全文获取类型
收费全文 | 4499篇 |
免费 | 241篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 50篇 |
儿科学 | 162篇 |
妇产科学 | 29篇 |
基础医学 | 563篇 |
口腔科学 | 120篇 |
临床医学 | 297篇 |
内科学 | 934篇 |
皮肤病学 | 65篇 |
神经病学 | 513篇 |
特种医学 | 198篇 |
外科学 | 661篇 |
综合类 | 198篇 |
预防医学 | 222篇 |
眼科学 | 75篇 |
药学 | 331篇 |
中国医学 | 6篇 |
肿瘤学 | 326篇 |
出版年
2023年 | 34篇 |
2022年 | 51篇 |
2021年 | 125篇 |
2020年 | 51篇 |
2019年 | 91篇 |
2018年 | 116篇 |
2017年 | 85篇 |
2016年 | 86篇 |
2015年 | 108篇 |
2014年 | 155篇 |
2013年 | 206篇 |
2012年 | 289篇 |
2011年 | 310篇 |
2010年 | 163篇 |
2009年 | 169篇 |
2008年 | 236篇 |
2007年 | 242篇 |
2006年 | 263篇 |
2005年 | 217篇 |
2004年 | 203篇 |
2003年 | 196篇 |
2002年 | 153篇 |
2001年 | 120篇 |
2000年 | 103篇 |
1999年 | 94篇 |
1998年 | 64篇 |
1997年 | 57篇 |
1996年 | 54篇 |
1995年 | 29篇 |
1994年 | 50篇 |
1993年 | 40篇 |
1992年 | 61篇 |
1991年 | 56篇 |
1990年 | 41篇 |
1989年 | 40篇 |
1988年 | 41篇 |
1987年 | 51篇 |
1986年 | 41篇 |
1985年 | 39篇 |
1984年 | 29篇 |
1983年 | 26篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 13篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 14篇 |
1967年 | 6篇 |
排序方式: 共有4750条查询结果,搜索用时 31 毫秒
41.
Role of nitric oxide in the biology, physiology and pathophysiology of reproduction 总被引:13,自引:0,他引:13
Following its benchmark discovery, nitric oxide (NO) is nowknown to play important functional roles in a variety of physiologicalsystems. Within the vasculature, NO induces vasodilation, inhibitsplatelet aggregation, prevents neutrophil/platelet adhesionto endothelial cells, inhibits smooth muscle cell proliferationand migration, regulates programmed cell death (apoptosis) andmaintains endothelial cell barrier function. NO generated byneurons acts as a neurotransmitter, whereas NO generated bymacrophages in response to invading microbes acts as an antimicrobialagent. Because neurons, blood vessels and cells of the immunesystem are integral parts of the reproductive organs, and inview of the important functional role that NO plays in thosesystems, it is likely that NO is an important regulator of thebiology and physiology of the reproductive system. Indeed, inthe past 10 years, NO has established itself as a polyvalentmolecule which plays a decisive role in regulating multiplefunctions within the female as well as the male reproductivesystem. This review provides an overview of the role of NO invarious reproductive organs under physiological and pathologicalconditions. 相似文献
42.
Shah P Patkar D Patankar T Shah J Srinivasa P Krishnan A 《Journal of postgraduate medicine》1999,45(3):84-86
Hypothalamic hamartomas are rare tumours of particular interest because of their unusual symptoms. Three cases of hypothalamic hamartomas are reported in children, who presented with precocious puberty and gelastic seizures. 相似文献
43.
44.
Sandford R; Sgotto B; Aparicio S; Brenner S; Vaudin M; Wilson RK; Chissoe S; Pepin K; Bateman A; Chothia C; Hughes J; Harris P 《Human molecular genetics》1997,6(9):1483-1489
PKD1 is the major locus of the common genetic disorder autosomal dominant
polycystic kidney disease (ADPKD). Analysis of the predicted protein
sequence of the human PKD1 gene, polycystin, shows a large molecule with a
unique arrangement of extracellular domains and multiple putative
transmembrane regions. The precise function of polycystin remains unclear
with a paucity of mutations to define key structural and functional
domains. To refine the structure of this protein we have cloned the genomic
region encoding the Fugu PKD1 gene. Fugu PKD1 spans 36 kb of genomic DNA
and has greater complexity with 54 exons compared with 46 in man.
Comparative analysis of the predicted protein sequences shows a lower level
of homology than in similar studies with identity of 40 and 59% similarity.
However key structural motifs including leucine rich repeats (LRR), a
C-type lectin and LDL-A like domains and 16 PKD repeats are maintained. A
region of homology with the sea urchin REJ protein was also confirmed in
Fugu but found to extend over 1000 amino acids. Several highly conserved
intra- and extra- cellular regions, with no known sequence homologies, that
are likely to be of functional importance were detected. The likely
structure of the membrane associated region has been refined with
similarity to the PKD2 protein and voltage gated Ca2+ and Na+ channels
highlighted over part of this area. The overall protein structure has
therefore been clarified and this comparative analysis derived structure
will form the basis for the functional study of polycystin and its
individual domains.
相似文献
45.
BenMohamed L Krishnan R Longmate J Auge C Low L Primus J Diamond DJ 《Human immunology》2000,61(8):764-779
CTL play a pivotal role in the immune response during viral infections. In this study, the HLA class II restricted T(H) requirement for optimal in vivo induction of HLA class I restricted CTL responses has been investigated. Towards this goal, transgenic mice expressing both HLA class I (A*0201 or A2.1) and class II (DRB1*0101 or DR1) molecules have been derived. Immunization of these mice with an HLA A*0201-restricted and CMV-specific CTL epitope (pp65(495-503)), and either of three different tetanus toxin-derived MHC class II-binding T(H) epitopes, resulted in a vigorous CTL response. CTL specific for the pp65(495-503) epitope were dramatically enhanced in mice expressing both the HLA-DR1 and HLA-A*0201 transgenes. Notably, preinjection of three TT peptides (TT(639-652), TT(830-843), and TT(947-967)) increased the capability of HLA A*0201/DR1 Tg mice to respond to subsequent immunization with the T(H) + CTL peptide mixture. These results indicate that the use of HLA A*0201/DR1 Tg mice constitute a versatile model system (in lieu of immunizing humans) for the study of both HLA class I and class II restricted T-cell responses. These studies provide a rational model for the design and assessment of new minimal-epitope vaccines based on their in vivo induction of a pathogen-specific CTL response. 相似文献
46.
A simple method is described for labelling cells with fluorescein and using them in artificial mixtures to assess cell separation procedures. The method facilitates the examination of the variables in a separation procedure. It is thus possible to tailor a separation procedure (for example panning with monoclonal antibody) to suit the specific requirements of the experiment. 相似文献
47.
Subcortical hyperintensities on brain magnetic resonance imaging: a comparison between late age onset and early onset elderly depressed subjects 总被引:1,自引:0,他引:1
G S Figiel K R Krishnan P M Doraiswamy V P Rao C B Nemeroff O B Boyko 《Neurobiology of aging》1991,12(3):245-247
Subcortical structural changes have been reported to occur in some elderly subjects with late age onset depression. Given the association between diseases affecting subcortical structures and affective disorders, this suggests that these structural changes may be involved in the etiology of late age onset depression in some patients. With the advent of Brain Magnetic Resonance Imaging (MRI), "in vivo" analysis of these subcortical structures is now possible. The authors report a higher occurrence of caudate (60% vs. 11%) and large deep white matter hyperintensities (60% vs. 11%) in late age onset elderly depressed subjects compared with early onset elderly depressed subjects. These results suggest that late age onset depression may be mediated by caudate and white matter structural changes in some patients. 相似文献
48.
A 60-year-old female developed a right parotid swelling six months after surgery for intra-oral squamous cell carcinoma. Fine needle aspiration (FNA) cytological smears showed dissociated large and small pleomorphic tumour cells with abundant mitoses and oncocytic features. A cytological diagnosis of parotid acinic cell carcinoma (ACC) was made. Histological study of the subtotal parotidectomy specimen showed a papillary cystic variety of acinic cell carcinoma (ACC-PCV). FNA cytological features in this case of ACC-PCV differs from the two previously reported cases in that it showed prominent oncocytic and high grade features and absence of papillary pattern in the cytological smears. ACC-PCV is an uncommon tumour and knowledge of its varied FNA cytological features is important for the diagnosis of this neoplasm. 相似文献
49.
Jonathan T. Sims Venkatesh Krishnan Ching-Yun Chang Sarah M. Engle Giacomo Casalini George H. Rodgers Nicoletta Bivi Brian J. Nickoloff Robert J. Konrad Stephanie de Bono Richard E. Higgs Robert J. Benschop Silvia Ottaviani Anabela Cardoso Ajay Nirula Mario Corbellino Justin Stebbing 《The Journal of allergy and clinical immunology》2021,147(1):107-111
50.
Neurovegetative symptoms in chronic pain and depression 总被引:1,自引:0,他引:1
The pattern and frequency of neurovegetative symptoms was studied in 57 patients with chronic pain. Seventy-nine percent of these patients had a diagnosable depressive illness, but endogenous depression was rare (5%). Patients with chronic pain were divided into major depressives, minor/intermittent depressives and patients with no depression. A control group of nonendogenous major depressives without pain was also utilized. Major depressives differed from the other two chronic pain groups in that there was more frequent or severe early waking, weight loss, anorexia, diminished libido and initial insomnia. Diurnal variation of mood was not a characteristic of major depression with chronic pain, and did not differ in frequency from the other two chronic pain groups. Major depressives exhibited a profile of neurovegetative symptoms very similar to that found in the control group of major depressives. Over one-third of minor/intermittent depressed patients with chronic pain exhibited atypical (reversed) vegetative symptoms of hyperphagia and weight gain. This finding, together with our review of the literature, suggests an important and previously unrecognized link between atypical depression and chronic pain. 相似文献