全文获取类型
收费全文 | 11031篇 |
免费 | 484篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 126篇 |
妇产科学 | 135篇 |
基础医学 | 1210篇 |
口腔科学 | 403篇 |
临床医学 | 652篇 |
内科学 | 3024篇 |
皮肤病学 | 180篇 |
神经病学 | 715篇 |
特种医学 | 234篇 |
外科学 | 1942篇 |
综合类 | 53篇 |
预防医学 | 252篇 |
眼科学 | 191篇 |
药学 | 895篇 |
中国医学 | 33篇 |
肿瘤学 | 1458篇 |
出版年
2023年 | 58篇 |
2022年 | 88篇 |
2021年 | 202篇 |
2020年 | 116篇 |
2019年 | 144篇 |
2018年 | 208篇 |
2017年 | 181篇 |
2016年 | 196篇 |
2015年 | 167篇 |
2014年 | 246篇 |
2013年 | 288篇 |
2012年 | 544篇 |
2011年 | 537篇 |
2010年 | 327篇 |
2009年 | 284篇 |
2008年 | 485篇 |
2007年 | 619篇 |
2006年 | 546篇 |
2005年 | 582篇 |
2004年 | 562篇 |
2003年 | 484篇 |
2002年 | 571篇 |
2001年 | 287篇 |
2000年 | 290篇 |
1999年 | 286篇 |
1998年 | 141篇 |
1997年 | 116篇 |
1996年 | 109篇 |
1995年 | 113篇 |
1994年 | 73篇 |
1993年 | 79篇 |
1992年 | 233篇 |
1991年 | 187篇 |
1990年 | 182篇 |
1989年 | 218篇 |
1988年 | 181篇 |
1987年 | 168篇 |
1986年 | 161篇 |
1985年 | 157篇 |
1984年 | 115篇 |
1983年 | 99篇 |
1982年 | 67篇 |
1979年 | 81篇 |
1978年 | 69篇 |
1977年 | 61篇 |
1976年 | 61篇 |
1974年 | 59篇 |
1973年 | 53篇 |
1972年 | 51篇 |
1969年 | 66篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Cold-adaptation of human rotavirus 总被引:2,自引:0,他引:2
S Matsuno S Murakami M Takagi M Hayashi S Inouye A Hasegawa K Fukai 《Virus research》1987,7(3):273-280
A human rotavirus strain was cold-adapted for possible future use as a live vaccine. The original strain was isolated in 1980 in primary cynomolgus monkey kidney cells and has a serotype I and subgroup II antigenicity. The virus was serially passaged in African green monkey kidney cells; it was cultivated at 37 degrees C at the first stage of passages, and the cultivation temperature was then shifted down stepwise by 3 degrees C per each 10 passages. Finally the virus was passaged 10 times at 25 degrees C (total passage number of 55). The virus formed small-size plaques with irregular shaped borders at 31 degrees C. Growth at 25 degrees C of the cold-adapted virus was higher than that of the original virus. There was no difference between the migration patterns of 11 dsRNA segments in polyacrylamide gel electrophoresis of the original and the cold-adapted viruses. 相似文献
72.
Dr. S. Shiosaka M. Tohyama H. Takagi Y. Takahashi Y. Saitoh T. Sakumoto H. Nakagawa N. Shimizu 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1980,39(4):377-388
Summary The ascending and descending components of the medial forebrain bundle (MFB) were investigated by means of horseradish peroxidase (HRP) with a sensitive substrate. The HRP was injected iontophoretically into the MFB at various levels from the anterior commissure to the posterior hypothalamus. In order to prevent the diffusion of HRP to other brain areas, a double micropipette system was used. The descending components of the MFB are derived from (1) the anterior cingulate area, infra- or prelimbic area, and sulcal cortex, (2) the lateral septal nucleus and diagonal band, (3) the bed nucleus of the stria terminalis, (4) the paraventricular nucleus (5) the substantia innominata, (6) the amygdaloid complex (AM), (7) the ventromedial (VM) and dorsomedial (DM) hypothalamic nuclei, (8) the entopeduncular nucleus and (9) nucleus periventricularis stellatocellularis. The ascending components of the MFB originate in: (1) the medial preoptic nucleus, (2) the nucleus periventricularis stellatocellularis and rotundocellularis, (3) the posterior hypothalamic nucleus, (4) the parafascicular nucleus, (5) the ventral premammillary nucleus, (6) the substantia grisea periventricularis, (7) the lateral habenular nucleus, (8) the VM and DM, (9) the paratenial nucleus, (10) the AM and (11) the arcuate nucleus.Abbreviations used in Figures and Tables a
nucleus accumbens
- abl
nucleus amygdaloideus basalis, pars lateralis
- abm
nucleus amygdaloideus basalis, pars medialis
- ac
nucleus amygdaloideus centralis
- AC
anterior cingulate area
- al
nucleus amygdaloideus lateralis
- am
nucleus amygdaloideus medialis
- ar
nucleus arcuatus
- CC
tractus corporis callosi
- CSDV
commissura supraoptica dorsalis, pars ventralis
- DB
diagonal band
- DM
nucleus dorsomedialis hypothalami
- EP
nucleus entopeduncularis
- ha
nucleus anterior hypothalami
- hl
nucleus lateralis hypothalami
- hp
nucleus posterior hypothalami
- IL
infralimbic area of frontal cortex
- lh
nucleus habenulae lateralis
- LH1
medial forebrain bundle (MFB) at the level of commissura anterior
- LH2
lateral preoptic area
- LH3
MFB at the level of the nucleus anterior hypothalami
- LH4
MFB at the level of the nucleus ventromedialis hypothalami
- LH5
MFB at the level of the nucleus posterior hypothalami
- MFB
medial forebrain bundle
- pf
nucleus parafascicularis
- PL
prelimbic area of frontal cortex
- pol
nucleus preopticus lateralis
- pom
nucleus preopticus medialis
- posc
nucleus preopticus, pars suprachiasmatica
- pt
nucleus parataenialis
- pv
nucleus premamillaris ventralis
- PV
nucleus paraventricularis
- pvs
nucleus periventricularis stellatocellularis
- pvr
nucleus periventricularis rotundocellularis
- SC
sulcal cortex
- SGPV
substantia grisea periventricularis
- SI
substantia innominata
- SL
lateral septal nucleus
- ST
bed nucleus of stria terminalis
- sum
nucleus supramamillaris
- TO
tractus opticus
- tmm
nucleus medialis thalami, pars medialis
- VM
nucleus ventromedialis hypothalami
The nomenclature used in this paper is according to König and Klippel's Stereotaxic Atlas (1967). 相似文献
73.
Opioid kappa-agonists had much more potent inhibitory effects on the high K+-evoked Met-enkephalin release from rat brain slices than did the mu- or delta-agonists. The opioid kappa- antagonist, MR2266 enhanced the evoked release of Met-enkephalin to a greater extent than did mu- or delta-antagonists in vitro and had a potent analgesia in mice in vivo. These findings suggest that the release of Met-enkephalin may be regulated in vitro and in vivo, mainly by presynaptic kappa-receptor-mediated mechanisms. 相似文献
74.
Atsuko Iwasa Yoshinao Oda Shuichi Kurihara Yoshihiro Ohishi Masafumi Yasunaga Izumi Nishimura Emi Takagi Hiroaki Kobayashi Norio Wake Masazumi Tsuneyoshi 《Pathology international》2008,58(12):757-764
Ovarian mature cystic teratomas (MCT) uncommonly undergo malignant transformation to squamous cell carcinoma (SCC). While alterations in the p53 tumor suppressor gene and protein have been shown, few studies have analyzed other molecular changes leading to this malignant conversion. The purpose of the present study was to investigate 21 samples of SCC arising in MCT for altered expression in known p53‐ and p16/Rb‐dependent cell cycle regulatory proteins, and the association between their expression and cellular proliferation and histological features. Overexpression of the p53 protein was observed in 14 SCC (67%), while four (19%) had point mutations in the p53 gene. Reduced expression of the p16 protein was observed in 18 SCC (86%), while p16 gene alterations (hypermethylation (29%) and point mutation (33%)) were found in 11 (52%). Furthermore, a statistically significant correlation was observed between p53 and Rb overexpression (P = 0.0010), and the overexpression of both p53 and Rb was respectively significantly correlated with increased cellular proliferation. The results indicate that alterations in both the p53 and p16‐Rb pathways are associated with SCC arising in MCT. 相似文献
75.
76.
Yamazaki K McGovern D Ragoussis J Paolucci M Butler H Jewell D Cardon L Takazoe M Tanaka T Ichimori T Saito S Sekine A Iida A Takahashi A Tsunoda T Lathrop M Nakamura Y 《Human molecular genetics》2005,14(22):3499-3506
The inflammatory bowel diseases (IBDs), Crohn's disease (CD) and ulcerative colitis, are chronic inflammatory disorders of the digestive tract. The pathogenesis of IBD is complicated, and it is widely accepted that immunologic, environmental and genetic components contribute to its etiology. To identify genetic susceptibility factors in CD, we performed a genome-wide association study in Japanese patients and controls using nearly 80,000 gene-based single nucleotide polymorphism (SNP) markers and investigated the haplotype structure of the candidate locus in Japanese and European patients. We identified highly significant associations (P = 1.71 x 10(-14) with odds ratio of 2.17) of SNPs and haplotypes within the TNFSF15 (the gene encoding tumor necrosis factor superfamily, member 15) genes in Japanese CD patients. The association was confirmed in the study of two European IBD cohorts. Interestingly, a core TNFSF15 haplotype showing association with increased risk to the disease was common in the two ethnic groups. Our results suggest that the genetic variations in the TNFSF15 gene contribute to the susceptibility to IBD in the Japanese and European populations. 相似文献
77.
Matsuguchi T Takagi A Matsuzaki T Nagaoka M Ishikawa K Yokokura T Yoshikai Y 《Clinical and diagnostic laboratory immunology》2003,10(2):259-266
Lactobacilli are nonpathogenic gram-positive inhabitants of microflora. At least some Lactobacillus strains have been postulated to have health beneficial effects, such as the stimulation of the immune system. Here we examined the stimulatory effects of lactobacilli on mouse immune cells. All six heat-killed Lactobacillus strains examined induced the secretion of tumor necrosis factor alpha (TNF-alpha) from mouse splenic mononuclear cells, albeit to various degrees. When fractionated subcellular fractions of Lactobacillus casei were tested for NF-kappaB activation and TNF-alpha production in RAW264.7, a mouse macrophage cell line, the activity was found to be as follows: protoplast > cell wall > polysaccharide-peptidoglycan complex. Both crude extracts and purified lipoteichoic acids (LTAs) from two Lactobacillus strains, L. casei and L. fermentum, significantly induced TNF-alpha secretion from RAW264.7 cells and splenocytes of C57BL/6, C3H/HeN, and C3H/HeJ mice but not from splenocytes of C57BL/6 TLR2(-/-) mice. Lactobacillus LTA induced activation of c-Jun N-terminal kinase activation in RAW264.7 cells. Furthermore, in HEK293T cells transected with a combination of CD14 and Toll-like receptor 2 (TLR2), NF-kappaB was activated in response to Lactobacillus LTA. Taken together, these data suggest that LTAs from lactobacilli elicit proinflammatory activities through TLR2. 相似文献
78.
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
79.
A pharmacological and histological examination of the microcirculation of the rat subcutaneous air-pouch: microcirculation of the rat air-pouch 总被引:1,自引:0,他引:1
The effects of histamine, 5-hydroxytryptamine (5-HT) and prostaglandin E2 (PGE2) on plasma protein extravasation in the rat subcutaneous air-pouch have been studied. Both histamine and 5-HT produced increases in plasma protein extravasation which were inhibited by specific receptor antagonists. Plasma protein extravasation induced by PGE2 was partially inhibited by either a 5-HT receptor antagonist (methysergide) or by a combination of H1 and H2 receptor antagonists (mepyramine and cimetidine). A combination of all three antagonists further reduced plasma protein extravasation. These results suggest that PGE2 increases vascular permeability indirectly via the degranulation of mast cells. This supposition was confirmed by histological evidence of extensive mast cell degranulation following the injection of PGE2 but not following histamine, 5-HT or saline injection. Using a technique of vascular labelling, following the intravenous injection of Monastral blue dye, plasma extravasation induced by histamine, 5-HT or PGE2 was observed to be restricted to post-capillary venules and was not observed in arterioles or capillaries. Electron microscopic examination of the tissue revealed the presence of monastral blue particles trapped between endothelial cells. These findings suggest that the microcirculation of the rat subcutaneous air-pouch behaves in an analogous manner to that of other tissues. 相似文献
80.
Takayama H Takagi H Larochelle WJ Kapur RP Merlino G 《Laboratory investigation; a journal of technical methods and pathology》2001,81(3):297-305
Hepatocyte growth factor/scatter factor (HGF/SF) can stimulate growth of gastrointestinal epithelial cells in vitro; however, the physiological role of HGF/SF in the digestive tract is poorly understood. To elucidate this in vivo function, mice were analyzed in which an HGF/SF transgene was overexpressed throughout the digestive tract. Nearly a third of all HGF/SF transgenic mice in this study (28 of 87) died by 6 months of age as a result of sporadic intestinal obstruction of unknown etiology. Enteric ganglia were not overtly affected, indicating that the pathogenesis of this intestinal lesion was different from that operating in Hirschsprung's disease. Transgenic mice also exhibited a rectal inflammatory bowel disease (IBD) with a high incidence of anorectal prolapse. Expression of interleukin-2 was decreased in the transgenic colon, indicating that HGF/SF may influence regulation of the local intestinal immune system within the colon. These results suggest that HGF/SF plays an important role in the development of gastrointestinal paresis and chronic intestinal inflammation. HGF/SF transgenic mice may represent a useful model for the study of molecular mechanisms associated with a subset of IBD and intestinal pseudo-obstruction. Moreover, our data identify previously unappreciated side effects that may be encountered when using HGF/SF as a therapeutic agent. 相似文献