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   12149篇
  免费   426篇
  国内免费   35篇
耳鼻咽喉   209篇
儿科学   169篇
妇产科学   217篇
基础医学   1506篇
口腔科学   371篇
临床医学   647篇
内科学   2778篇
皮肤病学   192篇
神经病学   895篇
特种医学   320篇
外科学   2153篇
综合类   60篇
预防医学   279篇
眼科学   256篇
药学   920篇
  1篇
中国医学   49篇
肿瘤学   1588篇
  2023年   88篇
  2022年   146篇
  2021年   249篇
  2020年   143篇
  2019年   199篇
  2018年   220篇
  2017年   182篇
  2016年   224篇
  2015年   206篇
  2014年   261篇
  2013年   369篇
  2012年   565篇
  2011年   623篇
  2010年   362篇
  2009年   335篇
  2008年   589篇
  2007年   640篇
  2006年   603篇
  2005年   635篇
  2004年   612篇
  2003年   615篇
  2002年   571篇
  2001年   323篇
  2000年   383篇
  1999年   317篇
  1998年   162篇
  1997年   112篇
  1996年   113篇
  1995年   101篇
  1994年   100篇
  1993年   93篇
  1992年   237篇
  1991年   190篇
  1990年   233篇
  1989年   219篇
  1988年   198篇
  1987年   191篇
  1986年   204篇
  1985年   145篇
  1984年   107篇
  1983年   82篇
  1982年   36篇
  1980年   42篇
  1979年   77篇
  1978年   62篇
  1977年   48篇
  1975年   38篇
  1974年   39篇
  1973年   36篇
  1972年   33篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Cerebral ischemia causes neuronal death and disruption of neural circuits in the central nervous system. Various neurological disorders caused by cerebral infarction can severely impair quality of life and are potentially fatal. Functional recovery in the chronic stage mainly depends on physical treatment and rehabilitation. We aim to establish cell therapy for cerebral ischemia using embryonic stem (ES) cells, which have self-renewing and pluripotent capacities. We previously reported that the transplanted monkey and mouse ES cell-derived neural progenitors, by stromal cell-derived inducing activity method, could survive and differentiate into various types of neurons and glial cells, and form the neuronal network in basal ganglia. In this report, we induced the differentiation of the neural progenitors from mouse ES cells using the serum-free suspension culture method and confirmed the expression of various basal ganglial neuronal markers and neurotransmitter-related markers both in vitro and in vivo, which was thought to be suitable for replacing damaged striatum after middle cerebral artery occlusion. This is the first report that used selectively induced telencephalic neural progenitors into ischemia model. Furthermore, we purified the progenitors expressing the neural progenitor marker Sox1 by fluorescence-activated cell sorting and Sox1-positive neural progenitors prevented tumor formation in ischemic brain for 2 months. We also analyzed survival and differentiation of transplanted cells and functional recovery from ischemic damage.  相似文献   
72.
Mice were forced to swim for 5 min in water at a temperature of 12 degrees C (cold water swim stress) or 32 degrees C (warm water swim stress), and stress-induced analgesia (SIA) was measured using the tail-flick test. The cold water swim stress induced non-opioid SIA as well as hypothermia, whereas the warm water swim stress caused opioid SIA. The in vivo binding of [(3)H]-Ro15-4513 was measured in the stressed mice and compared with that in control mice. The specific binding of [(3)H]-Ro15-4513 in the cerebral cortex, hippocampus, and cerebellum was significantly altered by forced swimming in cold water. Apparent association and dissociation rate of [(3)H]-Ro15-4513 binding were decreased, and the change in the dissociation rate was most pronounced in the hippocampus. In contrast, no significant alterations were observed in in vitro binding. The hypothermia induced by the cold water swim stress seems to be the main reason for alterations in the specific binding of [(3)H]-Ro15-4513. The kinetics of a saturable amount of [(3)H]-Ro15-4513 in the blood and brain were also measured. The relative ratio of the radioactivity concentration in the brain to that in the blood was significantly decreased by forced swimming in cold water, indicating that the cold water swim stress induced changes in the nonspecific binding of [(3)H]-Ro15-4513 in the brain. These results together with previous reports suggested that non-opioid SIA induced by the cold water swim stress might be related to alterations in the rates of general ligand-receptor interactions including GABA(A)/benzodiazepine system. Changes in the nonspecific binding might be also involved in non-opioid SIA.  相似文献   
73.
OBJECTIVES/HYPOTHESIS: Individual speech and language outcomes of deaf children with cochlear implants (CIs) are quite varied. Individual differences in underlying cognitive functions may explain some of this variance. The current study investigated whether behavioral inhibition skills of deaf children were related to performance on a range of audiologic outcome measures. DESIGN: Retrospective analysis of longitudinal data collected from prelingually and profoundly deaf children who used CIs. METHODS: Behavioral inhibition skills were measured using a visual response delay task that did not require hearing. Speech and language measures were obtained from behavioral tests administered at 1-year intervals of CI use. RESULTS: Female subjects showed higher response delay scores than males. Performance increased with length of CI use. Younger children showed greater improvement in performance as a function of device use than older children. No other subject variable had a significant effect on response delay score. A series of multiple regression analyses revealed several significant relations between delay task performance and open set word recognition, vocabulary, receptive language, and expressive language scores. CONCLUSIONS: The present results suggest that CI experience affects visual information processing skills of prelingually deaf children. Furthermore, the observed pattern of relations suggests that speech and language processing skills are closely related to the development of response delay skills in prelingually deaf children with CIs. These relations may reflect underlying verbal encoding skills, subvocal rehearsal skills, and verbally mediated self-regulatory skills. Clinically, visual response delay tasks may be useful in assessing behavioral and cognitive development in deaf children after implantation.  相似文献   
74.
A 62‐year‐old man with precordial pain and fever consulted a local practitioner. Blood tests revealed jaundice. Acute cholecystitis was diagnosed on ultrasonographic examination, and percutaneous transluminal gall‐bladder drainage was performed. The patient was referred to the Department of Surgery for operation. Imaging studies performed via a drain disclosed compression and stenosis of the lower portion of the common bile duct. A computed tomographic scan showed a multilocular nodule‐like low‐density area measuring 2.0 × 2.0 cm in diameter at the head of the pancreas. Endoscopic retrograde cholangiopancreatography disclosed compression and stenosis of the main pancreatic duct at the head of the pancreas. Angiographic examination revealed encasement of the intrapancreatic branch of the posterior pancreatic arcade, located in the same area as the compression stenosis of the bile duct. The results of imaging studies suggested cancer of the head of the pancreas, and a pancreatoduodenectomy was performed. The resected specimen included a mass measuring 3.5 × 2.7 × 1.7 cm, which was located at the head of the pancreas. On examination of a cut section, the mass was found to consist of small multilocular cysts. The cysts invaded the intrapancreatic bile duct. The histopathological diagnosis was serous cystadenoma.  相似文献   
75.
OBJECTIVES: The clinical features of myocarditis that developed during the influenza epidemic of winter 1998-1999 were investigated to emphasize the need for medical attention to this disease. METHODS: Nine patients were treated under diagnoses of acute myocarditis during the winter of 1998-1999. Five (two males and three females, mean age 52 +/- 18 years) were examined with myocarditis associated with influenza A. The diagnosis of influenza A myocarditis was based on electrocardiographic and echocardiographic abnormalities, increased creatine kinase levels and at least a four-fold increase in influenza A virus titers using paired sera. RESULTS: All patients had preceding flu-like symptoms and fever. Cardiac involvement developed between 4 and 7 days after the onset of influenza symptoms. Dyspnea progressively worsened in three patients, one went into shock and one had persistent fever, cough and mild dyspnea without apparent cardiac symptoms. Three patients had ST elevation associated with Q waves and one had complete left bundle branch block. The creatine kinase levels were abnormally increased and global wall motion of the left ventricle on echocardiography was decreased in all patients. Two patients had diagnoses of fulminant myocarditis. One patient died of pneumonia following cerebral infarction, but the left ventricular dysfunction normalized in the remaining four patients. CONCLUSIONS: Cardiac involvement occurred between 4 and 7 days after the onset of influenza symptoms, and worsening dyspnea was the most common symptom. Electrocardiography, echocardiography and creatine kinase levels should be checked to determine the potential for cardiac involvement when patients present with suspected influenza associated with worsening dyspnea or prolonged weakness. Increasing the awareness of influenza myocarditis may help in the earlier identification and treatment of this disease during influenza epidemics.  相似文献   
76.
The authors previously demonstrated that Ca2+/calmodulin (CaM)-dependent protein kinase IIalpha (CaM-KIIalpha) can phosphorylate neuronal nitric oxide synthase (nNOS) at Ser847 and attenuate NOS activity in neuronal cells. In the present study, they established that forebrain ischemia causes an increase in the phosphorylation of nNOS at Ser847 in the hippocampus. This nNOS phosphorylation appeared to be catalyzed by CaM-KII: (1) it correlated with the autophosphorylation of CaM-KIIalpha; (2) it was blocked by the CaM-KII inhibitor, KN-93; and (3) nNOS and CaM-KIIalpha were found to coexist in the hippocampus. Examination of the spatial relation between nNOS and CaM-KIIalpha in the brain revealed coexistence in the hippocampus but not in the cortex during reperfusion, with a concomitant increase in autophosphorylation of CaM-KIIalpha. The phosphorylation of nNOS at Ser847 probably takes place in nonpyramidal hippocampal neurons, which increased after 30 minutes of reperfusion in the hippocampus, whereas no significant increase was detected in the cortex. An intraventricular injection of KN-93 significantly decreased the phosphorylation of nNOS in the hippocampus. These results point to CaM-KII as a protein kinase, which by its colocalization may attenuate the activity of nNOS through its Ser847 phosphorylation, and may thus contribute to promotion of tolerance to postischemic damage in hippocampal neurons.  相似文献   
77.
78.
PURPOSE: The aim of this report was to indicate both the advantages and disadvantages of local cell transfer therapy using ex vivo expanded autologous tumor-specific T lymphocytes (ATTLs) for recurrent cases of malignant gliomas. EXPERIMENTAL DESIGN: Subjects are 10 cases of malignant gliomas consisting of 7 cases of glioblastoma multiforme, 2 cases of anaplastic astrocytoma, and 1 case of anaplastic oligoastrocytoma. All cases were recurrences. ATTLs were induced by coculturing peripheral blood mononuclear cells with autologous tumor cells in medium containing interleukin-1, -2, -4, and -6 and administered into the local tumor site in total numbers of 3-247 x 10(7) cells. As end points, tumor response and survival time were analyzed observing clinical state. RESULTS: Five cases responded to this therapy (namely, one case showed complete remission, and four cases had a partial response). There were three cases of no change, and two cases of progressive disease. The overall tumor response rate was 50%. No complications were noticed, except for two cases of minor local hemorrhage and eight cases of temporary fever. Nine cases died of further tumor progression, and one case died of aspiration pneumonia, and the cause-specific survival analysis indicates that the median survival time was 5 months from the initial ATTL injection. CONCLUSIONS: The results suggest that local administration of ATTLs is effective in recurrent malignant gliomas in that it demonstrated a high benefit:risk ratio with minor side effects. Although its antitumor effect may be temporary in some advanced cases, it is highly possible that the tumor could be stabilized when conditions are optimal.  相似文献   
79.
The coexistence of lung cancer and multiple myeloma (MM) is rare. A search of the English literature revealed only 5 case reports to date. We describe a case of MM that presented in a 78-year-old lung cancer patient after 20 months of treatment with gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor. We also review previously reported cases of concurrent development of lung cancer and MM.  相似文献   
80.
l ‐tri‐iodothyronine (3, 3', 5–triiodothyronine; T3) is an active form of the thyroid hormone (TH) essential for the development and function of the CNS. Though nongenomic effect of TH, its plasma membrane–bound receptor, and its signaling has been identified, precise function in each cell type of the CNS remained to be investigated. Clearance of cell debris and apoptotic cells by microglia phagocytosis is a critical step for the restoration of damaged neuron‐glia networks. Here we report nongenomic effects of T3 on microglial functions. Exposure to T3 increased migration, membrane ruffling and phagocytosis of primary cultured mouse microglia. Injection of T3 together with stab wound attracted more microglia to the lesion site in vivo. Blocking TH transporters and receptors (TRs) or TRα‐knock‐out (KO) suppressed T3‐induced microglial migration and morphological change. The T3‐induced microglial migration or membrane ruffling was attenuated by inhibiting Gi/o‐protein as well as NO synthase, and subsequent signaling such as phosphoinositide 3‐kinase (PI3K), mitogen‐activated protein kinase (MAPK)/extracellular signal‐regulated kinase (ERK). Inhibitors for Na+/K+‐ATPase, reverse mode of Na+/Ca2+ exchanger (NCX), and small‐conductance Ca2+‐dependent K+ (SK) channel also attenuated microglial migration or phagocytosis. Interestingly, T3‐induced microglial migration, but not phagocytosis, was dependent on GABAA and GABAB receptors, though GABA itself did not affect migratory aptitude. Our results demonstrate that T3 modulates multiple functional responses of microglia via multiple complex mechanisms, which may contribute to physiological and/or pathophysiological functions of the CNS. GLIA 2015:63:906–920  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