全文获取类型
收费全文 | 5792篇 |
免费 | 418篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 126篇 |
妇产科学 | 216篇 |
基础医学 | 848篇 |
口腔科学 | 95篇 |
临床医学 | 552篇 |
内科学 | 1291篇 |
皮肤病学 | 156篇 |
神经病学 | 416篇 |
特种医学 | 267篇 |
外国民族医学 | 5篇 |
外科学 | 798篇 |
综合类 | 61篇 |
一般理论 | 6篇 |
预防医学 | 505篇 |
眼科学 | 52篇 |
药学 | 331篇 |
中国医学 | 11篇 |
肿瘤学 | 437篇 |
出版年
2022年 | 39篇 |
2021年 | 81篇 |
2020年 | 44篇 |
2019年 | 73篇 |
2018年 | 82篇 |
2017年 | 68篇 |
2016年 | 74篇 |
2015年 | 76篇 |
2014年 | 117篇 |
2013年 | 164篇 |
2012年 | 255篇 |
2011年 | 283篇 |
2010年 | 154篇 |
2009年 | 140篇 |
2008年 | 267篇 |
2007年 | 270篇 |
2006年 | 224篇 |
2005年 | 243篇 |
2004年 | 247篇 |
2003年 | 239篇 |
2002年 | 213篇 |
2001年 | 216篇 |
2000年 | 224篇 |
1999年 | 162篇 |
1998年 | 103篇 |
1997年 | 85篇 |
1996年 | 67篇 |
1995年 | 52篇 |
1994年 | 64篇 |
1993年 | 49篇 |
1992年 | 143篇 |
1991年 | 110篇 |
1990年 | 120篇 |
1989年 | 116篇 |
1988年 | 115篇 |
1987年 | 120篇 |
1986年 | 88篇 |
1985年 | 94篇 |
1984年 | 79篇 |
1983年 | 65篇 |
1981年 | 40篇 |
1979年 | 59篇 |
1978年 | 45篇 |
1974年 | 50篇 |
1973年 | 50篇 |
1972年 | 42篇 |
1971年 | 47篇 |
1969年 | 38篇 |
1968年 | 35篇 |
1967年 | 45篇 |
排序方式: 共有6218条查询结果,搜索用时 15 毫秒
21.
The rate at which the acute phase protein response occurred after both major and minor surgery was explored. Increases in the plasma concentration of C-reactive protein (CRP), alpha-1-acid glycoprotein (alpha 1 AG) and fibrinogen were not detected until 6-8 h after the initial incision. The peak concentration of CRP occurred at 48 h and that of fibrinogen at 96 h; alpha 1 AG concentrations rose rapidly until 48 h followed by little change until about 120 h. Although there was widespread variation in the concentrations of individual proteins in patients, severity of injury did not seem to have a significant effect on the time course of the change. Plasma cortisol concentration and the total white blood cell count (WBC) reached their peaks before the acute phase proteins, cortisol at 6 h and WBC at 12 h. 相似文献
22.
23.
F. J. van der Woude A. F. Michael E. Muller G. K. van der Hem R. L. Vernier Y. Kim 《International journal of experimental pathology》1989,70(1):73-82
Glomerular visceral epithelial cells (GVEC) from normal human glomeruli were grown in tissue culture. Cell surface markers were studied by immunofluorescence microscopy using antibodies against lymphohaemopoietic differentiation antigens which are known to be present early (BA-1, OKB2, BA-2) and late (J5, anti CR1) in renal ontogenesis. Like foetal human glomerular epithelium, the cultured cells reacted with BA-1 and OKB2 (identifying an antigen expressed on B cells and polymorphonuclear leucocytes), and BA-2 (leukaemia-associated antigen), but were consistently negative for CR1 (C3b receptor); J5 which identifies the common acute lymphoblastic leukaemia antigen (CALLA) stained variably. Reactivity with antimyosin or anti factor VIII were absent. The cells produced an extracellular matrix containing laminin, type IV collagen, and fibronectin. This study supports the notion that GVEC undergo dedifferentiation as shown by the acquisition of lymphohaemopoietic differentiation antigens present early in renal ontogeny. In addition, the production of extracellular matrix constituents in vitro may be useful for the investigation of human glomerular basement membranes. 相似文献
24.
Contrast Limited Adaptive Histogram Equalization image processing to improve the detection of simulated spiculations in dense mammograms 总被引:1,自引:0,他引:1
Pisano Etta D. Zong Shuquan Hemminger Bradley M. DeLuca Marla Johnston R. Eugene Muller Keith Braeuning M. Patricia Pizer Stephen M. 《Journal of digital imaging》1998,11(4):193-200
The purpose of this project was to determine whether Contrast Limited Adaptive Histogram Equalization (CLAHE) improves detection of simulated spiculations in dense mammograms. Lines simulating the appearance of spiculations, a common marker of malignancy when visualized with masses, were embedded in dense mammograms digitized at 50 micron pixels, 12 bits deep. Film images with no CLAHE applied were compared to film images with nine different combinations of clip levels and region sizes applied. A simulated spiculation was embedded in a background of dense breast tissue, with the orientation of the spiculation varied. The key variables involved in each trial included the orientation of the spiculation, contrast level of the spiculation and the CLAHE settings applied to the image. Combining the 10 CLAHE conditions, 4 contrast levels and 4 orientations gave 160 combinations. The trials were constructed by pairing 160 combinations of key variables with 40 backgrounds. Twenty student observers were asked to detect the orientation of the spiculation in the image. There was a statistically significant improvement in detection performance for spiculations with CLAHE over unenhanced images when the region size was set at 32 with a clip level of 2, and when the region size was set at 32 with a clip level of 4. The selected CLAHE settings should be tested in the clinic with digital mammograms to determine whether detection of spiculations associated with masses detected at mammography can be improved.Key Words: mammography, image processing, contrast limited adaptive histogram equalization, observer studies, breast cancer, spiculations 相似文献
25.
Monocytes, like all leukocytes, undergo a series of sequential steps during extravasation from blood into tissues: tethering, rolling, adhesion and diapedesis. We have discovered an essential step, which we call locomotion, in which the monocyte moves from a site of firm adhesion to the nearest junction to begin diapedesis. Blocking CD11a-CD18 and CD11b-CD18 on human monocytes or adhesion molecules ICAM-1 and ICAM-2 on endothelial cells prevented the monocytes from reaching junctions. The blocked monocytes spun in circles as if they were unable to direct their movement despite being able to adhere and polarize normally. This step fills a gap in the paradigm of extravasation as a multistep process. 相似文献
26.
Freeze Dried Platelets for HLA Alloantibodies Absorption 总被引:1,自引:0,他引:1
Antibodies to HLA–A and B are specifically absorbed onto platelets. A method of absorption of these antibodies using freeze dried platelets is described. This method allows long-term storage and standardized absorption procedures. Anti-DR antibodies and cold lymphocytotoxins are recovered in the supernatant. 相似文献
27.
Dysfunction of the blood–cerebrospinal fluid barrier (BCB) has been implicated in the pathogenesis of Parkinson's disease (PD) and other neurodegenerative disorders. Therefore, we assayed serum and cerebrospinal fluid (CSF) from 30 parkinsonian patients and 30 controls for concentrations of albumin and IgG. The CSF/serum ratio for albumin (AQ), IgG (GQ), IgG-index as well as determination of oligoclonal bands were used to evaluate BCB function and to quantify humoral immune response within the central nervous system (CNS). Levels of AQ, GQ and IgG-index did not significantly differ in both groups. We found no dysfunction of the blood–CSF barrier or signs of local synthesis of IgG in the central nervous system of parkinsonian patients. Our data do not support the hypothesis of a dysfunctional BCB that contributes to pathophysiological mechanisms underlying PD. 相似文献
28.
Development of the maternal-fetal relationship was described by Rubin as an intimate "binding-in process." Recent technological advances enabled health care providers to observe, study, diagnose, and treat unborn children and led some to reconsider the relevance of the binding-in concept. Research has focused on prenatal attachment or bonding, maternal characteristics that influence prenatal attachment/bonding, and interventions to promote it. Before binding-in is dismissed as irrelevant, assessment of the prenatal attachment research, consideration of the impact of these ideas on pregnant women and their families, and the implications for maternity nurses must be examined. 相似文献
29.
Adamkiewicz J Behn M Brusselbach S Havemann K Muller R 《International journal of oncology》1993,2(4):503-512
A novel TRE-binding protein complex was detected specifically in 12 out of 13 small cell lung carcinoma (SCLC) cell lines. This complex was characterised by a lower electrophoretic mobility than the 'ubiquitous' complex present in all other carcinoma cell lines analysed. As shown by UV-crosslinking and South-Western blotting, the SCLC-specific complex contains a protein with an apparent M(r) > 100 kD, which is far bigger than all Fos and Jun proteins described to date. In addition, the DNA-binding specificity of this complex is different from the specificity of the 'ubiquitous' complex or a Fos/Jun heterodimer. 相似文献
30.
Deckardjanatpour K Muller W Chodosh L Gardner H Marquis S Coffey R Cardiff R 《International journal of oncology》1997,11(2):235-241
The mammary glands of control FVB and mice with MTV-LTR promoted transgenes were stained using immunohistochemistry to detect neu expression. Neu expression in the terminal end buds of developing mammary glands and during early pregnancy in FVB mice was confirmed by in situ hybridization. Neu was expressed in all tumors from mice with the neu transgene but not in tumors expressing transforming growth factor alpha (TGF alpha) or polyoma virus middle T (PyV-MT). Neu was also expressed sporadically in non-neoplastic mammary cells of transgenic neu mice. However, most mammary cells expressing neu were dysplastic. The differential expression of the neu transgene has important implications for the interpretation of transgenic biology. 相似文献