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   25540篇
  免费   990篇
  国内免费   118篇
耳鼻咽喉   319篇
儿科学   415篇
妇产科学   253篇
基础医学   3073篇
口腔科学   677篇
临床医学   1560篇
内科学   5979篇
皮肤病学   374篇
神经病学   2142篇
特种医学   1116篇
外科学   4265篇
综合类   89篇
预防医学   760篇
眼科学   605篇
药学   1788篇
中国医学   35篇
肿瘤学   3198篇
  2023年   111篇
  2022年   235篇
  2021年   379篇
  2020年   205篇
  2019年   261篇
  2018年   420篇
  2017年   294篇
  2016年   394篇
  2015年   387篇
  2014年   575篇
  2013年   698篇
  2012年   1138篇
  2011年   1185篇
  2010年   746篇
  2009年   668篇
  2008年   1225篇
  2007年   1273篇
  2006年   1339篇
  2005年   1367篇
  2004年   1318篇
  2003年   1264篇
  2002年   1342篇
  2001年   869篇
  2000年   855篇
  1999年   814篇
  1998年   381篇
  1997年   333篇
  1996年   293篇
  1995年   240篇
  1994年   211篇
  1993年   205篇
  1992年   523篇
  1991年   459篇
  1990年   422篇
  1989年   497篇
  1988年   416篇
  1987年   363篇
  1986年   397篇
  1985年   374篇
  1984年   290篇
  1983年   194篇
  1982年   110篇
  1981年   98篇
  1980年   94篇
  1979年   169篇
  1978年   118篇
  1977年   118篇
  1975年   93篇
  1969年   103篇
  1967年   88篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Late-onset chylothorax occurred 49 days after right lower lobectomy for lung cancer in a 76-year-old man. Chylothorax was successfully managed by conservative treatment with chest tube drainage and an enteral low-fat diet. Chylothorax may occur in the late period after pulmonary resection and systematic mediastinal lymph node dissection for lung cancer, for which conservative management is the treatment of choice.  相似文献   
32.
Human tumor–infiltrating lymphocytes (TILs) derived from pleural or ascitic fluid were incubated with recombinant interleukin 2 and transfected with human tumor necrosis factor (TNF) a gene by the lipofection procedure. The resulting TILs secreted significant amounts of TNF in the culture supernatant and exhibited cytotoxicity against established cell lines, such as K562 and Daudi, and autologous tumor cells. The TNF gene–transfected TILs exhibited an augmented killing of autologous tumor cells.  相似文献   
33.
Prednisolone concentrations in cornea, aqueous humor, and vitreous humor and the residual amount in conjunctival tissue were assayed by high-performance liquid chromatography during a 14-hour period after subconjunctival injection of prednisolone sodium succinate in rabbits. Prednisolone was concentrated in the corneal epithelium and reached a peak within 5 min, whereas the peak level of prednisolone in stroma-endothelium was achieved 1 h after the injection. There was an apparent linear binding of prednisolone with the ocular tissue homogenates and fluids except for the vitreous humor. However, the protein binding of prednisolone with vitreous humor showed marked concentration dependency. A pharmacokinetic model involving a rapid conversion to prednisolone from its ester prodrug, first-order transfer to various tissues, and first-order elimination of unbound prednisolone from vitreous humor succeeded in predicting the observed concentration-time profiles of prednisolone in various ocular tissues and fluids after subconjunctival injection at three different doses: 0.1, 1.0, and 10.0 mg/kg. The present model predicted that absorption into precorneal area and epithelium and direct penetration into aqueous humor and vitreous humor are 1.7, 0.1, and 0.2% of the applied dose, respectively, and that almost the entire dose (98%) is absorbed into the systemic circulation, with a half-life of 38 min.  相似文献   
34.
We encountered a rare case of hypersensitivity pneumonitis associated with bilateral hilar lymphadenopathy (BHL). The patient was a 53-year-old male, who developed dry cough and shortness of breath when using a humidifier since 1982. He was admitted to our hospital for further evaluation in 1987. Chest X-ray films showed BHL and ground glass appearance in the bilateral lung fields. Pulmonary function test indicated disturbance of diffusing capacity. Transbronchial lung biopsy revealed interstitial pneumonitis, and lymph node biopsy by mediastinoscopy showed lymphoid sinus histiocytosis without noncaseating granuloma. Provocation test using the humidifier was positive, and the diagnosis of humidifier lung with BHL was made.  相似文献   
35.
Aspiration pneumonia is the fourth cause of death in Japanese, of which 92% occurs in elderly people aged more than 65 years. Pneumonia in the elderly is mostly due to aspiration. Aspiration is caused by disturbance of the pharyngeal reflex and cough mechanisms are due to disturbances of brain activity. Respiratory diseases including bronchial asthma must be treated with consideration of brain activity.  相似文献   
36.
In six hundred and six consecutive patients undergoing coronary artery bypass grafting (CABG) within the past 17 years (May 1974 to March 1991), repeated CABG were performed on 10 patients (1.65%). The main reasons for repeated CABG were graft failure (GF) in 8, progression of native disease (NP) in 5 and incomplete revascularization (IR) in 3 patients. The incidence of GF was high either within a half year or around 5 years after CABG. Although all patients survived from reoperation, four patients continued to have mild angina pectoris. When the recurrence of angina is noted after CABG, coronary arteriography and if necessary PTCA should be done as soon as possible. If a second surgery is inevitable, maximum utilization of arterial graft and accomplishment of complete revascularization are emphasized.  相似文献   
37.
38.
Changes in the distribution of hyaluronic acid in the developing human retina were investigated histochemically with alcian blue staining and theStreptomyces hyaluronidase digestion method using 56 human embryos and fetuses ranging from 5 to 41 weeks of gestational age. Hyaluronic acid was first detected in the inner layer of the retina at 12 weeks. The site of accumulation extended towards the outer layer by 20 weeks. At the neonatal stage, longitudinal fibers, possibly the processes of Müller cells, were proved to contain hyaluronic acid. These findings suggest that Müller cells produce hyaluronic acid transiently from 12 weeks’ gestation to the neonatal stage.  相似文献   
39.
40.
The effects of KB-2796, 1-[bis(4-fluorophenyl)methyl]-4-(2,3,4-trimethoxybenzyl)piperazine-2HCl, on the low- and high-voltage activated Ca2+ currents (LVA and HVA ICa, respectively) and on oxidative metabolism were studied in neurons freshly dissociated from rat brain. KB-2796 reduced the peak amplitude of LVA ICa in a concentration-dependent manner with a threshold concentration of 10−7 M when the LVA ICa was elicited every 30 s in the external solution with 10 mM Ca2+. The concentration for half-maximum inhibition (IC50) was 1.9 × 10−6M. At 10−5 M or more of KB-2796, a complete suppression of the LVA ICa was observed in the majority of neurons tested. There was no apparent effect on the current-voltage (I-V) relationship and the current kinetics. KB-2796 delayed the reactivation and enhanced the inactivation of the Ca2+ channel for LVA ICa voltage- and time-dependently, suggesting that KB-2796 preferentially binds to the inactivated Ca2+ channel. KB-2796 at a concentration of3.0 × 10−6M also decreased the peak amplitude of the HVA ICa without shifting the I-V relationship. In addition, KB-2796 reduced the oxidative metabolism (the formation of reactive oxygen species) of the neuron in a concentration-dependent manner with a threshold concentration of3 × 10−6M. It is suggested that the inhibitory action of KB-2796 on the neuronal Ca2+ influx and the oxidative metabolism, in combination with a cerebral vasodilatory action, may reduce ischemic brain damage.  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