全文获取类型
收费全文 | 3742篇 |
免费 | 346篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 29篇 |
儿科学 | 103篇 |
妇产科学 | 43篇 |
基础医学 | 496篇 |
口腔科学 | 77篇 |
临床医学 | 303篇 |
内科学 | 706篇 |
皮肤病学 | 467篇 |
神经病学 | 194篇 |
特种医学 | 346篇 |
外科学 | 434篇 |
综合类 | 77篇 |
预防医学 | 241篇 |
眼科学 | 15篇 |
药学 | 288篇 |
中国医学 | 4篇 |
肿瘤学 | 334篇 |
出版年
2022年 | 23篇 |
2021年 | 73篇 |
2020年 | 41篇 |
2019年 | 74篇 |
2018年 | 80篇 |
2017年 | 70篇 |
2016年 | 80篇 |
2015年 | 87篇 |
2014年 | 117篇 |
2013年 | 147篇 |
2012年 | 186篇 |
2011年 | 206篇 |
2010年 | 119篇 |
2009年 | 119篇 |
2008年 | 146篇 |
2007年 | 160篇 |
2006年 | 150篇 |
2005年 | 144篇 |
2004年 | 116篇 |
2003年 | 122篇 |
2002年 | 88篇 |
2001年 | 97篇 |
2000年 | 86篇 |
1999年 | 117篇 |
1998年 | 96篇 |
1997年 | 88篇 |
1996年 | 79篇 |
1995年 | 73篇 |
1994年 | 53篇 |
1993年 | 59篇 |
1992年 | 58篇 |
1991年 | 68篇 |
1990年 | 72篇 |
1989年 | 111篇 |
1988年 | 88篇 |
1987年 | 75篇 |
1986年 | 49篇 |
1985年 | 56篇 |
1984年 | 45篇 |
1983年 | 37篇 |
1982年 | 35篇 |
1981年 | 32篇 |
1980年 | 33篇 |
1979年 | 34篇 |
1978年 | 27篇 |
1977年 | 28篇 |
1976年 | 22篇 |
1975年 | 27篇 |
1974年 | 26篇 |
1973年 | 22篇 |
排序方式: 共有4157条查询结果,搜索用时 46 毫秒
31.
Pseudomonas aeruginosa hemolytic phospholipase C suppresses neutrophil respiratory burst activity 总被引:4,自引:0,他引:4
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Pseudomonas aeruginosa is a persistent pathogen in the airways of patients with cystic fibrosis or bronchiectasis from other causes and appears to have evolved strategies to survive the inflammatory response of the host. We hypothesized that the secreted hemolytic phospholipase C (PLC) of P. aeruginosa (PlcHR) would decrease neutrophil respiratory burst activity. We found that while intact wild-type P. aeruginosa cells stimulated moderate respiratory burst activity from human neutrophils, an isogenic mutant pseudomonas (DeltaHR strain) containing a targeted deletion of the plcHR operon induced a much more robust oxidative burst from neutrophils. In contrast, a second pseudomonas mutant (DeltaN) containing a disruption in the gene encoding the nonhemolytic PLC (PlcN) was not different from the wild type in stimulating neutrophil O2.- production. Readdition of purified PlcHR to the DeltaHR strain suppressed neutrophil O2.- production to levels stimulated by wild-type bacteria. Interestingly, purified PlcHR decreased phorbol myristate acetate (PMA)- but not formyl methionyl-leucyl-proline (fMLP)-induced respiratory burst activity, suggesting interference by PlcHR with a protein kinase C (PKC)-specific signaling pathway. Accordingly, the PKC inhibitor bisindolylmaleimide inhibited the oxidative burst induced by either PMA or intact pseudomonas, but not by fMLP, whereas the p38 kinase inhibitor SB-203580 fully inhibited the respiratory burst induced by fMLP or the PlcHR-replete wild-type bacteria, but not PMA or the PlcHR-deficient DeltaHR bacterial mutant. We conclude that expression of PlcHR by P. aeruginosa suppresses bacterium-induced neutrophil respiratory burst by interfering with a PKC-dependent, non-p38 kinase-dependent pathway. 相似文献
32.
33.
34.
Karsten Nielsen Stein Meling Paulsen Preben Johansen 《Virchows Archiv : an international journal of pathology》1983,401(2):159-162
Summary A series of granular cell myoblastomas (GCM) and other benign and malignant tumours of soft tissue were examined for cytoplasmic content of carcinoembryonic antigen (CEA) by the two-layer conjugated immunoperoxidase technique. Using a commercial rabbit anti-CEA serum only granular cell myoblastomas showed positive cytoplasmic reaction. Pretreatment with periodic acid made this reaction less intense, but when the commercial rabbit anti-CEA serum was absorbed with tissue powder from normal human spleen the positive reaction was totally abolished. It is concluded that the positivity of GCM for CEA using commercial rabbit anti-CEA serum is due to the content of non-specific cross-reacting antigen (NCA) and maybe other cross-reacting glycoproteins in this tumour, and not to CEA as claimed in a previous study. 相似文献
35.
36.
37.
Neurofibromatosis 2 (NF2) is an inherited cancer syndrome resulting from
mutations in the NF2 tumor suppressor gene. Analysis of NF2 mutations has
revealed some general genotype-phenotype correlations. Severe disease has
been associated with mutations that produce a premature termination while
more mild disease has been associated with missense mutations. Here, we
provide experimental proof for these genotype-phenotype correlations by
demonstrating that nonsense mutations fail to produce stable merlin protein
while missense mutations result in the generation of merlin proteins
defective in negative growth regulation. This inability to suppress cell
growth may result from defects in the function of merlin at several levels,
including failure to form an intramolecular complex. Based on these
findings, we propose a model for merlin growth suppression that provides a
framework for analyzing NF2 patient mutations and merlin function.
相似文献
38.
JS Pooni Dr DWL Hukins PF Harris RC Hilton KE Davies 《Surgical and radiologic anatomy : SRA》1986,8(3):175-182
Posterior and anterior heights, cross-sectional area and shape were measured for all the intervertebral discs in four spines from elderly human cadavers. Disc height was a minimum at the T4-5 level; thoracic discs were less wedge-shaped than those in the cervical and lumbar regions. Cross-sectional area increased from the cranial to caudal extremity; at the L5-S1 level the nucleus pulposus occupied a high proportion of this area. Cervical discs tended to have an elliptical cross-sectional shape, thoracic discs were more circular and lumbar discs tended to have an elliptical cross-section which was flattened or re-entrant posteriorly. This shape distribution was quantified by defining a shape index which had a maximum value of 1 for a circular cross-section. Orientations of the reinforcing fibres in the outer lamellae of the anterior annulus fibrosus were measured from 27 discs by X-ray diffraction. For these measurements, C3-4, T7-8 and L2-3 were chosen as representative of cervical, thoracic and lumbar discs. The fibre tilt, with respect to the axis of the spine, was significantly less in the cervical discs (at 65 degrees) than in the thoracic and lumbar discs (about 70 degrees). These findings are interpreted in relation to differing functional requirements and possible mechanisms of failure in the cervical, thoracic and lumbar regions of the spine in the light of current knowledge on the biomechanics of the intervertebral disc. 相似文献
39.
The efficacy and credibility of a skin temperature--skin conductance meter (Teledyne Sleep Sentry) for detecting hypoglycemia was studied during night-time in 22 adult insulin-treated diabetics. Capillary blood glucose concentration was measured 99 times (when the alarm sounded, in case of hypoglycemic symptoms, and at 3 a.m.). Hypoglycemia was defined as a capillary blood glucose concentration of less than or equal to 3 mmol/l. Blood glucose was measured 61 times in connection with sounding of the alarm and 38 times without the alarm sounding. At 3 a.m. the Sleep Sentry sounded the alarm 22 times, of which hypoglycemia was present 6 times giving a diagnostical specificity or diagnostical true positive rate of 0.27 (95% confidence limits 0.11-0.50). In 35 of 38 cases of no alarm the blood glucose was greater than 3 mmol/l, giving a diagnostical sensitivity of 0.92 (95% confidence limits 0.79-0.98). The Sleep Sentry sounded the alarm in 6 of 9 cases of hypoglycemia, giving a nosological sensitivity of 0.67 (95% confidence limits 0.30-0.93). The Sleep Sentry did not sound the alarm in 35 of 51 cases of non-hypoglycemia, giving a nosological specificity of 0.69 (95% confidence limits 0.54-0.81). In other words, the Sleep Sentry detects about 2/3 of blood glucose values less than or equal to 3 mmol/l, but in addition it sounds a false alarm in 2/3 of the cases. 相似文献
40.