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   1677篇
  免费   76篇
  国内免费   4篇
耳鼻咽喉   30篇
儿科学   32篇
妇产科学   35篇
基础医学   259篇
口腔科学   33篇
临床医学   149篇
内科学   317篇
皮肤病学   35篇
神经病学   178篇
特种医学   130篇
外科学   299篇
综合类   13篇
预防医学   55篇
眼科学   20篇
药学   76篇
中国医学   2篇
肿瘤学   94篇
  2023年   21篇
  2022年   35篇
  2021年   48篇
  2020年   29篇
  2019年   31篇
  2018年   52篇
  2017年   31篇
  2016年   44篇
  2015年   39篇
  2014年   60篇
  2013年   94篇
  2012年   109篇
  2011年   117篇
  2010年   60篇
  2009年   54篇
  2008年   103篇
  2007年   108篇
  2006年   79篇
  2005年   97篇
  2004年   82篇
  2003年   80篇
  2002年   75篇
  2001年   14篇
  2000年   15篇
  1999年   13篇
  1998年   15篇
  1997年   10篇
  1996年   8篇
  1995年   10篇
  1994年   5篇
  1993年   7篇
  1992年   9篇
  1991年   8篇
  1990年   8篇
  1986年   5篇
  1985年   8篇
  1984年   4篇
  1956年   4篇
  1943年   4篇
  1935年   4篇
  1933年   19篇
  1932年   4篇
  1931年   5篇
  1930年   7篇
  1929年   4篇
  1925年   5篇
  1922年   4篇
  1914年   3篇
  1913年   5篇
  1912年   5篇
排序方式: 共有1757条查询结果,搜索用时 15 毫秒
21.
Triplication of chromosomal region 1p36.3 is a rare genomic rearrangement. In this report, we delineate the phenotypic spectrum associated with 1p36.3 triplications. We describe four patients with microtriplications of variable size, but with a strong phenotypic overlap, and compare them to previously described patients with an isolated triplication or duplication of this region. The 1p36.3 triplication syndrome is associated with a distinct phenotype, characterized by global developmental delay, moderate intellectual disability, seizures, behavioral problems, and specific facial dysmorphic features, including ptosis, hypertelorism, and arched eyebrows. The de novo occurrence of these microtriplications demonstrates the reduced reproductive fitness associated with this genotype, in contrast to 1p36.3 duplications which are mostly inherited and can be associated with similar facial features but with a less severe developmental phenotype. The shared triplicated region encompasses four disease-related genes of which GABRD and SKI are most likely to contribute to the phenotype.  相似文献   
22.
Summary The aim of the present study was to investigate the dose-dependent antiarrhythmic efficacy of lidocaine against electrically induced tachycardias in conscious, chronically instrumented postinfarction dogs. Programmed electrical stimulation (PES) was performed in 16 dogs 8 to 21 days after a 4 h occlusion of the left anterior descending coronary artery (LAD). Infusion of saline in 8 control animals with sustained ventricular tachycardia (SVT) inducible at baseline did not affect subsequent inducibility. In the treatment group 7 of 8 animals responded with SVT and one exhibited ventricular fibrillation at baseline. After an initial bolus of 1 mg/kg lidocaine intravenously (i.v.), the drug was infused at infusion rates of 40, 80 and 120 g/kg/min (i.v.). During 80 g/kg/min lidocaine (mean plasma level 3.5 g/ml) 7 out of 8 animals displayed an antiarrhythmic response; both the lower and the higher infusion rate were associated with a smaller antiarrhythmic efficacy (3 of 8 animals responded to 40 g/kg/min and 4 of 8 to 120 g/kg/min). Licocaine did not affect ventricular refractory periods, but induced an increase in intraventricular conduction time at all infusion rates, from 66.2 ms at baseline to 67.7 ms (p<0.05), 67.7 ms (p<0.05), 70.0 ms (p<0.01) respectively.In conclusion the present study demonstrates that lidocaine is of considerable value in the management of PES-induced ventricular arrhythmias in the postinfarction phase. However there is only a small optimal therapeutic plasma level range, where lidocaine exhibits its antiarrhythmic efficacy against this type of arrhythmia; this makes a carefully titration of the drug necessary both in the experimental and in the clinical setting. Send offprint requests to K. Krejcy at the above address  相似文献   
23.
Hirsch J  Ruge MI  Kim KH  Correa DD  Victor JD  Relkin NR  Labar DR  Krol G  Bilsky MH  Souweidane MM  DeAngelis LM  Gutin PH 《Neurosurgery》2000,47(3):711-21; discussion 721-2
OBJECTIVE: To evaluate an integrated battery of preoperative functional magnetic resonance imaging (fMRI) tasks developed to identify cortical areas associated with tactile, motor, language, and visual functions. METHODS: Sensitivity of each task was determined by the probability that a targeted region was activated for both healthy volunteers (n = 63) and surgical patients with lesions in these critical areas (n = 125). Accuracy of each task was determined by the correspondence between the fMRI maps and intraoperative electrophysiological measurements, including somatosensory evoked potentials (n = 16), direct cortical stimulation (n = 9), and language mapping (n = 5), and by preoperative Wada tests (n = 13) and visual field examinations (n = 6). RESULTS: For healthy volunteers, the overall sensitivity was 100% for identification of the central sulcus, visual cortex, and putative Wernicke's area, and 93% for the putative Broca's area (dominant hemisphere). For patients with tumors affecting these regions of interest, task sensitivity was 97% for identification of the central sulcus, 100% for the visual cortex, 91% for the putative Wernicke's area, and 77% for the putative Broca's area. These sensitivities were enhanced by the use of multiple tasks to target related functions. Concordance of the fMRI maps and intraoperative electrophysiological measurements was observed whenever both techniques yielded maps and Wada and visual field examinations were consistent with fMRI results. CONCLUSION: This integrated fMRI task battery offers standardized and noninvasive preoperative maps of multiple critical functions to facilitate assessment of surgical risk, planning of surgical routes, and direction of conventional, intraoperative electrophysiological procedures. Thus, a greater range of structural and functional relationships is brought to bear in the service of optimal outcomes for neurosurgery.  相似文献   
24.
This proof of principle study aimed to define a new and simple strategy for detection of endometrial cancer using epigenetic markers. We investigated DNA isolated from vaginal secretion collected from tampon for aberrant methylation of five genes (CDH13, HSPA2, MLH1, RASSF1A, and SOCS2) using MethyLight in 15 patients with endometrial cancer and 109 patients without endometrial cancer. All endometrial cancer patients revealed three or more methylated genes, whereas 91% (99 of 109) of the patients without endometrial cancer had no or fewer than three genes methylated in their vaginal secretion. The methods developed in this study provide the basis for a prospective clinical trial to screen asymptomatic women who are at high risk for endometrial cancer.  相似文献   
25.
Despite the use of multimodal therapy, higher-grade glioma is stilluniformly fatal in the adult population. There is a considerable differencebetween the length of survival in each given patient, even within the sametumor type and malignancy grade group, suggesting that there are factorsthat might differentially influence outcome. To identify such factors, 107patients with anaplastic or malignant glioma were retrospectivelyinvestigated. Clinical parameters and paraclinical data on the p53, mdm2,and EGFR genes at the DNA or protein level were evaluated by univariateanalysis and Cox proportional hazards regression modeling. Kaplan-Meiersurvival estimation demonstrated that immunohistochemical positivity formdm2 protein in patients with anaplastic astrocytoma or with glioblastomamultiforme was associated with a shorter survival time (p = 0.02).P53 gene mutations and immunopositivity for the epidermal growth factorreceptor (EGFR) protein were not significantly related to poor prognosis.The Cox proportional hazards model revealed immunohistochemical positivityfor p53, mdm2, or for both of them, the presence of postoperativeirradiation, and the extent of surgical resection of tumor to be variablessignificantly associated with prolonged survival. EGFR overexpression, ageover 60 years, and Karnofsky performance score below 40 points did notsignificantly shorten survival time. In conclusion, the present studyidentified immunohistochemically detected mdm2-protein overexpression as astatistically significant negative prognostic parameter in patients bearinganaplastic or malignant glioma. Association analysis of variables revealed apossible correlation between mdm2 and p53, which is also consistent with thebiological interaction mode of both proteins in vivo.  相似文献   
26.
27.
Data concerning treatment of secondary glioblastoma evolving from previously treated WHO II or III grade tumors are very scarce. The aim of this study was to evaluate the impact of surgical resection and adjuvant treatment on survival in patients with secondary glioblastoma. Thirty-nine patients with secondary glioblastoma evolving from previously treated lower grade gliomas between 2004 and 2015 were included. We evaluated the extent of resection, pathological parameters, adjuvant treatment, as well as survival after malignant transformation. The primary tumor grade was WHO II in 16 (41.0%) and WHO III in 23 (59.0%) patients. Median age was 43 years (range 23–67). Median KPS was 80 (range 60–100) before surgery, and 70 (range 50–100) after surgery. Gross total resection (GTR) of contrast-enhancing disease was achieved in 19 (48.7%) patients. Adjuvant treatment was radio-chemotherapy in 23 (59.0%), radiotherapy in three (7.7%), chemotherapy in five (12.8%) and none in eight (20.5%) patients. Median survival was 11 months (range 1–35) in the entire group. Time since initial diagnosis and previous treatment did not correlate with survival after glioblastoma. Failed GTR, poor KPS after surgery, and no adjuvant treatment were prognostic factors for shorter survival in univariate analysis (p?<?0.0001, p?=?0.028 and p?=?0.003). In selected patients, complete resection and adjuvant treatment may prolong survival in spite of multiple previous therapies.  相似文献   
28.
29.
Repetitive vibratory trauma in cyclists is one of the most common causes of ulnar nerve compression at the wrist. This study describes five cases of clinically suspected compression syndrome of the deep terminal branch of the ulnar nerve (DBUN) defined by high-resolution ultrasound (HRUS) with a 18-MHz linear transducer. Reliable HRUS visualization of the DBUN was feasible in all patients. The affected nerves had focally swollen and hypo-echoic changed segments. HRUS is a good imaging tool for the evaluation of a suspicious DBUN neuropathy if no electrodiagnostic testing is available or in patients with mild to moderate clinical symptoms with inconclusive electrodiagnostic results.  相似文献   
30.
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