全文获取类型
收费全文 | 10532篇 |
免费 | 527篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 188篇 |
儿科学 | 118篇 |
妇产科学 | 206篇 |
基础医学 | 1453篇 |
口腔科学 | 248篇 |
临床医学 | 711篇 |
内科学 | 2653篇 |
皮肤病学 | 147篇 |
神经病学 | 897篇 |
特种医学 | 442篇 |
外国民族医学 | 1篇 |
外科学 | 1744篇 |
综合类 | 70篇 |
一般理论 | 1篇 |
预防医学 | 358篇 |
眼科学 | 113篇 |
药学 | 744篇 |
中国医学 | 35篇 |
肿瘤学 | 985篇 |
出版年
2023年 | 51篇 |
2022年 | 102篇 |
2021年 | 144篇 |
2020年 | 78篇 |
2019年 | 102篇 |
2018年 | 137篇 |
2017年 | 102篇 |
2016年 | 97篇 |
2015年 | 116篇 |
2014年 | 197篇 |
2013年 | 201篇 |
2012年 | 411篇 |
2011年 | 468篇 |
2010年 | 278篇 |
2009年 | 278篇 |
2008年 | 443篇 |
2007年 | 477篇 |
2006年 | 479篇 |
2005年 | 454篇 |
2004年 | 498篇 |
2003年 | 434篇 |
2002年 | 490篇 |
2001年 | 442篇 |
2000年 | 492篇 |
1999年 | 411篇 |
1998年 | 136篇 |
1997年 | 104篇 |
1996年 | 107篇 |
1995年 | 83篇 |
1994年 | 73篇 |
1993年 | 84篇 |
1992年 | 321篇 |
1991年 | 277篇 |
1990年 | 294篇 |
1989年 | 271篇 |
1988年 | 241篇 |
1987年 | 229篇 |
1986年 | 197篇 |
1985年 | 193篇 |
1984年 | 140篇 |
1983年 | 110篇 |
1979年 | 76篇 |
1978年 | 61篇 |
1977年 | 74篇 |
1975年 | 54篇 |
1974年 | 59篇 |
1973年 | 48篇 |
1972年 | 57篇 |
1969年 | 51篇 |
1968年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
The present piece of research studied the spontaneous alpha rhythm of the human brain by combining the use of a whole-cortex neuromagnetometer and Magnetic Resonance Imaging. Single trials of spontaneous brain activity were recorded from ten human subjects asked to rest, with their eyes either closed or open, in relaxed wakefulness. MEG measurements were conducted over a period of one and a half years. The replicability of the results was confirmed for eight subjects out of ten. For three subjects, the alpha rhythm did not show any reductions due to the opening of the eyes. Both field map pattern and location of the estimated source were persistently stationary during each of the bursts of oscillations of the alpha rhythm. Dipoles were concentrated in clusters, indicating the existence of several spatially distributed sources. The calcarine fissure, the parieto-occipital sulcus and the surrounding occipital and parieto-occipital areas were identified as cortical sites of the brain where the alpha rhythm may originate. For four subjects, the majority of the sources were located near or in the calcarine fissure, while for five subjects, they were located near or in the parieto-occipital sulcus and for the remaining subject they were equally divided between the two generation sites. 相似文献
72.
Cloning and nucleotide sequencing of Vero toxin 2 variant genes from Escherichia coli O91:H21 isolated from a patient with the hemolytic uremic syndrome 总被引:14,自引:0,他引:14
Cellular DNA extracted from Escherichia coli strain B2F1 (O91:H21) was found to contain two separate DNA sequences that hybridized with a Vero toxin 2 (VT2)-specific gene probe under stringent conditions. These two sequences were cloned and both were shown to encode a variant of Vero toxin 2 (VT2vh). The nucleotide sequences of the operons encoding VT2vh, designated as vtx2ha and vtx2hb, were determined. The two operons were nearly identical (99% overall DNA homology) and both encoded A subunits of 319 amino acid residues and B subunits of 89 amino acid residues, the A and B subunit genes being separated by a stretch of 14 bp. The A and B subunit genes of the vtx2ha operon exhibited 98.6% and 95.5% DNA homology, respectively, with those of the slt-II operon encoding Shiga-like toxin II (or VT2) cloned from a strain from a patient with hemorrhagic colitis, while the A and B subunit genes of the vtx2ha operon showed 94.5% and 82.8% DNA homology, respectively, with those of the slt-IIv operon encoding a SLT-II variant cloned from a strain isolated from a pig with edema disease. The nucleotide sequences of the presumed promoters and presumptive ribosome binding sites in the vtx2ha, vtx2hb, and slt-II, and slt-IIv operons were identical. These results indicate that nucleotide sequences encoding a family of VT2-related toxins are present in various strains of E. coli and that the sequences of the genes for A subunits are better conserved than those of the B subunit genes. 相似文献
73.
Masaharu Muranaka Shuji Suzuki Kazuhiro Koizumi Hiroshi Igarashi Hiroshi Okumura Koyo Takeda Kenji Tadokoro Yoshihiko Horiuchi 《The Journal of allergy and clinical immunology》1978,62(5):276-282
All of the five commercially available benzylpenicillin preparations obtained from different sources and a PcG preparation prepared by filtration of a commercial PcG on Sephadex G10 elicited the systemic anaphylactic reactions in guinea pigs which had been immunized with benzylpenicilloyl (BPO)-Ascaris extract conjugate (BPO-As) mixed with aluminum hydroxide gel. These preparations could evoke no such reactions in guinea pigs immunized with BPO-bovine gamma globulin conjugate (BPO-BGG) emulsified with complete Freund's adjuvant. The severity of the systemic anaphylactic reactions correlated significantly with the titers of either 8-day passive cutaneous anaphylactic (8-day PCA) reactions or 4-hr PCA reactions evoked with the same benzylpenicillin preparations. In vitro benzylpenicillin preparation contracted the tracheas of the guinea pigs immunized with BPO-As. These results indicated that the commercially available benzylpenicillin preparations have enough antigenicity to evoke systemic anaphylactic reactions in guinea pigs immunized with BPO-As mixed with aluminum hydroxide gel. Such guinea pigs represent an animal model for investigation of penicillin allergy. 相似文献
74.
K Hirasawa M Takeda H Matsuzaki K Doi 《International journal of experimental pathology》1991,72(6):617-622
Testes of 8-week-old male Syrian hamsters which were inoculated intraperitoneally with 10(5) plaque-forming units of the D variant of encephalomyocarditis virus (EMC-D) were examined virologically and histologically. Viral replication was detected from 1 day post inoculation (1 DPI), became more prominent 3 DPI, and was no longer demonstrated 7 DPI. The weight of testis decreased in course of time and it was about 2% of that of control 6 weeks post inoculation (6 WPI). Histopathologically, degeneration and/or necrosis of germinal cells and spermatogonia were observed in many seminiferous tubules of all hamsters 3 DPI. At 7 DPI, luminal obstruction by cellular debris and subsequent replacement of them by mesenchymal cells were common in mildly atrophic tubules surrounded with inflammatory cells. Thereafter, atrophy of seminiferous tubules became severer with the lapse of time and, in addition to plasma cell infiltration, apparent increase in the number of Leydig cells was found in the interstices. No regenerative signs of germinal epithelia were detected by 6 WPI. This is the first report of EMC virus-induced orchitis. 相似文献
75.
H Tachibana K Kawabata M Takeda M Sugita J Kondo M Miyauchi A Matsuoka 《Rinsho byori. The Japanese journal of clinical pathology》1991,39(9):999-1004
Short-latency somatosensory (SSEPs), brainstem auditory evoked potentials (BAEPs) and event-related potentials (ERPs) were studied in 7 patients with Binswanger's encephalopathy, 12 patients with Alzheimer's disease and 17 normal subjects. Patients with Binswanger's encephalopathy showed significantly prolonged central conduction time (CCT) and P300 latency, and prolonged tendency of I-V IPL compared to those of normal subjects. In particular, CCT showed significant prolongation compared to that of patients with Alzheimer's disease. In patients with Alzheimer's disease, I-V IPL and P300 latency were significantly prolonged compared to those of normals although there was no significant difference in CCT between Alzheimer's disease and normal subjects. These results indicate some difference between Binswanger's encephalopathy and Alzheimer's disease from the electrophysiological aspects although both of these entities are characterized by progressive mental deterioration. 相似文献
76.
Takahiro Tsujimura Masashi Takeda Nobuyuki Terada Hiroshi Uramoto 《Pathology international》1991,41(8):642-646
Two cases of peritoneal papillary carcinoma are reported. The patient in the first case was a 71-year-old woman with symptoms of obstructive ileus. Laparotomy revealed a tumor in the omentum involving the transverse colon, and several small tumors in the peritoneum and pelvic wall. However, no primary site of the tumor was seen in the ovary, pancreas, or gastrointestinal tract. The patient in the second case was a 44-year-old woman with carcinomatous peritonitis. Postmortem examination revealed multiple tumors in the peritoneum, omentum, and pelvic wall. Tumors were also found in the cortex with mild invasion of the underlying parenchyma of the bilateral ovaries, although these lesions were thought to be metastatic. The histologic features of the tumor in both cases were those of tubulopapillary adenocarcinoma containing scattered psammoma bodies. The cells were positive with the PAS D technique, but negative with alcian blue staining. In both cases, the serum levels of CA-125 were considerably elevated, and the tumor cells showed positivity for CA-125, S 100 protein, cytokeratin and EMA by im-munohistochemistry. The present cases were most likely peritoneal serous papillary adenocarcinoma derived from extraovarian peritoneal mesothelium with miillerian potential, being different from the usual type of diffuse malignant mesothelioma. Acta Pathol Jpn 41: 642-646, 1991. 相似文献
77.
Y.?Takeda N.?Shiobara A.?R.?Saniabadi M.?Adachi K.?HiraishiEmail author 《Inflammation research》2004,53(7):277-283
Objective:Evolving evidence of anti-inflammatory effects is observed in patients with rheumatoid arthritis or ulcerative colitis following periodic adsorptive granulocyte and monocyte (GM) apheresis with a column containing cellulose acetate (CA) beads as apheresis carriers. This study was undertaken to obtain insights into mechanisms of anti-inflammatory actions of adsorptive GM apheresis with CA beads.
Methods:In a series of in-vitro experiments, we investigated the effects of plasma proteins and the leucocytes 2 integrin (CD18) on granulocyte adsorption to CA beads.
Results:Granulocyte adsorption to CA beads required plasma IgG, the complement C3 and was inhibited by an antibody to leucocytes CD18. Further, hepatocyte growth factor (HGF) and interleukin-1 receptor antagonist (IL-1ra) which have strong anti-inflammatory actions were released by granulocytes that adhered to CA beads.
Conclusions:Plasma IgG, C3 derived complement activation fragments and leucocytes CD18 are involved in granulocyte adhesion to CA beads and hence the release of HGF and IL-1ra.Received 27 October 2003; returned for revision 16 December 2003; accepted by M. J. Parnham 8 January 2004 相似文献
78.
Metabolism of senile amyloid precursor and amyloidogenesis. Age-related acceleration of apolipoprotein A-II clearance in the senescence accelerated mouse. 总被引:1,自引:1,他引:1 下载免费PDF全文
H. Naiki K. Higuchi T. Yonezu M. Hosokawa T. Takeda 《The American journal of pathology》1988,130(3):579-587
Serum clearance kinetics of murine senile amyloid-related high-density lipoprotein (HDL) apoprotein A-II (apo A-II) was examined in the senescence-accelerated mouse, prone (SAM-P/1) and resistant (SAM-R/1), with 125I-HDL purified from both strains. In SAM-R/1, with 125I-HDL purified from both strains. In SAM-R/1, the serum half-life of apo A-II was not altered with increasing age and was practically identical to that of apo A-I. In 2-month old SAM-P/1, the serum half-life of both apo A-I and apo A-II was generally the same as observed in SAM-R/1. However, at age 6 and 12 months, in SAM-P/1, the serum half-life of apo A-II decreased significantly and was less than that of apo A-I. These age-related changes in apo A-II clearance kinetics were observed regardless of the HDL donor. The authors also examined the tissue distribution of injected apo A-II, using 125I-apo A-II reconstituted HDL, and found that several organs trapped more 125I radioactivity in old SAM-P/1 than in young mice. This evidence strongly suggests that age-related changes in the metabolic environment of apo A-II might affect senile amyloidogenesis in SAM-P/1. 相似文献
79.
C-reactive protein levels in the serum of asthmatic patients. 总被引:1,自引:0,他引:1
Miyoshi Fujita Shigeharu Ueki Wataru Ito Takahito Chiba Masahide Takeda Norihiro Saito Hiroyuki Kayaba Junichi Chihara 《Annals of allergy, asthma & immunology》2007,99(1):48-53
BACKGROUND: Asthma is a chronic airway inflammatory disease caused by immune cells such as T lymphocytes and eosinophils. Recently, highly sensitive C-reactive protein (hs-CRP) assays have become available for detecting small changes in CRP levels within the reference range, allowing for the evaluation of clinical inflammation. OBJECTIVE: To investigate the relationship between hs-CRP levels and bronchial asthma. METHODS: We collected blood samples from 109 patients with bronchial asthma, with or without attacks, and measured serum eosinophil cationic protein levels, pulmonary function, and serum CRP levels using an hs-CRP assay. RESULTS: Mean serum hs-CRP levels were significantly higher in patients without attacks (0.473 mg/L) and with attacks (0.908 mg/L) (P < .001 for both) than in controls (0.262 mg/L). Serum hs-CRP levels were inversely correlated with forced expiratory volume in 1 second/forced vital capacity in asthmatic patients (r = -0.4915; P < .01). CONCLUSION: Serum hs-CRP levels may be related to the state of asthma exacerbation and allergic inflammation. 相似文献
80.
WSX-1 is required for resistance to Trypanosoma cruzi infection by regulation of proinflammatory cytokine production 总被引:6,自引:0,他引:6
Hamano S Himeno K Miyazaki Y Ishii K Yamanaka A Takeda A Zhang M Hisaeda H Mak TW Yoshimura A Yoshida H 《Immunity》2003,19(5):657-667
WSX-1 is a class I cytokine receptor with homology to the IL-12 receptors and is essential for resistance to Leishmania major infection. In the present study, we demonstrated that WSX-1 was also required for resistance to Trypanosoma cruzi. WSX-1-/- mice exhibited prolonged parasitemia, severe liver injury, and increased mortality over wild-type mice. WSX-1-/- splenocytes produced enhanced levels of Th2 cytokines, which were responsible for the prolonged parasitemia. Massive necroinflammatory lesions were observed in the liver of infected WSX-1-/- mice, and IFN-gamma that was overproduced in WSX-1-/- mice compared with wild-type mice was responsible for the lesions. In addition, vast amounts of various proinflammatory cytokines, including IL-6 and TNF-alpha, were produced by liver mononuclear cells in WSX-1-/- mice. Thus, during T. cruzi infection, WSX-1 suppresses liver injury by regulating production of proinflammatory cytokines, while controlling parasitemia by suppression of Th2 responses, demonstrating its novel role as an inhibitory regulator of cytokine production. 相似文献