全文获取类型
收费全文 | 21530篇 |
免费 | 1405篇 |
国内免费 | 115篇 |
专业分类
耳鼻咽喉 | 318篇 |
儿科学 | 578篇 |
妇产科学 | 334篇 |
基础医学 | 2515篇 |
口腔科学 | 655篇 |
临床医学 | 1841篇 |
内科学 | 4712篇 |
皮肤病学 | 475篇 |
神经病学 | 1247篇 |
特种医学 | 744篇 |
外国民族医学 | 7篇 |
外科学 | 3347篇 |
综合类 | 504篇 |
一般理论 | 13篇 |
预防医学 | 1445篇 |
眼科学 | 724篇 |
药学 | 2002篇 |
1篇 | |
中国医学 | 232篇 |
肿瘤学 | 1356篇 |
出版年
2023年 | 255篇 |
2022年 | 667篇 |
2021年 | 1050篇 |
2020年 | 646篇 |
2019年 | 866篇 |
2018年 | 1012篇 |
2017年 | 651篇 |
2016年 | 792篇 |
2015年 | 799篇 |
2014年 | 1082篇 |
2013年 | 1300篇 |
2012年 | 1864篇 |
2011年 | 1851篇 |
2010年 | 1132篇 |
2009年 | 792篇 |
2008年 | 1221篇 |
2007年 | 1181篇 |
2006年 | 1010篇 |
2005年 | 892篇 |
2004年 | 705篇 |
2003年 | 620篇 |
2002年 | 533篇 |
2001年 | 241篇 |
2000年 | 203篇 |
1999年 | 196篇 |
1998年 | 101篇 |
1997年 | 59篇 |
1996年 | 68篇 |
1995年 | 60篇 |
1994年 | 62篇 |
1993年 | 64篇 |
1992年 | 81篇 |
1991年 | 100篇 |
1990年 | 84篇 |
1989年 | 92篇 |
1988年 | 66篇 |
1987年 | 70篇 |
1986年 | 54篇 |
1985年 | 51篇 |
1984年 | 49篇 |
1983年 | 25篇 |
1982年 | 29篇 |
1981年 | 33篇 |
1980年 | 29篇 |
1979年 | 46篇 |
1978年 | 35篇 |
1977年 | 26篇 |
1975年 | 35篇 |
1974年 | 26篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Cerebral Processing of Acute Skin and Muscle Pain in Humans 总被引:12,自引:0,他引:12
102.
Inflammation: the link between insulin resistance, obesity and diabetes 总被引:41,自引:0,他引:41
Recent data have revealed that the plasma concentration of inflammatory mediators, such as tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), is increased in the insulin resistant states of obesity and type 2 diabetes, raising questions about the mechanisms underlying inflammation in these two conditions. It is also intriguing that an increase in inflammatory mediators or indices predicts the future development of obesity and diabetes. Two mechanisms might be involved in the pathogenesis of inflammation. Firstly, glucose and macronutrient intake causes oxidative stress and inflammatory changes. Chronic overnutrition (obesity) might thus be a proinflammatory state with oxidative stress. Secondly, the increased concentrations of TNF-alpha and IL-6, associated with obesity and type 2 diabetes, might interfere with insulin action by suppressing insulin signal transduction. This might interfere with the anti-inflammatory effect of insulin, which in turn might promote inflammation. 相似文献
103.
Babak S. Jahromi Yasuo Aihara Jinglu Ai Zhen-Du Zhang George Weyer Elena Nikitina Reza Yassari Khaled M. Houamed R. Loch Macdonald 《Neuroscience letters》2008
The pathogenesis of cerebral vasospasm after subarachnoid haemorrhage (SAH) involves sustained contraction of arterial smooth muscle cells that is maximal 6–8 days after SAH. We reported that function of voltage-gated K+ (KV) channels was significantly decreased during vasospasm 7 days after SAH in dogs. Since arterial constriction is regulated by membrane potential that in turn is determined predominately by K+ conductance, the compromised K+ channel dysfunction may cause vasospasm. Additional support for this hypothesis would be demonstration that K+ channel dysfunction is temporally coincident with vasospasm. To test this hypothesis, SAH was created using the double haemorrhage model in dogs and smooth muscle cells from the basilar artery, which develops vasospasm, were isolated 4 days (early vasospasm), 7 days (during vasospasm) and 21 days (after vasospasm) after SAH and studied using patch-clamp electrophysiology. We investigated the two main K+ channels (KV and large-conductance voltage/Ca2+-activated (KCa) channels). Electrophysiologic function of KCa channels was preserved at all times after SAH. In contrast, function of KV channels was significantly decreased at all times after SAH. The decrease in cell size and degree of KV channel dysfunction was maximal 7 days after SAH. The results suggest that KV channel dysfunction either only partially contributes to vasospasm after SAH or that compensatory mechanisms develop that lead to resolution of vasospasm before KV channels recover their function. 相似文献
104.
Mahmud Ahmad Hasan Abbas Sayedul Haque 《American journal of medical genetics. Part A》1993,46(4):369-371
A Pakistani kindred comprising 5 generations contained 9 males and 4 females with alopecia universalis as a single abnormality without any associated defects. The skin biopsy from the scalp showed hair follicles without hair. Analysis of the pedigree is strongly suggestive of autosomal recessive inheritance, and consanguineous loops could account for all affected persons being homozygous for the abnormal allele. © 1993 Wiley-Liss, Inc. 相似文献
105.
A strong promoter of bacteriophage MB78 does not have minus 35 consensus sequence although it has a TGn motif immediately
upstream of minus 10 sequence as well as the AT rich UP element. It is efficiently recognised by the sigma 70 RNA polymerase,
however, a phage-specific factor competes with sigma 70 RNA polymerase for binding to this region, the binding of the factor
being stronger than that of the polymerase. Contrary to the reports in the literature the polymerase appears not to bind to
the UP element whereas the phage-specific factor does. The latter seems to be involved in the regulation of the promoter activity.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
106.
107.
Plunkett FJ Franzese O Belaramani LL Fletcher JM Gilmour KC Sharifi R Khan N Hislop AD Cara A Salmon M Gaspar HB Rustin MH Webster D Akbar AN 《Mechanisms of ageing and development》2005,126(8):855-865
Patients with X-linked lymphoproliferative syndrome (XLP) experience excessive T cell proliferation after primary Epstein-Barr virus (EBV) infection, due to mutations in the signalling lymphocyte activation molecule (SLAM) associated protein (SAP) molecule. We examined the impact of dysfunctional proliferative control on the extent of CD8+ T cell differentiation in XLP patients who recovered from primary EBV infection. Although these young patients have normal numbers of lytic and latent EBV-epitope-specific CD8+ T cells, they were extremely differentiated as defined by loss of CCR7 and CD27, low telomerase activity and very short telomeres. This was not a direct effect arising from the loss of SAP, but was due to excessive T cell stimulation due to this defect. Thus, transduction of XLP CD8+ T cells with the catalytic component of telomerase (hTERT), but not SAP, prevented telomere loss and considerably extended proliferative lifespan in vitro. These results indicate that excessive proliferation in CD8+ T cells in XLP patients may lead to end-stage differentiation and loss of functional EBV-specific CD8+ T cells through replicative senescence. This may contribute to the defective immunity found in XLP patients who survive acute EBV infection who develop EBV-related B cell lymphomas before the fourth decade of life. 相似文献
108.
Felix S. B. Baumann G. Hashemi T. Niemczyk M. Ochsenfeld G. Ahmad Z. Shirani S. Blömer H. 《Inflammation research》1991,33(3-4):349-358
Summary
In vivo anaphylaxis is associated with respiratory distress and cardiovascular failure. The present investigation was designed to further characterize respiratory and cardiac anaphylactic events. In guinea pigs, sensitization was produced by subcutaneous application of ovalbumin together with Freund's adjuvant. Fourteen days after sensitization, the effects of an intravenous infusion of ovalbumin were tested in the anesthetized artificially ventilated guinea pigs. The renewed application of the antigen induced an initial increase of left ventricular pressure which was followed by a rapid decrease 5 min after antigenic challenge. Enddiastolic left ventricular pressure increased within 3 min, thus indicating left ventricular pump failure. In the same time range, ECG recordings uniformly showed signs of acute myocardial ischemia. In addition, heart rate steadily decreased. All animals died within 15 min. Simultaneously with cardiac anaphylactic malfunction, severe arterial hypoxia and carbon dioxide retention occurred, revealing respiratory distress.Histamine is known as a potent bronchoconstrictor via histamine H1-receptor stimulation. Administration of H1-recpetor antagonists to improve respiration may therefore provide further information on the contribution of pulmonary malfunction to anaphylactic cardiovascular shock. Therefore, additional experiments were performed with sensitized guinea pigs pretreated with the histamine H1-receptor blocker mepyramine. In these experiments the antigenic challenge induced a dissociation of cardiac and respiratory manifestation of anphylaxis. Despite inhibition of hypoxia and carbon dioxide retention, left ventricular pump failure and occurrence of myocardial ischemia were delayed but not suppressed.It is concluded that histamine is an important mediator of anaphylactic respiratory distress. However, vasoactive anaphylactic mediators other than histamine are primarily involved in anaphylactic cardiac malfunction occurring during the later phase of systemic anaphylaxis.Supported by grant Fe 250/1-1 from the Deutsche Forschungsgemeinschaft (DFG). 相似文献
109.
Bruce Ho PhD Woodrew Chao Reza Sadri Lu Huang Ricky Taira Henry Shih 《Journal of digital imaging》1995,8(4):180-190
A key advantage in the conversion from film-based to digital radiology is the possibility of a long-term on line electronic archival of patient studies. The popular approach based on optical disk jukeboxes for the long-term archive and magnetic disk storage for data caching is not economically attractive because of the cost of both the jukebox and the medium. Strategies for extending the archival system design with a tape jukebox have been studied. The proposed strategy calls for the use of high-ratio lossy compression together with low-cost tape storage to make long-term on line archiving more affordable. An intelligent prefetching algorithm based on hospital information system and radiologic information system triggers, which in turn are augmented by manual case preparation, can effectively overcome the longer latency of ad hoc retrievals. This longer latency is caused by both system-level bottlenecks and the sequential access constraint of the tape drive. Strategies for image clustering and tape allocation by patient classification also enhance retrieval efficiency. This archival design using image compression, prefetching, and clustering could be implemented in many of the existing teleradiology and picture archiving and communication systems. 相似文献
110.
Ahmad W Noci S Faiyaz ul Haque M Sarno T Aridon P Ahmad MM Amin-Ud-Din M Rafiq MA ul Haque S De Fusco M Ballabio A Franco B Casari G 《American journal of medical genetics》2001,100(1):62-65
Nonspecific X-linked mental retardation is a nonprogressive, genetically heterogeneous condition that affects cognitive function in the absence of other distinctive clinical manifestations. We report here linkage data on a large Pakistani family affected by a form of X-linked nonspecific mental retardation. X chromosome genotyping of family members and linkage analysis allowed the identification of a new disease locus, MRX53. The defined critical region spans approximately 15 cM between DXS1210 and DXS1047 in Xq22.2-26. A LOD score value of 3.34 at no recombination was obtained with markers DXS1072 and DXS8081. 相似文献