全文获取类型
收费全文 | 19044篇 |
免费 | 1162篇 |
国内免费 | 403篇 |
专业分类
耳鼻咽喉 | 321篇 |
儿科学 | 548篇 |
妇产科学 | 900篇 |
基础医学 | 2363篇 |
口腔科学 | 1100篇 |
临床医学 | 1865篇 |
内科学 | 1650篇 |
皮肤病学 | 159篇 |
神经病学 | 2605篇 |
特种医学 | 594篇 |
外国民族医学 | 1篇 |
外科学 | 2242篇 |
综合类 | 2458篇 |
预防医学 | 780篇 |
眼科学 | 302篇 |
药学 | 1678篇 |
6篇 | |
中国医学 | 606篇 |
肿瘤学 | 431篇 |
出版年
2024年 | 31篇 |
2023年 | 260篇 |
2022年 | 360篇 |
2021年 | 681篇 |
2020年 | 619篇 |
2019年 | 579篇 |
2018年 | 586篇 |
2017年 | 535篇 |
2016年 | 567篇 |
2015年 | 629篇 |
2014年 | 1004篇 |
2013年 | 1178篇 |
2012年 | 922篇 |
2011年 | 1113篇 |
2010年 | 914篇 |
2009年 | 877篇 |
2008年 | 836篇 |
2007年 | 796篇 |
2006年 | 781篇 |
2005年 | 689篇 |
2004年 | 609篇 |
2003年 | 502篇 |
2002年 | 407篇 |
2001年 | 379篇 |
2000年 | 368篇 |
1999年 | 331篇 |
1998年 | 294篇 |
1997年 | 287篇 |
1996年 | 298篇 |
1995年 | 300篇 |
1994年 | 303篇 |
1993年 | 229篇 |
1992年 | 220篇 |
1991年 | 201篇 |
1990年 | 182篇 |
1989年 | 161篇 |
1988年 | 171篇 |
1987年 | 143篇 |
1986年 | 150篇 |
1985年 | 202篇 |
1984年 | 164篇 |
1983年 | 110篇 |
1982年 | 149篇 |
1981年 | 126篇 |
1980年 | 83篇 |
1979年 | 69篇 |
1978年 | 80篇 |
1977年 | 43篇 |
1976年 | 27篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
81.
Mauro Zaffaroni Luciana Gallo Angelo Ghezzi Carlo L. Cazzullo 《Journal of neurology》1991,238(4):209-211
Summary We studied paired cerebrospinal fluid (CSF) and peripheral blood (PB) samples from 18 inactive multiple sclerosis (MS) patients and 10 with non-inflammatory neurological diseases. By means of a dual-colour cytofluorimetric micromethod we were able to count 1500 cells on average in each CSF sample. We found a significant reduction of CD45RA+ and CD4+CD45RA+ cells in the CSF of MS patients. Similarly, CD45RA+ and CD4+CD45RA+ CSF/PB ratios were lower compared with controls. The reduction of suppressor-inducer T-cells did not correlate with CD8+ cell levels in the CSF. The CD4+ subset ratio (CD4+CD45RA–/CD4+CD45RA+) was significantly increased in the CSF of MS patients. Our data suggest that the reduction of CD4+CD45RA+ cells in the PB is not due to a segregation of such cells in the CSF. Conversely, CSF changes reflect changes in the PB similar to these found for other T-cell subsets. 相似文献
82.
P. Lambin A. Gervais M. Levy E. Defendini M. Dubarry P. Lebon P. Rouger E. Schuller 《Journal of neuroimmunology》1991,35(1-3):179-189
Serum and cerebrospinal fluid (CSF) of 50 neurological patients (24 multiple sclerosis (MS), ten acquired immunodeficiency syndrome (AIDS) and 16 other neurological diseases (OND)) and ten controls were analyzed by enzyme-linked immunosorbent assay (ELISA) for IgG subclass quantification and for the calculation of intrathecal synthesis (ITS). Total IgG was determined by two methods: electroimmunodiffusion (EID) and ELISA. A highly significant correlation was established between both methods. The existence of ITS was proved by the IgG/albumin ratio, the IgG index, Tourtellotte's formula, and Schuller's formula. In AIDS patients all IgG subclasses showed an increase in the CSF, whereas in sera only the IgG1 was significantly increased. CSF of MS patients showed a predominant increase of IgG1 whereas no significant modification of IgG subclasses was observed in sera. In most of the AIDS patients there was an ITS of IgG1, IgG3 and IgG4, but rarely (3/10) IgG2. In contrast, a polyclonal ITS of IgG was exceptional (1/24) in MS patients. No significant correlation could be established between clinical data and IgG subclass ITS in MS. The variations of each IgG subclass in serum and in ITS were not significantly correlated. Measurement of each IgG subclass and calculation of ITS seems essential in order to analyze any subclass antibody repertory inside the central nervous system. 相似文献
83.
检查30例关节炎患者的关节液,结果示类风湿性关节炎患者关节液中白细胞数为330~72600/mm~3,粒细胞为9~97%,结合关节液的其它物理性质,对类风湿关节炎的诊断有一定参考价值。并观察到类风湿关节炎患者血清中IgG、IgA、IgM和关节液中IgG高于其它类型关节炎。 相似文献
84.
Functional properties of ramified microglia were investigated in primary cultures of rat cerebral cortical cells. These microglia could be readily identified in both fixed and living cultures through previously established features. Based on their destruction by 5 mM L-leucine methyl ester, a high level of intrinsic endocytotic activity was established. When cultures were incubated with fluorescent latex beads to assess phagocytosis, little or no such activity was exhibited by ramified cells. However, when cultures were incubated with dyes or other soluble tracer compounds, these cells always exhibited labeling. This labeling was selective for ramified microglia in the cultures and was demonstrated using a variety of compounds, including trypan blue, lucifer yellow, horseradish peroxidase (HRP), and India ink. Intracellular label could be observed in vesicular structures; this localization corresponded to an active cellular process. Also, cellular labeling was inhibited by the presence of colchicine. These features supported the inference that the labeling was attributable to pinocytosis, and this process appeared to account for the vast majority of endocytotic activity in the ramified microglia. Possible physiological significance of this pinocytotic activity was indicated by the accumulation of various neurotransmitters/modulators: gamma-aminobutyric acid and vasoactive intestinal polypeptide (VIP). Ramified cells in these cultures have been previously noted to exhibit a constant and rapid pattern of motility, which was consistently observed here through time-lapse video recording; pinocytosis and rapid motility were shown to concur in individual cells. Based on their high intrinsic pinocytotic activity and pattern of cellular motility, the ramified microglia specifically are suggested to serve a constitutive function of fluid cleansing within the interstitial spaces of brain tissue. 相似文献
85.
H. Rauschka K. Jellinger H. Lassmann F. Braier M. Schmidbauer 《European journal of neurology》2003,10(5):479-486
In cases with otherwise clinically typical Guillain-Barré syndrome (GBS), pronounced cerebrospinal fluid (CSF) pleocytosis or the mere presence of CSF-polymorphonuclear granulocytes should alert the physician to consider alternative diagnoses. Therefore, we retrospectively studied the neuropathology of central and peripheral nervous system in two cases with a CSF cell count of more than 50/microl and in three cases with a significant proportion of polymorphonuclear granulocytes in the CSF sediment. All cases fulfilled the required criteria for the diagnosis of GBS, the duration from onset to death ranged from 4 to 100 days. Neuropathological investigations included routine staining procedures and immunohistochemistry for antigens of glial and haematopoetic cells as well as for products of relevant neurotropic viruses. Demyelinating polyradiculitis was present in four cases, in one patient with a survival time of 4 days the type of damage to myelinated fibres was unclassifiable. In the central nervous system a consistent finding was diffuse activation of microglia, only one case showed mild meningeal and lower brainstem inflammation. Viral products were generally absent. In summary, the neuropathological findings confirm that marked CSF pleocytosis or the presence of polymorphonuclear granulocytes does not rule out the diagnosis of GBS. 相似文献
86.
目的 探讨D-dimer(DD)在中枢神经系统白血病及急性白血病诊断、治疗中的价值。方法 采用ELISA法检测54例急性白血病(AL)患者脑脊液(CSF)DD水平,并对其中伴中枢神经系统白血病(CNSL)22例进行动态观察,同时检测7例上呼吸道感染,9例贫血患者CSFDD水平作对照。结果 CNSL组明显高于非中枢神经系统白血病(NCNSL)组及对照组。22例CNSL患者鞘内注射化疗药后。20例达完全缓解(CR),DD值明显下降。2例无效者,CSFDD维持于较高水平。1例缓解后再次复发者,CSFDD含量再次升高。1例患者在CSF常规、生化确诊CNSL之前,CSF D-dirner已有改变。CNSL组CSFDD含量与CSF压力、白细胞数、蛋白含量均无明显相关关系。结论 DD对CNSL早期诊断、疗效观察、预后估计很有价值。 相似文献
87.
K. DAHLBORN J. HOSSAINI-HILALI S. BENLAMLIH B. E. KARLBERG 《Acta physiologica (Oxford, England)》1992,144(4):485-486
Human muscle samples were obtained with the percutaneous biopsy technique. The samples were membrane-hyperpermeabilized (skinned) using a chemical or freeze-drying technique. Short single fibre segments were dissected from the sample, transferred to an experimental chamber, connected to a force transducer and manipulator, and exposed to temperature-controlled solutions. The force generating-capacity, the sensitivity of the contractile apparatus to calcium and the caffeine threshold for calcium release from the sarcoplasmic reticulum could be studied in the short muscle fibre segments obtained from man with the percutaneous muscle biopsy technique. The average length of the fibre segments between the connectors was 0.44±0.21 mm. Thus, detailed studies of the contractile machinery can be made on human skinned muscle fibres with only minimal discomfort to the patient or subject during biopsy, which should be useful in studies of neuromuscular disease, muscle plasticity or in applied physiology. 相似文献
88.
Soluble Fcγ-binding components were detected in gingival fluid from periodontal lesions by incubation with biotinylated human Fcγ fragments. FcγIII receptor was identified by incubation of gingival fluid with monoclonal antibody. Sodium dodecyl sulfate-polyacrylamide gel electophoresis and Western transfer showed that most of the Fcγ-binding components had minimal mobility in a 4–15% gradient gel under nonreducing conditions. Under reducing conditions, the main band of Fcγ-binding components in gingival fluid migrated corresponding to protein A of 49 kDa. The pattern of Fcγ-binding components was similar in serum and gingival fluid except for the observation in gingival fluid of Fcγ-binding components migrating like standard proteins of 19 to 20 kDa, a size that corresponds to the polypeptide part of FcγII receptor and FcγIII receptor. 相似文献
89.
Å. JOLIN R. MYKLEBUST R. OLSEN L. J. BJERTNAES 《Acta anaesthesiologica Scandinavica》1994,38(1):75-81
In isolated rat lungs subjected to fat emulsion damage, a model simulating adult respiratory distress syndrome, we have previously reported that adenosine (ADO) reduces pulmonary vascular resistance (PVR) and the fluid filtration rate (FFR). In the present study the aim was to examine morphologically this effect of ADO. Two groups of isolated rat lungs were subjected to the injury. Marked and significant differences were found between the groups; in lungs not given ADO, FFR and airway pressure were higher and, as evaluated by electron microscopy, the endothelial lining was thin and partly disrupted. The epithelial cells of the alveolar walls were also partly disrupted and the alveolar septa were split enclosing interstitial edema. In lungs receiving ADO from the onset of exposure to fat emulsion, FFR was lower and ultrastructure did not differ from non–injured non–treated controls perfused for the same length of time. 相似文献
90.
目的 :探讨经鼻内窥镜修补脑脊液鼻漏的操作技巧及疗效。方法 :经鼻内窥镜手术修补脑脊液鼻漏 12例 ,在鼻内窥镜直视下寻找漏口 ,处理漏口周围黏膜 ,应用肌浆、鼻中隔和中鼻甲黏膜瓣、明胶海绵及EC耳脑胶或生物蛋白胶等修补漏口 ,用湿润烧伤膏油纱条填塞鼻腔 ,术后 4~ 10d抽取纱条。结果 :12例脑脊液鼻漏均 1次修补成功。结论 :经鼻内窥镜修补脑脊液鼻漏具有微创、安全、复发率低等优点。 相似文献