全文获取类型
收费全文 | 7290篇 |
免费 | 377篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 202篇 |
儿科学 | 135篇 |
妇产科学 | 79篇 |
基础医学 | 954篇 |
口腔科学 | 131篇 |
临床医学 | 436篇 |
内科学 | 1654篇 |
皮肤病学 | 339篇 |
神经病学 | 507篇 |
特种医学 | 359篇 |
外科学 | 1217篇 |
综合类 | 25篇 |
预防医学 | 176篇 |
眼科学 | 76篇 |
药学 | 578篇 |
中国医学 | 45篇 |
肿瘤学 | 792篇 |
出版年
2023年 | 37篇 |
2022年 | 36篇 |
2021年 | 148篇 |
2020年 | 57篇 |
2019年 | 100篇 |
2018年 | 142篇 |
2017年 | 109篇 |
2016年 | 118篇 |
2015年 | 161篇 |
2014年 | 161篇 |
2013年 | 223篇 |
2012年 | 376篇 |
2011年 | 364篇 |
2010年 | 242篇 |
2009年 | 211篇 |
2008年 | 381篇 |
2007年 | 375篇 |
2006年 | 437篇 |
2005年 | 474篇 |
2004年 | 446篇 |
2003年 | 408篇 |
2002年 | 475篇 |
2001年 | 172篇 |
2000年 | 189篇 |
1999年 | 208篇 |
1998年 | 150篇 |
1997年 | 105篇 |
1996年 | 103篇 |
1995年 | 78篇 |
1994年 | 54篇 |
1993年 | 59篇 |
1992年 | 99篇 |
1991年 | 113篇 |
1990年 | 83篇 |
1989年 | 86篇 |
1988年 | 82篇 |
1987年 | 78篇 |
1986年 | 81篇 |
1985年 | 77篇 |
1984年 | 42篇 |
1983年 | 53篇 |
1982年 | 19篇 |
1981年 | 27篇 |
1980年 | 17篇 |
1979年 | 34篇 |
1975年 | 15篇 |
1971年 | 28篇 |
1969年 | 19篇 |
1967年 | 19篇 |
1966年 | 17篇 |
排序方式: 共有7705条查询结果,搜索用时 15 毫秒
61.
Kandori A Yokoe M Sakoda S Abe K Miyashita T Oe H Naritomi H Ogata K Tsukada K 《Neuroscience research》2004,49(2):253-260
To develop a new measurement tool for quantitatively detecting the finger movement of a patient with Parkinson's disease (PD), we designed a magnetic sensing system consisting of a magnetic induction coil, a sensing coil, and a circuit unit. The sensing coil detects the inducted magnetic field that varies with the distance between the two coils, and the detected signals are demodulated in the circuit unit in order to obtain the variation voltage from the oscillation frequency. To obtain a coefficient for converting voltage to distance, we measured the output voltages for seven fixed finger positions of 12 normal volunteers. The voltage differences corresponding to the finger movement in 20 PD patients, six age-matched controls, and 12 normal volunteers were then recorded for 30s. To investigate the velocity and acceleration of the finger movement, we calculated their waveforms from the measured displacement waveform. We also detected the main frequency of the tapping rhythm by using a fast Fourier transform (FFT). The averaged amplitude of each waveform decreased with the disorder in the Hoehn-Yahr (HY) stage, while the averaged tapping frequency of PD patients did not have any correlation with this stage. It can be concluded that this magnetic sensing system can assess finger movement quantitatively. 相似文献
62.
Sudo N Aiba Y Oyama N Yu XN Matsunaga M Koga Y Kubo C 《International archives of allergy and immunology》2004,135(2):132-135
BACKGROUND: Intestinal microbiota are known to play an important role in the establishment of oral tolerance, thereby protecting the organism from food allergies. Dietary intake of nucleic acid (NA) is also reported to have such an anti-allergic effect; however, one unsolved question is whether or not dietary NA would act through a process of toll-like receptor 9 signaling activated by DNA containing a CpG motif, a well-known sequence leading to immunostimulatory activity. In this study, we focused on the question of whether the addition of dietary NA lacking CpG motifs would allow continued modulation of the Th1/Th2 balance. METHODS: Germ free (GF) and Bifidobacterium-infantis-monoassociated BALB/c mice were maintained on either an NA-free casein diet or on an NA-supplemented casein diet for 4 weeks. Thereafter, both the in vivo anti-casein antibody levels and in vitro splenocyte cytokine secretion pattern were evaluated. RESULTS: Feeding with a casein diet elicited a substantial increase in the serum anti-casein-specific IgG1, IgG2a, and IgE levels of GF mice fed the NA free-diet. The in vitro cytokine production profile showed that enhanced IL-4 production in the GF mice fed the NA free-diet was markedly reduced by the supplementation with dietary NA in both the GF and B.-infantis-monoassociated mice. In addition, IFN-gamma secretion increased in the B.-infantis-reconstituted mice fed the diet containing NA. CONCLUSIONS: These results suggest that dietary intake of NA devoid of CpG motifs may prevent the development of allergies via acceleration of Th1-dominant immunity. 相似文献
63.
Tenno T Fujiwara K Tochio H Iwai K Morita EH Hayashi H Murata S Hiroaki H Sato M Tanaka K Shirakawa M 《Genes to cells : devoted to molecular & cellular mechanisms》2004,9(10):865-875
Ubiquitination, a modification in which single or multiple ubiquitin molecules are attached to a protein, serves as a signalling function that controls a wide variety of cellular processes. To date, two major forms of polyubiquitin chain have been functionally characterized, in which the isopeptide bond linkages involve Lys48 or Lys63. Lys48-linked polyubiquitin tagging is mostly used to target proteins for degradation by the proteasome, whereas Lys63-linked polyubiquitination has been linked to numerous cellular events that do not rely on degradative signalling via the proteasome. Apparently linkage-specific conformations of polyubiquitin chains are important for these cellular functions, but the structural bases distinguishing Lys48- and Lys63-linked chains remain elusive. Here, we report NMR and small-angle X-ray scattering (SAXS) studies on the intersubunit interfaces and conformations of Lys63- and Lys48-linked di- and tetraubiquitin chains. Our results indicate that, in marked contrast to Lys48-linked chains, Lys63-linked chains are elongated molecules with no stable non-covalent intersubunit interfaces and thus adopt a radically different conformation from that of Lys48-linked chains. 相似文献
64.
Summary The host-vector system of an n-lkaneassimilating-yeast, Candida maltosa, which we previously constructed using an autonomously replicating sequence (ARS) region isolated from the genome of this yeast, utilizes C. maltosa J288 (leu2
–) as a host. As this host had a serious growth defect on n-alkane, we developed an improved host-vector system using C. maltosa CHI (his) as host. The vectors were constructed with the Candida ARS region and a DNA fragment isolated from the genome of C. maltosa. Since this DNA fragment could complement histidine auxotrophy of both C. maltosa CH1 and S. cerevisiae (hiss
–), we termed the gene contained in this DNA fragment C-HIS5. The vectors were characterized in terms of transformation frequency and stability, and the nucleotide sequence of C-HISS was determined. The deduced amino acid sequence (389 residues) shared 51% homology with that of HISS of S. cerevisiae (384 residues; Nishiwaki et al. 1987). 相似文献
65.
Neuromedin B (NMB) is a mammalian bombesin (BN)-like peptide that exerts its function via the neuromedin B receptor (NMB-R). The NMB/NMB-R system is involved in stress response, and therefore we examined behavioral properties in female mice lacking NMB-R using a restraint-induced stress paradigm. Thirty minutes of restraint in a wire mesh cage constituted a sufficient stress stimulus for mice as evidenced by elevated blood glucose concentrations in stressed wild-type and NMB-R-deficient mice. Using a one-trial passive avoidance test, stressed NMB-R-deficient mice exhibited a marked reduction in memory performance. NMB-R-deficient mice exhibited elevated spontaneous activity in a novel environment compared to non-stressed mutant mice after 30-min stress, and a similar difference was also observed between stressed/non-stressed wild-type mice. An elevated plus maze test showed that the stress stimulus had no effect on anxiety in either wild-type or NMB-R-deficient mice. Furthermore, pain response of wild-type and NMB-R-deficient mice induced by electric foot shock was not affected under either stressed or non-stressed conditions. These results indicate that impaired memory performance in stressed NMB-R-deficient mice is not a consequence of changes in spontaneous activity, anxiety, or pain response, and suggest that the NMB/NMB-R pathway may play a role in regulating the stress response via the neural system that controls learning and memory. 相似文献
66.
Gender-specific haplotype association of collagen α2 (XI) gene in ossification of the posterior longitudinal ligament of the spine 总被引:5,自引:0,他引:5
Maeda S Koga H Matsunaga S Numasawa T Ikari K Furushima K Harata S Takeda J Sakou T Komiya S Inoue I 《Journal of human genetics》2001,46(1):1-4
Among Japanese, ossification of the posterior longitudinal ligament of the spine (OPLL) is a leading cause of myelopathy,
showing ectopic bone formation in the paravertebral ligament. We have provided genetic evidence that the collagen α2 (XI)
(COL11A2) locus of chromosome 6 constitutes susceptibility for OPLL. Five distinct single nucleotide polymorphisms (SNPs), identified
in COL11A2, were combined to construct possible haplotypes by the use of a maximum likelihood program. Estimated haplotype frequency
was compared in OPLL patients and non-OPLL controls. We report a gender-specific association of the COL11A2 haplotype with OPLL. The frequency of the most commonly observed haplotype was significantly higher in male patients (P = 0.0003) compared with controls, but not in female patients (P = 0.21). OPLL is predominantly observed in males, with a prevalence ratio of 2 : 1, and our gender-specific associations
indicate that genetic factors involving COL11A2 play a specific role in the etiology of OPLL exclusively in males.
Received: September 5, 2000 / Accepted: October 2, 2000 相似文献
67.
Inden K Hatta M Kunishima H Kanemitsu K Kaku M 《Rinsho byori. The Japanese journal of clinical pathology》2005,53(4):345-349
The Department of Clinical Laboratory plays an important role in the hospital and has much information about patients and pathogens. Laboratory data are essential to support clinical physicians who diagnose and treat patients. For nosocomial infections, laboratory-based surveillance is recognized as essential to confirm outbreaks. Therefore, the role of the Department of Clinical Laboratory is very important in infection control. In Tohoku University Hospital, we have an Infection Control Unit located in the Department of Clinical Laboratory. The core role of the Infection Control Unit is diagnosis, treatment and preventative healthcare associated with infections. The Infection Control Team (ICT) performs rounds in the hospital (The ICT members are ICN, ICD, a microbiological technologist and a dietician), consultations about clinical cases, infection control, and organize the regional infection control network, "Miyagi Infection Control Network". The ICT rounds are performed once a week in two wards, and two times a year for one ward. The consultations are an important role of the ICD, and concern clinical infection cases and infection control in our hospital and the other regional hospitals, and produce advice on appropriate clinical information. The regional network is important for the collection of information about the pathogens and the susceptibility of antimicrobial agents in the region. "Miyagi Infection Control Network" has held a forum 5 times a year from 1999, and 300-400 healthcare workers join the forum and discuss infection control. 相似文献
68.
C H Lai U M Babu K Matsunaga Z A Nagy J Klein H A Turchin P H Maurer 《Experimental and clinical immunogenetics》1986,3(1):38-48
The proliferative T cell responses to poly(GluLysTyr) (GLT) and poly(GLULysPhe) (GLPhe) are restricted by the E alpha E beta class II MHC molecule (E) in most responded strains. Some nonresponder strains that carry responder E beta, but cannot express cell surface E molecules, can complement with other nonresponder strains that provide the missing E alpha chain needed for the expression of E molecules and for responsiveness to GLT and GLPhe. Here another type of complementation is described between two E-nonexpressor haplotypes, H-2f and H-2s, which result in E-nonexpressor F1 hybrids, which are responders to GLT. The restriction element involved in this response is an Af/As hybrid molecule. The data support the hypothesis that conformational determinants resulting from the free association of alpha and beta chains in heterozygotes can increase the immune potential of the individual. 相似文献
69.
70.
Takaaki Ohmori Ryo Tabei Keiji Fukui Kazuhiko Sadamoto Saburo Sakaki 《Pathology international》1989,39(3):190-194
Two cases of meningioma revealing conspicuous plasmo lymphocytic tissue and hyalinized fibrous tissue components are reported. Histopathological examination of the plasmo lymphocytic infiltration was performed. Both lesions showed polyclonality of plasma cells as revealed by positive reactions for 1gG and paraimmunoglobulin χ- and λ light chains, and amyloid infiltration into the fibrous stroma and blood vessel walls. The histochemical and immunohistochemical characteristics of the lesion in relation to its etiology are briefly discussed. Acta Pathol. Jpn. 32: 190∼194, 1989. 相似文献