全文获取类型
收费全文 | 753篇 |
免费 | 59篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 31篇 |
妇产科学 | 5篇 |
基础医学 | 80篇 |
口腔科学 | 28篇 |
临床医学 | 88篇 |
内科学 | 120篇 |
皮肤病学 | 5篇 |
神经病学 | 149篇 |
特种医学 | 59篇 |
外科学 | 115篇 |
综合类 | 3篇 |
预防医学 | 27篇 |
眼科学 | 9篇 |
药学 | 63篇 |
肿瘤学 | 27篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 19篇 |
2018年 | 17篇 |
2017年 | 21篇 |
2016年 | 27篇 |
2015年 | 19篇 |
2014年 | 21篇 |
2013年 | 43篇 |
2012年 | 64篇 |
2011年 | 56篇 |
2010年 | 48篇 |
2009年 | 37篇 |
2008年 | 60篇 |
2007年 | 51篇 |
2006年 | 39篇 |
2005年 | 33篇 |
2004年 | 39篇 |
2003年 | 49篇 |
2002年 | 40篇 |
2001年 | 16篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1990年 | 6篇 |
1988年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1960年 | 2篇 |
1956年 | 1篇 |
1949年 | 1篇 |
1947年 | 2篇 |
1942年 | 1篇 |
1940年 | 1篇 |
1939年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有813条查询结果,搜索用时 15 毫秒
1.
Die Anaesthesiologie - Die Intensive Care Unit-Acquired Weakness (ICUAW) stellt eine der häufigsten neuromuskulären Komplikationen in der Intensivmedizin dar. Besonders bei... 相似文献
2.
We evaluated the acquisition and performance of a high-precision locomotor task in patients with Parkinson's disease (PD) and healthy subjects. All subjects walked on a treadmill and had to step repetitively as low as possible over an obstacle without touching it. During blocks 1 and 2, the subjects had full vision and received additional acoustic warning and feedback signals. During block 3, vision became restricted. Changes in foot clearance and the number of obstacle hits were evaluated. Initially, PD patients performed poorer and improved foot clearance slower. After task repetition, the groups performed similarly. Restricting vision deteriorated performance in both groups. The similar performance of PD patients after task repetition might indicate that adequate training could improve adaptive locomotor behavior in PD patients. 相似文献
3.
Frank Marusch Andreas Koch Uwe Schmidt Hubertus Wenisch Michael Ernst Thomas Manger Stefanie Wolff Matthias Pross Jörg Tautenhahn Ingo Gastinger Hans Lippert 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2002,387(2):94-100
BACKGROUND: The problems associated with rectal surgery are frequently discussed with no reference being made to the distance of the tumor from the anal verge. This study examined the effect of the location of the tumor on early postoperative results. PATIENTS AND METHODS: This was a multicenter study involving 75 German hospitals and 3756 patients, of whom 1463 had rectal carcinoma. On the basis of the location of the tumor (distance from the anal verge), four groups were distinguished: <4, 4-7.9, 8-11.9, and 12-16 cm. RESULTS: Resection and abdominoperineal resection rates and the incidence of postoperative complications depended on the location of the tumor. Significantly higher resection rates and fewer specific complications, and a significant reduction in overall postoperative morbidity were found with tumor locations more than 8 cm from the anal verge. The highest anastomotic leak rate was observed with anastomoses less than 7 cm from the anal verge. The logistic regression showed that the distance of the tumor from the anal verge is an independent variable for the development of an anastomotic leak. CONCLUSIONS: Early results are greatly affected by the location of the rectal carcinoma. This applies to both abdominoperineal resection rates and specific postoperative complications, such as anastomotic leak rate and operation morbidity in general. 相似文献
4.
Jeroen Kool Sebastiaan M van Liempd Huub van Rossum Danny A van Elswijk Hubertus Irth Jan N M Commandeur Nico P E Vermeulen 《Drug metabolism and disposition》2007,35(4):640-648
A high resolution screening (HRS) technology is described, in which gradient high-performance liquid chromatography (HPLC) is connected on-line to three parallel placed bioaffinity detection systems containing mammalian cytochromes P450 (P450s). The three so-called enzyme affinity detection (EAD) systems contained, respectively, liver microsomes from rats induced by beta-naphthoflavone (CYP1A activity), phenobarbital (CYP2B activity), and dexamethasone (CYP3A activity). Each P450-EAD system was optimized for enzyme, substrate, and organic modifier (isopropyl alcohol, methanol, and acetonitrile) in flow injection analysis mode. Characteristic P450 ligands were used to validate the P450-EAD systems. IC(50) values of the ligands were measured and found to be similar to those obtained with conventional microtiter plate reader assays. Detection limits (n = 3; signal-to-noise ratio = 3) of potent inhibitors ranged from 1 to 3 pmol for CYP1A activity, 4 to 17 pmol for CYP2B activity, and 4 to 15 pmol for CYP3A activity. The three optimized P450-EAD systems were subsequently coupled to gradient HPLC and used to screen compound mixtures for individual ligands. Finally, to increase analysis efficiency, a HRS system was constructed in which all three P450-EAD systems were coupled on-line and in parallel to gradient HPLC. The triple parallelized P450-EAD system was shown to enable rapid profiling of individual components in complex mixtures for inhibitory activity to three different P450s. 相似文献
5.
IFN-alpha enhances CD40 ligand-mediated activation of immature monocyte-derived dendritic cells 总被引:22,自引:0,他引:22
Luft T Luetjens P Hochrein H Toy T Masterman KA Rizkalla M Maliszewski C Shortman K Cebon J Maraskovsky E 《International immunology》2002,14(4):367-380
Type I IFN are immune modulatory cytokines that are secreted during early stages of infection. Type I IFN bridge the innate and the adaptive immune system in humans and mice. We compared the capacity of type I and II IFN to induce the functional maturation of monocyte-derived dendritic cells (MoDC). Extending our earlier observation that type I IFN promote DC maturation, we report that these cytokines also enhance DC differentiation by augmenting CD40 ligand (CD40L)-induced cytokine secretion by MoDC. Type I IFN alone were poor inducers of MoDC maturation as compared with other stimuli. They up-regulated the expression of HLA-DR, CD80, CD86, partially CCR7 but not CD83, partially reduced antigen-uptake function, increased the levels of IL-12p35 mRNA, and prolonged surface expression of peptide-MHC class I complexes for presentation to cytotoxic T lymphocytes, but did not induce migration towards CCL21 chemokine. However, type I IFN were potent co-factors for CD40L-mediated function. Here, they enhanced CD40L-mediated IL-6, IL-10 and IL-12p70 secretion. Furthermore, when combined with IL-1beta and/or IL-4, IFN-alpha2a type I IFN increased CD40L-mediated IL-12p70 production by 2- to 3-fold, and biased the IL-12 p40/p70 ratio towards the IFN-gamma inducing p70 heterodimer, this correlating with higher levels of IFN-gamma secretion by allogeneic T cell subsets and NK cells. Our results suggest that the rapid expression of CD40L, IFN and IL-1beta at sites of infection and inflammation can act in concert on immature DC, thereby linking innate and adaptive immune responses. In this way, type I IFN play a dual role as DC maturation factors and enhancers of CD40L-mediated DC activation. 相似文献
6.
7.
BACKGROUND: MADRS cut-off scores for moderate and severe depression were estimated in relation to the Hamilton Depression Rating Scale (HAMD(17)) and the Clinical Global Impressions Scale (CGI). METHOD: HAMD(17), MADRS, and CGI ratings from patients with major depression (DSM-IV) were analyzed (N=85). Receiver operating characteristics (ROC) curves were applied. RESULTS: Mean age was 51.4+/-14.5 years, 69% were female. Mean MADRS scores were 23.4+/-13.2, HAMD(17), MADRS, and CGI scores were highly correlated (r>0.85; P<0.0001). Best separation between moderate and severe depression according to CGI criteria was achieved with a MADRS score of 31 (sensitivity 93.5%, specificity 83.3%). LIMITATIONS: Studies to validate severity gradations including DSM-IV or ICD-10 diagnostic severity categories are recommended. CONCLUSIONS: Empirically based MADRS cut-off scores to separate moderate from severe depression on the basis of HAMD(17) and CGI severity ratings in patients with major depression were yielded. 相似文献
8.
NRE, the nitrogen regulatory protein of Penicillium chrysogenum, contains a single Cys2/Cys2-type zinc-finger motif followed immediately by a highly basic region. The zinc-finger domain was expressed to Escherichia coli as a fusion protein with -galactosidase. In order to test the putative DNA-binding ability of NRE, the intergenic promoter region of the nitrate reductase/nitrite reductase gene cluster (niiA-niaD) of Penicillium was sequenced. Our results show that NRE is a DNA-binding protein and binds to the intergenic promoter regions of the P. chrysogenum niiA-niaD and acvA-pcbC gene cluster, encoding the first two enzymes in penicillin biosynthesis. Three of the four high-affinity NRE-binding sites contained two GATA core elements. In one of the recognition sites for NRE, one GATA motif was replaced by GATT. The two GATA elements showed all possible orientations, head-to-head, head-to-tail and tail-to-tail, and were separated by between 4 and 27 bp. Missing-contact analysis showed that all three purines in both of the GATA core sequences and the single adenine residue in each of the complementary TATC sequences were involved in the binding of NRE. Moreover, loss of purines in the flanking regions of the GATA elements also affect binding of NRE, as their loss causes reduced affinity. 相似文献
9.
10.