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   14455篇
  免费   656篇
  国内免费   90篇
耳鼻咽喉   194篇
儿科学   400篇
妇产科学   105篇
基础医学   1601篇
口腔科学   420篇
临床医学   866篇
内科学   4182篇
皮肤病学   197篇
神经病学   1057篇
特种医学   538篇
外科学   2490篇
综合类   85篇
预防医学   436篇
眼科学   334篇
药学   864篇
中国医学   20篇
肿瘤学   1412篇
  2023年   99篇
  2022年   152篇
  2021年   342篇
  2020年   175篇
  2019年   217篇
  2018年   297篇
  2017年   249篇
  2016年   256篇
  2015年   302篇
  2014年   371篇
  2013年   492篇
  2012年   683篇
  2011年   832篇
  2010年   454篇
  2009年   374篇
  2008年   704篇
  2007年   763篇
  2006年   760篇
  2005年   661篇
  2004年   706篇
  2003年   671篇
  2002年   701篇
  2001年   413篇
  2000年   398篇
  1999年   412篇
  1998年   176篇
  1997年   145篇
  1996年   132篇
  1995年   119篇
  1994年   102篇
  1993年   86篇
  1992年   291篇
  1991年   246篇
  1990年   250篇
  1989年   284篇
  1988年   215篇
  1987年   205篇
  1986年   197篇
  1985年   177篇
  1984年   131篇
  1983年   102篇
  1982年   69篇
  1981年   55篇
  1979年   78篇
  1978年   49篇
  1977年   51篇
  1975年   48篇
  1974年   47篇
  1973年   50篇
  1971年   47篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
1. Spike generation by stimulation of the parafascicular nucleus of thalamus was extracellularly recorded in the nucleus accumbens of chloral hydrate-anesthetized adult Wistar rats using a silver-wire microelectrode attached along a seven-barreled micropipette, each of which was filled with dopamine, SKF 38393 (D-1 agonist), bromocriptine (D-2 agonist), haloperidol, SCH 23390 (D-1 antagonist) and domperidone (D-2 antagonist). The drugs were microiontophoretically applied to the target neurons recorded. 2. Effects of dopamine receptor antagonists on the inhibition of the spike generation by conditioning stimuli applied to the ventral tegmental area preceding the test stimulus to the parafascicular nucleus and those of dopamine agonists on the test stimulus-induced spikes were examined. 3. The parafascicular nucleus stimulation-induced spikes were inhibited by dopamine as well as D-1 and D-2 agonists and by the conditioning stimulation of the ventral tegmental area. The conditioning stimulation-induced inhibition was antagonized by haloperidol and SCH 23390, but not by domperidone. 4. Activation of D-1 receptors, which make probably synaptic contact with dopaminergic nerve terminals from the ventral tegmental area, is considered to result in inhibition of the neuronal activity of the nucleus accumbens neurons receiving input from the parafascicular nucleus of the thalamus. In addition, D-2 receptors located extrajunctionally may be involved in the inhibition of the same neurons in the nucleus accumbens.  相似文献   
4.
We experienced a rare case of giant cell tumor (GCT) arising in the 5th rib involving the 5th vertebral body and transverse process. A 57-year-old man presented with a well-defined mass in the left thoracic cavity on chest x ray examination. Chest computed tomography showed a heterogeneous 7cm-diameter mass originating in the posterior segment of the left 5th rib. The tumor had spread to the 5th thoracic vertebra destroying the left half of the body and transverse process. Magnetic resonance imaging showed a heterogeneous-intensity mass involving the 4th to 6th ribs. A radical excision of the tumor followed by a 50 Gy radiotherapy was performed after embolization of the feeding arteries. The pathological diagnosis was a GCT. The patient remains well without evidence of recurrence for 6 years following surgery. The present case is only the 14th case of GCT arising in the rib to have been reported in Japan.  相似文献   
5.
BACKGROUND: To understand the immunopathological features of oral lichen planus (OLP), we analyzed the expression of chemokines in the epithelial cell layers. Methods: Epithelia from OLP or healthy gingiva were collected by laser microdissection. The chemokine and chemokine receptor expressions in the epithelia were analyzed by DNA microarray. RESULTS: High levels of MIP-3alpha/LARC/CCL20 and its receptor CCR6 were expressed in the lesional epithelia. Furthermore, DC-CK1/CCL18, ELC/CCL19, SDF-1/CXCL12 and CXCR4 expressions were also increased. Immunohistologial analysis showed that high numbers of Langerhans cells (LCs) were present in the epithelia of OLP. Lesional epithelia also expressed high levels of the ligands specific for CXCR3 (e.g. MIG/CXCL9, IP-10/CXCL10 and I-TAC/CXCL11) and CCR5 (e.g. RANTES/CCL5). CONCLUSIONS: Infiltration of LCs is orchestrated by CCR6. Further, LCs residing in the lesional epithelia may be a mature phenotype. Moreover, infiltration of T cells in OLP could be mediated by signaling pathways through CXCR3 and CCR5.  相似文献   
6.
BACKGROUND: The objective of this study was to evaluate the efficacy and safety of first-line high-dose chemotherapy (HDCT) combined with peripheral blood stem cell transplantation (PBSCT) for patients with advanced extragonadal germ cell tumors (EGGCT). METHODS: Six male patients with advanced non-seminomatous EGGCT were treated with HDCT combined with PBSCT following 2-3 cycles of conventional-dose induction chemotherapy. The regimens used for HDCT were carboplatin, etoposide and ifosfamide (ICE) in five patients and ICE plus paclitaxel (T-ICE) in one patient, and that for induction therapy was cisplatin, etoposide and bleomycin (PEB) in all patients. As a rule, HDCT was continuously administered until alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin normalized (beta-HCG). RESULTS: Following 1-6 courses of HDCT (median, 4 courses), beta-HCG and AFP were normalized in all patients, and five and one patient were diagnosed as showing partial remission and stable disease, respectively. Five patients underwent surgical resection of residual tumors after HDCT, yielding necrotic tissue in two, mature teratoma in two, and viable cancer tissue in one, and the surgical margin was negative in all patients. At a median follow-up of 36 months, five patients were alive and disease-free, whereas the remaining one died of disease progression. Although all patients had grade 3 hematological toxicity, there was no treatment-related death by combining PBSCT. CONCLUSIONS: First-line HDCT with PBSCT could be safely administered to patients with advanced EGGCT, and the antitumor effect of this treatment was comparatively favorable. First-line HDCT therefore may represent an attractive option for patients with advanced EGGCT.  相似文献   
7.
OBJECTIVE: Standard chemotherapy shows relatively low long-term survival in patients with poor-risk testicular germ cell tumor (GCT). First-line high-dose chemotherapy (HD-CT) may improve the result. High-dose carboplatin, etoposide, ifosfamide chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT) was investigated as first-line chemotherapy in patients with advanced testicular GCT. METHODS: Fifty-five previously untreated testicular GCT patients with Indiana 'advanced disease' criteria received three cycles of bleomycin, etoposide and cisplatin (BEP) followed by one cycle of HD-CT plus PBSCT, if elevated serum tumor markers were observed after three cycles of the BEP regimen. RESULTS: Thirty patients were treated with BEP alone, because the tumor marker(s) declined to normal range. Twenty-five patients received BEP and HD-CT. One patient died of rhabdomyolysis due to HD-CT. Three and six (13% and 25%) out of 24 patients treated with BEP and HD-CT achieved marker-negative and marker-positive partial responses, respectively. The other patients achieved no change. Fifteen (63%) are alive and 14 (58%) are free of disease at a median follow-up time of 54 months. Severe toxicity included treatment-related death (4%). CONCLUSIONS: HD-CT with peripheral stem cell support can be successfully applied in a multicenter setting. HD-CT demonstrated modest anticancer activity for Japanese patients with advanced testicular GCT and was well tolerated. This regimen might be examined for further investigation in randomized trials in first-line chemotherapy for patients with poor-risk testicular GCT.  相似文献   
8.
A 67-year-old man was admitted to our hospital due to esophageal cancer. Cancer existed at the lower esophagus and subtotal esophagectomy and lymphadenectomy was performed. The postoperative course was uneventful. Pathological findings revealed moderately differentiated squamous cell carcinoma that metastasized to the abdominal lymph nodes which include the paraaortic lymph nodes. He complained of anorexia three months after the operation and was found to have multiple liver and mediastinal lymph node metastases. He was admitted for chemotherapy. Before starting chemotherapy, he suddenly died without any sign of hemorrhage or respiratory disorder. Autopsy showed metastatic lesions to the heart and mediastinal lymph nodes, liver, thoracic vertebrae, kidney, adrenal gland and heart. Metastatic nodules in the heart were on the ventricular septum where the conducting system exists. No direct invasion from the pericardium was observed. Blockade of the conducting system of the heart was considered to have caused the severe arrhythmia and sudden cardiac arrest.  相似文献   
9.
10.
A new method of determining urinary polyamine concentration was compared with other techniques, namely, high pressure liquid chromatography (HPLC) and a polyamine test-enzyme kit. The values obtained by the new method, HPLC, and polyamine test-enzyme kit correlated well for all the fractions: diamine, spermidine and spermine. The correlation between the new method and the polyamine test-enzyme kit gave r = 0.9702, y = 1.1359x + 5.1266 (n = 48).  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