantly greater tendency to shift
size when inherited paternally. As transgenic mice carrying human AR cDNAs
with 45 and 66 CAG repeats do not display repeat instability, we attempted
to model trinucleotide repeat instability by generating transgenic mice
with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions
in their genomic context. Studies of independent lines of AR YAC transgenic
mice with CAG 45 alleles reveal intergenerational instability at an overall
rate of approximately 10%. We also find that the 45 CAG repeat tracts are
significantly more unstable with maternal transmission and as the
transmitting mother ages. Of all the CAG/CTG repeat transgenic mice
produced to date the AR YAC CAG 45 mice are unstable with the smallest
trinucleotide repeat mutations, suggesting that the length threshold for
repeat instability in the mouse may be lowered by including the appropriate
flanking human DNA sequences. By sequence-tagged site content analysis and
long range mapping we determined that one unstable transgenic line has
integrated an approximately 70 kb segment of the AR locus due to
fragmentation of the AR YAC. Identification of the cis - acting elements
that permit CAG tract instability and the trans -acting factors that
modulate repeat instability in the AR YAC CAG 45 mice may provide insights
into the molecular basis of trinucleotide repeat instability in humans.
相似文献
4.
Two girls (a 5 year old and a 21 month old) experiencing mononucleosis syndrome with coincidental human herpesvirus (HHV)-7 and Epstein-Barr virus (EBV) infections are described. One patient had primary HHV-7 infection and reactivated EBV infection. The other had primary HHV-7 and EBV infections. These cases indicated that HHV-7 is capable of inducing infectious mononucleosis-like illness. Multiple herpesvirus infection in one of the patients also suggests that interaction among herpesviruses can occur in vivo. The consequence of this interaction may have clinical implications. 相似文献
5.
Founder effect in spinal and bulbar muscular atrophy (SBMA) 总被引:3,自引:2,他引:3
Tanaka F; Doyu M; Ito Y; Matsumoto M; Mitsuma T; Abe K; Aoki M; Itoyama Y; Fischbeck KH; Sobue G 《Human molecular genetics》1996,5(9):1253-1257
We analyzed the polymorphic (CAG)n and (GGC)n repeats of the androgen
receptor gene in 113 unrelated X-linked spinal and bulbar muscular atrophy
(SBMA) X chromosomes and 173 control X chromosomes in Japanese males. The
control chromosomes had an average CAG repeat number of 21 +/- 3 with a
range from 14-32 repeat units, and SBMA chromosomes had a range from 40-55
with a median of 47 +/- 3 copies. The control chromosomes had seven
different alleles of the (GGC)n repeat with the range of 11 to 17; the most
frequent size of (GGC)n was 16 (79%), while (GGC)17 was very rare (1%).
However, in SBMA chromosomes only two alleles were seen; the most frequent
size of (GGC)n was 16 (61%) followed by 17 (39%). (GGC)n size distribution
was significantly different between SBMA and control chromosomes (P <
0.0001), indicating the presence of linkage disequilibrium. There was no
allelic association between the (CAG)n and (GGC)n microsatellites among
control subjects as well as SBMA patients, which suggests that a founder
effect makes a more significant contribution to generation of Japanese SBMA
chromosomes than new mutations.
相似文献
6.
ObjectivesThe aim of the present study is to evaluate the feasibility and safety of performing PNL under local anesthesia in a selected group of patients who are at high risk for general anesthesia.Patients and methodsForty seven patients underwent PNL under local anesthesia. There were 38 males and 9 females with a mean age of 62 years. All patients were at medical high-risk for general anesthesia, with an American Society of Anesthesiologists (ASA) score of 3. The indications for local anesthesia in this study were obstructed single functioning kidney with azotemia in 29 patients, hepatic insufficiency in 8 patients, cardiac problems in 7 patients and 3 patients had hepatocellular carcinoma. The mean stone size was 2.7 cm (range 2–3.1 cm). Local infiltration with 10–20 cc of 2% lidocaine at the site of puncture was used in all cases. Narcotics were given 30 min prior to the procedure and medazolam was given intraoperatively upon demand. Utrasound guided puncture was performed in all cases and tract dilatation was then done under fluoroscopy using high pressure balloon catheter in 35 and Alken's metal dilators in 12 cases. Stones were then retrieved after disintegration in the same cession in 33 patients, while the other 14 patients underwent staged PNL, where a 12 Fr. nephrostomy tube was placed in the first stage, followed by tract dilatation and stone retrieval one week later.ResultsOut of 47 patients included, 44 had successful PNL either one stage (30 patients) or two stages (14 patients). Only 3 patients could not tolerate pain and the procedure was terminated after placement of nephrostomy tube and stone retrieval was completed later under general anesthesia.ConclusionOur results demonstrated that PNL under local anesthesia with narcotics and sedatives seems to be a satisfying solution for the treatment of a selected group of patients with renal pelvic stones and who have high anesthetic risk. However, additional studies with different groups of patients are required to validate our results. 相似文献
7.
Decreased expression of phospholipase C-beta 2 isozyme in human platelets with impaired function 总被引:4,自引:4,他引:4
Platelets from a patient with a mild inherited bleeding disorder and abnormal platelet aggregation and secretion show reduced generation of inositol 1,4,5-trisphosphate, mobilization of intracellular Ca2+, and phosphorylation of pleckstrin in response to several G protein mediated agonists, suggesting a possible defect at the level of phospholipase C (PLC) activation (see accompanying report). A procedure was developed that allows quantitation of platelet PLC isozymes. After fractionation of platelet extracts by high-performance liquid chromatography, 7 out of 10 known PLC isoforms were detected by immunoblot analysis. The amount of these isoforms in normal platelets decreased in the order PLC- gamma 2 > PLC-beta 2 > PLC-beta 3 > PLC-beta 1 > PLC-gamma 1 > PLC- delta 1 > PLC-beta 4. Compared with normal platelets, platelets from the patient contained approximately one-third the amount of PLC-beta 2, whereas PLC-beta 4 was increased threefold. These results suggest that the impaired platelet function in the patient in response to multiple G protein mediated agonists is attributable to a deficiency of PLC-beta 2. They document for the first time a specific PLC isozyme deficiency in human platelets and provide an unique opportunity to understand the role of different PLC isozymes in normal platelet function. 相似文献
8.
Possible effect of secretor locus on plasma concentration of factor VIII and von Willebrand factor 总被引:2,自引:1,他引:2
A significant fraction (30%) of the genetically determined variance in plasma concentration of the von Willebrand factor antigen (vWf:Ag) has been shown to be related to ABH determinants. Individuals with blood group O, who have the highest amounts of blood group H substance, have the lowest concentration of vWf:Ag. The Lewis substances, Le(a) and Le(b), are biochemically closely related to the ABH substances as both can be produced from the same precursor substance. We studied the effect of the presence of the Lewis antigens on the plasma concentration of vWf:Ag and factor VIII antigen (VIII:Ag) in 323 individuals of different ABO groups from a series of twins and in 58 blood donors of blood group O. Among persons belonging to blood group O, those with the Le(a) antigen had a higher concentration of both vWf:Ag and VIII:Ag than individuals lacking Le(a). Le(a+b-) people are nonsecretors and Le(a-b+) people are secretors of ABH substance. Thus, the lowest concentration of vWf:Ag and VIII:Ag was found in group O secretors. The effect is most likely due to an effect of the secretor locus. This finding may be of importance for the detection of carriers of hemophilia A and for the diagnosis of type I von Willebrand disease. 相似文献
9.
10.