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   15476篇
  免费   656篇
  国内免费   120篇
耳鼻咽喉   193篇
儿科学   303篇
妇产科学   192篇
基础医学   2043篇
口腔科学   326篇
临床医学   885篇
内科学   4666篇
皮肤病学   335篇
神经病学   906篇
特种医学   660篇
外科学   2228篇
综合类   50篇
一般理论   4篇
预防医学   464篇
眼科学   276篇
药学   1156篇
中国医学   32篇
肿瘤学   1533篇
  2023年   82篇
  2022年   158篇
  2021年   239篇
  2020年   150篇
  2019年   169篇
  2018年   260篇
  2017年   209篇
  2016年   290篇
  2015年   298篇
  2014年   354篇
  2013年   492篇
  2012年   742篇
  2011年   827篇
  2010年   468篇
  2009年   406篇
  2008年   806篇
  2007年   863篇
  2006年   836篇
  2005年   846篇
  2004年   833篇
  2003年   808篇
  2002年   874篇
  2001年   360篇
  2000年   351篇
  1999年   338篇
  1998年   222篇
  1997年   161篇
  1996年   149篇
  1995年   132篇
  1994年   138篇
  1993年   159篇
  1992年   326篇
  1991年   278篇
  1990年   228篇
  1989年   276篇
  1988年   238篇
  1987年   240篇
  1986年   243篇
  1985年   214篇
  1984年   139篇
  1983年   116篇
  1982年   73篇
  1981年   65篇
  1980年   53篇
  1979年   89篇
  1978年   66篇
  1977年   56篇
  1969年   52篇
  1968年   47篇
  1967年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
T Shioya  M Kagaya  A Onodera  S Miura  K Miura  M Miura 《Arerugī》1991,40(10):1334-1338
The purpose of this study was to clarify the bronchodilating effect of pirenzepine (PZ) and to verify its mechanism. Ten asthmatic patients (6 men, 4 women: aged 20 to 65, 5 atopic 5 non-atopic) and ten non-asthmatic volunteers (8 men, 2 women: aged 25 to 60) were studied. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1.0) and peak expiratory flow rate (PEFR) were measured after intravenous administration of 20 mg PZ. PZ increased FVC, FEV1.0 and PEFR significantly by 15%, 29% and 37% respectively in asthmatic patients (p less than 0.01). We also studied the effects of PZ on the contractile responses of tracheal smooth muscle to intra-arterially administered acetylcholine (ACh) and the electrical stimulation of the vagus nerves (VNS) using isometric technique in situ in 5 mongrel dogs. PZ significantly inhibited the contractile responses elicited with ACh at doses larger than 1000 micrograms/kg (p less than 0.01). PZ also significantly inhibited the contractile responses elicited by VNS at doses larger than 100 micrograms/kg (p less than 0.01). These data demonstrate that intravenously administered PZ dilates the airway in asthmatic patients and also suggest that the bronchodilating effect of PZ related to inhibition of the M1 and M3 muscarinic receptors.  相似文献   
52.
We describe a patient with acute lymphoblastic leukemia (ALL) in whom hemopoiesis recovered after an autologous marrow graft purged by in vitro hyperthermia. A 17-year-old woman was diagnosed as having ALL in April 1985. After clinical remission was induced, marrow cells were harvested. The marrow cells were treated with hyperthermia at 42.0 degrees C for 1 h in the presence of alpha-interferon to eliminate residual leukemic cells, and then cryopreserved. In January 1990, during her fourth remission she was treated with busulfan and cyclophosphamide, and then received the thawed autologous marrow. Her hematopoietic recovery was prompt with normal trilineage regeneration without any life-threatening complications. She is in good health without evidence of a leukemic relapse at 6 months after autologous bone marrow transplantation. This case suggests that human multilineage progenitor cells retain self-renewal capacity in vivo even after treatment with heat and alpha-interferon in vitro followed by the freezing and thawing procedures.  相似文献   
53.
When nasotracheal intubation with a fiberoptic bronchoscope is performed, the tube may be blocked in the nasal cavity or larynx, resulting in several complications including epistaxis and hoarseness. We review the causes and complications of tube blockage and discuss optimal techniques for minimizing it.  相似文献   
54.
IgA immune complexes and polymeric IgA are presumed to play important roles in the development and progression of IgA nephropathy. Complex-forming glycoprotein heterogenous in charge (protein HC), being inhibitors of neutrophilic chemotaxis, has been reported as binding to IgA. As a working hypothesis it was assumed that complexes of protein HC and IgA are present in glomeruli from IgA nephropathy patient in stable state. In this study, we examined the glomerular deposition of protein HC in 40 patients with IgA nephropathy and in 10 patients with non-IgA nephropathy. We used highly specific antibody against protein HC, that does not cross-react with alpha-1-microglobulin. An immunofluorescent study revealed that 10 out of the 40 patients (25%) showed an intensity of 1+, 16 (40%) showed weak positive (+/-), and the other 14 (35%) were negative. There was no deposition of protein HC in non-IgA nephropathy patients. Histopathological analysis demonstrated a significant correlation between the intensity of glomerular-deposited protein HC and pathological activity (p less than 0.005); the latter was defined as having either crescents in more than 15% of the remaining glomeruli (excluding global sclerotic glomeruli), or segmental necrosis or sclerosis in more than 30% of the remaining glomeruli. A significant correlation was observed between pathological activity and the intensity of deposited IgG, IgA and IgM (p = 0.01), and lambda chain (p less than 0.005). Considering anti-inflammatory activity of protein HC, these results suggest that protein HC cannot protect sufficiently acute inflammation or tissue damages due to co-deposited IgG and IgM and/or other factors.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
55.
The patient was a 48-year-old male who was diagnosed with unstable angina. He had worsening cardiogenic shock during coronary angiography. Emergency coronary artery bypass grafting (CABG) was performed. He had a methicillin-resistant Staphylococcus aureus (MRSA) mediastinitis on day 22 after CABG. Drains were placed in the anterior mediastinum, left thoracic cavity, and abscess cavity, and another drain was placed in the mediastinal space for continuous cleansing with povidone iodine, oxydol. For antibiotics, teicoplanin (TEIC) was administered intravenously and to the local site via the cleansing drain for about one month. No MRSA was detected by culture in discharges from the mediastinal drain. Inflammatory findings were improved, and the patient was discharged and resumed everyday life without recurrence of inflammation as of eight months. Although the number of cases of MRSA mediastinitis is small and accumulation of cases is necessary to investigate therapeutic methods and selection of antibiotics, our department will select closed continuous cleansing and TEIC for antibiotics as the first choice for MRSA mediastinitis, and accumulate cases to investigate its efficacy.  相似文献   
56.
J Hamada  H Seto  M Miura  J Kuratsu  Y Ushio 《Neurosurgery》1990,27(4):647-649
A rare case of suprasellar pituitary adenoma arising from the pars tuberalis in a 53-year-old woman is presented. The tumor was located exclusively above the diaphragma sellae, and no invasion into the sella turcica was noted.  相似文献   
57.
58.
Mechanism of methylmercury cytotoxicity   总被引:2,自引:0,他引:2  
Although a large number of epidemiological, clinical, and pathological studies on methylmercury intoxication have been published, these investigations have not been able to elucidate the detailed mechanisms by which the metal alkyl causes a wide variety of biological dysfunctions. Thus, the cultured cells which are free from the influence of whole body complexities, such as absorption, distribution, metabolism, etc., which complicate the interpretation of in vivo experimental results, attract the attention of many scientists who are interested in clarifying the mode of toxic action of methylmercury. The aim of this article is to review the recent studies on the toxicity of methylmercury at the cellular level and to outline the mechanisms which have been proposed to be responsible for cell injuries.  相似文献   
59.
Y Takahashi  T Miura 《Toxicology》1989,56(3):253-262
Male Jcl:Wistar rats were exposed continuously to 0.2 ppm ozone (O3) and 4 ppm nitrogen dioxide (NO2), alone and in combination, for 1 and 2 months to examine the effects of combined gas on the xenobiotic metabolizing systems of lung microsomes. The cytochrome P-450 content increased to 200% and 253% of the control values during 2-month exposures to O3, while it was not increased by NO2 exposures. Addition of NO2 to O3 reduced the increased level of cytochrome P-450 to 179% and 178% of the control values. The activities of cytochrome P-450-dependent monooxygenase, benzo[a]pyrene hydroxylase and 7-ethoxycoumarin O-deethylase were changed in the same fashion by exposures to NO2 and O3. The 7-ethoxycoumarin O-deethylase activity was increased to 147% and 142% of the control values by O3 exposure, whereas it was decreased to 71% and 75% of the control values by NO2 exposures. This activity was decreased to 124% and 97% of the control values by combination of O3 with NO2 after 1 and 2 months, respectively. Similarly, the benzo[a]pyrene hydroxylase activity was increased to 157% and 153% of the control values during O3 exposures, while it was not changed by NO2 exposures. Addition of NO2 to O3 reduced the activity to 140% and 115% of the control values after 1 and 2 months, respectively. The alteration of coumarin hydroxylase activity was different from those of others. This activity decreased to 44% and 29% of the control values after 1- and 2-month exposures to NO2, respectively, and was also decreased by O3 exposures. However, the magnitude of decrease was not reinforced by combination of NO2 with O3. These results indicate that an increased level of xenobiotic metabolizing activity produced by O3 exposures is lowered by combination with NO2. These phenomena may be antagonistic effects of these gases on the xenobiotic metabolizing systems of lung microsomes.  相似文献   
60.
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