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   61064篇
  免费   5616篇
  国内免费   4286篇
耳鼻咽喉   676篇
儿科学   606篇
妇产科学   611篇
基础医学   6251篇
口腔科学   902篇
临床医学   7706篇
内科学   8234篇
皮肤病学   588篇
神经病学   2904篇
特种医学   2384篇
外国民族医学   36篇
外科学   6682篇
综合类   11390篇
现状与发展   13篇
一般理论   3篇
预防医学   4298篇
眼科学   1669篇
药学   6582篇
  58篇
中国医学   4311篇
肿瘤学   5062篇
  2024年   268篇
  2023年   901篇
  2022年   2432篇
  2021年   3103篇
  2020年   2540篇
  2019年   1949篇
  2018年   2107篇
  2017年   2073篇
  2016年   1848篇
  2015年   3008篇
  2014年   3770篇
  2013年   3444篇
  2012年   5007篇
  2011年   5346篇
  2010年   3708篇
  2009年   2998篇
  2008年   3495篇
  2007年   3258篇
  2006年   3166篇
  2005年   2911篇
  2004年   1953篇
  2003年   1851篇
  2002年   1547篇
  2001年   1242篇
  2000年   1168篇
  1999年   1114篇
  1998年   694篇
  1997年   633篇
  1996年   501篇
  1995年   471篇
  1994年   357篇
  1993年   268篇
  1992年   322篇
  1991年   308篇
  1990年   214篇
  1989年   167篇
  1988年   184篇
  1987年   156篇
  1986年   103篇
  1985年   81篇
  1984年   60篇
  1983年   32篇
  1982年   29篇
  1981年   31篇
  1980年   23篇
  1979年   38篇
  1978年   13篇
  1977年   11篇
  1975年   11篇
  1973年   12篇
排序方式: 共有10000条查询结果,搜索用时 51 毫秒
21.
Open reduction combined with external compressive skeletal fixation was used to treat twenty-seven patients who had a separated fracture of the patella. Fixation was obtained by the use of two compressive clamps applied to stainless-steel pins that were inserted just proximal and distal to the proximal and distal poles of the patella. Range-of-motion exercises for the knee were begun at two weeks and the pins were removed at three to four weeks. All of the fractures healed. Twenty-four patients regained a range of motion that was equal to that of the opposite knee. There was no evidence of chronic osteomyelitis. Osteoarthritis was noted in one patient who refused excision of a portion of the patella.  相似文献   
22.
It has been suggested that gains of chromosomes 7 and 17 and loss of Y occur in renal papillary adenoma and that progression to papillary renal cell carcinoma is marked by gains of additional chromosomes, most frequently 12, 16, and 20. Previous studies have included very few lesions of <5 mm in diameter, a requirement of the present definition of papillary adenoma. Ten papillary adenomas (ranging from 1 to 5 mm in diameter) from autopsy material and 10 surgically resected papillary renal cell carcinomas were studied with fluorescence in situ hybridization in paraffin sections using centromeric probes for chromosomes 7, 12, 16, 17, 20, and Y diluted 1:100 with tDenHyb1 buffer. The signals in 50 to 150 nuclei were counted in each tumor. Controls for all the probes were normal renal tissues from the same patients. Three or more signals per nucleus were frequently observed in papillary adenomas: chromosome 7 (range, 10 to 50%; > or = 30% in 9 of 10), 17 (range, 10 to 47%; > or = 30% in 7), 16 (range, 1 to 63%; > or = 10% in 5), 12 (range, 0 to 32%; > or =10% in 4), and 20 (range, 5 to 49%; > or = 10% in 5). Loss of the Y chromosome was observed in 80 to 90% of nuclei in 9 adenomas from males. Three or more signals were frequent in papillary renal cell carcinomas: chromosome 7 (range, 32 to 63%; > or =30% in 10 of 10), 17 (range, 28 to 61%; > or = 30% in 7), 16 (range, 0 to 45%; > or = 10% in 6), 12 (range, 1 to 37, > or = 10% in 5), 20 (range, 2 to 44%; > or = 10% in 4). No signal for Y was observed in 12 to 88% (> or = 81% in 6) of nuclei in 7 carcinomas from males. Statistical analysis showed no difference between adenomas and carcinomas. Gains of chromosomes 7, 17, 16, 12, and 20 and loss of the Y chromosome occur early in the evolution of papillary renal cell neoplasia in tumors that are only a few millimeters in diameter. Progressive gains of these chromosomes do not appear to correlate with the transition from adenoma to carcinoma.  相似文献   
23.
Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired chronic hemolytic anemia associated with an unusual susceptibility to hemolytic crisis, infection, and venous thrombosis which would be aggravated by a number of factors including surgery. We report a case of PNH undergoing percutaneous transluminal coronary angioplasty and discuss the corresponding perioperative management.  相似文献   
24.
Twenty-seven in-patients with obstetric DIC in our hospital from Jan. 1971 to Dec. 1990 were analysed retrospectively. The incidence was 0.12% in the first decade and 0.02%, in the second, showing a difference of significance between them. The most common predisposing factors included amniotic fluid embolism, abruptio placenta and hemorrhagic shock. Bleeding from multi-organs in various extent and coagulation disorders occurred in all those 27 cases. [Besides anti-shock treatment, heparin was employed together with fibrinogen in 4 postpartum and 1 antepartum DIC patients, fibrinogen alone in 8 cases, and hysterectomy in 11 cases. 17 patients were saved and 9 died. It is important that early diagnosis and much attention paid to clinical characteristics together with serial laboratory tests. Key management should include prompt treatment and eradication of predisposing factors. Quick decision spite of to terminate the pregnancy and even hysterectomy should be done in some risks.  相似文献   
25.
The effect of ibopamine (IBO) (SB 7505, SK&F 100168-A), a new drug for the treatment of congestive heart failure, and its active metabolite epinine (EPN) (N-methyldopamine), on the catecholamine content of hypothalamus and brainstem was studied in vitro after monoamine oxidase inhibition with pargyline. IBO and EPN increased levels of epinephrine (EPI) in a concentration- and time-dependent manner in both brain areas without significantly affecting the concentration of other catecholamines. Inhibition of either dopamine beta-hydroxylase, the neuronal EPI and norepinephrine uptake system, or esterase hydrolysis of IBO prevented the increase of EPI, whereas inhibition of phenylethanolamine N-methyltransferase, enzymatic dealkylation or the neuronal dopamine or serotonin uptake system had no influence on the increase of EPI levels. These results suggest that IBO after hydrolysis to EPN can be converted enzymatically to EPI by dopamine beta-hydroxylase in hypothalamus and brainstem. EPN seems to be accumulated into adrenergic and noradrenergic neurons by the high affinity uptake system. Changes in the EPI content of the central nervous system neurons might be responsible for some of the pharmacologic effects of IBO.  相似文献   
26.
27.
The immediate, short-term and long-term depressor effects, the immediate effects on cardiac functions in grade II and grade III vascular hypertension, and the effects on angiotensin II in grade III vascular hypertension by acupuncture at otoacupoint Heart were studied in 30 cases of vascular hypertensive patients. The immediate depressor effect of acupuncture at otoacupoint Stomach was also recorded for comparison. It was found that acupuncture at otoacupoint Heart produced marked immediate depressor effect, and the short-term effective rate was 100%, the long-term effective rate was 63.3%, as well as evident immediate effects on cardiac functional activities in grade II and grade III hypertension and marked effects on angiotensin II in grade III hypertension. Acupuncture at otoacupoint Stomach produced no depressor effect on vascular hypertension.  相似文献   
28.
51例应用Begg正畸技术矫治错畸形,各种类型的牙性及轻度骨性错畸形,均取得满意的效果。对牙轴唇倾并伴有深覆的安氏Ⅱ类错打开咬合、内收前牙的效果尤佳。  相似文献   
29.
超声引导下肿瘤内注射^90钇玻璃微球的肝癌综合治疗   总被引:12,自引:0,他引:12  
董宝玮  梁萍 《中华医学杂志》1994,74(8):471-473,T048
超声引导下对28例肝癌病人进行了肿瘤内注射^90钇玻璃微球(Y-90GT MS)为主的综合性治疗(部分病人配合肿块周边注射无水酒精及门静脉穿刺化疗)。随访2~16个月(平均7.9个月),病人全健在。肿瘤缩小率为91%,其中显著缩小达75%;肿块回声呈致密增强,少数呈混合型或等回声型;肿瘤内及周边血流信号显著减少;原甲胎蛋白升高者13例,11例显著下降,其中6例降至正常;病人症状减轻,全身情况改善。  相似文献   
30.
The over-representation of chromosome 12p sequences is crucial for the development of invasive testicular germ cell tumors. Testicular cancer patients may have metastatic tumors of diverse histologic types, including adenocarcinoma, undifferentiated carcinoma, sarcoma, or other malignancies that lack features of germ cell tumors. We sought to investigate the possible germ cell origin of such tumors using interphase fluorescence in situ hybridization. In all, 10 metastatic malignant somatic-type tumors from patients with histories of testicular cancer, as well as one malignant somatic-type tumor from a patient with primary mediastinal germ cell tumor were studied and included: adenocarcinoma (five cases), poorly differentiated carcinoma (one), sarcoma (four), and neuroendocrine carcinoma (one). The tumors were analyzed using fluorescence in situ hybridization using 12p spectrum green and 12 centromeric spectrum orange probes in paraffin sections. The patients ranged in age from 27 to 55 years (mean, 43). Colon and lung cancers from patients without germ cell tumors were used as controls. Adequate signals were observed in all tumors. Gain of chromosome 12p was seen in six tumors. None of the control tumors showed 12p amplification. Fluorescence in situ hybridization for 12p amplification in routinely processed surgical specimens is a useful adjuvant diagnostic tool in confirming the germ cell origin of metastatic tumors having the histologic appearance of somatic-type neoplasms.  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