全文获取类型
收费全文 | 3674篇 |
免费 | 283篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 159篇 |
妇产科学 | 63篇 |
基础医学 | 440篇 |
口腔科学 | 63篇 |
临床医学 | 502篇 |
内科学 | 719篇 |
皮肤病学 | 48篇 |
神经病学 | 194篇 |
特种医学 | 413篇 |
外科学 | 360篇 |
综合类 | 91篇 |
一般理论 | 1篇 |
预防医学 | 390篇 |
眼科学 | 36篇 |
药学 | 263篇 |
中国医学 | 2篇 |
肿瘤学 | 184篇 |
出版年
2022年 | 21篇 |
2021年 | 30篇 |
2020年 | 30篇 |
2019年 | 40篇 |
2018年 | 73篇 |
2017年 | 42篇 |
2016年 | 51篇 |
2015年 | 51篇 |
2014年 | 70篇 |
2013年 | 116篇 |
2012年 | 144篇 |
2011年 | 168篇 |
2010年 | 109篇 |
2009年 | 109篇 |
2008年 | 136篇 |
2007年 | 170篇 |
2006年 | 156篇 |
2005年 | 159篇 |
2004年 | 129篇 |
2003年 | 131篇 |
2002年 | 103篇 |
2001年 | 118篇 |
2000年 | 152篇 |
1999年 | 119篇 |
1998年 | 93篇 |
1997年 | 106篇 |
1996年 | 87篇 |
1995年 | 78篇 |
1994年 | 83篇 |
1993年 | 77篇 |
1992年 | 73篇 |
1991年 | 79篇 |
1990年 | 61篇 |
1989年 | 84篇 |
1988年 | 85篇 |
1987年 | 65篇 |
1986年 | 65篇 |
1985年 | 60篇 |
1984年 | 30篇 |
1983年 | 47篇 |
1982年 | 30篇 |
1981年 | 27篇 |
1980年 | 27篇 |
1979年 | 24篇 |
1978年 | 24篇 |
1977年 | 27篇 |
1976年 | 17篇 |
1975年 | 29篇 |
1974年 | 24篇 |
1973年 | 17篇 |
排序方式: 共有3966条查询结果,搜索用时 15 毫秒
31.
32.
M L Nicholson P S Veitch P K Donnelly A J Flower P R Bell 《Transplantation proceedings》1990,22(4):1811-1812
33.
Righting the medical record. Transforming chronicle into story 总被引:1,自引:0,他引:1
W J Donnelly 《JAMA》1988,260(6):823-825
Narratives of illness in medical records and case presentations in teaching hospitals say surprisingly little about an important matter: what patients understand and feel. Nowadays, medical narratives tend to neglect or objectify subjective experience, including symptoms. Such narratives concentrate, in the manner of chronicles, on events in the exterior, objective world rather than the interior world of the sick. Medical students and physicians will construct more balanced accounts of human illness once they envision these accounts as "story", a form of narrative that traditionally accesses subjective experience as well as objective events. One can effectively begin the process of transforming medical chronicles into stories simply by asking patients what they know and how they feel about their situation and by documenting the response, using some of the patient's words, in the history of present illness. These actions will identify and preserve important information, facilitate empathy in all care givers who hear or read the history, and signal to everyone the physician's serious interest in patients as persons. Getting the voice of the patient into the history of present illness will not only help to right the medical record, but also help to right the relationship of physician and patient. 相似文献
34.
Glycodelin is a major secretory product of the uterine glandular epithelial cells of the human and non-human primate during the late luteal phase of the menstrual cycle and early pregnancy. Since progesterone levels are elevated during these periods we sought to determine how progesterone modulates glycodelin gene expression. Co-transfection of various deletions of the baboon glycodelin promoter with the progesterone receptor (PR) into Ishikawa cells, a human endometrial cell line, revealed that full progesterone responsiveness is retained within the region -119/+48. In COS-1 cells, a kidney cell line, progesterone failed to elevate luciferase levels when various deletion constructs and the PR were co-transfected. Mutation of the Sp1 site in the -67/+48 region lowered basal expression but did not affect the ability of progesterone to increase expression of the luciferase reporter in Ishikawa cells. These findings suggest that Sp1 sites are not involved in the progesterone regulation of the baboon glycodelin gene. We propose that progesterone induces a factor that regulates glycodelin gene expression in the uterus since we failed to obtain a similar response in a non-uterine cell line. 相似文献
35.
Hormonal fluctuations associated with the menstrual cycle influence
appetite control and eating behaviour. Energy intake varies during the
reproductive cycle in humans and animals, with a periovulatory nadir and a
luteal phase peak. Patterns of macronutrient selection show less
consistency but a number of studies report carbohydrate cravings in the
premenstrual phase, particularly in women with premenstrual syndrome. The
cyclical nature of food cravings are frequently, but not invariably,
associated with depression. Fluctuations in appetite, cravings and energy
intake during the menstrual cycle may occur in parallel with cyclical
rhythms in serotonin, which can be accompanied by affective symptoms. The
premenstrual phase can be considered as a time when women are especially
vulnerable to overconsumption, food craving and depression; this is often
associated with low serotonin activity.
相似文献
36.
Telfer JF; Thomson AJ; Cameron IT; Greer IA; Norman JE 《Human reproduction (Oxford, England)》1997,12(10):2306-2312
Superoxide, an agent which attenuates the half-life of nitric oxide, is
metabolized and synthesized by superoxide dismutase (SOD) and xanthine
oxidase, respectively. Over the last few years much work has focused on the
role of nitric oxide in human parturition. The aim of this study was to
determine whether the onset of human parturition is associated with a
change in the expression of copper/zinc superoxide dismutase (Cu/Zn SOD),
manganese superoxide dismutase (Mn SOD) or xanthine oxidase within the
uterus. Samples of myometrium, placenta, decidua and fetal membranes were
obtained from women before and after the onset of labour at term.
Immunocytochemistry was used to localize Cu/Zn SOD, Mn SOD and xanthine
oxidase and measure SOD enzyme activity. Cu/Zn and Mn SOD-like
immunoreactivity was detected in syncytiotrophoblast cells, villous stromal
cells and endothelial cells of blood vessels in the placenta. In the
myometrium Cu/Zn and Mn SOD were localized to myocytes and endothelial
cells and to some vascular smooth muscle cells. In the fetal membranes we
observed staining for Cu/Zn SOD and Mn SOD in the amnion, chorion,
extravillous trophoblast and decidua. There was no difference in SOD enzyme
activity or staining intensity for SOD between different cell types before
and during labour. Xanthine oxidase immunoreactivity was identified in each
of the tissues examined and again there was no difference in immunostaining
in tissues obtained from women delivered before or after the onset of
labour. These results show that the pregnant uterus is capable of both
synthesizing and degrading superoxide and suggest that superoxide dismutase
and xanthine oxidase may play a role in the maintenance of uterine
quiescence during pregnancy, but not in the initiation of parturition.
相似文献
37.
Baugh JA Chitnis S Donnelly SC Monteiro J Lin X Plant BJ Wolfe F Gregersen PK Bucala R 《Genes and immunity》2002,3(3):170-176
The macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine and regulates the anti-inflammator effects of glucocorticoids. An important role for MIF within the cytokine cascade is to act in concert with endogenous glucocorticoids to control the set-point and magnitude of the inflammatory response. Elevated expression of MIF in the circulation and in the synovial joint has been documented in rheumatoid arthritis. MIF also has been linked to the development of joint damage and disease pathology in experimental animal models. We describe herein a novel CATT-tetranucleotide repeat polymorphism at position -794 of the human Mif gene and show that it functionally affects the activity of the MIF promoter in gene reporter assays. We describe four genotypes which comprise 5, 6, 7, or 8-CATT repeat units and show that the 5-CATT allele has the lowest level of basal and stimulated MIF promoter activity in vitro. The presence of the low expressing, 5-CATT repeat allele correlated with low disease severity in a cohort of rheumatoid arthritis patients. 相似文献
38.
Hydrosalpinges adversely affect markers of endometrial receptivity 总被引:22,自引:10,他引:22
Meyer WR; Castelbaum AJ; Somkuti S; Sagoskin AW; Doyle M; Harris JE; Lessey BA 《Human reproduction (Oxford, England)》1997,12(7):1393-1398
While in-vitro fertilization (IVF) was initially developed in women with
tubal factor infertility, recent clinical studies have suggested that the
presence of hydrosalpinges lowers implantation and pregnancy rates. We
postulated that these hydrosalpinges cause impaired endometrial
receptivity. A total of 103 women with hydrosalpinges were prospectively
evaluated, and compared with 55 infertile and 44 fertile controls. All
women had endometrial biopsies during the window of implantation, analysed
by conventional histological criteria, and also stained for three integrin
markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha
vbeta3). Women with hydrosalpinges (cases) expressed significantly less of
the alpha vbeta3 integrin compared with controls. There was no difference
in expression of alpha1beta1 or alpha4beta1 among groups. A significantly
greater number of cases had out of phase histology and missing alpha vbeta3
(type I defects) and absent integrin expression despite normal histological
maturation (type II) defects, compared with controls. Of 20 women with
impaired endometrial receptivity who were also biopsied after hydrosalpinx
surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven
percent of type I and 57% of type II defects were corrected
postoperatively. Using markers of endometrial receptivity, this study
demonstrates that inflammatory hydrosalpinges have an adverse effect on
endometrial receptivity, which in some cases may be overcome by surgical
treatment of the hydrosalpinx.
相似文献
39.
Direct molecular diagnosis of myotonic dystrophy 总被引:2,自引:0,他引:2
B. K. Hecht A. Donnelly A. K. Gedeon R. W. Byard E. A. Haan J. G. Mulley 《Clinical genetics》1993,43(6):276-285
Hecht BK, Donnelly A, Gedeon AK, Byard RW, Haan EA, Mulley JC. Direct molecular diagnosis of myotonic dystrophy. Clin Genet 1993: 43: 276–285. © Munksgaard, 1993 Myotonic dystrophy (DM) arises from an unstable trinucleotide (CTGn) repeat sequence within the DM locus at 19q13.3. Twenty-three myotonic dystrophy families containing 205 persons with no symptoms, minimal manifestations, classic DM or congenital DM were investigated to validate the application of the pM10M6 probe to direct molecular diagnosis. Affected family members had been diagnosed clinically and the unaffected family members had been assigned carrier probabilities close to either zero or 100%, using closely linked flanking markers. Southern analysis identified all 89 DM gene carriers as having expansions of the unstable element. PstI detected all small expansions of the repeat sequence as easily seen discrete bands; but large expansions were usually seen as diffuse smears, sometimes difficult to distinguish from lane background. EcoRI concentrated these diffuse smears, associated with somatic instability, into discrete bands which were easy to detect; but it did not resolve the smaller expansions present in 9 (10%) of the DM carriers. It is essential that PstI and EcoRI gels are run in parallel to detect all DM gene carriers. The extent of expansion of CTG correlated with age of onset and disease severity. Biopsies of various fetal tissues from two terminated pregnancies confirmed the diagnosis obtained by CVS and revealed no heterogeneity between tissues at this developmental stage. Further expansion occurred during the culture of CVS cells, indicating that direct prenatal diagnosis needs to be carried out on CVS tissue rather than on cultured cells. The intergenerational change of the repeat sequence from DM parent to DM offspring showed a significant parental sex difference for those parents with large expansions. Contraction of the unstable element was observed in the three males carrying the largest expansions and could explain why congenital DM is exclusively of maternal origin. 相似文献
40.