全文获取类型
收费全文 | 4104篇 |
免费 | 323篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 201篇 |
妇产科学 | 58篇 |
基础医学 | 528篇 |
口腔科学 | 165篇 |
临床医学 | 417篇 |
内科学 | 817篇 |
皮肤病学 | 31篇 |
神经病学 | 216篇 |
特种医学 | 577篇 |
外科学 | 417篇 |
综合类 | 143篇 |
预防医学 | 280篇 |
眼科学 | 175篇 |
药学 | 251篇 |
中国医学 | 4篇 |
肿瘤学 | 126篇 |
出版年
2022年 | 25篇 |
2021年 | 74篇 |
2020年 | 36篇 |
2019年 | 47篇 |
2018年 | 61篇 |
2017年 | 53篇 |
2016年 | 56篇 |
2015年 | 92篇 |
2014年 | 77篇 |
2013年 | 143篇 |
2012年 | 148篇 |
2011年 | 138篇 |
2010年 | 140篇 |
2009年 | 106篇 |
2008年 | 153篇 |
2007年 | 124篇 |
2006年 | 158篇 |
2005年 | 145篇 |
2004年 | 130篇 |
2003年 | 118篇 |
2002年 | 109篇 |
2001年 | 93篇 |
2000年 | 90篇 |
1999年 | 77篇 |
1998年 | 160篇 |
1997年 | 139篇 |
1996年 | 139篇 |
1995年 | 122篇 |
1994年 | 92篇 |
1993年 | 92篇 |
1992年 | 79篇 |
1991年 | 60篇 |
1990年 | 65篇 |
1989年 | 97篇 |
1988年 | 97篇 |
1987年 | 85篇 |
1986年 | 82篇 |
1985年 | 89篇 |
1984年 | 54篇 |
1983年 | 60篇 |
1982年 | 44篇 |
1981年 | 34篇 |
1980年 | 49篇 |
1979年 | 32篇 |
1978年 | 30篇 |
1977年 | 31篇 |
1976年 | 36篇 |
1975年 | 33篇 |
1971年 | 20篇 |
1970年 | 19篇 |
排序方式: 共有4450条查询结果,搜索用时 31 毫秒
51.
Mutations in the Ca(2+)-sensing receptor gene cause autosomal dominant and sporadic hypoparathyroidism 总被引:3,自引:0,他引:3
Baron J; Winer KK; Yanovski JA; Cunningham AW; Laue L; Zimmerman D; Cutler GB Jr 《Human molecular genetics》1996,5(5):601-606
Parathyroid hormone secretion is negatively regulated by a 7- transmembrane
domain, G-protein coupled Ca(2+)-sensing receptor. We hypothesized that
activating mutations in this receptor might cause autosomal dominant
hypoparathyroidism (ADHP). Consistent with this hypothesis, we identified,
in two families with ADHP, heterozygous missense mutations in the
Ca(2+)-sensing receptor gene that cosegregated with the disorder. None of
50 normal controls had either mutation. We also identified a de novo,
missense Ca(2+)-sensing receptor mutation in a child with severe sporadic
hypoparathyroidism. The amino acid substitution in one ADHP family affected
the N-terminal, extracellular domain of the receptor. The other mutations
involved the transmembrane region. Unlike patients with acquired
hypoparathyroidism, patients with these mutations had hypercalciuria even
at low serum calcium concentrations. Their greater hypercalciuria
presumably reflected activation of Ca(2+)-sensing receptors in kidney
cells, where the receptor negatively regulates calcium reabsorption. This
augmented hypercalciuria increases the risk of renal complications and thus
has implications for the choice of therapy.
相似文献
52.
Successful outcome with day 4 embryo transfer after preimplantation diagnosis for genetically transmitted diseases 总被引:4,自引:5,他引:4
Preimplantation genetic diagnosis was performed in 61 day 3 embryos
obtained by in-vitro fertilization from seven patient carriers of
haemophilia, Marfan's syndrome, Bloch-Sulzemberg syndrome (incontinentia
pigmentosa) or X chromosome-linked immune deficiency, retinitis pigmentosa,
and FG syndrome, which is characterized by mental retardation and
hypotonia. After multiplex polymerase chain reaction, 16 embryos were
diagnosed as being unaffected, and these were transferred to the uterus on
the following day (day 4). Of these embryos, six (37.5%) implanted,
resulting in the delivery of a singleton and a twin pregnancy, a late
second trimester miscarriage (twins at week 20) and a first trimester
miscarriage at week 8. All the diagnoses were confirmed by amniocentesis.
We report for the first time a late day 4 transfer of biopsied human
embryos undergoing preimplantation genetic diagnosis. This transfer
schedule allows an extra day to perform genetic analyses on single
blastomeres and to monitor any adverse effect of the biopsy procedure.
相似文献
53.
54.
A L Clayton U Beckford C Roberts S Sutherland A Druce J Best S Chantler 《Journal of medical virology》1985,17(3):275-282
A rapid simultaneous enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies was investigated for herpes simplex virus (HSV) detection. All HSV isolated (n = 127) were detected, whereas no response was obtained with HSV negative preparations. Equivalent results were obtained from 275 of 277 clinical specimens in the monoclonal ELISA and in an ELISA using polyclonal antibodies, confirming that appropriately selected monoclonal antibodies may be as efficacious as polyclonal antibodies in antibody-based assays. In clinical specimens, the rate of HSV detection (sensitivity) relative to tissue culture isolation was low for both assays, and the major factor responsible for this was the low concentration of virus present in some specimens. The sensitivity of ELISA obtained in routine use varied with different panels of unselected specimens and was related to the speed of development of the cytopathic effect. These results emphasise the need for caution in assigning a definitive sensitivity level to ELISA tests evaluated on different panels of specimens. 相似文献
55.
56.
How to use Chlamydia antibody testing in subfertility patients 总被引:1,自引:9,他引:1
Screening for tubal factor subfertility by means of Chlamydia antibody
testing (CAT) was introduced into the initial work-up of subfertile couples
several years ago. The results reported, however, are heterogeneous, and no
uniformity exists in cut-off levels of titres, or in definitions of tubal
factor subfertility. We performed a prospective cohort study to evaluate
the implications of varying the definitions of tubal pathology and of
modifying the cut-off levels on the clinical impact of CAT in predicting
tubal factor subfertility. In 227 consecutive patients who attended our
fertility clinic, the Chlamydia IgG antibody titre was determined and
related to tuboperitoneal abnormalities at laparoscopy as a reference
standard. According to received operating characteristic (ROC) curve
analysis, a titre of 16 is the optimum cut-off level. Increasing the
cut-off level improves specificity and positive likelihood ratio (LR+), at
the expense of sensitivity and negative LR (LR-). Changing the definition
of tubal factor subfertility from unspecified tuboperitoneal abnormalities
into extensive adhesions and/or bilateral distal tubal occlusion improves
LR+, LR- and kappa significantly. We conclude that CAT is more accurate in
predicting severe distal tubal pathology than unspecified tuboperitoneal
abnormalities. Although from a statistical point of view a titre of 16 is
the optimum cut-off level, from a clinical point of view 32 or 64 may be
preferable, depending on the aim of screening and the inception cohort.
相似文献
57.
Anxiety during pregnancy and fetal attachment after in-vitro fertilization conception 总被引:3,自引:4,他引:3
McMahon CA; Ungerer JA; Beaurepaire J; Tennant C; Saunders D 《Human reproduction (Oxford, England)》1997,12(1):176-182
The aim of this study was to compare 70 couples who had conceived by in-
vitro fertilization (IVF) with 63 matched controls for the prevalence of
anxiety and quality of attachment to the baby during pregnancy. Results for
mothers showed no group differences using a global measure of anxiety, the
Spielberger State-Trait Anxiety Inventory. However, pregnancy-specific
measures revealed significantly higher levels of anxiety in IVF mothers
about the survival and normality of their unborn babies, about damage to
their babies during childbirth and about separating from their babies after
birth. When IVF mothers were differentiated according to the number of
treatment cycles, more differences in anxiety level were revealed, with
most increases occurring in mothers who had experienced two or more
treatment cycles. IVF fathers did not differ from controls on the global
anxiety measure. No data on pregnancy-specific anxiety were available for
fathers. Neither IVF mothers nor IVF fathers differed from controls on
measures of attachment to the baby during pregnancy. Results are discussed
in the context of the need for researchers to employ differentiated and
issue-specific measures to identify concerns that may be unique to IVF
couples. Clinical implications regarding the need for psychological support
during pregnancy are also discussed.
相似文献
58.
Synergistic induction of interleukin-1 by endotoxin and toxic shock syndrome toxin-1 using rat macrophages. 总被引:5,自引:5,他引:5 下载免费PDF全文
We studied interleukin-1 (IL-1) secretion by rat peritoneal exudate macrophages stimulated with purified toxic shock syndrome toxin-1 (TSST-1). TSST-1 was observed to be a more potent inducer of IL-1 than was endotoxin. The induction of IL-1 secretion by TSST-1 was not blocked by polymyxin B but could be blocked by monoclonal antibodies directed against TSST-1. Synergistic induction of IL-1 was observed when the cells were stimulated with TSST-1 and endotoxin. The sequence of addition was found to be important for the synergistic response. Enhanced IL-1 production was observed only when macrophages were exposed to endotoxin before or simultaneously with TSST-1. Prior exposure of macrophages to TSST-1 had no enhancing effect on endotoxin-induced IL-1 secretion. We conclude that stimulation of the macrophage by endotoxin enhances the responsiveness of the cells to TSST-1 and may thereby play a role in the pathogenesis of toxic shock syndrome. 相似文献
59.
60.