全文获取类型
收费全文 | 1364篇 |
免费 | 83篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 65篇 |
妇产科学 | 5篇 |
基础医学 | 162篇 |
口腔科学 | 88篇 |
临床医学 | 106篇 |
内科学 | 240篇 |
皮肤病学 | 26篇 |
神经病学 | 63篇 |
特种医学 | 128篇 |
外科学 | 158篇 |
综合类 | 125篇 |
预防医学 | 85篇 |
眼科学 | 39篇 |
药学 | 99篇 |
中国医学 | 7篇 |
肿瘤学 | 51篇 |
出版年
2023年 | 12篇 |
2022年 | 24篇 |
2021年 | 40篇 |
2020年 | 15篇 |
2019年 | 21篇 |
2018年 | 28篇 |
2017年 | 27篇 |
2016年 | 33篇 |
2015年 | 43篇 |
2014年 | 59篇 |
2013年 | 59篇 |
2012年 | 93篇 |
2011年 | 72篇 |
2010年 | 62篇 |
2009年 | 58篇 |
2008年 | 87篇 |
2007年 | 63篇 |
2006年 | 52篇 |
2005年 | 42篇 |
2004年 | 41篇 |
2003年 | 33篇 |
2002年 | 32篇 |
2001年 | 35篇 |
2000年 | 21篇 |
1999年 | 25篇 |
1998年 | 52篇 |
1997年 | 44篇 |
1996年 | 34篇 |
1995年 | 23篇 |
1994年 | 30篇 |
1993年 | 23篇 |
1992年 | 5篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 16篇 |
1988年 | 13篇 |
1987年 | 25篇 |
1986年 | 12篇 |
1985年 | 13篇 |
1984年 | 4篇 |
1983年 | 8篇 |
1982年 | 14篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1972年 | 2篇 |
排序方式: 共有1463条查询结果,搜索用时 15 毫秒
1.
Akira Sawaki Nobumasa Mizuno Kuniyuki Takahashi Tsuneya Nakamura Masahiro Tajika Hiroki Kawai Toshifumi Isaka Hiroshi Imaoka Yasuyuki Okamoto Masatoshi Aoki Hiroyuki Inoue Ahmed AS Salem Yasushi Yatabe Kenji Yamao 《Digestive endoscopy》2006,18(1):40-44
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed. 相似文献
2.
Coronary artery bypass grafts: visualization with MR imaging 总被引:1,自引:0,他引:1
3.
Norethisterone enanthate (NET-En), an established intramuscular long-acting contraceptive agent, has previously been shown to be effective in inhibiting fertility in two rodent species even 4 days after oral ingestion. Pharmacokinetics of NET and NET-En were studied after oral and intramuscular doses in two animal species and a few women. The results suggest that the NET-En was absorbed within a day in all the species after oral dose. The estimates of relative bioavailability ranged from 13 to 51% in rabbits, monkeys, and women. The elimination half-life was 5–10 days. The presence of the active component, NET, in the circulation over the experimental period of 15 days suggests that NET-En could be useful as a long-acting oral pill. The suppression of progesterone levels during the luteal phase of menstrual cycle in women also supports this finding. 相似文献
4.
5.
Intra-lesional injections of collagenase are ineffective in the treatment of keloid and hypertrophic scars. 总被引:2,自引:0,他引:2
Norbert Kang Branavan Sivakumar Roy Sanders Charles Nduka David Gault 《Journal of plastic, reconstructive & aesthetic surgery》2006,59(7):693-699
The treatment of keloid and hypertrophic scars remains difficult. Enzymatic digestion of keloid scars has been previously proposed as an effective treatment strategy for reducing the volume of keloid scars. To test this, we administered intra-lesional injections of pure collagenase (between 600 and 4500 units for each scar) into the keloid and hypertrophic scars of seven human volunteers (five keloid and two hypertrophic scars). Five patients (three keloid and two hypertrophic) received more than one injection of collagenase. The treatment resulted in a temporary reduction in scar volume for three of the patients with keloid scars. However, scar volumes for these three patients returned to the same (or greater) levels after 6 months of follow-up. Treatment with collagenase produced no change in scar volume for the two patients with hypertrophic scar. Side effects were numerous and severe including; pain, swelling, blistering, ulceration and ecchymosis at the site of injection. One patient required admission to hospital for 48 h after the first injection. Maximum length of follow-up was 6 months. None of the seven patients completed the study and returned for final follow-up at 2 years. This pilot study suggests that treatment of keloid and hypertrophic scars with intra-lesional injections of collagenase is ineffective. 相似文献
6.
7.
Backscatter imaging is useful for inspecting structures that are accessible only from one side. However, indications provided by scattered radiation are typically weak, convoluted and difficult to interpret. This paper explores the use of the coded aperture technique to detect flaws using gamma-ray backscatter imaging. The viability of this approach is demonstrated with indications obtained from Monte Carlo simulations of radiation scattering measurements. The results show that, with a 2 mm wide beam of 137Cs photons, flaws as small as 1.5 mm in width can be detected using this technique. Indications of changes in flaw size, location, multiplicity and density were also observable. In addition, it is possible to quantify, from the decoded indications, the flaw location and its size. 相似文献
8.
Evaluation of a new enzyme-linked immunosorbent assay test for rotavirus antigen in faeces 总被引:6,自引:0,他引:6
下载免费PDF全文
![点击此处可从《Journal of clinical pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A new commercial test for the diagnosis of rotavirus gastroenteritis was assessed. With some modifications it compared favourably with electron microscopy and immunofluorescence. 相似文献
9.
Competitive control of the self-renewing T cell repertoire 总被引:1,自引:0,他引:1
We develop a mathematical model for the self-renewing part of the T cell
repertoire. Assuming that self-renewing T cells have to be stimulated by
immunogenic MHC-peptide complexes presented on the surfaces of
antigen-presenting cells, we derive a model of T cell growth in which
competition for MHC-peptide complexes limits T cell clone sizes and
regulates the total number of self-renewing T cells in the animal. We show
that for a sufficient diversity and/or degree of cross-reactivity, the
total T cell number hardly depends upon the diversity of the T cell
repertoire or the diversity of the set of presented peptides. Conversely,
for repertoires of lower diversity and/or cross-reactivity, steady-state
total T cell numbers may be limited by the diversity of the T cells. This
provides a possible explanation for the limited repertoire expansion in
some, but not all, mouse T cell re-constitution experiments. We suggest
that the competitive interactions described by our model underlie the
normal T cells numbers observed in transgenic mice, germ-free mice and
various knockout mice.
相似文献
10.
Pattern of Sequence Variation Across 213 Environmental Response Genes 总被引:10,自引:0,他引:10
Robert J. Livingston Andrew von Niederhausern Anil G. Jegga Dana C. Crawford Christopher S. Carlson Mark J. Rieder Sivakumar Gowrisankar Bruce J. Aronow Robert B. Weiss Deborah A. Nickerson 《Genome research》2004,14(10A):1821-1831
To promote the clinical and epidemiological studies that improve our understanding of human genetic susceptibility to environmental exposure, the Environmental Genome Project (EGP) has scanned 213 environmental response genes involved in DNA repair, cell cycle regulation, apoptosis, and metabolism for single nucleotide polymorphisms (SNPs). Many of these genes have been implicated by loss-of-function mutations associated with severe diseases attributable to decreased protection of genomic integrity. Therefore, the hypothesis for these studies is that individuals with functionally significant polymorphisms within these genes may be particularly susceptible to genotoxic environmental agents. On average, 20.4 kb of baseline genomic sequence or 86% of each gene, including a substantial amount of introns, all exons, and 1.3 kb upstream and downstream, were scanned for variations in the 90 samples of the Polymorphism Discovery Resource panel. The average nucleotide diversity across the 4.2 MB of these 213 genes is 6.7 × 10-4, or one SNP every 1500 bp, when two random chromosomes are compared. The average candidate environmental response gene contains 26 PHASE inferred haplotypes, 34 common SNPs, 6.2 coding SNPs (cSNPs), and 2.5 nonsynonymous cSNPs. SIFT and Polyphen analysis of 541 nonsynonymous cSNPs identified 57 potentially deleterious SNPs. An additional eight polymorphisms predict altered protein translation. Because these genes represent 1% of all known human genes, extrapolation from these data predicts the total genomic set of cSNPs, nonsynonymous cSNPs, and potentially deleterious nonsynonymous cSNPs. The implications for the use of these data in direct and indirect association studies of environmentally induced diseases are discussed. 相似文献