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   14659篇
  免费   968篇
  国内免费   661篇
耳鼻咽喉   63篇
儿科学   304篇
妇产科学   81篇
基础医学   1047篇
口腔科学   26篇
临床医学   1264篇
内科学   3606篇
皮肤病学   36篇
神经病学   327篇
特种医学   887篇
外国民族医学   9篇
外科学   1781篇
综合类   2783篇
现状与发展   3篇
预防医学   576篇
眼科学   19篇
药学   1541篇
  3篇
中国医学   884篇
肿瘤学   1048篇
  2024年   28篇
  2023年   211篇
  2022年   310篇
  2021年   423篇
  2020年   362篇
  2019年   372篇
  2018年   356篇
  2017年   479篇
  2016年   474篇
  2015年   496篇
  2014年   855篇
  2013年   835篇
  2012年   820篇
  2011年   905篇
  2010年   745篇
  2009年   807篇
  2008年   795篇
  2007年   826篇
  2006年   777篇
  2005年   637篇
  2004年   486篇
  2003年   506篇
  2002年   402篇
  2001年   368篇
  2000年   345篇
  1999年   264篇
  1998年   254篇
  1997年   235篇
  1996年   242篇
  1995年   208篇
  1994年   202篇
  1993年   147篇
  1992年   144篇
  1991年   151篇
  1990年   87篇
  1989年   103篇
  1988年   84篇
  1987年   61篇
  1986年   56篇
  1985年   72篇
  1984年   51篇
  1983年   35篇
  1982年   44篇
  1981年   41篇
  1980年   41篇
  1979年   33篇
  1978年   23篇
  1977年   27篇
  1976年   18篇
  1975年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Summary A system which can be used for injection or infiltration of large volumes of fluid is described. This consists of a syringe which fills automatically from a reservoir through an inlet/outlet valve.  相似文献   
2.
Hepatic venous outflow tract obstruction, Budd-Chiari syndrome (BCS), leads to portal hypertension and to the development of collaterals that bypass the obstruction. Described here is a BCS patient with an unusually large transdiaphragmatic collateral between the left hepatic and left innominate veins, which decompressed the oesophageal varices. This has not been reported earlier in the literature.  相似文献   
3.
As part of the strategy for the design of macromolecular carriers for drug targeting, the disposition characteristics of macromolecules were studied in mice bearing tumors that served as target tissues. Eight kinds of macromolecules including four polysaccharides and four proteins with different molecular weights and electric charges were used; tissue distribution and tumor localization after intravenous injection were studied. Pharmacokinetic analysis revealed that the tissue radioactivity uptake rate index calculated in terms of clearance was different among the tested compounds; especially, the urinary radioactivity excretion clearances and the total hepatic radioactivity uptake clearances varied widely. Compounds with low molecular weights (approximately 10 kD) or positive charges showed lower tumor radioactivity accumulation; radioactivity was rapidly eliminated from the plasma via rapid urinary excretion or extensive hepatic uptake, respectively. On the other hand, large and negatively charged compounds, carboxymethyl dextran, bovine serum albumin, and mouse immunoglobulin G, showed higher radioactivity accumulation in the tumor (calculated total amounts were 15.6, 10.8, and 20.8% of the dose, respectively) and prolonged retention in the circulation. These results demonstrated that the total systemic exposure rather than the uptake rate index was correlated with total tumor uptake. Molecular weight and electric charge of the macromolecules significantly affected their disposition characteristics and, consequently, determined radioactivity accumulation in the tumor. It was concluded that a drug–carrier complex designed for systemic tumor targeting should be polyanionic in nature and larger than 70,000 in molecular weight.  相似文献   
4.
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   
5.
6.
In contrast to conventional film angiography, the perfusion pattern of hepatic arterial chemotherapy was consistently visualized by DSA in 40 patients with implanted Infusaid pump or Port-A devices. Incomplete perfusion of a liver region by the cytotoxic agent was recognized by DSA as accurately as by nuclide scintigraphy. Furthermore, DSA appeared to be more sensitive in determining aberrantly perfused extrahepatic regions; this was especially true when there was a nonligated right hepatic artery. Specific details of vascular lesions and associated complicating events also could be satisfactorily analyzed by DSA only.  相似文献   
7.
Background : The present paper addressed the issue of whether pretreatment with intravenous (IV) chemotherapy affects response rate or survival in patients receiving hepatic artery chemotherapy (HAC). Methods : Case note reviews of 164 patients treated in a teaching hospital from June 1990 to July 1996 were carried out. Results : The response rate and carcino-embryonic antigen (CEA) fall in the two groups was almost identical. There was a nonsignificant survival advantage in the non-pretreatment group. Conclusions : Previous administration of IV chemotherapy did not affect the CEA response of patients receiving HAC.  相似文献   
8.
为了解幼儿的肝功能和HBsAg携带情况,我们于1991年肝炎发病高峰季节对我县四所幼儿园共824名幼儿进行了ALT、TTT、ZnTT、HBsAg检测。结果ALT、TTT均升高1例,有体征;ALT单项升高6例,无症状;HBsAg阳性58例,其中9例ALT升高,4例TTT升高。幼儿园是幼儿集中的地方、同吃、同住、接触密切,对HBsAg阴性者接种乙肝疫苗,对ALT升高者不能忽视以免发生肝炎流行。  相似文献   
9.
The aim of this study was to detect the sites and frequency of possible lesions by brain magnetic resonance imaging (MRI; 1,5T) in a group of 16 neurologically asymptomatic patients with hepatic form of Wilson's disease (WD; seven untreated and nine under treatment). Abnormal MR findings of the brain were found in 75% of patients. Lesions in brain parenchyma were detected in all untreated, drug-naive patients and in 44% of treated patients. Abnormal signal in globus pallidus, putamen, and caudate nucleus was revealed in 86, 71 and 71% of treated and in 33, 33 and 22% of untreated patients, respectively. In five of eight patients with putaminal pathology (62.5%) and in four of seven patients with caudate nuclei involvement (57%), only proton density 2-weighted sequence (PDW) exhibited sensitivity for lesion detection, with both T1W and long echo T2W sequences being insensitive. This superiority of PDW sequence was even more pronounced in the group of untreated patients in whom 80% of putaminal pathology was visible exclusively on this sequence. The lower frequency of lesions in the group of treated in comparison with untreated patients indicated that they might be reversible in the course of chronic chelating therapy.  相似文献   
10.
目的 探讨青年人大肠癌的误诊原因,以便早期诊断治疗。方法 回顾性分析62例青年人大肠癌的诊断及其治疗效果。结果 本组直肠癌36例中被误诊为结肠炎7例,痔疮并出血5例,痢疾3例,肛周脓肿并肛瘘2例;结肠癌26例中被误诊为阑尾周围脓肿3例,结肠炎2例,缺铁性贫血1例。误诊率37.1%。结论 青年人大肠癌早期临床症状不明显,恶性程度高,预后差,其治疗水平有赖于对这些特征的认识,力争早期诊断及治疗。  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