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   27138篇
  免费   1483篇
  国内免费   149篇
耳鼻咽喉   299篇
儿科学   411篇
妇产科学   357篇
基础医学   3429篇
口腔科学   801篇
临床医学   1820篇
内科学   7068篇
皮肤病学   515篇
神经病学   1625篇
特种医学   815篇
外科学   4678篇
综合类   132篇
一般理论   1篇
预防医学   853篇
眼科学   661篇
药学   1734篇
  1篇
中国医学   69篇
肿瘤学   3501篇
  2023年   132篇
  2022年   253篇
  2021年   540篇
  2020年   303篇
  2019年   385篇
  2018年   514篇
  2017年   423篇
  2016年   531篇
  2015年   509篇
  2014年   672篇
  2013年   816篇
  2012年   1236篇
  2011年   1384篇
  2010年   756篇
  2009年   628篇
  2008年   1110篇
  2007年   1257篇
  2006年   1218篇
  2005年   1257篇
  2004年   1164篇
  2003年   1220篇
  2002年   1100篇
  2001年   910篇
  2000年   924篇
  1999年   884篇
  1998年   316篇
  1997年   249篇
  1996年   268篇
  1995年   217篇
  1994年   194篇
  1993年   172篇
  1992年   692篇
  1991年   626篇
  1990年   578篇
  1989年   660篇
  1988年   555篇
  1987年   512篇
  1986年   520篇
  1985年   475篇
  1984年   306篇
  1983年   237篇
  1982年   136篇
  1980年   110篇
  1979年   219篇
  1978年   172篇
  1977年   138篇
  1974年   110篇
  1971年   123篇
  1970年   100篇
  1969年   126篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
151.
A patient with cerebral deep sinus thrombosis, which was not diagnosed on the first examination, is reported. A 46-year-old woman presented with headache and vomiting. Neurological examination and a brain computed tomography (CT) scan showed no obvious abnormal findings. The patient suffered disturbed consciousness on the day after the examination, and was admitted to our emergency centre. A CT scan and magnetic resonance imaging revealed an ischaemic lesion in the left basal ganglia, suggesting deep sinus occlusion. Anticoagulant therapy was administered. One day after admission, a CT scan showed a haematoma and severe brain swelling in the same region. Cerebral angiography demonstrated a straight sinus occlusion. Intracranial pressure was not controlled with hypothermia, and the patient died 25 days after admission. Review of the initial CT scan revealed subtle, early findings of deep venous thrombosis that were missed on first examination.  相似文献   
152.
153.
The magnetic resonance phase-contrast technique for the measurement of flow velocity and volume in true and false lumens was studied in six patients with chronic dissecting aneurysms. Phase-contrast images were obtained at a level perpendicular to the dissecting aneurysms of the descending aorta. As the maximum diameter of aneurysms increased, the ratio of the cross-sectional area of the false to the true lumen increased and the peak average velocity in the true lumen during systole was decreased. This technique proved invaluable for determining prognosis and operability for this condition.  相似文献   
154.
A CASE OF METASTATIC YOLK SAC TUMOR OF TESTIS IN A CHILD   总被引:1,自引:0,他引:1  
We report a case of testicular yolk sac tumor in a child aged 3 years and 6 months with multiple bulky metastases to lung and retroperitoneum (stage 11182). After three courses of chemotherapy with a PV 8 regimen (cisplatin, vinblastine and bleomycin). complete and partial responses were obtained for lung and retroperitoneal lymph node metastases, respectively. The patient was followed-up closely. However, on the basis of a re-elevated alpha-letoprotein (AFP) after 4 months' follow-up, he was treated with three courses of salvage chemotherapy with a modified VAB-6 regimen (cyclophosphamide. etoposide. actinomycin D, bleomycin and cisplatin), lollowed by retroperitoneal lymph node dissection. Histologically, only necrotic tissue was found. There is no evidence of recurrence 24 months after lymphadenectomy. There is very little information in the literature on the appropriate management of postchemotherapy residual mass in pediatric testicular tumors.  相似文献   
155.
A 10-year experience with 2,441 patients over 65 years of age undergoing operations for non-upper gastrointestinal tracts was reviewed to evaluate both the incidence of postoperative upper gastrointestinal bleeding and the clinical risk factors associated with the complication. A total of 18 (0.7%, 7 males and 11 females) patients had overt postoperative upper gastrointestinal bleeding of non-variceal origin documented by endoscopic findings or blood transfusions. Of these, the complication developed in 10 (1.5%) of 646 patients after an operation for biliary or pancreatic disease, 1 (1.5%) of 64 for aneurysmal or obstructive arterial disease, 5 (1.1%) of 43 for colorectal cancer and 2 (0.3%) of 916 for hernia. The incidences of bleeding after an operation for obstructive jaundice (3.8%), for biliary or pancreatic malignancy (4.5%), and of unavoidable diversion colostomy for colorectal anastomosis (3.1%) were significantly higher than for non-jaundice (0.6%), for non-malignancy (1.1%) and of postoperative upper gastrointestinal bleeding in the present study. The origins of bleeding were gastric ulcer in 11, acute gastric mucosal lesion in 4, duodenal ulcer in 1 and other in 2. All cases of bleeding were treated and met success in hemostasis using H2-blockers. Of these, however, 5 patients died of multiple organ failure despite discontinued hemorrhage, prophylactic use of H2-blockers showed a decrease in occurrence of postoperative upper gastrointestinal bleeding in the present study.  相似文献   
156.
Infusion of muscimol (5×10−5 M, 60 min) into the nucleus accumbens (NAC) through a dialysis membrane caused a significant increase in extracellular dopamine (DA) and its metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC). Fos-like immunoreactivity induced by intra-NAC infusion of muscimol was seen ipsilaterally in many accumbofugal target areas, but no Fos-positive neurons were seen in the vicinity of the dialysis membrane in the NAC. Sequential staining of Fos and tyrosine hydroxylase (TH) immunoreactivities revealed that a portion of A10 dopaminergic neurons were double-labelled. These results suggest that muscimol in the NAC disinhibits mesolimbic DA neuronal activity possibly through activity of the accumbofugal GABA neuron system.  相似文献   
157.
In order to clarify the appearance of monocytoid B lymphocytes (MBLs) in abscess-forming granulomatous lymphadenitis (AGL) and the relation between AGL and cat-scratch disease (CSD), 48 cases of AGL were studied histologically. MBLs were present in about 50% of AGL cases. Warthin-Starry (WS) silver stain-positive bacteria, which are the causative agent of CSD, were present in 52.4% of AGL cases with MBLs and 59.2% of AGL cases without MBLs. The appearance of MBLs in AGL was not related to various clinical features, including disease interval from initial lymphadenopathy to lymph node biopsy. Histologically, epithelioid cell clusters appeared in about 70% of MBL-positive AGL cases, but were not observed in MBL-negative AGL. Therefore, a close interaction between MBLs and epithelioid cells in AGL is suggested, and we emphasize that the histological features of some AGL cases resemble those of toxoplasmic lymphadenitis.  相似文献   
158.
A 27-year-old woman developed chickenpox postpartum. Her 2-month-old son who was breast fed also acquired chickenpox 16 days after the onset of the mother's illness. Varicella-zoster virus (VZV) DNA was detected in maternal breast milk by the polymerase chain reaction. These results suggest that transmission of VZV may occur via maternal breast milk.  相似文献   
159.
Pulmonary aspergillosis associated with old tuberculosis is generally resistant to treatment. Thus, if patients are treated only with conservative therapy, their condition continues to deteriorate due to repetitive hemoptysis, and may even become critical. Surgical treatment is required for these patients; however, it is extremely difficult to resect the lesion due to severe adhesions to the chest wall and vascular proliferation surrounding the lesion. We performed preoperative arterial embolization, achieving good results in three patients with hemoptysis caused by pulmonary aspergillosis. The feeding arteries were embolized using microcoils and/or gelatin sponges, and a lobectomy was safely carried out in all patients. We concluded that preoperative arterial embolization is a safe and effective technique to prevent massive hemorrhage occurring at the time of surgery. This work was presented at the 11th Annual Meeting of the Japanese Association for Chest Surgery, held in Kyoto, Japan, May 13–14, 1994  相似文献   
160.
OBJECTIVES: Microwaves produce various detrimental changes based on actions of heat or non-specific stress, although the effects of microwaves on pregnant organisms has not been uniform. This study was designed to clarify the effect of exposure to microwaves during pregnancy on endocrine and immune functions. METHODS: Natural killer cell activity and natural killer cell subsets in the spleen were measured, as well as some endocrine indicators in blood--corticosterone and adrenocorticotrophic hormone (ACTH) as indices of the hypothalamic-pituitary-adrenal axis--beta-endorphin, oestradiol, and progesterone in six female virgin rats and six pregnant rats (nine to 11 days gestation) exposed to microwaves at 10 mW/cm2 incident power density at 2450 MHz for 90 minutes. The same measurements were performed in control rats (six virgin and six pregnant rats). RESULTS: Skin temperature in virgin and pregnant rats increased immediately after exposure to microwaves. Although splenic activity of natural killer cells and any of the subset populations identified by the monoclonal antibodies CD16 and CD57 did not differ in virgin rats with or without exposure to microwaves, pregnant rats exposed to microwaves showed a significant reduction of splenic activity of natural killer cells and CD16+CD57-. Although corticosterone and ACTH increased, and oestradiol decreased in exposed virgin and pregnant rats, microwaves produced significant increases in beta-endorphin and progesterone only in pregnant rats. CONCLUSIONS: Microwaves at the power of 10 mW/cm2 produced activation of the hypothalamic-pituitary-adrenal axis and increased oestradiol in both virgin and pregnant rats, suggesting that microwaves greatly stress pregnant organisms. These findings in pregnant rats suggest that--with exposure to microwaves--pregnancy induces immunosuppression, which could result in successful maintainance of pregnancy. This enhancement of adaptability to heat stress with pregnancy may be mediated by activation of placental progesterone and placental or pituitary beta-endorphin.  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