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   4693篇
  免费   229篇
  国内免费   41篇
耳鼻咽喉   28篇
儿科学   56篇
妇产科学   43篇
基础医学   668篇
口腔科学   174篇
临床医学   283篇
内科学   1162篇
皮肤病学   104篇
神经病学   480篇
特种医学   99篇
外科学   840篇
综合类   16篇
预防医学   84篇
眼科学   103篇
药学   429篇
中国医学   36篇
肿瘤学   358篇
  2023年   31篇
  2022年   42篇
  2021年   89篇
  2020年   42篇
  2019年   79篇
  2018年   86篇
  2017年   78篇
  2016年   79篇
  2015年   100篇
  2014年   100篇
  2013年   139篇
  2012年   254篇
  2011年   280篇
  2010年   153篇
  2009年   124篇
  2008年   236篇
  2007年   241篇
  2006年   250篇
  2005年   264篇
  2004年   259篇
  2003年   248篇
  2002年   229篇
  2001年   141篇
  2000年   145篇
  1999年   125篇
  1998年   66篇
  1997年   48篇
  1996年   53篇
  1995年   39篇
  1994年   45篇
  1993年   33篇
  1992年   84篇
  1991年   88篇
  1990年   61篇
  1989年   74篇
  1988年   56篇
  1987年   43篇
  1986年   46篇
  1985年   47篇
  1984年   44篇
  1983年   20篇
  1982年   22篇
  1981年   19篇
  1979年   29篇
  1978年   21篇
  1975年   18篇
  1973年   19篇
  1970年   17篇
  1969年   17篇
  1967年   20篇
排序方式: 共有4963条查询结果,搜索用时 15 毫秒
41.
Objective Peripherally inserted central catheters (PICCs) are widely used in patients with hematologic malignancies. However, the risks of PICC-related complications during chemotherapy for acute myeloid leukemia (AML) are not fully understood. Methods We conducted a retrospective review of 128 adult patients with AML who received induction therapy by way of PICC insertion between 2012 and 2019. Results The median duration of PICC insertion was 30 days. The incidence rate of catheter-related bloodstream infection (CRBSI) was 2.4% at 30 days, and women were more likely to suffer from CRBSI than men. Local reactions at the insertion site were observed in 56 patients; however, these events did not predict CRBSI. The incidence rates of catheter-related thrombosis (CRT) were 1.6% at 30 days. Obesity put patients at an increased risk for CRT. Unexpected PICC removal occurred in 59 patients, and women were at a higher risk of catheter removal than men. Conclusion Low PICC-related complication rates, possibly associated with high rates of catheter removal, were observed during intensive chemotherapy for AML. Women and obese patients require careful monitoring of their PICC. Procedures to achieve appropriate PICC removal without increasing the complication rate need to be considered.  相似文献   
42.
After BNT162b2 messenger ribonucleic acid (mRNA) coronavirus disease 2019 (COVID-19) vaccination, a 30-year-old man developed bilateral lateral gaze palsy, diplopia, absent tendon reflexes, and ataxic gait. Serum anti-GQ1b and anti-GT1a immunoglobulin G (IgG) antibodies were strongly positive. Based on those findings, he was diagnosed with Miller Fisher syndrome (MFS). Intravenous immunoglobulin therapy was administered, and his symptoms fully recovered within approximately 3 months. To the best of our knowledge, this is the first report to describe the development of MFS after COVID-19 mRNA vaccination.  相似文献   
43.

Background

To investigate the expression of parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor 1 (PTH1R) in clinical specimens of normal and diseased bladders. PTHrP is a unique stretch-induced endogenous detrusor relaxant that functions via PTH1R. We hypothesized that suppression of this axis could be involved in the pathogenesis of bladder disease.

Methods

PTH1R expression in clinical samples was examined by immunohistochemistry. Normal kidney tissue from a patient with renal cancer and bladder specimens from patients undergoing ureteral reimplantation for vesicoureteral reflux or partial cystectomy for urachal cyst were examined as normal control organs. These were compared with 13 diseased bladder specimens from patients undergoing bladder augmentation. The augmentation patients ranged from 8 to 31 years old (median 15 years), including 9 males and 4 females. Seven patients had spinal disorders, 3 had posterior urethral valves and 3 non-neurogenic neurogenic bladders (Hinman syndrome).

Results

Renal tubules, detrusor muscle and blood vessels in normal control bladders stained positive for PTH1R. According to preoperative urodynamic studies of augmentation patients, the median percent bladder capacity compared with the age-standard was 43.6% (range 1.5–86.6%), median intravesical pressure at maximal capacity was 30 cmH2O (range 10–107 cmH2O), and median compliance was 3.93 ml/cmH2O (range 0.05–30.3 ml/cmH2O). Detrusor overactivity was observed in five cases (38.5%). All augmented bladders showed negative stainings in PTH1R expression in the detrusor tissue, but positive staining of blood vessels in majority of the cases.

Conclusions

Downregulation of PTH1R may be involved in the pathogenesis of human end-stage bladder disease requiring augmentation.  相似文献   
44.
45.
We measured salivary adiponectin levels in saliva samples collected in two different ways and compared the results. Using the Salivette system, we collected samples from 30 healthy females into test tubes. Salivary adiponectin levels were evaluated using a commercial enzyme immunoassay kit for plasma but with a slightly modified method. While there was a significant correlation between adiponectin levels in plasma and test‐tube saliva (p<0.05), no correlation between adiponectin levels in plasma and Salivette‐sampled saliva was apparent. These findings suggest that test‐tube sampling is more reliable than use of the Salivette system for measuring salivary adiponectin levels.  相似文献   
46.
Small polydisperse circular (spc) DNA was isolated from mouse thymocytes and cloned into the HindIII site of lambda vector Charon 7. Fifty-six recombinants from this spc DNA library were analyzed. R repeats, which were originally found near immunoglobulin genes, were enriched in spc DNA clones relative to their representation in the chromosome. In one clone, the R sequence was linked to Bam and MIF sequences and the contiguous arrangement was truncated from both ends. In another clone, composite Bam/R and R repeats existed as a pair in inverted repeat orientation. Truncation occurred from the 5' side without affecting the 3' ends. In both clones, short direct repeats flanked the repeated sequences. The possible role of R sequences in transposition and circular formation is discussed.  相似文献   
47.
Plasma lipid peroxidation in hyperlipidemic chickens   总被引:3,自引:0,他引:3  
Laying and genetically defective non-laying hens were evaluated for plasma lipid and plasma peroxidation levels. The non-layers developed extreme hyperlipidemia as well as greatly increased levels of lipid peroxidation. It was concluded that the concurrent presence of lipid peroxidation products must be considered when evaluating hyperlipidemic causes of atherosclerosis in the chicken.  相似文献   
48.
Combined large cell neuroendocrine carcinoma   总被引:1,自引:0,他引:1  
We report a case of combined large cell neuroendocrine carcinoma. A 78-year-old man with vertigo was referred to our hospital where chest X-ray revealed a tumor shadow in the right lung. A transbronchial lung biopsy specimen verified a diagnosis of non-small cell lung carcinoma (cT1N0M0). Right lower lobectomy with mediastinal lymph node dissection (#7,8,9) was performed. A postoperative histological diagnosis was combined large cell neuroendocrine carcinoma of a component of squamous cell carcinoma [pT4 (pm) N2M0]. The patient received concurrent chemoradiotherapy due to upper mediastinal lymph node metastasis 4 months after surgery. The chemoradiotherapy well responded and the patient remains well 9 months after surgery.  相似文献   
49.
The drainage of the superficial middle cerebral vein (SMCV) is classified into four subtypes. The sphenobasal vein (SBV) drains from the SMCV to the pterygoid venous plexus at the temporal skull base. Epidural procedures in the standard anterior transpetrosal approach (ATPA) may damage the route of the SBV. We report a case in which modified surgical procedures via the ATPA were used to preserve the SBV. A 45-year-old man complained of right facial pain. Magnetic resonance images revealed a right cerebellopontine tumor suggestive of an epidermoid cyst. Right carotid angiography revealed that the SMCV drained into the pterygoid venous plexus via the SBV. The convexity dura mater of the temporal lobe was cut and the anterior part of the temporal lobe was retracted subdurally. The SBV was visualized from the subdural side. The basal dura mater of the temporal lobe posterior to the SBV was cut and the posterior part of the temporal lobe was retracted epidurally. After dissecting the dura mater medial to the greater petrosal nerve and to the edge of the petrous apex, the petrous apex was exposed and drilled out without injuring the SBV. The superior petrous sinus and the tentorium were cut. The tumor compressed the root exit zone of the trigeminal nerve. The tumor was grossly totally removed. The modified ATPA (epidural anterior petrosectomy with subdural visualization of the SBV) is effective in preserving the SBV.  相似文献   
50.
The effects of left ventricular assist system (LVAS) implantation on renal hemodynamics remains to be fully elucidated. We evaluated renal function and intrarenal blood flow in five advanced heart failure patients who had been supported with a Toyobo LVAS for bridge to heart transplantation. Renal function expressed as estimated glomerular filtration rate (eGFR) was calculated using the modified formula of Modification of Diet in Renal Disease. Mean blood velocities in the bilateral segmental arteries during systolic and diastolic perfusion were measured using duplex Doppler sonography, and renal vascular resistance (resistive index [RI]) of the segmental arteries was defined as (peak systolic velocity [PSV]-end-diastolic velocity [EDV])/PSV. All studies were performed before and after implantation (mean duration of support, 15.6±10.9 months). LVAS implantation significantly improved eGFR (42.7±7.9 to 64.1±16.3mL/min, P<0.05). Beat-by-beat measurements of heart rate did not change significantly. Mean PSV decreased significantly (38.2±8.9 to 28.3±2.2cm/s, P<0.05), and mean EDV increased significantly (8.3±3.2 to 11.3±1.3cm/s, P<0.05), and thus, mean RI was significantly improved (0.79±0.06 to 0.60±0.04, P<0.01). In conclusion, in advanced heart failure patients, pulsatile LVAS implantation is associated with improved renal function, and this improvement may be mediated in part through an improvement of intrarenal hemodynamics.  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