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   2559篇
  免费   138篇
  国内免费   29篇
耳鼻咽喉   18篇
儿科学   23篇
妇产科学   19篇
基础医学   291篇
口腔科学   162篇
临床医学   196篇
内科学   655篇
皮肤病学   40篇
神经病学   253篇
特种医学   137篇
外科学   317篇
综合类   17篇
预防医学   63篇
眼科学   45篇
药学   221篇
中国医学   24篇
肿瘤学   245篇
  2022年   19篇
  2021年   53篇
  2020年   34篇
  2019年   39篇
  2018年   46篇
  2017年   25篇
  2016年   38篇
  2015年   36篇
  2014年   42篇
  2013年   60篇
  2012年   80篇
  2011年   101篇
  2010年   57篇
  2009年   55篇
  2008年   104篇
  2007年   132篇
  2006年   106篇
  2005年   99篇
  2004年   112篇
  2003年   109篇
  2002年   102篇
  2001年   112篇
  2000年   130篇
  1999年   79篇
  1998年   39篇
  1997年   33篇
  1996年   33篇
  1994年   14篇
  1993年   27篇
  1992年   61篇
  1991年   52篇
  1990年   77篇
  1989年   67篇
  1988年   46篇
  1987年   59篇
  1986年   40篇
  1985年   38篇
  1984年   40篇
  1983年   26篇
  1980年   15篇
  1979年   26篇
  1978年   16篇
  1977年   16篇
  1976年   20篇
  1974年   19篇
  1972年   26篇
  1969年   17篇
  1968年   18篇
  1967年   17篇
  1966年   14篇
排序方式: 共有2726条查询结果,搜索用时 15 毫秒
991.
992.
993.
Summary The capability of complement fixation of pemphigus antibodies was tested using combined in vitro complement immunofluorescent (IF) staining methods. Three sera out of 25 serum samples from 22 pemphigus patients revealed positive reactions, while all other sera gave negative results. Specificity control tests confirmed the positive reactions to be specific for complement staining. Complement fixing pemphigus antibodies were titrated lower than corresponding IgG antibodies and were demonstrable only in the extensive stage of the disease. Thus, the present work supplied evidence that pemphigus antibodies fix complement in vitro. However, the discrepancy still remains between the in vivo deposition of complement in most cases of pemphigus and in vitro capability of complement fixation in only few cases. More investigations should be needed to explain the exact role of complement in pemphigus acantholysis.
Zusammenfassung Mit Hilfe von dem kombinierten in vitro-Immunofluores-cenzkomplementfixationstest wurde in vitro-Bindung von Komplement durch Pemphigusantikörper untersucht. Drei Seren aus den 25 Seren von 22 Patienten mit Pemphigus zeigten positive Bindung von Komplement (K3), während die übrigen Seren negative Befunde zeigten. Die Spezifitätskontrolltests bestätigten, daß die positive Reaktionen spezifisch für Komplementfixation waren. Diese Komplementbindungsantikörper zeigten einen niedrigeren Titer als die korrespondierenden IgG-Antikörper und konnten nur im ausgedehnten Krankheitszustand gefunden werden. Diese Ergebnisse belegten, daß Pemphigusantikörper das Komplement in vitro fixieren. Jedoch gibt es Diskrepanzen zwischen in vivo-Komplementsvorkommen und in vitro-Komplementsbindung. Die genaue Rolle des Komplements bei der Pemphigusacantholyse muß noch weiter untersucht werden.
  相似文献   
994.

Background

Self-expandable metallic stent (SEMS) placement is a widely used, effective therapy for unresectable malignant stricture of the lower bile duct.

Aims

We evaluated the short-term outcome of the newly developed WallFlex® Biliary RX Partially Covered Stent in patients with malignant lower and middle biliary stricture in five tertiary referral centers.

Methods

The subjects of this study were 52 patients in whom WallFlex® Biliary RX Stents were inserted into the bile duct for malignant stenosis of the middle and lower bile duct at five medical facilities between April 2009 and November 2009.

Results

The stent placement success rate was 100%. Effective biliary decompression was achieved in all patients. The incidence of early complications was 7.7% (4/52). Stent occlusion occurred in two patients (3.8%) (one dislocation, one migration); cholecystitis occurred in two patients (3.8%). Neither acute pancreatitis nor stent kinking in the bile duct occurred.

Conclusions

The present results revealed that the new WallFlex® Biliary RX Partially Covered SEMSs were useful for the short-term relief of biliary obstruction due to unresectable distal biliary malignancies.  相似文献   
995.
996.
Endoscopic ultrasonography-guided biliary drainage (EUS-BD) has been carried out as an alternative to the percutaneous or surgical approach when endoscopic retrograde cholangiopancreatography fails. However, there is no standard technique or device for EUS-BD. In this review, we focus on how we choose the stents and described our tips on this EUS-BD technique. The plastic stent (PS) and the self-expandable metallic stent (SEMS) are used for EUS-BD. The latter is further divided into the fully covered SEMS (FCSEMS), partially covered SEMS (PCSEMS), and uncovered SEMS (UCSEMS) types. Although PS is not expensive, the duration of stent patency is short. SEMS is expensive but the duration of stent patency is long. With UCSEMS, basically there is no stent malpositioning; however, if the gap between the bile duct and the GI tract becomes displaced, bile leakage from the mesh of the stent is likely to occur. Though there is no bile leakage with FCSEMS, the side branch of the bile duct may become occluded, and migration and dislocation sometimes occur. PCSEMS is basically similar to FCSEMS. When EUS-BD was first developed, drainage by PS was common, although reports on drainage by SEMS have increased recently.  相似文献   
997.
Silicone oil is an important adjunct for intraocular tamponade in treating retinal detachment. We report a case in which image findings suggested migration and intracranial accumulation of intraocular silicone. We detected silicone oil in the lateral ventricle that showed hyperdensity on computed tomography, slight hyperintensity on T1-weighted magnetic resonance images, and slight hypointensity on T2-weighted images. Applied silicone-selective imaging and proton magnetic resonance spectroscopy confirmed the diagnosis of intraventricular silicone.  相似文献   
998.
We investigated the prognoses of 103 children with acute encephalopathy at more than one year from the onset. The patients were divided into five groups according to the clinical courses during the acute stage;group 1:1 case with metabolic disorder, group, 2:24 with cytokine storms, group, 3:68 with prolonged convulsion more than 30 minutes, group, 4:5 with severe refractory status epilepticus, and group, 5:5 with the main symptom of impaired consciousness. We checked the past histories, etiologies, severities of consciousness loss, complications and disabilities including higher cortical dysfunction in their medical charts. The average age of onset in all cases was 3 years, with the highest age of 6 years 5 months in group 4. Regarding the past histories, febrile seizures, asthma and theophylline medication were prominent though they were not significantly different. Regarding etiologies, influenza infection, 36 cases, and HHV-6 infection, 7 cases, were prominent though they were not significantly different. Complicating disabilities comprised mental retardation, 89.3%, higher cortical dysfunction, 77.7%, epilepsies, 68.9%, and motor disturbance, 27.2%. The severity of disabilities increased in the order of 1, 2, 3, 4, 5. Attention deficit and visiospacial disturbance were the main symptoms of higher cortical dysfunction.  相似文献   
999.

Purpose

To describe in detail the characteristic chest computed tomography (CT) findings of Birt-Hogg-Dubé (BHD) syndrome.

Materials and methods

Thin-section chest CT scans of consecutive 12 patients with genetically diagnosed BHD syndrome were retrospectively evaluated by two observers, especially about the characteristics (distribution, number, size, shape and relation to pleura) of pulmonary cysts. Interobserver agreement in the identification of abnormalities on the CT images was achieved using the κ statistic, and the degree of interobserver correlation for the characterization of pulmonary cysts was assessed using the Spearman rank correlation coefficient.

Results

Multiple pulmonary cysts were seen in all patients. The number of cysts in each patient was various (range, 29-407), and cysts of various sizes (from a few mm to 2 cm or more) were seen in all patient. 76.6% (mean) of cysts were irregular-shaped, and 40.5% (mean) of cysts were located along the pleura. The mean extent score of cysts was 13% of the whole lung, and the distribution of cysts was predominantly in the lower medial zone. Finally, cysts abutting or including the proximal portions of lower pulmonary arteries or veins were also seen in all patients.

Conclusion

Multiple, irregular-shaped cysts of various sizes with lower medial lung zone predominance are characteristic CT findings of BHD syndrome. Cysts abutting or including the proximal portions of lower pulmonary arteries or veins may also exist in this syndrome in a high probability.  相似文献   
1000.
ADAM8 expression is increased in the interface tissue around a loosened hip prosthesis and in the pannus and synovium of patients with rheumatoid arthritis, but its potential role in these processes is unclear. ADAM8 stimulates osteoclast (OCL) formation, but the effects of overexpression or loss of expression of ADAM8 in vivo and the mechanisms responsible for the effects of ADAM8 on osteoclastogenesis are unknown. Therefore, to determine the effects of modulating ADAM expression, we generated tartrate‐resistant acid phosphatase (TRAP)–ADAM8 transgenic mice that overexpress ADAM8 in the OCL lineage and ADAM8 knockout (ADAM8 KO) mice. TRAP‐ADAM8 mice developed osteopenia and had increased numbers of OCL precursors that formed hypermultinucleated OCLs with an increased bone‐resorbing capacity per OCL. They also had an enhanced differentiation capacity, increased TRAF6 expression, and increased NF‐κB, Erk, and Akt signaling compared with wild‐type (WT) littermates. This increased bone‐resorbing capacity per OCL was associated with increased levels of p‐Pyk2 and p‐Src activation. In contrast, ADAM8 KO mice did not display a bone phenotype in vivo, but unlike WT littermates, they did not increase RANKL production, OCL formation, or calvarial fibrosis in response to tumor necrosis factor α (TNF‐α) in vivo. Since loss of ADAM8 does not inhibit basal bone remodeling but only blocks the enhanced OCL formation in response to TNF‐α, these results suggest that ADAM8 may be an attractive therapeutic target for preventing bone destruction associated with inflammatory disease. © 2011 American Society for Bone and Mineral Research.  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