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   23733篇
  免费   1145篇
  国内免费   159篇
耳鼻咽喉   210篇
儿科学   542篇
妇产科学   264篇
基础医学   3214篇
口腔科学   410篇
临床医学   1421篇
内科学   6325篇
皮肤病学   579篇
神经病学   1760篇
特种医学   979篇
外科学   4004篇
综合类   123篇
预防医学   565篇
眼科学   572篇
药学   1457篇
中国医学   38篇
肿瘤学   2574篇
  2023年   140篇
  2022年   290篇
  2021年   489篇
  2020年   275篇
  2019年   354篇
  2018年   505篇
  2017年   388篇
  2016年   473篇
  2015年   499篇
  2014年   729篇
  2013年   816篇
  2012年   1395篇
  2011年   1572篇
  2010年   879篇
  2009年   792篇
  2008年   1388篇
  2007年   1543篇
  2006年   1506篇
  2005年   1645篇
  2004年   1656篇
  2003年   1690篇
  2002年   1566篇
  2001年   288篇
  2000年   239篇
  1999年   327篇
  1998年   402篇
  1997年   323篇
  1996年   312篇
  1995年   269篇
  1994年   243篇
  1993年   219篇
  1992年   169篇
  1991年   148篇
  1990年   132篇
  1989年   116篇
  1988年   119篇
  1987年   98篇
  1986年   102篇
  1985年   97篇
  1984年   106篇
  1983年   78篇
  1982年   75篇
  1981年   77篇
  1980年   70篇
  1979年   55篇
  1978年   50篇
  1977年   47篇
  1976年   40篇
  1975年   32篇
  1972年   27篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Preface     
  相似文献   
22.
Skull metastasis of thyroid carcinoma is rare. The majority of skull metastases of thyroid carcinoma are of the follicular subtype, rather than thyroid papillary carcinoma. In this report, a 55-year-old woman with skull metastasis from thyroid papillary carcinoma is presented. The metastatic lesion of the skull was hypervascular and osteolytic, and the bleeding was profuse during resection. There have been only four reports of skull metastasis from thyroid papillary carcinoma. The mean period from the initial diagnosis of thyroid carcinoma until the detection of skull metastasis is 23.3 years, whereas in this patient, it was about 2 years. Therefore, in the clinical course of thyroid papillary carcinoma, skull metastasis should be considered, and the patient should be meticulously followed up.  相似文献   
23.
A new surgical technique to treat retroperitoneal tumors with supradiaphragmatic vena caval invasion is described. In this technique, hepatic warm ischemia can be avoided with reversed hepatic outflow through the portal vein and neither hypothermic circulatory arrest nor cardiopulmonary bypass is necessary using centrifugal blood pump-driven bypass.  相似文献   
24.
We report herein a case of spontaneous subcapsular hepatic hemorrhage which occurred in a 33-year-old woman 1 day after she had been delivered of her second child by cesarean section following an uneventful pregnancy. She complained of right upper quadrant pain on the 1st postoperative day, and computed tomography (CT) showed subcapsular low-density masses in both liver lobes, while extravasation was demonstrated by CO2 intraarterial digital subtraction angiography (IADSA). The hemorrhage was successfully controlled by transcatheter arterial embolization (TAE). However, on the 3rd day after TAE, an exploratory laparotomy was performed to establish an exact diagnosis to explain the persistent abdominal pain and abnormal liver function tests. Subcapsular hematomas in both lobes were confirmed and no visible laceration was present. The patient recovered gradually by spontaneous absorption of the hematomas and was discharged on the 22nd postoperative day. Spontaneous hepatic hemorrhage associated with pregnancy is a very rare complication, and establishing a correct diagnosis and initiating appropriate therapy are essential for this life-threatening disease.  相似文献   
25.
The aim of this study was to assess the significance of C3 deposition in IgA nephropathy in children and adolescents. One hundred and two patients aged 5–21 years (57 male and 45 female) were studied. The findings of C3 deposition were classified into 8 groups by immunofluorescent (IF) pattern and intensity as follows: group MC3+ (N = 12): mesangiocapillary pattern and 3+ in intensity; group MC2+ (N = 13): mesangiocapillary and 2+; group MC1 + (N = 4): mesangiocapillary and 1 +; group M3+ (N = 11): mesangial and 3+; group M2+ (N = 24): mesangial and 2+; group M1 + (N=18): mesangial 1 +; group S (N = 12): only segmentally positive; and group N (N = 8): negative. Histological changes were scored semiquantitatively as an activity index (cellular proliferation, necrosis, interstitial cell infiltration, and cellular crescents) and a chronicity index (mesangial sclerosis, segmental and global glomerular sclerosis, fibrous crescents, adhesion and tubulo-interstitial change). IF findings were scored semiquantitatively and laboratory findings were also studied. The following results were obtained: 1) The scores of total activity index in MC groups were higher than in the M, S or N groups, and the greater the degree of C3 deposition, the higher the score; 2) Such result was not evident in the chronicity index; 3) High IF scores of IgG and IgM were found in the MC3+ and MC2+ groups; 4) Hematuria was more severe in MC3+ and MC2+ than in other groups, and proteinuria was more prominent in the MC than other groups. Thus the degree of C3 deposition was parallel with histological activity and urinary findings.  相似文献   
26.
-Hydroperoxy diethyl peroxide, a novel compound found in the tunic of ascidians, has two peroxide moieties per molecule. Since ascidians are a widely served food item in Japan, human exposure to this compound potentially exists in the seafood preparation industries. No toxicological data have so far been published on this compound, and so we determined the intraperitoneal 6-day LD50 in mice and conducted histopathological examinations. The 6-day LD50, was found to be 199 mg/kg with 95% confidence limits of 126–314 mg/kg. Histopathological examination revealed necrosis induced in a variety of cells that had been directly exposed to the compound. These cells included hepatocytes, parenchymal pancreatic cells and fat cells. It is concluded that direct contact with this compound is likely to elicit cellular necrosis of various organs. The specific toxicological effects are probably dependent on the route of exposure.  相似文献   
27.
Abstract: Historical changes in forensic psychiatric evaluation on criminal responsibility and proceedings in psychopathological findings of amphetamine psychosis are reviewed at first. The classification of amphetamine related mental disorders are proposed in 6 types. Among them, the clinical characteristics and psychopathological features of “Anxiety-situational reaction type” (Fukushima) are described. According to some reasonable grounds, offenders diagnosed as anxiety-situational reaction type should be evaluated as diminished responsibility in place of irresponsibility. Finally, two cases of murder committed under the influence of amphetamine, are reported in detail.  相似文献   
28.
1. Effects of potassium (K) supplementation (100 mEq/day) on urinary sodium (Na) excretion and on the secretion of atrial natriuretic polypeptide (ANP) during salt loading (350 mEq/day) were studied in 12 healthy salt-resistant normotensives under strictly controlled metabolic ward conditions. 2. Urinary volume and Na excretion on the first day of the high salt period (HSP) were significantly greater in the K-supplemented group (KG) than in the control group (CG). 3. There was a significant gain in bodyweight after salt loading in both groups, with a significantly greater gain in CG on the second day of HSP. Haematocrit decreased significantly during salt loading in both groups, the degree of which was significantly greater in CG. 4. Plasma norepinephrine decreased significantly during salt loading in both groups, the degree of which was significantly less in KG than in CG. A significant increase in plasma ANP was observed in CG on and after the second day of HSP, while a significant increase in plasma ANP was observed on the fifth day of HSP in KG. 5. These findings indicate that K supplementation accelerates diuresis and natriuresis, resulting in moderate suppression of volume expansion induced by salt loading and that this accelerated diuresis and natriuresis is not a result of the action of ANP.  相似文献   
29.
We have previously shown that interleukin (IL)-1beta and tumour necrosis factor (TNF)-alpha mRNA levels in rat alveolar macrophages are increased in by endotoxin (lipopolysaccharide; LPS)- stimulation and further enhanced by culturing with low-Mg2+ medium. We have now investigated the mechanisms of underlying this enhancement by using some specific signal transduction inhibitors. The enhanced elevation of both mRNAs levels was suppressed by pretreatment with TMB-8 (which inhibits calcium release from the endoplasmic reticulum) or dexamethasone (which inhibits nuclear factor [NF]-kappaB and activator protein [AP]-1), but not with verapamil or nifedipine (which inhibits calcium channels). The enhancment of IL-1beta, but not TNF-alpha mRNA levels, was suppressed by pretreatment with W-7 (which inhibits calmodulin), whereas the enhancement of TNF-alpha mRNA levels was suppressed by pretreatment with U73122 (which inhibits phospholipase C). Curcumin (an inhibitor of AP-1), suppressed the increases in both mRNAs induced by low-Mg2+ medium alone, but had no suppressive effect on the levels of either mRNA after LPS-stimulation in low-Mg2+ medium. Pyrrolidine dithiocarbamate (an inhibitor of NF-kappaB) prevented the elevation of TNF-alpha mRNA levels induced by low-Mg2+ medium without LPS-stimulation, but had no suppressive effect on IL-1beta mRNA levels. From these results, we conclude that the enhanced elevation of IL-1beta and TNF-alpha mRNA levels seen in LPS-stimulated alveolar macrophages in low-Mg2+ medium occurs partly via the same, and partly via different, signaling pathways.  相似文献   
30.
A 52 year-old woman noticed general fatigue, polyarthralgia, and muscle weakness of lower extremities in October 2001. In December, she felt difficulty in walking due to muscle weakness. In January 2002, she admitted another hospital because of dyspnea on exertion and edema of lower extremities. Laboratory test revealed leukocytopenia, the elevation of creatine kinase and positive anti-U1-RNP antibodies. Her chest computed tomography (CT) showed severe interstitial pneumonia. Cardiac echogram revealed that she had pericardial effusion and pulmonary hypertension. Then she was transferred to Keio University Hospital and she was diagnosed as having mixed connective tissue disease (MCTD) manifestating myositis, interstitial pneumonia, pulmonary hypertension and pericarditis. Prednisolone (PSL) 60mg daily following to methylprednisolone (mPSL) pulse therapy was begun and her symptoms were gradually improved. In middle of February, she complained of high fever over 39.0 degrees C. Bacterial culture tests were negative and laboratory data indicated pancytopenia and a high level of serum ferritin. Bone marrow aspiration revealed hemophagocytosis in bone marrow specimens and she was diagnosed as having hemophagocytic syndrome associated with MCTD. mPSL pulse therapy was not effective and intermittent cyclophosphamide pulse therapy (IV-CY) was performed resulting in improvement of the symptoms. This case suggested the effectiveness of IV-CY therapy in patients with corticosteroid-resistant HPS associated with connective tissue diseases.  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