全文获取类型
收费全文 | 1184篇 |
免费 | 58篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 50篇 |
妇产科学 | 44篇 |
基础医学 | 162篇 |
口腔科学 | 17篇 |
临床医学 | 119篇 |
内科学 | 208篇 |
皮肤病学 | 32篇 |
神经病学 | 115篇 |
特种医学 | 131篇 |
外科学 | 77篇 |
综合类 | 37篇 |
预防医学 | 89篇 |
眼科学 | 5篇 |
药学 | 71篇 |
1篇 | |
中国医学 | 6篇 |
肿瘤学 | 60篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 20篇 |
2017年 | 11篇 |
2016年 | 16篇 |
2015年 | 20篇 |
2014年 | 25篇 |
2013年 | 42篇 |
2012年 | 32篇 |
2011年 | 54篇 |
2010年 | 51篇 |
2009年 | 56篇 |
2008年 | 42篇 |
2007年 | 50篇 |
2006年 | 55篇 |
2005年 | 52篇 |
2004年 | 38篇 |
2003年 | 26篇 |
2002年 | 36篇 |
2001年 | 26篇 |
2000年 | 24篇 |
1999年 | 24篇 |
1998年 | 45篇 |
1997年 | 50篇 |
1996年 | 46篇 |
1995年 | 23篇 |
1994年 | 33篇 |
1993年 | 29篇 |
1992年 | 21篇 |
1991年 | 19篇 |
1990年 | 20篇 |
1989年 | 27篇 |
1988年 | 37篇 |
1987年 | 19篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1982年 | 15篇 |
1981年 | 15篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1972年 | 2篇 |
1925年 | 2篇 |
排序方式: 共有1247条查询结果,搜索用时 15 毫秒
71.
Intestinal uptake of quercetin-3-glucoside in rats involves hydrolysis by lactase phlorizin hydrolase 总被引:4,自引:0,他引:4
Quercetin has antioxidant, anti-inflammatory, antiproliferative and anticarcinogenic properties. In plant foods, quercetin occurs mainly bound to various sugars via a beta-glycosidic link. We hypothesized that lactase phlorizin hydrolase (LPH), an enzyme at the brush border membrane of intestinal cells, is involved in the in vivo intestinal uptake of quercetin-sugars. To study this, we measured the appearance of quercetin metabolites in plasma and perfusate after perfusing the jejunum and ileum with 50 micro mol/L quercetin-3-glucoside in an in situ rat perfusion model. LPH was inhibited by the selective LPH inhibitor N-butyldeoxygalactonojirimycin (0, 0.5, 2 or 10 mmol/L) (n = 5 rats/group). Quercetin in plasma and perfusion buffer was determined by HPLC with CoulArray detection. Results are given as means +/- SEM. In the perfusion buffer, 13.8 +/- 0.7 micro mol/L quercetin-3-glucoside was hydrolyzed during intestinal passage. Co-perfusion with 0.5, 2 and 10 mmol/L N-butyldeoxygalactonojirimycin resulted in 38% (P < 0.05), 50% (P < 0.01) and 67% (P < 0.01) less hydrolysis, respectively. Plasma concentrations of quercetin in the corresponding groups were 36% (P = 0.12), 55% (P < 0.01) and 75% (P < 0.01) lower than in controls (1.23 +/- 0.22 micro mol/L). These data suggest that LPH is a major determinant of intestinal absorption of quercetin-3-glucoside in rats. 相似文献
72.
73.
P. K. Kommareddi T. S. Nair Y. Raphael S. A. Telian A. H. Kim H. A. Arts H. K. El-Kashlan T. E. Carey 《Journal of the Association for Research in Otolaryngology》2007,8(4):435-446
Choline transporter-like protein 2 (CTL2) is a multi-transmembrane protein expressed on inner ear supporting cells that was
discovered as a target of antibody-induced hearing loss. Its function is unknown. A 64 kDa band that consistently co-precipitates
with CTL2 from inner ear extracts was identified by mass spectroscopy as cochlin. Cochlin is an abundant inner ear protein
expressed as multiple isoforms. Its function is also unknown, but it is suspected to be an extracellular matrix component.
Cochlin is mutated in individuals with DFNA9 hearing loss. To investigate the CTL2–cochlin interaction, antibodies were raised
to a cochlin-specific peptide. The antibodies identify several cochlin polypeptides on western blots and are specific for
cochlin. We show that the heterogeneity of the cochlin isoforms is caused, in part, by in vivo post-translational modification by N-glycosylation and, in part, caused by alternative splicing. We verified that antibody to CTL2 co-immunoprecipitates cochlin
from the inner ear and antibody to cochlin co-immunoprecipitates CTL2. Using cochlear cross-sections, we show that CTL2 is
more widely distributed than previously described, and its prominent expression on cells facing the scala media suggests a
possible role in homeostasis. A prominent but previously unreported ribbon-like pattern of cochlin in the basilar membrane
was demonstrated, suggesting an important role for cochlin in the structure of the basilar membrane. CTL2 and cochlin are
expressed in close proximity in the inner sulcus, the spiral prominence, vessels, limbus, and spiral ligament. The possible
functional significance of CTL2–cochlin interactions remains unknown. 相似文献
74.
Liu J Zheng BS Aposhian HV Zhou YS Chen ML Zhang AH Waalkes MP. 《Journal of the peripheral nervous system : JPNS》2002,7(3):208-208
Optimization of a previously disclosed sorbitol dehydrogenase inhibitor (SDI, II) for potency and duration of action was achieved by replacing the metabolically labile N,N-dimethylsulfamoyl group with a variety of heterocycles. Specifically, this effort led to a series of novel, in vitro potent SDIs with longer serum half-lives and acceptable in vivo activity in acutely diabetic rats (e.g., 62, 67, and 69). However, the desired in vivo potency in chronically diabetic rats, ED90 less than or equal to 5 mg/kg/day, was achieved only through further modification of the piperazine linker. Several members of this family, including 86, showed better than the targeted potency with ED90 values of 1-2 mg/kg/day. Compound 86 was further profiled and found to be a selective inhibitor of sorbitol dehydrogenase, with excellent pharmacodynamic/pharmacokinetic properties, demonstrating normalization of sciatic nerve fructose in a chronically diabetic rat model for approximately 17 h, when administered orally at a single dose of 2 mg/kg/day. 相似文献
75.
Production of cytokines by bone marrow cells obtained from patients with multiple myeloma 总被引:3,自引:4,他引:3
Previous work with continuously cultured multiple myeloma lines suggested that cytokine production by tumor cells may mediate some of the medical complications of this disease. To further investigate this issue, we assayed freshly obtained bone marrow (BM) cells from myeloma patients for the in vitro production of cytokines and the presence of cytokine RNA. Production of cytokine protein was assessed by bioassays with the aid of specific neutralizing anticytokine antibodies. These assays detected interleukin-1 (IL-1) and tumor necrosis factor (TNF) secretion by myeloma BM cells, which was significantly greater than secretion from similarly processed BM cells of control individuals. In contrast, lymphotoxin and interleukin-2 (IL-2) production could not be detected. The levels of IL-1 and TNF produced in vitro peaked at 24 hours of culture and correlated with stage and the presence (or absence) of extensive osteolytic bone disease. Northern blot analysis demonstrated the presence of IL-1 beta and TNF RNA in uncultured myeloma BM cells but no detectable IL-1 alpha or lymphotoxin RNA. In addition, the amount of cytokine RNA correlated with protein production, being significantly greater in patients' BM cells than in control marrow. These data suggest a role for IL-1 beta and/or TNF in the pathophysiology of multiple myeloma and argue against a role for lymphotoxin or IL-2. 相似文献
76.
TM Sankary ; G Yang ; JM Romeo ; PP Ulrich ; MP Busch ; BD Rawal ; GN Vyas 《Transfusion》1994,34(8):656-660
BACKGROUND: Since screening for antibody to hepatitis C virus (HCV) was introduced in 1990, posttransfusion hepatitis has been reduced to nearly background levels. This has led to reconsideration of the value of testing donated blood for elevated alanine aminotransferase (ALT). The contribution of ALT testing in detecting seronegative infection was evaluated by the performance of polymerase chain reaction (PCR) for hepatitis B virus (HBV) or HCV in plasma from ALT-elevated blood units. STUDY DESIGN AND METHODS: Testing was performed on 375 units of plasma, derived from an equivalent of 47,500 blood donations, with a highly sensitive hemi-nested PCR procedure. Using a triplet of primers directed at the conserved regions of HBV DNA and 5'-noncoding regions of HCV RNA, the hemi-nested PCR assay can reliably amplify 10 viral molecules to levels detectable in ethidium bromide-stained agarose gels. Pools of plasma from groups of four donors were screened with hemi-nested PCR. For any reactive pools, the plasma from individual donors was retested twice on different aliquots. RESULTS: Two of 375 units, both with midrange ALT elevation, were repeatedly reactive in hemi-nested PCR (one each for HBV DNA and HCV RNA). However, samples from the two suspect donors tested 9 and 5 months later revealed no seroconversion, elevated ALT, or viral genomes in hemi-nested PCR. CONCLUSION: The lack of confirmed HBV or HCV infection in this study representing an estimated 47,500 voluntary blood donations suggests that routine ALT testing for further prevention of posttransfusion hepatitis after exclusion of HBV- and/or HCV-seropositive blood may be superfluous. 相似文献
77.
Arlin ZA; Fanucchi MP; Gee TS; Kempin SJ; Mertelsmann R; Young CW; Clarkson BD 《Blood》1982,60(5):1224-1226
Twenty-four adults with ALL were treated with AMSA alone or in combination. Twenty-two were treated at time of relapse and two patients after failing primary induction therapy. All had been treated with anthracyclines prior to receiving AMSA. Of the 22 patients with ALL in relapse, 4 achieved a complete remission. Two of these patients have relapsed while receiving maintenance chemotherapy; one died 1 mo after achieving remission due to the occurrence of cholycystitis in the setting of pancytopenia and one patient underwent bone marrow transplantation and is in remission at 8 mo after the second remission. Both patients who failed primary induction therapy remain in remission at 11 and 36 mo, respectively. The use of AMSA should be considered for patients with ALL who fail primary induction as well as those whose leukemia becomes resistant to conventional agents. 相似文献
78.
Reilly MP 《中国医学前沿杂志(电子版)》2011,(4):100
<正>背景:该研究旨在评价在现有的冠状动脉粥样硬化的病变中,遗传因素对粥样硬化斑块进展及特异性心肌梗死是否存在显著作用。方法:对欧洲后裔参与者冠状动脉造影表型进行了两项全基因组关联研究(GWAS),为寻找冠状动脉疾病(CAD)易感性基因位点,研究比较了有异常(n=12393)和无异常的(对照组n=7383)个体;为寻找心肌梗死易感性基因位点,也同时比较了造影证实存在CAD并且有心肌梗死的个体(n=5783)与虽有CAD但无心肌梗死的个体(n=3644)。 相似文献
79.
Josje H. E. Arts Martijn W. de Koning Nanne Bloksma C. Frieke Kuper 《Inhalation toxicology》2013,25(5):259-269
The present study investigated whether airway responses of sensitized rats to trimellitic anhydride (TMA) were concentration dependent and whether these were related to irritation by TMA. Groups of BN and Wistar rats were sensitized by two dermal applications of TMA (50% w/v, followed by 25% w/v in vehicle). Controls received vehicle (acetone–olive oil 4:1, v/v). All animals were challenged 3 wk after the first sensitization by inhalation of one of a range of concentrations of TMA (0.2–61 mg/m3 for BN rats, 15–250 mg/m3 for Wistar rats). Breathing pattern, breathing frequency, and tidal volume were measured before, during, and after challenge to assess allergic and irritative airway responses. One day after challenge, nonspecific airway responsiveness to a range of concentrations of methacholine was measured. At necropsy on the same day, blood was withdrawn for measuring total serum immunoglobulin E (IgE) and organs were weighed. Larynx, trachea and lungs were examined histopathologically. In BN rats, TMA sensitization elevated total IgE levels; subsequent inhalation challenge with 2 mg/m3 of TMA and higher caused laryngeal inflammation with squamous epithelial metaplasia, and pulmonary hemorrhages. Concentration-related decreases in breathing frequency and alterations in breathing pattern, which differed from the irritation-induced pattern, were also observed at these levels. Inhalation challenge with TMA concentrations of 12 mg/m3 and higher increased lung weight. Increased nonspecific airway responsiveness was observed at the 2 next higher tested concentrations of 46 and 61 mg/m3. In unsensitized BN rats, only laryngeal squamous metaplasia was observed, albeit at higher challenge concentrations of TMA, and decreased breathing frequency, a typical breathing pattern characteristic of irritation. Identically sensitized Wistar rats showed airway inflammation and pulmonary hemorrhages upon challenge with TMA, but no functional changes, even at distinctly irritating concentrations of TMA up to 250 mg/m3. In conclusion, TMA challenge of sensitized BN rats caused challenge concentration-related allergic airway inflammation, asthmalike changes in breathing pattern, and increased nonspecific airway responsiveness. The lowest no-observed-effect level (NOEL) based on the most sensitive endpoint investigated was 0.2 mg/m3, a value that is well below the irritation concentration. The presence of a NOEL in the sensitized BN rat suggests that assessment of safe human exposure levels is feasible. 相似文献
80.