首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   630篇
  免费   51篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   4篇
妇产科学   6篇
基础医学   60篇
口腔科学   17篇
临床医学   50篇
内科学   167篇
皮肤病学   3篇
神经病学   180篇
特种医学   12篇
外科学   38篇
综合类   4篇
预防医学   12篇
眼科学   1篇
药学   60篇
肿瘤学   66篇
  2023年   2篇
  2022年   5篇
  2021年   17篇
  2020年   7篇
  2019年   17篇
  2018年   14篇
  2017年   13篇
  2016年   16篇
  2015年   14篇
  2014年   12篇
  2013年   17篇
  2012年   36篇
  2011年   35篇
  2010年   20篇
  2009年   11篇
  2008年   18篇
  2007年   22篇
  2006年   21篇
  2005年   23篇
  2004年   26篇
  2003年   31篇
  2002年   22篇
  2001年   17篇
  2000年   30篇
  1999年   25篇
  1998年   24篇
  1997年   14篇
  1996年   13篇
  1995年   7篇
  1994年   5篇
  1993年   10篇
  1992年   21篇
  1991年   15篇
  1990年   9篇
  1989年   10篇
  1988年   7篇
  1987年   10篇
  1986年   9篇
  1985年   10篇
  1984年   3篇
  1983年   4篇
  1982年   3篇
  1981年   6篇
  1980年   4篇
  1979年   5篇
  1978年   7篇
  1977年   5篇
  1976年   2篇
  1975年   2篇
  1968年   2篇
排序方式: 共有682条查询结果,搜索用时 15 毫秒
91.
Organ culture of blood vessels is a useful technique to investigate the long-term effects of drugs. Organ culture in a serum-free condition is so far the best way to maintain differentiated cell function. However some functional changes may occur from freshly isolated blood vessel (fresh) presumably due to lack of some key factors for vascular homeostasis in the medium. We investigated the long-term effects of addition of adult rat serum on acetylcholine-induced endothelium-dependent relaxation (EDR). Rat isolated mesenteric arteries were cultured for 3 days without (0% serum) or with 3% serum. In 0% serum, EDR was significantly impaired from fresh, whereas sodium nitroprusside-induced relaxation of smooth muscle didn't change. Addition of 3% serum significantly normalized the impaired EDR. Acute treatment with N-acetyl-l-cysteine or a mitochondrial inhibitor, rotenone normalized the impaired EDR in 0% serum. Mitochondrial superoxide production increased in the endothelium with 0% serum, which was normalized by 3% serum. Mitochondrial membrane potential increased in the endothelium with 0% serum, which was not normalized by 3% serum. In summary, the increased endothelial mitochondrial membrane potential in 0% serum may lead to mitochondrial reactive oxygen species (ROS) production and subsequent impairment of EDR. Addition of adult serum normalized the impaired EDR in part through inhibiting the increased mitochondrial ROS but not the membrane potential.  相似文献   
92.
Amyotrophic lateral sclerosis (ALS) is a late-onset, fatal disorder in which the motor neurons degenerate. The discovery of new drugs for treating ALS has been hampered by a lack of access to motor neurons from ALS patients and appropriate disease models. We generate motor neurons from induced pluripotent stem cells (iPSCs) from familial ALS patients, who carry mutations in Tar DNA binding protein-43 (TDP-43). ALS patient-specific iPSC-derived motor neurons formed cytosolic aggregates similar to those seen in postmortem tissue from ALS patients and exhibited shorter neurites as seen in a zebrafish model of ALS. The ALS motor neurons were characterized by increased mutant TDP-43 protein in a detergent-insoluble form bound to a spliceosomal factor SNRPB2. Expression array analyses detected small increases in the expression of genes involved in RNA metabolism and decreases in the expression of genes encoding cytoskeletal proteins. We examined four chemical compounds and found that a histone acetyltransferase inhibitor called anacardic acid rescued the abnormal ALS motor neuron phenotype. These findings suggest that motor neurons generated from ALS patient-derived iPSCs may provide a useful tool for elucidating ALS disease pathogenesis and for screening drug candidates.  相似文献   
93.
94.
Several studies have reported that anorexia nervosa (AN) patients have high levels of alexithymia. However, relatively little is known about the underlying neurobiological relationships between alexithymia and AN. We used functional magnetic resonance imaging to examine the brain responses in 30 AN patients and 20 healthy women during the processing of negative words concerning interpersonal relationships. We investigated the relationship between alexithymia levels and brain activation in AN. AN patients showed significant activation of the orbitofrontal cortex, dorsolateral prefrontal cortex and medial prefrontal cortex while processing negative words concerning interpersonal relationships, as compared to the processing of neutral words. Moreover, the subjective rating of unpleasantness with negative words and neural activities in the amygdala, posterior cingulate cortex (PCC) and anterior cingulate cortex (ACC) negatively correlated with the level of alexithymia in AN. Our neuroimaging results suggest that AN patients tend to cognitively process negative words concerning interpersonal relationships, resulting in activation of the prefrontal cortex. Lower activation of the amygdala, PCC and ACC in response to these words may contribute to the impairments of emotional processing that are hallmarks of alexithymia. Functional abnormalities associated with alexithymia may be involved in the emotional processing impairments in AN patients.  相似文献   
95.
Shortening hospital stays has become a key focus in psychiatric care in recent years. However, patients with schizophrenia account for about 60% of inpatients in psychiatry departments in Japan. This study was designed to investigate the relationship between quality of life (QOL) and key indicators for long-term hospital stays among schizophrenia inpatients. A further aim was to elucidate the clinical determinants of QOL among long-stay inpatients. The study sample consisted of 217 inpatients with schizophrenia. Age, duration of illness, duration of hospitalization, years of education, body mass index, neurocognitive function, drug-induced extrapyramidal symptoms, involuntary movements, psychiatric symptoms, and dose equivalents of antipsychotics and anticholinergic agents were used as index factors. Pearson linear correlation and regression analyses were performed to examine the associations between QOL and the above-mentioned factors. Negative symptoms, psychological discomfort, and resistance as rated on the Brief Psychiatric Rating Scale (BPRS) were correlated with all subscale scores of the Japanese version of the Schizophrenia Quality of Life Scale (JSQLS). Stepwise regression showed that negative symptoms, psychological discomfort, and resistance predicted the dysfunction of psycho-social activity score and the dysfunction of motivation and energy score on the JSQLS. This study shows that active treatment for negative symptoms, psychological discomfort, and resistance should be recommended to improve QOL among inpatients with schizophrenia.  相似文献   
96.
Although induction immunochemotherapy including high‐dose cytarabine and rituximab followed by high‐dose chemotherapy (HDC) with autologous stem cell transplantation (ASCT) is recommended for younger patients (≤65 years old) with untreated mantle cell lymphoma (MCL), no standard induction and HDC regimen has been established. We conducted a phase II study of induction immunochemotherapy of R‐High‐CHOP/CHASER followed by HDC of LEED with ASCT in younger patients with untreated advanced MCL. Eligibility criteria included untreated MCL, stage II bulky to IV, and age 20‐65 years. Patients received 1 cycle of R‐High‐CHOP followed by 3 cycles of CHASER every 3 weeks. Peripheral blood stem cells (PBSC) were harvested during CHASER. LEED with ASCT was delivered to patients who responded to R‐High‐CHOP/CHASER. Primary endpoint was 2‐year progression‐free survival (PFS). From June 2008 to June 2012, 45 patients (median age 59 years; range 38‐65 years) were enrolled. PBSC were successfully harvested from 36 of 43 patients. Thirty‐five patients completed ASCT. Two‐year PFS was 77% (80% CI 68‐84), which met the primary endpoint. Five‐year PFS and overall survival were 52% (95% CI 34‐68%) and 71% (95% CI 51‐84%), respectively. Overall response and complete response rates after induction immunochemotherapy were 96% and 82%, respectively. The most common grade 4 toxicities were hematological. In younger patients with untreated MCL, R‐High‐CHOP/CHASER/LEED with ASCT showed high efficacy and acceptable toxicity, and it can now be considered a standard treatment option.  相似文献   
97.
In the endothelium-denuded arteries cultured in the presence of FBS, morphological (i.e. smooth muscle disorientation and increase in collagen fiber) and phenotypic changes in smooth muscle were observed. Correlated with these changes, contractile force induced by high concentration of KCl and norepinephrine was significantly decreased. In addition, Ca-induced contraction in the permeabilized muscle was also significantly reduced. The reduced contractility in the FBS-treated arteries was partially recovered by the treatment with L-NMMA. In the endothelium-intact arteries cultured in the presence of FBS or PDGF, substance P and ionomycin-mediated, endothelium-dependent relaxation (EDR) was significantly decreased compared to the arteries cultured in serum-free condition. In addition, amounts of NO production and total recoverable eNOS mRNA was reduced in the FBS and PDGF-treated arteries. In these arteries, however, cGMP-dependent relaxation in smooth muscle was not impaired. These results suggest that long-term treatment of vascular tissue with growth-activating agents causes morphological or phenotypic changes nad up-regulation of NO production in smooth muscle, resulting in a reduced contractility. Furthermore, longterm treatment with these agents impairs NO-mediated EDR by decreasing eNOS mRNA and NO production.  相似文献   
98.
Eight opiate agonists, administered by the intracerebroventricular (i.c.v.) route, were evaluated as analeptics in pentobarbital-anesthetized rabbits. Morphine, codeine, ethylketocyclazocine, N-allylnormetazocine, meperidine and methadone, but not etorphine or D-Ala2-Met-enkephalin, given i.c.v. 40 min after pentobarbital (30 mg/kg i.v.), produced significant shortening of the duration of anesthesia as determined by the loss of the righting reflex. No apparent relationship was found between this and analgesic potency, nor with the specific receptor subtypes with which these agonists are known to interact. With active compounds, such as morphine, codeine and methadone, producing narcotic sedation, it was necessary to pretreat the animals with naltrexone to unmask the analeptic effect. It is concluded that the analeptic effect produced by certain opiate drugs is not specifically related to any of the subtypes of opiate receptors thus far described.  相似文献   
99.
To elucidate the effect of platelet-activating factor (PAF) on ion transport function of airway epithelial cells, we studied bioelectric properties of cultured tracheal and bronchial epithelia from dogs under short-circuit conditions in vitro. Addition of PAF (10(-5) mol/L) to mucosal solution of Ussing chamber increased short-circuit current of tracheal epithelium from 3.3 +/- 0.7 to 8.5 +/- 1.2 microA/cm2 (p less than 0.001). This effect was dose dependent, and there was a corresponding increase in transepithelial potential difference. In contrast, PAF was without effect when it was added to the submucosal side. Electrical properties of bronchial epithelium remained unchanged by PAF. The PAF-induced increase in short-circuit current was not affected by amiloride but abolished by diphenylamine-2-carboxylate, bumetanide, or Cl-free medium. The effects of PAF were not altered by AA-861 or U-60257, but attenuated by indomethacin and piroxicam, and dose-dependently blocked by CV 6209 and WEB 2086. Mucosal, but not submucosal, addition of PAF increased the rate of prostaglandin release from tracheal epithelium. These results suggest that PAF selectively stimulates Cl secretion across tracheal epithelium, probably through activation of its specific receptors and the subsequent production of prostaglandins.  相似文献   
100.
BACKGROUND/AIMS: Quality of life can be adversely affected in many patients who suffer phonation disorders such as hoarseness and dysphonia following esophagectomy. The present study investigated postoperative phonation disorders in 15 patients who underwent esophagectomy for esophageal cancer. METHODOLOGY: None of the patients had signs of hoarseness before or after surgery. Aerodynamic testing to assess phonatory function testing and laryngoscopy for observing laryngeal movements were performed before and after surgery. As a control, the same tests were conducted in 20 patients treated for gastric cancer by gastrectomy. RESULTS: For esophagectomy patients, mean postoperative flow rate was significantly increased and maximum postoperative phonation time was significantly decreased after operation. Laryngoscopy confirmed postoperative paralysis of left laryngeal movements and excessive adduction of the right, unaffected vocal cord during phonation in 8 of 15 esophagectomy patients, although hoarseness was not reported by any patient. No significant changes were observed for mean postoperative flow rate or maximum postoperative phonation time following surgery in gastrectomy patients. CONCLUSIONS: Surgical procedures in the vicinity of the recurrent laryngeal nerve appear to be the cause of postoperative phonation disorders in patients undergoing esophagectomy for esophageal cancer, and these disorders can occur in the absence of symptoms such as hoarseness and dysphonia.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号