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   1341篇
  免费   131篇
  国内免费   148篇
耳鼻咽喉   41篇
儿科学   72篇
妇产科学   10篇
基础医学   114篇
口腔科学   30篇
临床医学   223篇
内科学   313篇
皮肤病学   46篇
神经病学   41篇
特种医学   321篇
外科学   102篇
综合类   29篇
预防医学   47篇
眼科学   14篇
药学   139篇
  1篇
中国医学   2篇
肿瘤学   75篇
  2023年   5篇
  2022年   3篇
  2021年   8篇
  2020年   18篇
  2019年   24篇
  2018年   35篇
  2017年   31篇
  2016年   31篇
  2015年   49篇
  2014年   37篇
  2013年   59篇
  2012年   35篇
  2011年   41篇
  2010年   58篇
  2009年   59篇
  2008年   39篇
  2007年   119篇
  2006年   33篇
  2005年   45篇
  2004年   22篇
  2003年   22篇
  2002年   28篇
  2001年   29篇
  2000年   22篇
  1999年   21篇
  1998年   80篇
  1997年   80篇
  1996年   71篇
  1995年   62篇
  1994年   44篇
  1993年   51篇
  1992年   8篇
  1991年   16篇
  1990年   13篇
  1989年   50篇
  1988年   33篇
  1987年   34篇
  1986年   27篇
  1985年   23篇
  1984年   19篇
  1983年   12篇
  1982年   27篇
  1981年   14篇
  1980年   14篇
  1979年   7篇
  1978年   4篇
  1977年   16篇
  1976年   29篇
  1975年   13篇
排序方式: 共有1620条查询结果,搜索用时 0 毫秒
1.
Intestinal schistosomiasis japonica: CT-pathologic correlation   总被引:1,自引:0,他引:1  
  相似文献   
2.
3.
4.
A G209A mutation in the alpha-synuclein gene was recently discovered in a large Italian kindred and three unrelated Greek kindreds with autosomal dominant Parkinson's disease (PD). Subsequently, another mutation in the gene (G88C) was also identified in a German family with autosomal PD. These results indicate that the alpha-synuclein gene may have an important role in the pathogenesis of PD. This study was designed to screen the existence of both mutations of the alpha-synuclein gene among 100 Chinese patients with PD, including 80 with sporadic and 20 with familial PD. Results showed that none of our patients, both sporadic and familial PD, had either of the two mutations of this gene. We therefore conclude that although of great interest, these two mutations are not relevant for the pathogenesis of PD in a Han Chinese population.  相似文献   
5.
Marrow regeneration after mechanical depletion   总被引:1,自引:0,他引:1  
Brecher  G; Tjio  JH; Smith  WW; Haley  JE 《Blood》1976,48(5):679-686
The origin of marrow regeneration after mechanical depletion was reinvestigated in mouse chimeras. The results were compatible with the local origin of stem cells from remnants of incompletely removed marrow, but not with their origin from a common precursor of both bone and hemopoietic cell lines. In transplanted femurs depleted by a modified technique of in vivo evacuation of marrow, hemopoietic regeneration failed to occur. The presence of hemopoietic stem cells in the Haversian canals was thus excluded. The demonstration of ample hemopoiesis with minimal bone formation in nondepleted controls in which bone marrow initially became necrotic provided new evidence that osteogenesis was not a prerequisite of hemopoietic regeneration.  相似文献   
6.
A 15 year old boy with autoimmune polyendocrinopathy-candidosis-ectodermal dystrophy syndrome suffered recurrent episodes of severe intractable diarrhoea, steatorrhoea, and hypocalcaemia. The only treatment modality, which controlled the malabsorption syndrome, was immunosuppression with intravenous high dose methylprednisolone and oral methotrexate maintenance therapy.  相似文献   
7.
A 54-year-old man was treated with weekly 24-h infusion of high-dose 5-fluorouracil (2600 mg/m2) and leucovorin (100 mg/m2) for metastatic colon cancer. At first, he tolerated the treatment well and no significant toxicity was identified. After a total of eight courses of treatment, a stable disease was observed, but mild shortness of breath was found on occasion. The patient had no previous history of cardiac disease and the heart performance assessed by left ventricular ejection fraction before treatment was normal. Unfortunately, acute pulmonary edema with lethal cardiogenic shock occurred during the ninth course of treatment, in spite of intensive medical treatment. The chest X-ray showed extreme cardiomegaly. Repeated assessment of his heart function by echocardiogram and ventricular ejection fraction revealed a very poor cardiac performance. Toxic cardiogenic shock during weekly 24-h infusion of high-dose 5-fluorouracil and leucovorin is extremely rare. To the best of our knowledge, no case has been reported in the English literature. We report a case and the relevant literature about the incidence, clinical picture and possible pathophysiology on 5-fluorouracil-related cardioxicity is reviewed.   相似文献   
8.
OBJECTIVE: We tested the ability of magnesium sulfate to reduce hypertension and neonatal growth retardation in an animal model of preeclampsia. STUDY DESIGN: On day 17 of pregnancy, osmotic minipumps were inserted subcutaneously to continuously deliver either vehicle (saline control group), or N-nitro-L-arginine methyl ester (L-NAME) (50 mg/kg/day), or L-NAME (50 mg/kg/day) in combination with magnesium sulfate (60 mg/kg/day). Prior to insertion, blood pressure and heart rate were monitored with a pneumatic tail cuff device. Blood pressure measurements were repeated on days 18, 20, and 21 of pregnancy. Blood was obtained on days 17 and 21, along with urine, to assess magnesium levels and degree of proteinuria. Pups were weighed and measured at 48 hours postpartum. RESULTS: Rats receiving L-NAME developed hypertension within 24 hours of implantation (108 +/- 3.9 vs. 123 +/- 3.4 mmHg, p < 0.05). Magnesium sulfate, given along with L-NAME did not prevent mean blood pressure from increasing, but reduced it by day 21 compared to L-NAME given alone (107 +/- 3.4 vs. 122 +/- 8.7 mmHg, respectively, p < 0.05). Magnesium sulfate reduced neonatal growth retardation by improving the weight of the pups compared to pups from maternal rats given L-NAME alone (6.1 +/- 0.1 vs. 5.2 +/- 0.3 grams, respectively, p < 0.05). CONCLUSION: Maternal magnesium sulfate reduces blood pressure and increases neonatal size compared to L-NAME without magnesium. These findings support a beneficial effect of magnesium in preeclampsia.  相似文献   
9.
Carthamus tinctorius L. (Compositae) is used in Chinese medicine to treat heart disease and inflammation. In our previous study, we found that C. tinctorius L. inhibited lipopolysaccharides (LPS)‐induced tumor necrosis factor‐alpha (TNF‐α) activation, JNK expression, and apoptosis in H9c2 cardiomyoblast cells. The present study was performed to investigate the protective effect of C. tinctorius extract (CTF) on LPS‐challenged H9c2 myocardioblast cell and to explore the possible underlying mechanism. Cell viability assay showed that LPS treatment decreased the cell viability of H9c2 cell, whereas CTF treatment reversed LPS cytotoxicity in a dose‐dependent manner, especially in the LPS + CTF 25 (μg/mL) group. LPS treatment‐induced apoptosis was determined by transferase‐mediated dUTP nick end labeling assay, and by Western blot. LPS‐induced apoptotic bodies were decreased following CTF treatment. Expression of TNF‐α, FAS‐L, FAS, FADD, caspase‐8, BID, and t‐BID was significantly increased in LPS‐treated H9c2 cells. In contrast, it was significantly suppressed by the administration of CTF extract. In addition, CTF treatment activates antiapoptotic proteins, Bcl‐2 and p‐Bad, and downregulates Bax, cytochrome‐c, caspase‐9, caspase‐3, and apoptosis‐inducing factor expression. Furthermore, CTF exerted cytoprotective effects by activating insulin‐like growth factor‐I (IGF‐I) signaling pathway leading to downregulation of the apoptotic proteins involved in FAS death receptor pathway. In addition, AG1024 and IGF‐I receptor (IGF‐IR) inhibitor and siRNA silencing reverses the effect of CTF implying that CTF functions through the IGF‐IR pathway to inhibit LPS‐induced H9c2 apoptosis. These results suggest that treatment with CTF extract prevented the LPS‐induced apoptotic response through IGF‐I pathway.  相似文献   
10.
Patellofemoral joint: kinematic MR imaging to assess tracking abnormalities   总被引:4,自引:0,他引:4  
Shellock  FG; Mink  JH; Fox  JM 《Radiology》1988,168(2):551-553
The patellofemoral joint was imaged with magnetic resonance (MR) in the axial plane while the knee was positioned from 0 degrees to 32 degrees of flexion (nine positions). These multiple sequential images obtained within the early phases of flexion of the knee were viewed in a "cine-loop" format, producing a kinematic study that clearly demonstrated the relationship of the patella to the trochlear groove. Four healthy subjects and one patient with known bilateral subluxing patellae were studied. The preliminary results suggest that kinematic MR imaging of the patellofemoral joint is potentially useful for the evaluation of patellar tracking abnormalities.  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