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   15304篇
  免费   656篇
  国内免费   82篇
耳鼻咽喉   153篇
儿科学   324篇
妇产科学   244篇
基础医学   1879篇
口腔科学   410篇
临床医学   926篇
内科学   3857篇
皮肤病学   288篇
神经病学   837篇
特种医学   532篇
外科学   2971篇
综合类   42篇
一般理论   1篇
预防医学   345篇
眼科学   226篇
药学   1016篇
中国医学   36篇
肿瘤学   1955篇
  2021年   230篇
  2020年   125篇
  2019年   177篇
  2018年   227篇
  2017年   190篇
  2016年   232篇
  2015年   251篇
  2014年   325篇
  2013年   406篇
  2012年   651篇
  2011年   740篇
  2010年   460篇
  2009年   375篇
  2008年   683篇
  2007年   789篇
  2006年   823篇
  2005年   767篇
  2004年   787篇
  2003年   750篇
  2002年   753篇
  2001年   459篇
  2000年   485篇
  1999年   465篇
  1998年   201篇
  1997年   192篇
  1996年   160篇
  1995年   123篇
  1994年   128篇
  1993年   117篇
  1992年   368篇
  1991年   328篇
  1990年   288篇
  1989年   316篇
  1988年   251篇
  1987年   253篇
  1986年   250篇
  1985年   285篇
  1984年   145篇
  1983年   132篇
  1982年   76篇
  1979年   108篇
  1978年   89篇
  1977年   78篇
  1974年   66篇
  1973年   65篇
  1972年   63篇
  1971年   68篇
  1969年   79篇
  1968年   93篇
  1966年   84篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
1.
2.

Background

There were few studies assessed the postoperative sarcopenia in patients with cancers. The objective of present study was to assess whether postoperative development of sarcopenia could predict a poor prognosis in patients with adenocarcinoma of esophagogastric junction, (AEG) and upper gastric cancer (UGC).

Methods

Patients with AEG and UGC who were judged as non-sarcopenic before surgery were reassessed the presence of postoperative development of sarcopenia 6 months after surgery. Patients were divided into the development group or non-development group, and clinicopathological factors and prognosis between these two groups were analyzed.

Results

The 5-year overall survival rates were significantly poorer in the development group than non-development group (68.0% vs. 92.6%, P?=?0.0118). Multivariate analyses showed that postoperative development of sarcopenia was an independent prognostic factor for poor overall survival (P?=?0.0237).

Conclusions

Postoperative development of sarcopenia was associated with a poor prognosis in patients with AEG and UGC.  相似文献   
3.
4.
We report a 53-year-old woman with severe Graves' ophthalmopathy accompanied by uncontrolled myasthenia gravis. She presented remarkable exophthalmos, chemosis, and restriction of eye movement. Despite plasma exchange, steroid pulse therapy, local injection of steroid, and irradiation, ocular symptoms did not ameliorate. Since optic neuropathy was seen, orbital decompression surgery was performed in the left eye. Bilateral chemosis was improved after the surgery. Five years after surgery, there was no ocular palsy in the operated left eye, but in the contralateral eye. For the good prognosis of the eye movement, orbital decompression might be recommended in the severe Graves' ophthalmopathy accompanied by the optic neuropathy and/or ophthalmoplegia with proptosis.  相似文献   
5.
BACKGROUND: In patients with chronic kidney disease (CKD), although strong associations have been observed between malnutrition and atherosclerosis, the relationship between serum albumin concentration and angiographic changes of coronary artery disease (CAD) remains poorly explored. The goal of the present study was, in patients with CKD, to clarify the relationship between the angiographic severity of CAD and serum albumin concentration reflecting either inflammation or nutrition or both. METHODS: In this study, 100 end-stage renal disease (ESRD) patients were enrolled, who commenced long-term dialysis therapy at our hospital and underwent coronary angiography within 3 months of the first haemodialysis (HD) session. Mean age was 63+/-11 years, 20% of the subjects were female and 62% had diabetes. Severity of CAD was evaluated in terms of (i) number of vessels exhibiting CAD (>or=75% stenosis) and (ii) Gensini score (GS). Clinical characteristics and laboratory findings were recorded at initiation of long-term HD therapy. We then evaluated a possible association with the presence and degree of CAD. RESULTS: Sixty-four patients exhibited signs of CAD. Forty-one among them (64%) had multivessel disease. On univariate logistic regression analysis, age, diabetes and hypoalbuminaemia were significantly associated with multivessel CAD. Univariate linear regression analysis demonstrated a positive correlation of age and diabetes with GS, and an inverse correlation of BMI and serum albumin level with GS. Stepwise regression analysis showed age and serum albumin level to be independently associated with multivessel CAD and GS. The ROC curves demonstrated best cut-off levels of age and albumin for predicting multivessel CAD to be 70 years and 3.15 g/dl, respectively. CONCLUSION: Hypoalbuminaemia at the initiation of dialysis is an important predictor of advanced CAD, particularly in male and in diabetic patients. It may reflect mainly a state of inflammation. However, malnutrition as a confounding factor cannot be entirely excluded.  相似文献   
6.
We applied a forearm flap combined with a gracilis muscle flap for total reconstruction of the lower lip. The motor nerve of the gracilis muscle was repaired to the buccal branch in the cheek. The patient obtained good sphincter function for eating and speaking, and he could inflate a balloon without air leakage.  相似文献   
7.
Neurosonography by advanced transvaginal sonography has revealed normal and abnormal intracranial morphology. Transvaginal 3D sonography demonstrates bony structures, multiplanar analysis of inside detailed morphology, tomographic ultrasound imaging in any cutting sections, 3D sonoangiography and volume calculation of ventricles and/or intracranial lesions. Longitudinal assessment of normal and abnormal CNS development is easy by serial scanning. However, the transvaginal approach has several limitations due to its observation by use of a high-frequency transducer from the fetal parietal region. Evaluation of the brainstem and posterior fossa, which are located far from the parietal ultrasound windows of the anterior fontanelle or sagittal suture, is sometimes hard by transvaginal sonography. Visualization of bilateral temporal areas is getting difficult with advanced gestational weeks because of bilateral acoustic shadows due to ossification of parietal bones. Demonstration of frontal/occipital areas is sometimes impossible in late pregnancy due to scan-angle limitation of the transvaginal transducer. From our experiences, the main difference between transvaginal 3D ultrasound and MRI is demonstration of the whole gyral and sulcal formation and brainstem in the late second and third trimesters. Although MRI is a useful modality which can compensate for pitfalls of transvaginal 3D ultrasound, 3D ultrasound is sometimes superior to MRI in detecting cysts in cyst and intracranial calcification. Transvaginal 3D ultrasound is much superior to MRI in detecting bony structures and angioarchitectonics and in volumetric assessment. Regarding objective and accurate prenatal diagnosis, any less-invasive modalities can be used. After considering each advantage and disadvantage of transvaginal 3D ultrasound and MR imaging, it is suggested to use the different technologies according to what is to be detected and evaluated.  相似文献   
8.
BACKGROUND AND PURPOSETo detect areas of cerebral perfusion from bypass arteries after vascular reconstruction, we administered selective intraarterial microsphere tracer into the external carotid arteries and determined (via single-photon emission computed tomography [IA-SPECT]) whether the distribution of radiotracer matched the arteriographic distribution of contrast material as shown on external carotid angiograms.METHODSWe compared the extent of regional distribution of tracer after external carotid artery injection of 20 to 40 MBq of 99mTc-HMPAO or 99mTc-ECD with that of contrast medium on the external carotid angiograms in 582 cortical regions in 12 patients with atherosclerotic occlusive disease and in 18 patients with moyamoya disease.RESULTSMarked accumulation of tracer was found only in the expected, specific, newly developed areas of cerebral perfusion from bypass arteries. The regional distribution of tracer corresponded to that of contrast medium in 523 regions (90%) and did not correspond in 59 regions (10%). Significant overestimation of the distribution of contrast material relative to that of tracer was observed in the patients with moyamoya disease.CONCLUSIONSPECT showed slightly different distribution of tracer from that predicted by conventional angiography. IA-SPECT should enhance the analysis of newly developed areas of cerebral perfusion from the bypass arteries.  相似文献   
9.
The effects of monoamine oxidase-A (MAO-A) inhibitors with epinephrine on intraocular pressure in the pigmented rabbit were studied. MAO-A inhibitors were used topically with or without various concentrations of epinephrine. For the measurement of intraocular pressure, applanation pneumatonography was used and tissue MAO activities were determined by radiometric assay. After topical administration with clorgyline, MAO-A activities in the bulbar conjunctiva and the iris-ciliary body were remarkably inhibited, whereas MAO-B inhibition was minimal. Maximal reduction of intraocular pressure with 0.05% epinephrine was 3.2 mmHg. Single administration of clorgyline, amiflamine, moclobemide or CGP 11305-A caused decreases in the intraocular pressure of 2.0, 2.5, 1.8 and 2.4 mmHg, respectively. In the coadministration experiments with epinephrine, the ocular hypotensive effects of epinephrine were potentiated with clorgyline, amiflamine, moclobemide and CGP 11305-A (6.6, 4.8, 5.6 and 5.8 mmHg). On the contrary, they were not influenced by the MAO-B inhibitor deprenyl. These results indicated that MAO-A inhibitors potentiated the ocular hypotensive effects of epinephrine, and that the coadministration of a reversible MAO-A inhibitor with epinephrine might be useful for patients with glaucoma.  相似文献   
10.
Living-donor liver transplantation (LDLT) has become an established technique to treat children with end-stage liver disease. Biliary atresia (BA), one of the most common indications for liver transplantation in children, can be associated with situs inversus (SI). In the past, the presence of SI has been considered to be an absolute contraindication for liver transplantation because of the technical difficulties. Recently, some reports of successful diseased-donor liver transplantation in patients with BA complicated by SI have been published; however, few reports of that with LDLT exist. The technical difficulties involved with LDLT for such cases have not been described. Herein, we present 4 successful cases of LDLT for BA with SI. Complex anomalies associated with SI, such as a hepatic artery arising from the supraceliac aorta, a preduodenal portal vein, and absence of the retrohepatic inferior vena cava, increase the technical difficulties involved with the operation. Additional caution is required in LDLT because a living-donor graft has short vessels and the availability of vascular grafts from the donor is limited. In conclusion, LDLT for BA complicated by SI can be managed successfully with technical modifications and scrupulous attention. This series represents the largest reported group of patients with BA complicated by SI who underwent a successful LDLT procedure.  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