全文获取类型
收费全文 | 6374篇 |
免费 | 298篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 117篇 |
妇产科学 | 95篇 |
基础医学 | 684篇 |
口腔科学 | 65篇 |
临床医学 | 474篇 |
内科学 | 1871篇 |
皮肤病学 | 63篇 |
神经病学 | 285篇 |
特种医学 | 242篇 |
外科学 | 977篇 |
综合类 | 81篇 |
一般理论 | 1篇 |
预防医学 | 300篇 |
眼科学 | 28篇 |
药学 | 434篇 |
中国医学 | 7篇 |
肿瘤学 | 937篇 |
出版年
2023年 | 31篇 |
2022年 | 62篇 |
2021年 | 81篇 |
2020年 | 51篇 |
2019年 | 57篇 |
2018年 | 100篇 |
2017年 | 72篇 |
2016年 | 81篇 |
2015年 | 112篇 |
2014年 | 146篇 |
2013年 | 178篇 |
2012年 | 274篇 |
2011年 | 271篇 |
2010年 | 189篇 |
2009年 | 183篇 |
2008年 | 277篇 |
2007年 | 302篇 |
2006年 | 340篇 |
2005年 | 323篇 |
2004年 | 271篇 |
2003年 | 302篇 |
2002年 | 277篇 |
2001年 | 256篇 |
2000年 | 267篇 |
1999年 | 244篇 |
1998年 | 96篇 |
1997年 | 101篇 |
1996年 | 73篇 |
1995年 | 69篇 |
1994年 | 75篇 |
1993年 | 73篇 |
1992年 | 156篇 |
1991年 | 132篇 |
1990年 | 138篇 |
1989年 | 138篇 |
1988年 | 115篇 |
1987年 | 113篇 |
1986年 | 107篇 |
1985年 | 83篇 |
1984年 | 56篇 |
1983年 | 49篇 |
1982年 | 26篇 |
1981年 | 26篇 |
1980年 | 22篇 |
1979年 | 38篇 |
1978年 | 25篇 |
1977年 | 33篇 |
1973年 | 21篇 |
1970年 | 23篇 |
1969年 | 24篇 |
排序方式: 共有6705条查询结果,搜索用时 31 毫秒
41.
The effects of lung volume and respiratory airflow on airway resistance were studied in five anesthetized and paralyzed patients. Airway resistance measured during the inspiratory phase with intermittent constant airflow inflatoins decreased in inverse correlationship to increases in lung volume. Airway resistance measured during the expiratory phase with an airway interruption technique, on the other hand, increased with a linear relationship to the expiratory airflow as expressed by a function of Y = K1 + K2X. K1, calculated from the values of airway resistance corresponding to three different airflows, was unaffected by intentional expiratory resistance loading. Thus, simultaneously with the measurement of airway resistance by this method, expiratory gas sampling with a Douglas bag can be done if necessary. Since the K2 value of the endotracheal tube used in this study (Portex® I.D. 8mm, length 26cm) was quite high (5.0cmH2O·1–2·sec2), depending on the airflow, the presence of the endotracheal tube strongly affected the measurement of airway resistance during general anesthesia. K1 measured by the above method, however, may be considered as the best way to evaluate the lower airway resistance independent of either lung volume or expiratory airflow.(Sakai T, Yoshida H, Yano H et al.: Measurement of airway resistance in anesthetized and paralyzed subjects: proposal for evaluation of K1 values. J Anesth 2: 139–145, 1988) 相似文献
42.
Granuloma formation and hemopoiesis induced by C36-48-mycolic acid-containing glycolipids from Nocardia rubra 总被引:2,自引:3,他引:2
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
As previously reported (I. Yano, I. Tomiyasu, S. Kitabatake, and K. Kaneda, Acta Leprologica 2:341-349, 1984), Nocardia rubra, one of the nonpathogenic actinomycetes, possesses three classes of mycolic acid-containing glycolipid, i.e., glucose mycolate, trehalose dimycolate, and trehalose monomycolate. The carbon chain length of their mycolic acids is shorter (C36-48) than that in mycobacteria (longer than C70), and the glycolipid consists of only alpha-mycolic acid. One intravenous administration of 500 micrograms of each purified glycolipid to ICR mice in the form of water-in-oil-in-water emulsion without any protein antigens caused prominent granuloma formation in the lungs, spleen, and liver. The lung index in the treated mice was about 3.5 times larger than that in the control mice (given water-in-oil-in-water emulsion only) at 1 week after the injection and then rapidly declined, while spleen and liver indices peaked at 2 weeks after the injection and persisted longer. The granuloma consisted of macrophages, some of which phagocytized glycolipid micelles, lymphocytes, monocytes, and neutrophils. In addition, many small hemopoietic islands were observed in the liver sinusoids, where various immature blood cells were trapped by the prominent cytoplasmic projections of Kupffer cells. The granuloma formation and hemopoiesis observed here are considered to be the most characteristic morphological expression of macrophage activation in these organs. This is the first report to show that such histological changes can be induced by chemically defined and homogeneous mycolic acid-containing glycolipids other than those of mycobacteria. 相似文献
43.
Purification and partial characterization of heat-stable enterotoxin of enterotoxigenic Escherichia coli. 总被引:6,自引:10,他引:6
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Heat-stable enterotoxin was purified from a strain of enterotoxigenic Escherichia coli 53402 A-1 from human intestine. The cells were cultured in Casamino Acids-yeast extract-salts medium, and the purification procedure consisted of protamine sulfate treatment of the culture supernatant, ultrafiltration with an Amicon PM-10 membrane, diethylaminoethyl-cellulose column chromatography, hydroxyapatite column chromatography, Bio-Gel P-10 gel filtration, 90% ethanol extraction, and preparative polyacrylamide gel disc electrophoresis. About 300-fold purification was achieved, with a yield of about 12%. However, the homogeneity of the purified heat-stable enterotoxin was not rigorously demonstrated. The purified heat-stable enterotoxin had an absorption maximum at about 275 nm, and its isoelectric point was about 3.90. The molecular weight of the purified heat-stable enterotoxin was ca. 4,000 by Sephadex G-100 gel filtration. The minimum effective dose of purified heat-stable enterotoxin was about 2.5 ng in the suckling mouse assay. The purified heat-stable enterotoxin gave a positive reaction in not only the suckling mouse assay but also the mouse intestinal loop test and the guinea pig skin permeability test. 相似文献
44.
Activation of protease-activated receptor 2 stimulates proliferation and interleukin (IL)-6 and IL-8 secretion of endometriotic stromal cells 总被引:3,自引:0,他引:3
Hirota Y Osuga Y Hirata T Harada M Morimoto C Yoshino O Koga K Yano T Tsutsumi O Taketani Y 《Human reproduction (Oxford, England)》2005,20(12):3547-3553
BACKGROUND: Inflammation has been proposed to play essential roles in the pathophysiology of endometriosis, in which neutrophils and mast cells have been suggested to be involved. We studied whether the protease-activated receptor 2 (PAR2), which is activated by enzymes from neutrophils and mast cells, in endometriotic stromal cells (ESC) has any implication in the development of the disease. METHODS: Cultured ESC were stimulated with various concentrations of a specific PAR2 agonist peptide. Proliferating activity of the cells was determined using immunostaining of proliferating cell nuclear antigen (a cell proliferation marker), 5-bromo-2'-deoxyuridine incorporation into DNA and cell count. The concentrations of interleukin (IL)-6 and IL-8 were measured using specific enzyme-linked immunosorbent assay kits. The phosphorylation of three mitogen-activated protein kinases (MAPK), i.e. p38 MAPK, p42/44 MAPK and stress-activated protein Kinase/c-jun N terminal Kinase, in ESC was examined with Western blot analysis. RESULTS: Activation of PAR2 stimulated the proliferation of ESC and the secretion of IL-6 and IL-8 from ESC in a dose-dependent manner. Activation of PAR2 stimulated the phosphorylation of all three MAPK, and inhibitors of each MAPK suppressed the PAR2 activation-induced proliferation of ESC. CONCLUSIONS: The activation of PAR2 in ESC may be involved in the pathophysiology of endometriosis by inducing the growth and inflammation of endometriotic lesions. 相似文献
45.
Molecular analysis of the short arm of chromosome 3 in small-cell and non-small-cell carcinoma of the lung 总被引:23,自引:0,他引:23
H Brauch B Johnson J Hovis T Yano A Gazdar O S Pettengill S Graziano G D Sorenson B J Poiesz J Minna 《The New England journal of medicine》1987,317(18):1109-1113
Previous studies have suggested that the loss of DNA sequences on the short arm of chromosome 3 (3p) is associated with small-cell lung carcinoma. We therefore looked for loss of 3p alleles in tumor tissue from 42 patients with either small-cell or non-small-cell lung carcinoma. All 13 patients with small-cell lung carcinoma who were heterozygous for one or more alleles at 3p in normal tissue had the loss of at least one codominant allele in the tumor tissue. Cell lines of small-cell lung carcinoma from an additional eight patients were homozygous for 3p alleles; this result was significantly different from the predicted frequency of homozygosity. The tumor tissue studied included cell lines of small-cell lung carcinoma obtained from biopsy specimens, an autopsy sample, and an excised lymph node containing tumor cells. Loss of alleles at 3p was observed in tumor samples obtained before and after chemotherapy. Four of 15 evaluable patients with non-small-cell carcinoma of the lung had loss of 3p alleles. We conclude that loss of alleles at 3p is a change found consistently in small-cell lung carcinoma and occasionally in non-small-cell lung carcinoma. 相似文献
46.
Enhanced expression of type I interferon and toll-like receptor-3 in primary biliary cirrhosis 总被引:6,自引:0,他引:6
Takii Y Nakamura M Ito M Yokoyama T Komori A Shimizu-Yoshida Y Nakao R Kusumoto K Nagaoka S Yano K Abiru S Ueki T Matsumoto T Daikoku M Taniguchi K Fujioka H Migita K Yatsuhashi H Nakashima M Harada M Ishibashi H 《Laboratory investigation; a journal of technical methods and pathology》2005,85(7):908-920
47.
Shirai Y Hashimoto M Kato R Kawamura YI Kirikae T Yano H Takashima J Kirihara Y Saito Y Fujino MA Dohi T 《Journal of clinical immunology》2004,24(1):42-52
Despite the huge number of colonized Gram-negative bacteria in the colon, the normal colon maintains its homeostasis without any excessive immune response. To investigate the potential mechanisms involved, human colonic lamina propria mononuclear cells (LPMCs) obtained from uninflamed mucosa were cultured with lipopolysaccharide (LPS) prepared from Bacteroides vulgatus (BV-LPS) or Bacteroides fragilis (BF-LPS), as representatives of indigenous flora, or pathogenic Salmonella minnesota (SM-LPS). Colonic LPMCs failed to produce inflammatory cytokines in response to any type of LPS. Colonic macrophages barely expressed mRNA for MD-2, an essential association molecule for LPS signaling via Toll-like receptor 4. Further, BV-LPS induced CD25 and Foxp3 expression in lymphocytes and CD4(+)CD25(+) cells expressed IL-10 mRNA. Thus, the low expression of functioning LPS receptor molecules and induction of IL-10-producing CD4(+)CD25(+) lymphocytes by indigenous LPS may play a central role in the maintenance of colonic immunological homeostasis. 相似文献
48.
Korthuis PT Asch SM Anaya HD Morgenstern H Goetz MB Yano EM Rubenstein LV Lee ML Bozzette SA 《Journal of acquired immune deficiency syndromes (1999)》2004,35(3):253-260
BACKGROUND: Lipid screening is recommended for patients taking protease inhibitors (PIs). METHODS: We examined data from the Veterans Administration Immunology Case Registry to assess lipid screening among HIV-infected veterans who received PIs for at least 6 consecutive months during 1999 and 2001. We estimated crude and adjusted associations between lipid screening and patient characteristics (age, gender, HIV exposure, and race/ethnicity), comorbidities (AIDS, cardiovascular disease, diabetes, hypertension, smoking, and hyperlipidemia), and facility characteristics (urban location, case management, guidelines, and quality improvement programs). RESULTS: Among 4065 patients on PIs, clinicians screened 2395 (59%) for lipids within 6 months of initiating treatment. Adjusting for patient characteristics, comorbidities, facility traits, and clustering, lipid screening was more common among patients who were cared for in urban areas (relative risk [RR] = 1.3, confidence limits: 1.0-1.5), diabetic (RR = 1.2, confidence limits: 1.1-1.3), or previously hyperlipidemic (RR = 1.4, confidence limits: 1.3-1.5) and less common among patients with a history of intravenous drug use (IVDU) (RR = 0.90, confidence limits: 0.79-1.0) or unknown HIV risk (RR = 0.85, confidence limits: 0.75-0.95). CONCLUSIONS: Six in 10 patients taking PIs receive lipid screening within 6 months of PI use. Systemic interventions to improve overall HIV quality of care should also address lipid screening, particularly among patients with unknown or IVDU HIV risk and those cared for in nonurban areas. 相似文献
49.
Jun Yamauchi Hidehiro Narita Shoichi Kutsumizu Shinichi Yano 《Macromolecular chemistry and physics.》1995,196(11):3825-3831
Temperature-dependent ESR spectra of Cu2+-Cu2+ pairs in ethylene/methacrylic acid copolymer neutralized with Cu(II) were reexamined in detail. The resonance positions and the linewidths of one of the ESR fine-structure lines showed thermal distension of the Cu2+-Cu2+ distance, and the slopes in the temperature variations changed at the temperature associated with melting of the polymer crystallites. No meaningful anomalies were observed around the temperature at which the preceding endothermic transition takes place. In this transition, the Cu2+-Cu2+ pairs seems to enter a disordered state, keeping almost the same paired structure. In contrast to this irreversible order-disorder transition, the melting process in the most part of the polyethylene crystallite phases starts to impose stress upon the Cu2+-Cu2+ pairs, accompanying the slope changes of the ESR parameters. These reversible variations with remarkable thermal hysteresis are compatible with the DSC analyses. 相似文献
50.
Hanibuchi M Yano S Nishioka Y Yanagawa H Miki T Sone S 《Clinical & experimental metastasis》2000,18(5):353-360
The formation of metastases in multiple organs and acquired multi-drug resistance (MDR) are the major obstacles for treatment
of human small-cell lung cancer (SCLC). To explore the possibility of immunological overcoming of multiple-organ metastases
produced by refractory SCLC, we established the MDR variant (SBC-3/DOX), expressing P-glycoprotein, of parental SBC-3 cells
by culturing with gradually increasing concentration of adriamycin. Both SBC-3 and SBC-3/DOX cells expressed a high amount
of ganglioside GM2, an ideal target of SCLC cells. A mouse-human chimeric anti-GM2 monoclonal antibody (KM966) induced antibody-dependent
cellular cytotoxicity (ADCC) mediated by human mononuclear cells (lymphocytes and monocytes) and complement-dependent cytotoxicity
(CDC) mediated by human AB serum against SBC-3/DOX cells to a similar extent compared with parental SBC-3 cells. Pretreatment
of human effector cells with various cytokines induced further enhancement of the KM966-dependent ADCC against SBC-3/DOX cells.
Intravenous injection of SBC-3 or SBC-3/DOX cells into natural killer (NK) cell-depleted severe combined immunodeficient (SCID)
mice developed metastases in multiple organs (liver, kidneys and lymph nodes). Interestingly, SBC-3/DOX cells produced metastases
more rapidly than SBC-3 cells, suggesting more aggressive phenotype of SBC-3/DOX cells than their parental cells in vivo. Systemic treatment with KM966, given on days 2 and 7, drastically inhibited the formation of multiple-organ metastases produced
by both SBC-3 and SBC-3/DOX cells, indicating that KM966 can eradicate metastasis by SCLC cells irrespective of MDR phenotype.
These findings suggest that the mouse-human chimeric KM966 targets the GM2 antigen, and might be useful for the immunological
circumvention of multiple-organ metastases of refractory SCLC.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献