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   828篇
  免费   61篇
  国内免费   2篇
耳鼻咽喉   20篇
儿科学   14篇
妇产科学   8篇
基础医学   115篇
口腔科学   15篇
临床医学   52篇
内科学   187篇
皮肤病学   2篇
神经病学   86篇
特种医学   71篇
外科学   97篇
综合类   10篇
预防医学   12篇
眼科学   15篇
药学   71篇
中国医学   9篇
肿瘤学   107篇
  2022年   13篇
  2021年   28篇
  2020年   15篇
  2019年   20篇
  2018年   32篇
  2017年   23篇
  2016年   18篇
  2015年   18篇
  2014年   19篇
  2013年   29篇
  2012年   39篇
  2011年   52篇
  2010年   20篇
  2009年   18篇
  2008年   32篇
  2007年   49篇
  2006年   42篇
  2005年   47篇
  2004年   54篇
  2003年   36篇
  2002年   52篇
  2001年   27篇
  2000年   27篇
  1999年   23篇
  1998年   7篇
  1997年   9篇
  1996年   9篇
  1995年   6篇
  1994年   9篇
  1993年   4篇
  1992年   6篇
  1991年   6篇
  1990年   10篇
  1989年   9篇
  1988年   8篇
  1987年   9篇
  1986年   4篇
  1985年   7篇
  1984年   3篇
  1983年   6篇
  1982年   4篇
  1980年   5篇
  1978年   5篇
  1972年   3篇
  1971年   3篇
  1970年   3篇
  1969年   4篇
  1968年   4篇
  1967年   3篇
  1966年   3篇
排序方式: 共有891条查询结果,搜索用时 31 毫秒
11.
12.
Surgical intervention is expected to improve the quality of life in patients with intractable epilepsy by providing adequate seizure control. Although many previous studies showed various rates of seizure freedom, definite conclusions have not yet been made regarding outcomes. In order to clarify the long-term postoperative outcome for a period up to 10 years, a retrospective review of our patients was performed longitudinally by using the survival analysis method. The postoperative state of epilepsy in 76 patients who underwent resection surgery was assessed based on Engel’s criteria. In addition, Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom. In this patient group, abnormal lesion were detected by MRI in 70 out of 76 cases, and the ictal onset zone was finally identified within temporal lobe in 51 cases. The most favorable outcome, defined as Engel Class Ia, was observed in 26 (37%), 24 (40%), and 18 (41%) cases at 2, 5, and 10 years after surgery, respectively. The Kaplan-Meier survival curve in the overall group estimated the probability of seizure freedom as 75% (95% confidence interval [CI] 70–80%), 67% (62–72%), and 51% (45–57%) at 2, 5, and 10 years follow up, respectively. Half of all seizure recurrences occurred within the first 2 postoperative years. In this study, we showed that long-term favorable outcome of seizure control following resection surgery can be achieved in more than half of the patients.  相似文献   
13.
We have developed a feedback-controlled bolus plus infusion (FC-B/I) method for monitoring the interaction between positron emission tomography (PET) ligands and their specific target molecules with PET. The usefulness of the FC-B/I method was evaluated by the direct interaction between [11C]raclopride, a dopamine D2 receptor (D2R) ligand, and cold raclopride (10 and 100 μg/kg) in the brains of conscious monkeys. The present results demonstrated that the FC-B/I method could achieve the equilibrium state of [11C]raclopride in the striatum of monkey brain, and also that the cold raclopride-induced reduction of [11C]raclopride binding to D2R was observed in a dose-dependent manner. Good correlations of distribution volume ratio of the striatum to cerebellum between the conventional bolus plus infusion (B/I) method and the FC-B/I method as well as between the conventional bolus injection method and the FC-B/I method were observed. These results indicated that the system could be a useful tool for the evaluation of interaction between drug candidates and their target molecules like enzymes, receptors, and transporters by using of their specific PET ligands.  相似文献   
14.

Background

A retrospective analysis indicated that the incidence of delayed gastric emptying (DGE) was less after using a circular stapler (CS) for duodenojejunostomy than that after hand-sewn (HS) anastomosis in pylorus-preserving pancreaticoduodenectomy (PpPD). This randomized clinical trial compared the incidence of DGE postoperative after CS duodenojejunostomy with that of conventional HS anastomosis in PpPD.

Methods

We randomly assigned 101 patients (age 20–80) undergoing PpPD to receive CS duodenojejunostomy (group CS, n?=?50) or HS duodenojejunostomy (group HS, n?=?51) in two Japanese cancer center hospitals between 2011 and 2013. The patients were stratified by institution and size of the main pancreatic duct (<3 or ≥3 mm). The primary endpoint was the incidence of grade B or C DGE according to the international definition with a non-inferiority margin of 5 %. This trial is registered with University hospital Medical Information Network (UMIN) Center: UMIN000005463.

Results

Per-protocol analysis of data on 95 patients showed that grade B or C DGE was found in 4 (8.9 %) of 45 patients who underwent CS anastomosis and in 8 (16 %) of 50 patients who underwent HS anastomosis (P?=?0.015). There were no differences in the overall incidence of DGE (P?=?0.98), passage of the contrast medium through the anastomosis (P?=?0.55), or hospital stays (P?=?0.22).

Conclusions

CS duodenojejunostomy is not inferior to HS anastomosis with respect to the incidence of clinically significant DGE, justifying its use as treatment option.
  相似文献   
15.
Chlorogenic acid (CGA) is a polyphenol found in coffee and medicinal herbs such as Lonicera japonica. In this study, the effect of CGA-induced relaxation on carbachol (CCh)-induced contraction of mouse urinary bladder was investigated. CGA (30–300 μg/ml) inhibited CCh- or U46619-induced contraction in a concentration-dependent manner. SQ22536 (adenylyl cyclase inhibitor) recovered CGA-induced relaxation of CCh-induced contraction; however, ODQ (guanylyl cyclase inhibitor) did not have the same effect. In addition, 3-isobutyl-1-methylxanthine (IBMX) enhanced CGA-induced relaxation; however, forskolin or sodium nitroprusside did not have the same effect. Moreover, Ro 20–1724, a selective phosphodiesterase (PDE) 4 inhibitor, enhanced CGA-induced relaxation, but vardenafil, a selective PDE5 inhibitor, did not have the same effect. In the presence of CCh, CGA increased cyclic adenosine monophosphate (cAMP) level, whereas SQ22536 inhibited the increase of cAMP levels. Moreover, higher cAMP levels were obtained with CGA plus IBMX treatment than the total cAMP levels obtained with separate CGA and IBMX treatments. In conclusion, these results suggest that CGA inhibited CCh-induced contraction of mouse urinary bladder by partly increasing cAMP levels via adenylyl cyclase activation.  相似文献   
16.
Graefe's Archive for Clinical and Experimental Ophthalmology - Recently, artificial intelligence has been used to determine sex using fundus photographs alone. We had earlier reported that sex...  相似文献   
17.
SARS-CoV-2 is the causative agent of COVID-19, which is a global pandemic. SARS-CoV-2 is transmitted rapidly via contaminated surfaces and aerosols, emphasizing the importance of environmental disinfection to block the spread of virus. Ultraviolet C radiation and chemical compounds are effective for SARS-CoV-2 disinfection, but can only be applied in the absence of humans due to their toxicities. Therefore, development of disinfectants that can be applied in working spaces without evacuating people is needed. Here we showed that TiO2-mediated photocatalytic reaction inactivates SARS-CoV-2 in a time-dependent manner and decreases its infectivity by 99.9% after 20 min and 120 min of treatment in aerosol and liquid, respectively. The mechanistic effects of TiO2 photocatalyst on SARS-CoV-2 virion included decreased total observed virion count, increased virion size, and reduced particle surface spike structure, as determined by transmission electron microscopy. Damage to viral proteins and genome was further confirmed by western blotting and RT-qPCR, respectively. The multi-antiviral effects of TiO2-mediated photocatalytic reaction implies universal disinfection potential for different infectious agents. Notably, TiO2 has no adverse effects on human health, and therefore, TiO2-induced photocatalytic reaction is suitable for disinfection of SARS-CoV-2 and other emerging infectious disease-causing agents in human habitation.  相似文献   
18.
Xenopus Zic3 is a Xenopus homologue of mouse Zic and Drosophila pair-rule gene, odd-paired. We show here that Zic3 has significant roles both in neural and neural crest development in Xenopus embryo. Expression of Zic3 is first detected in prospective neural plate region at gastrulation. Onset of the expression was earlier than most proneural genes and followed chordin expression. The expression was induced by blockade of BMP4 signal. Overexpression of Zic3 resulted in hyperplastic neural and neural crest derived tissue. In animal cap explant, the overexpression of Zic3 induced expression of all the proneural genes and neural crest marker genes. These findings suggest that Zic3 can determine the ectodermal cell fate and promote the earliest step of neural and neural crest development.  相似文献   
19.
Summary We report a rare case of secondary involvement of the gallbladder by metastatic renal cell carcinoma. A 71-year-old man was diagnosed as having a polypoid mass within the gallbladder when he underwent right nephrectomy for a renal cell carcinoma. A preoperative diagnosis of simultaneous carcinoma of the gallbladder was made, and extended cholecystectomy with regional lymphadenectomy was performed five months after the initial operation.Postoperative histological examination of the polypoid mass within the gallbladder and a pancreatic mass excised during the second surgery revealed these resected tumors to be identical to the clear cell type of renal cell carcinoma. We feel that this case presents synchronous involvement of the gallbladder and pancreas by metastatic renal cell carcinoma of the right kidney.  相似文献   
20.
Caldesmon150, a protein composed of the Mr 150,000/147,000 doublet, alternately binds to calmodulin and actin filaments in a Ca2+-dependent "flip-flop" fashion. In all fibroblast cell lines examined, we also found a Mr 77,000 protein that crossreacts with anti-caldesmon150 antibody by using an immunoprecipitation technique [Owada, M.K., Hakura, A., Iida, K., Yahara, I., Sobue, K. & Kakiuchi, S. (1984) Proc. Natl. Acad. Sci. USA 81, 3133-3137]. In this report, we examine the tissue distribution of caldesmon by the method of immunoblotting, using caldesmon-specific antibody. Both caldesmon150 and caldesmon77 show widespread distribution in the tissues examined. Caldesmon77 is more widely distributed than caldesmon150, and we have purified caldesmon77 from bovine adrenal medulla. Its molecular weight estimated by NaDodSO4/polyacrylamide gel electrophoresis was 77,000, and a tetramer of this polypeptide may constitute the native molecule (Mr, 300,000). Caldesmon77 possesses a number of features in common with caldesmon150, including flip-flop binding to calmodulin and actin filaments depending on the concentration of Ca2+ and crossreactivity with caldesmon150-specific antibody. Analysis of caldesmon77-F actin interaction by sedimentation and electrophoresis revealed that 0.5 mg of caldesmon77 bound to 1 mg of F actin. This indicated that the molar ratio between caldesmon77 (tetramer) and actin monomer was calculated to be 1:12-14. In addition, caldesmon77 regulated the actin-myosin interaction in Ca2+-sensitive actomyosin obtained from adrenal medulla. These results suggest that caldesmon77 might be a ubiquitous actin-linked regulator of nonmuscle contractile processes, including those in adrenal medulla.  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