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   10439篇
  免费   431篇
  国内免费   896篇
耳鼻咽喉   122篇
儿科学   154篇
妇产科学   178篇
基础医学   1570篇
口腔科学   96篇
临床医学   613篇
内科学   1962篇
皮肤病学   51篇
神经病学   616篇
特种医学   216篇
外国民族医学   3篇
外科学   1070篇
综合类   1334篇
现状与发展   7篇
一般理论   5篇
预防医学   547篇
眼科学   505篇
药学   1227篇
中国医学   287篇
肿瘤学   1203篇
  2024年   30篇
  2023年   144篇
  2022年   62篇
  2021年   60篇
  2020年   44篇
  2019年   23篇
  2018年   36篇
  2017年   21篇
  2016年   27篇
  2015年   59篇
  2014年   131篇
  2013年   71篇
  2012年   1834篇
  2011年   1968篇
  2010年   356篇
  2009年   136篇
  2008年   1086篇
  2007年   1102篇
  2006年   997篇
  2005年   820篇
  2004年   674篇
  2003年   631篇
  2002年   453篇
  2001年   266篇
  2000年   334篇
  1999年   151篇
  1998年   80篇
  1997年   23篇
  1996年   13篇
  1995年   16篇
  1994年   6篇
  1993年   6篇
  1992年   7篇
  1991年   3篇
  1990年   2篇
  1989年   12篇
  1988年   9篇
  1987年   8篇
  1986年   6篇
  1985年   7篇
  1984年   10篇
  1983年   13篇
  1982年   10篇
  1981年   8篇
  1980年   4篇
  1979年   2篇
  1978年   1篇
  1964年   2篇
  1960年   1篇
  1959年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
A rapid and high selective ultra?performance liquid chromatography (UPLC) with tandem mass spectrometry method for simultaneous determination of six compounds including albiflorin, paeoniflorin, picroside I, picroside II, saikosaponin A, and saikosaponin D in rat plasma was developed and validated using butyl p-hydroxybenzoate as an internal standard. One-step direct protein precipitation with acetonitrile was used to extract the compounds from the rat plasma samples. Chromatographic separation was achieved using an ACQUITY UPLC BEH C18 column (100 mm × 2.1 mm, 1.7 µm) at a flow rate of 0.4 mL/min, using gradient mode containing 0.1% formic acid in water and acetonitrile were used as the Mobile phase A and B. Electrospray ionization in negative ion mode and multiple reaction monitoring were used to identify and quantify active components. Calibration curves showed good linearity (R2 > 0.9908) over a wide concentration range for all compounds. The intra- and interday precision (relative standard deviation) ranged 2.4%–7.0% and 2.6%–8.0%, respectively. The accuracy (relative error) was from ?13.0% to 13.2% at all quality control levels. The recovery ranged from 81.1% to 92.5%. The validated method was successfully applied to pharmacokinetic study in rats after oral administration of Qing Gan?Shu Yu?Fang. The results show that one can draw a conclusion that these six active ingredients can be quickly absorbed and play a pharmacodynamic role rapidly in vivo.  相似文献   
2.
Eighteen trabeculectomy specimens of congenital glaucoma were examined by light and transimssion electron microscopy. The results showed that the primary anomalies in congenital glaucoma included the developmental defects of trabecular meshwork, excessive collagen fibrils in the trabecular matrix, shifting forward of ciliary muscle fibres and persistent mesenchymal tissues in the anterior-chamber angle. The authors also pointed out the importance of the secondary lesions of the trabecular meshwork in the pathogenesis of congenital glaucoma. Eye Science 1994; 10:50-56.  相似文献   
3.
Objective To observe changes of hepatic hemodynamics and hepatic functional reserve after splenectomy and periesophagogastric devascularization. Methods From July 2006 to August 2007, thirty patients with portal hypertension caused by hepatitis B cirrhosis underwent splenectomy and periesophagogastric devascuiarization. The PVPG (portal venous pressure gradient) was measured by inductor continually during operation. The HAF (hepatic artery flow), PVF (portal venours flow) and hepatic arterial RI(resistant index) were measured with Doppler sonography. The EHBF(effective hepatic blood flow) and ICGR15 (indocyaninegreen retention rate at 15 minutes) were obtained respectively by indocyaninegreen clearance test before and after the operation. Results PVPG after laparotomy (19±4) mm Hg, ligating the splenic artery(14±4) mm Hg, splenectomy(14±3)mm Hg and periesophagogastric devascularization (12±4) mm Hg showed a tendency to decrease progressively. The PVF decreased [from (42±14) ml/s to (16±8) ml/s] and HAF increased in compensation after operation. The EHBF increased [from (0.48±0.10) L/min to (0.56±0.10) L/min], and the ICGR15 decreased (from 23%±8% to 18%±4%) postoperatively. Conclusion After splenectomy and periesophagogastric devascularization, the hepatic functional reserve improves at least in a short term notwithstanding the decrease of PVPG and PVF.  相似文献   
4.
Objective: To explore the effect of Shenfu Injection, SFI) on the secondary aplastic anemia (AA) of tumor patients after chemotherapy (CT).Methods: The 15 cases of SFI treated group, 10 cases of control group, 25 cases of SFI + granulocyte-macrophage colony stimulating factor (GMCSF) treated group and the group of 23 GM-CSF-treated tumor cases of secondary AA after CT were compared, with their increasing rate and the rebound speed of neutrophil, platelet, bone marrow nucleated RBC, granulocyte, and megakaryocyte all being investigated.Results: The increasing rate and rebound speed of granulocyte, platelet, and the increasing rate of bone marrow nucleated RBC, granulocyte, megakaryocyte were obviously higher than those of the control, and the clinical manifestations were also obviously improved. The increasing rate of platelet, bone marrow nucleated RBC, megakaryocyte of the SFI + GM-CSF group were higher than those of the group which used GM-CSF alone, while the increasing rate of granulocyte in blood and bone marrow in both groups was similar.Conclusion: Significant efficacy was shown in SFI for the treatment of secondary AA of tumor patients after CT.  相似文献   
5.
In the management of ankle joint fractures, re- duction and fixation of the lateral malleolus should be emphasized. The lateral maUeolus should have anatomical reduction and fixation should be reliable. Fibular integrity is essential in stabilizing the ankle joint. Routine section of the fibula may result in separation of the inferior tibiofibular joint, ankle instability and talus displacement. Eventually this leads to traumatic arthritis. So special attention should be paid to fibular resection, even partial removal of the fibula for transplantation should be carried out carefully.  相似文献   
6.
To identify differentially expressed genes between obese individuals and normal control, we have undertaken suppression subtractive hybridization (SSH). Omental adipose tissues were obtained via abdominal surgery for appendicitis in both 13 obese subjects[BMI (body mass index) 〉 30 kg/m(2)] and 13 normal subjects (BMI 〉 18 and 〈 25 kg/m(2)).  相似文献   
7.
BACKGROUND: In recent years some reports have been published propagating microsurgical resection of ventral foramen magnum meningiomas (VFMMs). Operative approaches to these lesions have been studied by various authors, but remain controversial. OBJECTIVE: To discuss the operative technique and outcome in patients with VFMMs who had been treated via a far lateral suboccipital approach. DESIGN: Retrospectively clinic case investigation. SETTING: Department of Neurosurgery, the Ninth People's Hospital, Medical School of Shanghai Jiao Tong University. PARTICIPANTS: Between January 1997 and June 2003, 10 patients were treated surgically with VFMMs in Department of Neurosurgery, the Ninth People's Hospital, Medical School of Shanghai Jiao Tong University. In the series of 10 patients, ages ranged from 37 to 72 years, mean (53±10) years, were consisted of 6 males and 4 females. All the subjects were informed of the treatment plan and agreed to join the experiment. Early symptoms included headache and upper cervical pain. The time between the first occurrence of symptoms and the diagnosis ranged from 6 months to 17 months, mean (10.3±3.4) months. Main presenting symptoms were unilateral upper extremity sensory and motor deficits in 6 cases, swallowing difficulties in 2 and spastic quadriparesis in 2. VFMMs were demonstrated as round by the computed tomographic (CT) scan and magnetic resonance imaging (MRI) in all patients. The maximum diameter of tumors ranged from 2 to 4 cm, mean (2.55±0.57) cm, including 2 cm in one case, 2.0-3.0 cm in six and 3.0-4.0 cm in three. METHODS: ①All tumors were removed via the far lateral suboccipital approach. Resection of the posterior 5 mm of the condyle was necessary in one patient whose tumors' diameter were 2 cm. The patient was situated in the lateral decubitus position. The head was fixed in a Mayfield headrest. A C-shaped incision made behind the ear 2 cm medial to the mastoid process, turning vertically down to the level C4, to expose the extradural segment of the vertebral artery (VA). After the dura was opened longitudinally behind VA entry point, the tumor was revealed to identify the complete cranial nerves and the intracranial VA under magnification of the surgical microscope. Every attempt should be made to keep the arachnoid and the dentate ligament was sectioned. Then the tumor was debulked significantly, and dissected away from the cranial nerves and the blood vessels with microsurgical techniques. If it was risk to dissect tumor from the vertebral artery, its branches, or any cranial nerve, the progression was discontinued and portion of the tumor was left behind. After resection of the tumor, the site of its attachment was coagulated and the involved layer of dura was resected. ②The degree of tumor resection was classified based on Al-Mefty's grade into three categories: gross-total resection: excision of the dural attachment and drilling of adjacent bone; near-total resection: a few millimeters of insulated and cauterized tumor were left on the vertebral artery or other vital; subtotal resection: more than 50% of the tumor mass were removed. ③All patients underwent clinical examination for lower cranial nerves or long tract deficits on the first day postoperatively. CT or MRI and neurological examinations were performed at 3 months of follow-up. MAIN OUTCOME MEASURES: Operative effect. RESULTS: All ten patients with VFMMs were treated via a far lateral suboccipital approach. Gross total resection was achieved in 6 patients, near-total resection was carried out in 2 and subtotal resection in 2 patients. One patients died in the postoperative period due to acute respiratory distress syndrome, five patients kept normal neurological status, whereas other four patients suffered from lower cranial nerve deficits and aspiration pneumonia was observed in two of them. The data of following up for 3 months showed that 2 patients still had lower cranial nerve deficit and others recovered from their illness. No tumor relapse or increment was found in CT or MRI scans. CONCLUSION: Most of VFMMs could be totally removed via a far lateral suboccipital approach with or without resection of the occipital condyle according to the tumor size, allowing most of these patients to achieve a good outcome in a 3 months follow-up.  相似文献   
8.
Purpose:To report a rare sign, paracentral corneal dellen that developed in a middleaged female patient with Graves ophthalmopathy.Methods:A paracentral corneal dellen developed in the left eye in a 42-year-old woman who was diagnosed as Graves ophthalmopathy. The patient had remarkable upper eyelid retraction, upper eyelid lag and upward motility restriction. The Graves ophthalmopathy was classified as Grade Ⅳ according to NOSPECS classification.Results:Local artificial tear film and 0.3% Tobramycin eye drops were administered to both eyes.Twenty-four hours later, the left corneal dellen disappeared.Conclusions:Graves ophthalmopathy can lead to paracentral corneal dellen because of severe upper eyelid retraction and upward motility restriction of the eye in spite of the lack of lagophthalmos. Artificial tear drop and antibiotic eye drop therapy helped even though the patient did not have corneal exposure. Eye Science 2003;19:174-175.  相似文献   
9.
IN T R O D U C T IO NSuperoxide dism utase (SO D )is an im portantendogenous free radica scavenger, itelim inates superoxide anion free radicals through dis proportionation, and itprotects the nerve cells in the process ofcere bralischem ia reperfusion in…  相似文献   
10.
Intravenous leiomyomatosis is a rare uterineneoplasm, histologically characterized by nodularmasses of benign smooth muscle growing withinthe uterine and pelvic veins. The entity has ty-pical gross and microscopic features. A case of intravenous leiomyomatosisassociated with uterine leiomyoma, adenomyosisand early pregnancy was reported. The condi-tion was recognized during surgery for uterinefibroids. This is, to our knowledge, the thirdcase of intravenOUs leiomyomatosis associatedwith pregnancy so far reported.  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