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   827篇
  免费   37篇
  国内免费   2篇
耳鼻咽喉   8篇
儿科学   6篇
妇产科学   3篇
基础医学   65篇
口腔科学   40篇
临床医学   49篇
内科学   203篇
神经病学   136篇
特种医学   17篇
外科学   211篇
综合类   3篇
预防医学   7篇
眼科学   3篇
药学   79篇
肿瘤学   36篇
  2024年   1篇
  2023年   11篇
  2022年   13篇
  2021年   31篇
  2020年   13篇
  2019年   23篇
  2018年   17篇
  2017年   16篇
  2016年   18篇
  2015年   16篇
  2014年   17篇
  2013年   26篇
  2012年   43篇
  2011年   72篇
  2010年   37篇
  2009年   36篇
  2008年   60篇
  2007年   59篇
  2006年   63篇
  2005年   70篇
  2004年   50篇
  2003年   43篇
  2002年   38篇
  2001年   10篇
  2000年   5篇
  1999年   11篇
  1998年   8篇
  1997年   12篇
  1996年   6篇
  1995年   3篇
  1994年   5篇
  1993年   4篇
  1992年   2篇
  1991年   4篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   3篇
  1980年   1篇
  1978年   2篇
  1975年   1篇
  1968年   1篇
  1963年   1篇
  1962年   1篇
排序方式: 共有866条查询结果,搜索用时 26 毫秒
91.
We synthesized a novel series of benzocycloalkene derivatives and evaluated their binding affinities to melatonin receptors. To control the spatial position of the amide group, one of the important pharmacophores, we incorporated an endo double bond, an exo double bond (E- and Z-configurations), and a chiral center (R- and S-configurations) at position 1. The indan derivatives with the S-configuration at position 1 were the most promising in terms of potency and selectivity for the human melatonin receptor (MT(1) site), while compounds with the R-configuration showed little potential. Our next attempt was to investigate the most favorable conformation of the methoxy group, the other important pharmacophore for binding to the MT(1) receptor. The introduction of a methyl group at position 5 of the indene ring conserved affinity; however, at position 7, it caused a decrease in affinity. These results suggested that the substitution at position 7 forced the methoxy group to adopt an unfavorable orientation. The optimization of the condensed ring size and substituents led to (S)-8d [(S)-N-[2-(2,3-dihydro-6-methoxy-1H-inden-1-yl)ethyl]propionamide], which had high affinity for the human MT(1) receptor (K(i) = 0.041 nM) but no significant affinity for the hamster MT(3)receptor (K(i) = 3570 nM). In addition, a practical synthetic method of chiral N-[2-(2,3-dihydro-1H-inden-1-yl)ethyl]alkanamides employing asymmetric hydrogenation with (S)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl-Ru has been established.  相似文献   
92.
The lifetime prevalence rate of obsessive-compulsive disorder (OCD) is more than 2 percent of the population. Its contemporary pathophysiological models have been explored. As serotonin reuptake inhibitors and cognitive behavior therapy are both considered first-line treatments of OCD, the treatment interventions provide us with clues. In this review, the authors summarized that genetics, neuropathology in the cortico-striatal-thalamic-cortical (CTSC) circuits, the association between OCD and Tourette's syndrome, the possibility of autoimmune-mediated pathophysiology containing PANDAS, serologic surveys of patients, and animal models including transgenic mice. Further research, genetic, neuroimmunological, and neuroimaging works may ultimately be useful in developing new treatments of OCD.  相似文献   
93.
Accumulating evidence suggests that the glycine modulatory site on the NMDA receptor could be potential therapeutic target for cognitive deficits in schizophrenia. The present study was undertaken to examine the effects of the glycine transporter-1 (GlyT-1) inhibitor, (R)-(N-[3-(4'-fluorophenyl)-3-(4'-phenylphenoxy)propyl])sarcosine (NFPS), on cognitive deficits in mice after repeated administration of the NMDA receptor antagonist phencyclidine (PCP). PCP (10 mg/kg/day for 10 days)-induced cognitive deficits were significantly improved by subsequent subchronic (2-week) administration of NFPS (1.0 and 3.0 mg/kg/day) or D-serine (600 mg/kg/day). However, PCP-induced cognitive deficits were not improved by a single administration of NFPS (3.0 mg/kg). Furthermore, Western blot analysis revealed that levels of GlyT-1 in the hippocampus, but not frontal cortex, of the PCP (10 mg/kg/day for 10 days)-treated mice were significantly higher than those of saline-treated mice. An in vivo microdialysis study revealed that repeated PCP administration significantly decreased the extracellular levels of glycine in the hippocampus, but not frontal cortex, of mice. These findings suggest that repeated PCP administration increased the density of GlyT-1 in the hippocampus of mouse brain, and that the GlyT-1 inhibitor NFPS could ameliorate cognitive deficits in mice after repeated administration of PCP.  相似文献   
94.
Adult-type aneurysms in the arterial duct are rare, and their spontaneous prognosis is poor. We performed surgical treatment of an aneurysm in the arterial duct in a 62-year-old male. The patient had had hoarseness since November 2003, and was referred to our hospital in March 2004. Thoracic CT and aortography demonstrated a sacciform aneurysm in the aorta in the distal arch region on the lesser curvature side. The patient was diagnosed as having an adult-type aneurysm in the nonpatent arterial duct, and underwent surgical treatment in April 2004. Thoracotomy in the fourth left intercostal space was performed up to the thoracic aorta, and a sacciform aneurysm, measuring 35 mm x 32 mm, was detected in the arterial duct. The recurrent laryngeal nerve adhering to the front surface of the aneurysm was overextended. Under partial extracorporeal circulation, the aneurysm was excised, and replaced by an artificial blood vessel. The postoperative course was satisfactory, and the patient was discharged from the hospital 14 days after surgery. The surgical outcome was good, and the hoarseness was improved. Taking possible complications into consideration, surgical treatment can be recommended in the early stage.  相似文献   
95.

Background

No definitive evidence exists regarding use of adjuvant chemotherapy (AC) for high-risk cases after radical nephroureterectomy (RNU), and the benefit of AC remains controversial. The aims of this study were to evaluate the efficacy of AC in patients with upper tract urothelial carcinoma (UTUC) and to determine those who qualified for AC.

Patients and Methods

From 1990 to 2015, 449 patients with nonmetastatic UTUC underwent RNU at 6 Kitasato University-affiliated hospitals. Eight patients who received neoadjuvant chemotherapy were excluded from this study. One hundred patients (23%) received platinum-based AC for a median of 3 courses. Disease-free survival and cancer-specific survival (CSS) were estimated using the Kaplan–Meier method. Multivariate analyses were performed with the Cox proportional hazards regression model, controlling for the effects of clinicopathological factors.

Results

The median age was 69 years, and the median follow-up period was 35.7 months. In multivariate analyses, factors independently predictive of poorer survival included pT stage (≥pT3), lymph node status (pN+), tumor grade (Grade 3), lymphovascular invasion, and soft tissue surgical margin. For the risk stratification model, patients were categorized into 3 groups on the basis of these 5 risk factors. In the high-risk group (at least 3 risk factors, 83 patients), 41 patients (49%) were treated with AC, and the 5-year CSS rate was higher in the AC group compared with the non-AC group (P = .02).

Conclusion

Having more than 3 risk factors defined the high-risk group among UTUC patients after RNU. AC was associated with improved CSS in patients with high-risk UTUC.  相似文献   
96.
Prexasertib is a novel inhibitor of checkpoint kinase 1. The primary objective of this study was to evaluate prexasertib tolerability in Japanese patients with advanced solid tumors. This nonrandomized single‐arm open‐label phase 1 study of prexasertib consisted of 2 dose levels, 80 mg/m2 and the global‐recommended dose based on a US study of 105 mg/m2, administered intravenously once every 14 days (n = 6 for each dose). Transition to the higher dose proceeded if the frequency of dose‐limiting toxicity observed in cycle 1 was <33% at the lower dose. Safety measures, pharmacokinetics and antitumor activity were assessed. A total of 12 patients were treated. Two patients, one in each dose group, experienced dose‐limiting toxicities of febrile neutropenia, one grade 4 and the other grade 3; both patients recovered and continued the study treatment. The grade 4 treatment‐emergent adverse events related to study treatment were neutropenia (6 patients [50.0%]), leukopenia (4 patients [33.3%]), and 1 instance each (8.3%) of anemia, febrile neutropenia and thrombocytopenia. Neutropenia was generally transient and reversible; 11 patients (91.7%) required granulocyte colony‐stimulating factor treatment during the study. There were no discontinuations due to adverse events or deaths. The prexasertib pharmacokinetics displayed dose‐independent and time‐independent behavior across both dose levels, similar to the profile observed in the US‐based phase 1 study. Eight patients had a best overall response of stable disease. These data are consistent with the known safety profile for prexasertib and confirm its tolerability in Japanese patients with advanced solid tumors.  相似文献   
97.
Aim/Background. MUC5AC and MUC6 are two major types of mucin that are abundantly present in the stomach; both of them form a gel of high viscosity that provides protection and lubrication. Expressions of MUC5AC and MUC6 are seen in pancreatic neoplasms, whereas the relationships between MUC5AC/MUC6 expression and clinicopathological factors and patient prognosis in invasive ductal carcinoma (IDC) of the pancreas have not been investigated. The aim of this study was to investigate MUC5AC and MUC6 expressions in IDC with special reference to clinicopathological factors and patient prognosis. Methods. Tissue samples were taken from 33 patients with IDC of the pancreas after radical surgical treatment. MUC5AC and MUC6 expressions were examined immunohistochemically. Results. The expressions of MUC5AC and MUC6 were observed in the cytoplasm of the tumor cells. MUC5AC and MUC6 immunoreactivities in the cancer tissues were found in 21 (63.6%) and 15 (45.5%) of 33 cases of IDC of the pancreas, respectively. MUC5AC-negative expression was associated significantly with lymphatic invasion, venous invasion, lymph node metastasis, and MUC5AC-positive patients showed significant better survival than those MUC5AC-negative patients. MUC6 expression was significantly related to tumor location, whereas MUC6 expression did not show significant relationship with patient survival. Conclusion. The results indicate that MUC5AC expression plays an important role in impacting tumor progression in IDC of the pancreas. MUC5AC expression is a benefit to better survival of patients with IDC of the pancreas. MUC6 expression is not involved in tumor progression in IDC of the pancreas.  相似文献   
98.
99.
100.
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