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   7183篇
  免费   446篇
  国内免费   21篇
耳鼻咽喉   32篇
儿科学   211篇
妇产科学   192篇
基础医学   1203篇
口腔科学   163篇
临床医学   665篇
内科学   1536篇
皮肤病学   287篇
神经病学   684篇
特种医学   210篇
外科学   599篇
综合类   45篇
一般理论   3篇
预防医学   679篇
眼科学   68篇
药学   510篇
中国医学   26篇
肿瘤学   537篇
  2023年   60篇
  2022年   92篇
  2021年   159篇
  2020年   165篇
  2019年   207篇
  2018年   216篇
  2017年   165篇
  2016年   201篇
  2015年   231篇
  2014年   288篇
  2013年   367篇
  2012年   557篇
  2011年   554篇
  2010年   319篇
  2009年   265篇
  2008年   460篇
  2007年   481篇
  2006年   463篇
  2005年   431篇
  2004年   359篇
  2003年   349篇
  2002年   301篇
  2001年   82篇
  2000年   62篇
  1999年   56篇
  1998年   63篇
  1997年   48篇
  1996年   45篇
  1995年   36篇
  1994年   28篇
  1993年   25篇
  1992年   32篇
  1991年   35篇
  1990年   34篇
  1989年   22篇
  1988年   26篇
  1987年   21篇
  1986年   28篇
  1985年   24篇
  1984年   12篇
  1983年   14篇
  1982年   22篇
  1981年   21篇
  1979年   13篇
  1978年   16篇
  1977年   14篇
  1976年   15篇
  1974年   13篇
  1971年   14篇
  1967年   11篇
排序方式: 共有7650条查询结果,搜索用时 15 毫秒
941.
942.
Abstract: Peripheral blood progenitor cells (PBPCs) were collected without prior association with chemotherapy but after the administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) produced in Chinese hamster ovary cells (CHO-GM, regramostim), Escherichia coli (E. coli-GM, molgramostim), or yeast (Yeast-GM, sargramostim) and used in conjunction with autologous bone marrow after high-dose chemotherapy in 69 patients with breast cancer or melanoma. The mean peripheral white blood cell (WBC) counts increased by 2.2 to 2.7-fold after regramostim, 4.5 to 7.3-fold after molgramostim and 4.3-fold after sargramostim. All patients underwent three leukaphereses. The mean (& standard error) total nucleated pheresed cells per kg × 108 were 4.15 & 0.56, 15.10 & 1.77 and 7.24 & 1.00 for patients receiving regramostim, molgramostim or sargramostim respectively. The mean (& standard error) granulocyte-macrophage colony-forming units per kg × 104 mobilized into the PB were 8.75 & 3.63, 71.03 & 17.85, and 65.11 & 18.74 for patients receiving regramostim, molgramostim, or sargramostim respectively. The total mean (& standard error) CD34+ cells per kg × 107 collected by three leukaphereses were 3.28 & 1.62, 1.34 & 0.51 and 2.57 & 1.93, for patients receiving regramostim, molgramostim or sargramostim respectively. The use of either molgramostim- or sargramostim-primed PBPCs led to complete elimination of absolute leukopenia with a WBC count under 100/mm3 in 64% and 77% of patients treated, respectively. Patients receiving molgramostim-primed PBPCs required fewer red blood cells transfusions than patients receiving regramostim-primed PBPCs (p = 0.0062). Our data indicate that PBPCs collected without prior association with chemotherapy but after either molgramostim or sargramostim with autologous bone marrow support and GM-CSF shorten the hematopoietic recovery after myeloablative chemotherapy in patients with breast cancer or melanoma.  相似文献   
943.
Zusammenfassung Das simultane Vorkommen von Lupus-erythematodes-(LE-) und Lichen-ruber-planus-(LP-) artigen Symptomen wird als LE/LP-Overlap-Syndrom (LE/LP-OS) bezeichnet. Es wird definiert durch das gleichzeitige Vorkommen klinischer, histologischer und immunhistologischer Charakteristika beider Krankheitsbilder. In der Literatur sind bisher 47 Patienten mit dieser seltenen Erkrankung beschrieben, wobei die klinischen Erscheinungsbilder heterogen sind: Die einzelnen Hauterscheinungen zeigen ein zwischen LE und LP intermedi?res Erscheinungsbild (Typ I=intermedi?rer Typ) oder aber ein Nebeneinander von LE- und LP-typischen Effloreszenzen (Typ II=polarer Typ). Zur Bestimmung der H?ufigkeit und Charakteristika des LE/LP-OS untersuchten wir retrospektiv unser LE-Patientengut von 1984–1995: In 5 F?llen wurde die Diagnose eines LE/LP-OS gestellt. Das LE/LP-OS ist demnach im untersuchten Kollektiv h?ufiger als bisher angenommen. Aufgrund der gro?en Variationsbreite der klinischen, histologischen und immunhistologischen Befunde und Fehlen pathognomonischer Merkmale des LE/LP-OS, wird die Diagnose m?glicherweise zu selten gestellt. Da sich jedoch aus der Diagnose therapeutische Konsequenzen ergeben, werden Kriterien vorgestellt, die Erkennen und Abgrenzung des LE/LP-OS erleichtern. Eingegangen am 25. August 1997 Angenommen am 17. Dezember 1997  相似文献   
944.
Background and purpose A large number of patients with epilepsy in the pediatric population have medically intractable epilepsy. In this age group seizures are usually daily or weekly, and response to antiepileptic therapy is poor, especially for those with neurological abnormalities and symptomatic epilepsies. However, several authors have already demonstrated similarly favorable long-term post-surgical seizure control when comparing pediatric and adult populations. In this article we aim to report the experience of the Ribeirão Preto Epilepsy Surgery Program in pediatric epilepsy surgery.Patients and methods We analyzed 107 patients with medically intractable epilepsy operated on between July 1994 and December 2002, considering age at surgery, seizure type, pathological findings, and seizure outcome. All data were prospectively collected according to protocols previously approved by the institution ethics committee.Results We analyzed a total of 115 operations performed in 107 patients. There was no difference in sex distribution. Complex partial seizures occurred in 31.4% of the patients, followed by tonic seizures (25.9%), focal motor seizures (15.4%), and infantile spasms (13.3%). The most common etiologies were cortical developmental abnormalities (25.2%), tumors (16.8%), mesial temporal sclerosis (15.9%), Rasmussen syndrome (6.5%), and tuberous sclerosis (6.5%). Overall post-surgical seizure outcome showed 67.2% of the patients within Engel classes I and II, reaching 75.0% when patients with callosotomies were excluded.Conclusions Post-surgical seizure control in the pediatric population is similar to that in adult patients, despite the fact that epilepsies in this age group are more frequently of extratemporal origin, suggesting that surgery should be considered in children as soon as intractability is determined.  相似文献   
945.
In this paper, we studied the influence of uremia and hemodialysis on oxidative parameters and delta-aminolevulinic acid dehydratase (delta-ALA-D) activity in control subjects, patients with chronic renal failure (CRF) on hemodialysis treatment (HD) and in patients not undergoing hemodialysis (ND). An increased lipid peroxidation was observed in the serum of HD and ND patients, as measured by the MDA serum levels. However, the level of MDA from erythrocytes was only elevated in HD patients. Blood catalase activity was increased in HD and ND groups. This study also showed a decreased activity of blood delta-aminolevulinic acid dehydratase (delta-ALA-D) in both groups of patients. This study demonstrated a positive correlation between ALA-D activity and hemoglobin, suggesting that inhibition of this enzyme might enhance anemia in CRF. A negative correlation was found between the alteration in delta-ALA-D activity and oxidative stress, which may indicate that the inhibition of ALA-D can be used as an index of oxidative stress.  相似文献   
946.
Hypouricaemia due to an isolated renal tubular defect is a rare condition. Several members from an affected family are described. The propositus is a 12-year-old girl with hypouricaemia (0.7–1.1 mg/dl) and increased fractional excretion of uric acid (50%). Pyrazinamide and sulphinpyrazone tests revealed an attenuated response in this subject to both drugs. The mother and one of the propositus' two brothers have the same defect. The other brother has uric acid levels at the lower limit of normal and increased fractional excretion of uric acid. These results suggest familial hypouricaemia due to a pre-secretory reabsorptive tubular defect, transmitted by autosomal dominant inheritance.  相似文献   
947.
BACKGROUND AND PURPOSE: The purpose of this study is to investigate the efficacy of a new needle insertion method (tapping instead of pushing) in reducing attendant tissue motion. This can be useful in applications where tissue motion due to needle insertion is problematic such as e.g. MRI-guided prostate brachytherapy and breast biopsies. In this study we will focus on prostate motion due to needle insertion. MATERIAL AND METHODS: Prostate motion due to needle insertion was measured in 30 patients, who were transperineally implanted with fiducial gold markers for position verification in prostate intensity modulated radiotherapy. In total 32 needles were manually pushed into the prostate and 29 were tapped with a prototype robotic system. The prostate motion in the cranio-caudal direction was measured on the video record of the ultrasound images. Differences in prostate motion between the two needle insertion methods were analysed making use of SPSS. RESULTS: The mean prostate motion was 5.6mm (range 0.3-21.6) when the needle was pushed and 0.9 mm (range 0-2.0) when the needle was tapped into the prostate (p<0.001). CONCLUSION: Prostate motion was significantly less when the needle was tapped into the prostate compared to when the needle was pushed. This result is important for the development of a tapping, MRI-guided, prostate implant robotic system.  相似文献   
948.
Primary progressive aphasia (PPA) is rare. Only limited series have been reported with SPECT or PET. Moreover, in the majority of studies, the left-to-right asymmetry ratio was used, leading to difficulties in right hemisphere analyzes. METHODS: Twenty-nine patients with clinical criteria of PPA (Mesulam and Weintraub) were included and compared with 12 control subjects. Complete language examination was performed in all patients. SPECT was performed on a double-head gamma camera after intravenous injection of hexamethylpropyleneamine oxime (22 patients and 12 control subjects) or ethylcysteinate dimer (7 patients). Nineteen regions of interest (ROIs) were drawn on each hemisphere in all patients using the Talairach atlas. The perfusion index (PI = cortex-to-cerebellum ratio) was calculated for each ROI. Atrophy was quantified on MRI by consensus of 3 observers in 16 cortical ROIs. ANOVAs were used to compare the PI between (a). patients and control subjects, (b). patients with (n = 15) or without (n = 14) lexicosemantic abnormalities (LS+ vs. LS-) and patients with (n = 19) or without (n = 10) arthric disorders (A+ vs. A-), and (c). patients with or without atrophy. RESULTS: In the 29 patients, the PI was significantly lower in the left temporopolar, left lateral temporal, left Wernicke, left parietal, and right lateral temporal cortex when compared with control subjects (P < 0.001). In LS+ patients versus control subjects, the PI significantly decreased in the left temporal cortex (lateral temporal; medial temporal; temporopolar; Wernicke), left Broca, left parietal, and right lateral temporal cortex (P < 0.001). In addition, LS+ versus LS- comparison showed a significant decrease in the left lateral, left medial temporal, and left Broca cortex (P < 0.001). In comparison with control subjects, the PI was not significantly different in A+ patients, whereas in A- patients the PI was significantly decreased in the left and right lateral temporal cortex, left Wernicke, and left parietal cortex. Moreover, the PI significantly decreased in the left lateral temporal region in A+ patients compared with A- patients. Finally, in patients without atrophy, the PI significantly decreased in the right and left lateral temporal cortex and the left parietal cortex (P < 0.01). CONCLUSION: Our study demonstrates that right-handed patients with PPA present a decreased perfusion in the bilateral temporal cortex. Moreover, in these regions, morphologic abnormalities are preceded by perfusion abnormalities. Finally, our results show that large left temporal dysfunction occurs in patients with LS disorders.  相似文献   
949.
Introduction The authors present the case of a 5-year-old girl with traumatic hydrocephalus secondary to a retroclival haematoma associated with atlanto-occipital dislocation (AOD) after a motor vehicle accident. Clinical history and neuroimaging of the patient are described. Discussion Computed tomography (CT) imaging of the head revealed a retroclival haematoma with secondary hydrocephalus. The cranio-cervical junction showed an AOD that was initially overlooked. Traumatic AOD is a rare diagnosis although in the recent years it has become an emergent entity due to the improvement of emergency medical treatment on the field. Conclusion An initial diligent imaging study and interpretation should be made to avoid misdiagnosis and to provide adequate treatment. This is the first case reported of the association of AOD, hydrocephalus and retroclival haematoma. A brief review of the literature is also presented.  相似文献   
950.
BACKGROUND AND OBJECTIVES: serotonin transporter (5-HTT) gene allelic variants were shown to be associated with Neuroticism and Harm Avoidance but the results were not replicated in other studies. The current investigation was undertaken in a further attempt to study the relationship between 5-HTT polymorphism and personality traits. SUBJECTS AND METHODS: to evaluate a spectrum of personality traits, MMPI was administered to a sample including patients with affective disorders (n=114), patients with schizophrenia spectrum illnesses (n=110) and psychiatrically well controls (n=124). All groups were genotyped for VNTR-17 and functional insertion-deletion (5-HTTLPR) polymorphisms. RESULTS: an association was found between 5-HTTLPR polymorphism and scores on three MMPI scales: Psychopathic deviance, Paranoia and Schizophrenia in patients with affective disorders and S chizophrenia in normal subjects. Both affected and control individuals with 'ss' genotype exhibited lower scores on these scales. CONCLUSION: we demonstrated that functional deletion/insertion allelic variation associated with decreased expression of serotonin transporter ('s' allele or 'ss' genotype) may restrict expression of schizoid traits in normal subjects and patients with affective disorders.  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