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   816篇
  免费   37篇
  国内免费   3篇
耳鼻咽喉   8篇
儿科学   30篇
妇产科学   28篇
基础医学   137篇
口腔科学   22篇
临床医学   82篇
内科学   185篇
皮肤病学   7篇
神经病学   59篇
特种医学   10篇
外科学   118篇
综合类   2篇
预防医学   29篇
眼科学   4篇
药学   47篇
中国医学   2篇
肿瘤学   86篇
  2021年   13篇
  2020年   6篇
  2019年   5篇
  2018年   12篇
  2016年   12篇
  2015年   9篇
  2014年   19篇
  2013年   16篇
  2012年   27篇
  2011年   47篇
  2010年   27篇
  2009年   22篇
  2008年   37篇
  2007年   44篇
  2006年   43篇
  2005年   58篇
  2004年   36篇
  2003年   46篇
  2002年   41篇
  2001年   24篇
  2000年   18篇
  1999年   23篇
  1998年   23篇
  1997年   11篇
  1996年   12篇
  1995年   9篇
  1994年   6篇
  1992年   14篇
  1991年   11篇
  1990年   15篇
  1989年   9篇
  1988年   11篇
  1987年   15篇
  1986年   11篇
  1985年   9篇
  1984年   13篇
  1983年   5篇
  1982年   5篇
  1980年   4篇
  1979年   8篇
  1978年   4篇
  1977年   8篇
  1976年   6篇
  1975年   6篇
  1974年   5篇
  1973年   5篇
  1971年   5篇
  1970年   6篇
  1969年   6篇
  1967年   4篇
排序方式: 共有856条查询结果,搜索用时 31 毫秒
61.
Background Reactive oxygen species are as being related to the pathophysiology of endstage renal disease (ESRD). We measured the plasma hydroxyl radical (·OH)-producing ability and ·OH-scavenging activity in patients with ESRD to clarify the pathophysiological states involved. Methods We used electron spin resonance to measure plasma N-t-butyl-α-phenylnitron radical spin adduct (pPBN rsa) as ·OH-producing ability and plasma 3,3,5,5-tetramethyl-1-pyrroline-N-oxide radical spin adduct (pM4PO rsa) as ·OH-scavenging activity. Oxidative injuries were evaluated by determining oxidised low-density lipoprotein (Ox-LDL). Results The pPBN rsa of the ESRD patients was lower than that of the controls (1.83 vs 2.94 μmol/g protein). The pM4PO rsa of the ESRD patients was higher than that of the controls (3.85 vs 3.15 mmol l-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl hydrogen phosphate] potassium salt (EPC-K1)/g protein). The pPBN rsa and pM4PO rsa were correlated, both in the ESRD patients and in the controls (r = 0.47 and r = 0.53). Ox-LDL was correlated with hemodialysis (HD) duration (r = 0.49) and was negatively correlated with pPBN rsa (r = −0.54), which indicates that oxidative stress was increased as HD therapy was prolonged and suppressed pPBN rsa. Conclusions There was an imbalance between ·OH-producing ability and ·OH-scavenging activity, in the ESRD patients, and this may be responsible for compromising the health of ESRD patients.  相似文献   
62.
63.
Prenatal diagnoses of I-cell disease were carried out by examination of the amniotic fluid and cultured amniotic cells in four cases of high-risk pregnancy in three different families. Three of the four fetuses were diagnosed as having I-cell disease, on the basis of observation of abnormally increased activity of lysosomal acid hydrolases in the amniotic fluid and their decreased activity in cultured amniotic cells, thus leading to therapeutic abortion. α-Mannosidase in the amniotic fluid of the fetuses with I-cell disease exhibited significant alterations in pH profile,K m value, thermal stability and isoelectric focusing pattern, compared with the enzyme in normal controls. The results indicate that prenatal diagnosis of I-cell disease may be accomplished by demonstration of altered enzymological characteristics of α-mannosidase in the supernatant of amniotic fluid. The significance of the alteration of α-mannosidase in the amniotic fluid is not known.  相似文献   
64.
A case of a giant aneurysm arising from the basilar artery is presented. The patient a 41--year-old female, had recent memory disturbance, miscalculations and hemiparesis on admission. Vertebral angiograms displayed a giant aneurysm measuring approximately 66 mm in diameter arising from the basilar artery, a tortuous vertebral artery, an extremely dilated basilar artery and an agenesis of the left carotid artery. Due to the enormous size of the aneurysm and its location in the deep intracranial portion, radical surgery was abandoned. Six months following her discharge, she died. At autopsy, the giant aneurysm arising from the top of the basilar artery was found, existing just beneath the third ventricle and extending to the left basal ganglia. The lateral ventricle, the third ventricle and the Sylvian fissure were filled by hematoma resulting from the rupture of the aneurysm. It is possible that this giant aneurysm could be considered a vascular anomaly, and hence be distinguished from saccular aneurysms.  相似文献   
65.
66.
A 7-year-old boy, who was noted to be a slow runner at the age of 2 years, had progressive muscle weakness and atrophy, preferentially affecting distal muscles. At 3 years of age, he had scoliosis and difficulty in standing on tip-toe. Serum creatine kinase was 1074 IU/l. Muscle CT scan showed low-density areas in the lower legs and upper arms, but predominantly in the gastrocnemius and soleus muscles. Biopsy of the biceps brachii muscle showed moderate dystrophic changes with normal dysferlin expression on immunohistochemical and western blot analyses. Although muscle involvement mimicked that seen in Miyoshi myopathy (MM), the very early onset of the disease and scoliosis were quite unusual for MM. We, therefore, made the diagnosis of early onset dysferlin-positive distal muscular dystrophy, probably a new type of distal muscular dystrophy.  相似文献   
67.
Nishikawa M  Ohata K  Baba M  Terakawa Y  Hara M 《Neurosurgery》2004,54(6):1430-4; discussion 1434-5
OBJECTIVE AND IMPORTANCE: We describe an alternative surgical technique for treatment of Chiari I malformation associated with ventral compression and instability of the region. An expansive suboccipital cranioplasty and a rigid occipitocervical fixation are performed in one stage. METHODS: The occipitocervical fixation is performed by use of metal rods fixed on the cranial side by screws inserted into the diploic layer of occipital bone and on the caudal side by screws inserted into the pedicle of the axis or in a transarticular fashion into the lateral masses of axis and atlas vertebra. A large piece of autologous bone is placed in the region between the rostral edge of cranial decompression and the axis, with the aim of achieving both expansive suboccipital cranioplasty and occipitocervical fusion. RESULTS: We performed this procedure in two patients with Chiari I malformation associated with basilar invagination and occipitalization of the atlas. Postoperatively, decompression of the brainstem and restoration of normal cerebrospinal fluid flow at the craniovertebral junction were confirmed radiologically, and the patients were relieved of their symptoms. At 1 and 3 years of follow-up, respectively, solid bone fusion was observed between the occipital bone and axis in both patients. CONCLUSION: Simultaneous posterior decompression and occipitocervical fixation with an alternative instrumentation technique is discussed. The procedure can be performed regardless of the size of suboccipital craniectomy. Screw insertion into the diploic layer of the occipital bone has not been described previously.  相似文献   
68.
In Japan, 8 lines of genetically modified (GM) potato (2 lines of NewLeaf potato; NL, 3 lines of NewLeaf Plus potato; NLP, and 3 lines of NewLeaf Y potato; NLY) have already been authorized as safe for use in foods and feeds. We have developed polymerase chain reaction (PCR) methods for the qualitative detection of the GM potatoes for the screening and the identification of NL, NLP and NLY. The gene encoding uridine diphosphate (UDP)-glucose pyrophosphorylase (UGPase) was used as a taxon specific gene. We designed the primer pair to detect the cryIIIA genes as a screening method for GM potatoes because the gene should be inserted in all 8 lines of the GM potatoes. For identification of NL, NLP and NLY, we further designed three specific primer pairs for the different recombinant DNAs (r-DNA) specifically introduced into NL, NLP, or NLY. In addition, to identify the 3 lines of NLY that have been introduced with the same r-DNA, the three line-specific primer pairs for the border sequence between the r-DNA and genomic DNA of NLY 3 lines were designed. Six lines of GM potato used as the test material were specifically identified using the each primer pair under the same PCR condition. The detection limits of all the GM potatoes should be approximately 0.1%. Furthermore, the specificity and reproducibility of the methods were confirmed in a six-laboratory collaborative study.  相似文献   
69.
Generation of a transgenic animal model of hyperthyroid Graves' disease   总被引:6,自引:0,他引:6  
Graves' disease (GD) is an organ-specific autoimmune disease characterized by hyperthyroidism. Agonistic anti-thyrotropin receptor antibodies (thyroid-stimulating antibodies, TSAb), which mimic the thyrotropin (TSH) action, are thought to cause GD. The precise immunological mechanism of TSAb production, however, remains elusive. Previous immunization approaches using TSH receptor led to transient hyperthyroidism, but did not seem sufficient for comprehensive understanding of the development of autoimmune responses. To create GD-related autoimmunity in mice, we here generated TSAb-transgenic mice in which a patient-derived TSAb is expressed in B cells. Expression of the human TSAb in mice resulted in various manifestations of hyperthyroidism including increased free thyroxine levels with concomitantly decreased TSH levels, increased thyroid uptake of technetium pertechnetate, hyperthermia and thyroid hyperplasia. We found a correlation between the serum levels of human TSAb immunoglobulin and free thyroxine. In addition, conventional B cells expressing the TSAb were partially deleted in the periphery while B1 cells expressing the TSAb persisted and accumulated in the peritoneal cavity, a finding consistent with previous demonstrations that the maintenance of B1 cells plays an important role in the development of autoimmune diseases. Thus, our transgenic mouse may provide a novel and useful animal model for elucidating the pathogenesis and pathophysiology of GD.  相似文献   
70.
The role of ficolins in innate immunity   总被引:11,自引:0,他引:11  
Matsushita M  Fujita T 《Immunobiology》2002,205(4-5):490-497
Ficolins are a group of proteins containing both a collagen-like domain and a fibrinogen-like domain and are found in varying tissues. Ficolins present in sera have a lectin activity toward N-acetylglucosamine through their fibrinogen-like domains. The domain organizations between ficolins and mannose-binding lectin (MBL) are very similar in that both consist of a collagen-like domain and a carbohydrate-binding domain, although their carbohydrate-binding moieties are different. MBL acts as an opsonin and activates complement in association with MBL-associated serine proteases (MASPs) and sMAP, a truncated protein of MASP-2, via the lectin pathway. Like MBL, two types of human serum ficolins, L-ficolin/P35 and H-ficolin, are associated with MASPs and sMAP, and activate the lectin pathway. In addition, L-ficolin/P35 acts as an opsonin. These findings indicate that serum ficolins play an important a role in innate immunity in a similar manner to MBL.  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