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   10160篇
  免费   610篇
  国内免费   81篇
耳鼻咽喉   70篇
儿科学   257篇
妇产科学   267篇
基础医学   1385篇
口腔科学   142篇
临床医学   773篇
内科学   2608篇
皮肤病学   122篇
神经病学   1450篇
特种医学   411篇
外科学   1001篇
综合类   16篇
一般理论   3篇
预防医学   465篇
眼科学   129篇
药学   768篇
中国医学   10篇
肿瘤学   974篇
  2024年   26篇
  2023年   168篇
  2022年   288篇
  2021年   513篇
  2020年   283篇
  2019年   398篇
  2018年   430篇
  2017年   321篇
  2016年   372篇
  2015年   386篇
  2014年   555篇
  2013年   638篇
  2012年   828篇
  2011年   865篇
  2010年   495篇
  2009年   450篇
  2008年   638篇
  2007年   581篇
  2006年   569篇
  2005年   510篇
  2004年   366篇
  2003年   322篇
  2002年   278篇
  2001年   50篇
  2000年   46篇
  1999年   68篇
  1998年   47篇
  1997年   41篇
  1996年   36篇
  1995年   25篇
  1994年   24篇
  1993年   18篇
  1992年   16篇
  1991年   28篇
  1990年   21篇
  1989年   25篇
  1988年   26篇
  1987年   15篇
  1986年   15篇
  1985年   11篇
  1984年   9篇
  1983年   7篇
  1982年   4篇
  1981年   9篇
  1980年   4篇
  1979年   8篇
  1978年   4篇
  1970年   2篇
  1967年   2篇
  1966年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
163.

Objective

Recent views on schizophrenia outcome and treatment suggest that symptomatic remission is possible, and a definition of remission has been proposed by the Remission in Schizophrenia Working Group (RSWG).This study evaluated whether patients who achieved remission after several years of illness (R) showed psychopathological differences at the onset of their disorder compared to non-remitted (NR) patients.

Method

Forty-eight patients with first-episode schizophrenia were evaluated with the Positive and Negative Symptoms Scale (PANSS) both at the onset of illness and after a mean period of 16 years. Patients were defined as R or NR according to the RSWG criteria.

Results

Eighteen patients (37.5%) were classified as R at follow-up. At onset, R patients showed a lower illness severity, less severe negative and general psychopathology symptoms compared to NR. Furthermore, they underwent fewer psychotic episodes than NR over the course of follow-up. Remission was predicted by lower severity of negative and general psychopathology symptoms at onset and by lesser number of psychotic episodes during follow-up.

Conclusions

The symptomatic remission may be a viable outcome in schizophrenia, particularly for patients with a mild illness and less severe negative symptoms at onset and with few psychotic episodes over time.  相似文献   
164.

Aims

The aim of the study is to describe the course of the echocardiographically measured pulmonary artery systolic pressure (PAsP) in a series of patients included in the Italian Pulmonary Embolism Registry (IPER).

Methods

Patients with confirmed PE received an echo-Doppler evaluation within 24 hours from hospital admission and after one year. Pulmonary hypertension (PH) was considered “likely” , “possible” or “unlikely” with a right ventricular-right atrial (RV-RA) pressure gradient > 45 mm Hg, between 32 and 45 mm Hg and ≤ 31 mm Hg and no additional echocardiographic variables suggestive of PH, respectively.

Results

We studied 286 patients (169 females and 117 males, mean age 67 ± 15; mean follow-up 387 ± 45 days): 240 had a baseline tricuspid regurgitation (TR) and a RV-RA gradient of variable degree. PH was considered likely, unlikely and possible in 97, 93 and 50 patients respectively. At FU echocardiography, 6 patients (2.1%) had a likely PH and all of them were part of the group of 97 patients with a baseline likely PH; 24 patients (8.4%) had a possible PH, and 67% of them had an initial likely PH. No patients with a baseline unlikely PH or without TR developed a follow-up PH (both likely or possible). The probability to show a likely PH at FU echocardiography for patients with a baseline RV-RA gradient > 45 mm Hg was 6.2%, while the probability not to have a likely PH for patients with a baseline RV-RA gradient ≤ 45 mm Hg was 100%.

Conclusion

In our study population of patients with acute PE, we observed that those presenting with a baseline echocardiographic RV-RA pressure gradient ≤ 45 mm Hg were completely free from a likely PH after 1-year.  相似文献   
165.
Human parturition is an inflammatory process that can be activated prematurely by pathological stimuli. This study investigated the expression of G protein-coupled receptors GPR43 and GPR41 receptors in human uteroplacental tissues and the role of short-chain fatty acids (SCFA) in modulating inflammatory pathways in fetal membranes. Expression of GPR43 and GPR41 was investigated in uteroplacental tissues collected from women delivering at term or preterm after ethical approval and patient informed consent. The effect of SCFA on expression of inflammatory genes was assessed in amnion explants after culture with a mimetic of infection (lipopolysaccharide, LPS). Sodium propionate effect on LPS-induced neutrophil chemotaxis was evaluated by transwell assay. GPR43 and GPR41 mRNA expression was higher in myometrium and fetal membranes collected from women after the onset of labor. GPR43 protein expression localized to immune cells and vascular endothelium in the myometrium and epithelium of fetal membranes. Treatment with LPS significantly increased mRNA expression of GPR43 and inflammatory genes. Cotreatment with LPS and sodium propionate decreased LPS-induced expression of inflammatory genes including IL-6, IL-8, cyclooxygenase-2, IL-1α, intercellular adhesion molecule-1, and platelet endothelial cell adhesion molecule-1 but not IL-1β or lymphocyte function-associated antigen-1. Sodium propionate reduced LPS-induced neutrophil chemotaxis and protein secretion of the neutrophil chemoattractant IL-8. Finally, fetal membrane expression of GPR43 was significantly higher in women delivering preterm with evidence of infection. GPR43-SCFA interactions may represent novel pathways that regulate inflammatory processes involved in human labor. Suppression of inflammatory pathways by SCFA may be therapeutically beneficial for pregnant women at risk of pathogen-induced preterm delivery.  相似文献   
166.
167.
168.
The plasma membrane of cardiac myocytes presents complex invaginations known as the transverse-axial tubular system (TATS). Despite TATS's crucial role in excitation-contraction coupling and morphological alterations found in pathological settings, TATS's electrical activity has never been directly investigated in remodeled tubular networks. Here we develop an ultrafast random access multiphoton microscope that, in combination with a customly synthesized voltage-sensitive dye, is used to simultaneously measure action potentials (APs) at multiple sites within the sarcolemma with submillisecond temporal and submicrometer spatial resolution in real time. We find that the tight electrical coupling between different sarcolemmal domains is guaranteed only within an intact tubular system. In fact, acute detachment by osmotic shock of most tubules from the surface sarcolemma prevents AP propagation not only in the disconnected tubules, but also in some of the tubules that remain connected with the surface. This indicates that a structural disorganization of the tubular system worsens the electrical coupling between the TATS and the surface. The pathological implications of this finding are investigated in failing hearts. We find that AP propagation into the pathologically remodeled TATS frequently fails and may be followed by local spontaneous electrical activity. Our findings provide insight on the relationship between abnormal TATS and asynchronous calcium release, a major determinant of cardiac contractile dysfunction and arrhythmias.  相似文献   
169.
Copper chaperone for superoxide dismutase 1 (SOD1), CCS, is the physiological partner for the complex mechanism of SOD1 maturation. We report an in vitro model for human CCS-dependent SOD1 maturation based on the study of the interactions of human SOD1 (hSOD1) with full-length WT human CCS (hCCS), as well as with hCCS mutants and various truncated constructs comprising one or two of the protein's three domains. The synergy between electrospray ionization mass spectrometry (ESI-MS) and NMR is fully exploited. This is an in vitro study of this process at the molecular level. Domain 1 of hCCS is necessary to load hSOD1 with Cu(I), requiring the heterodimeric complex formation with hSOD1 fostered by the interaction with domain 2. Domain 3 is responsible for the catalytic formation of the hSOD1 Cys-57-Cys-146 disulfide bond, which involves both hCCS Cys-244 and Cys-246 via disulfide transfer.  相似文献   
170.
Although the causes of dyslexia are still debated, all researchers agree that the main challenge is to find ways that allow a child with dyslexia to read more words in less time, because reading more is undisputedly the most efficient intervention for dyslexia. Sophisticated training programs exist, but they typically target the component skills of reading, such as phonological awareness. After the component skills have improved, the main challenge remains (that is, reading deficits must be treated by reading more--a vicious circle for a dyslexic child). Here, we show that a simple manipulation of letter spacing substantially improved text reading performance on the fly (without any training) in a large, unselected sample of Italian and French dyslexic children. Extra-large letter spacing helps reading, because dyslexics are abnormally affected by crowding, a perceptual phenomenon with detrimental effects on letter recognition that is modulated by the spacing between letters. Extra-large letter spacing may help to break the vicious circle by rendering the reading material more easily accessible.  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