全文获取类型
收费全文 | 1165篇 |
免费 | 101篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 49篇 |
妇产科学 | 10篇 |
基础医学 | 195篇 |
口腔科学 | 28篇 |
临床医学 | 107篇 |
内科学 | 328篇 |
皮肤病学 | 6篇 |
神经病学 | 103篇 |
特种医学 | 121篇 |
外科学 | 82篇 |
综合类 | 21篇 |
预防医学 | 69篇 |
眼科学 | 4篇 |
药学 | 52篇 |
中国医学 | 2篇 |
肿瘤学 | 98篇 |
出版年
2022年 | 5篇 |
2021年 | 6篇 |
2020年 | 9篇 |
2019年 | 14篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 20篇 |
2014年 | 25篇 |
2013年 | 43篇 |
2012年 | 38篇 |
2011年 | 39篇 |
2010年 | 38篇 |
2009年 | 36篇 |
2008年 | 41篇 |
2007年 | 69篇 |
2006年 | 40篇 |
2005年 | 41篇 |
2004年 | 46篇 |
2003年 | 46篇 |
2002年 | 37篇 |
2001年 | 44篇 |
2000年 | 47篇 |
1999年 | 47篇 |
1998年 | 45篇 |
1997年 | 34篇 |
1996年 | 32篇 |
1995年 | 31篇 |
1994年 | 28篇 |
1993年 | 33篇 |
1992年 | 34篇 |
1991年 | 12篇 |
1990年 | 22篇 |
1989年 | 31篇 |
1988年 | 26篇 |
1987年 | 25篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1975年 | 13篇 |
1974年 | 5篇 |
1972年 | 7篇 |
1970年 | 4篇 |
排序方式: 共有1278条查询结果,搜索用时 15 毫秒
1.
2.
3.
Research letter: How should abridged scientific articles be presented in journals? A survey of readers and authors 下载免费PDF全文
Marcus Müllner Fabian Waechter Sara Schroter Barbara Squire 《Canadian Medical Association journal》2005,172(2):203-205
SEVERAL SCIENTIFIC AND GENERAL MEDICAL JOURNALS publish full-length articles on their Web sites and abridged versions in their print journals. We surveyed a stratified random sample of BMJ readers and authors to elicit their preferred format for the abridged print version. Each participant received a research paper abridged in 3 different formats: conventional abridged version, journalistic version and enhanced-abstract version. Overall, 45% (95% confidence interval [CI] 42%–48%) of the respondents said they liked the conventional version most, 31% (95% CI 28%–34%) preferred the journalistic version and 25% (95% CI 22%–27%) preferred the enhanced-abstract version. Twenty-eight percent (95% CI 25%–32%) indicated that use of the journalistic format for abridged articles would very likely stop them from submitting papers to BMJ, and 13% (95% CI 11%–16%) said the use of the enhanced-abstract version would stop them from submitting to BMJ. Publishers of general medical journals who publish shortened articles should consider that authors and readers prefer a more conventional style of abridged papers. 相似文献
4.
5.
6.
Studies of proteins that inhibit tissue factor activity have generally been conducted using either an extracted tissue homogenate ("thromboplastin") or tissue factor protein reconstituted into phospholipid vesicles rather than with tissue factor expressed in cell membranes (its physiological environment). In the present study, a human fibroblast cell strain was used to evaluate the effects of lipoprotein associated coagulation inhibitor (LACI), placental anticoagulant protein (PAP), and apolipoprotein A-II (apo A-II) on human tissue factor in cell membranes. LACI was tested from 7.8 to 500 pmol/L on fibroblasts cultured at cell densities ranging from 3,500 to 9,925 cells/well, and caused a progressive inhibition of tissue factor activity. PAP was tested from 3.9 nmol/L to 1 mumol/L at cell densities ranging from 4,500 to 15,400 cells/well and caused up to 83% inhibition of tissue factor activity. Inhibition by these proteins appeared to be influenced by cell density as well as whether the cells were intact or disrupted. Apo A-II, up to 1 mumol/L, did not inhibit the tissue factor activity of intact or disrupted fibroblasts at any cell density examined even though it did inhibit the activity of tissue factor in phospholipid vesicles. Of these inhibitors of tissue factor-dependent activation of factor X, LACI was the most effective in suppressing the generation of factor Xa activity. The effects obtained with apo A-II are clearly dependent on the nature of the tissue factor preparation with which it is tested. The disparity between the inhibitory effect of apo A-II on the activity of tissue factor reconstituted into lipid vesicles and the absence of effect on the activity of tissue factor remaining in cell membranes serves to reemphasize the necessity of reexamining results obtained with model systems using as nearly physiological reagents as possible. 相似文献
7.
8.
An orthotopic metastatic prostate cancer model in SCID mice via grafting of a transplantable human prostate tumor line 总被引:2,自引:0,他引:2
Wang Y Xue H Cutz JC Bayani J Mawji NR Chen WG Goetz LJ Hayward SW Sadar MD Gilks CB Gout PW Squire JA Cunha GR Wang YZ 《Laboratory investigation; a journal of technical methods and pathology》2005,85(11):1392-1404
Metastasis is the major cause of prostate cancer deaths and there is a need for clinically relevant in vivo models allowing elucidation of molecular and cellular mechanisms underlying metastatic behavior. Here we describe the development of a new in vivo model system for metastatic prostate cancer. Pieces of prostate cancer tissue from a patient were grafted in testosterone-supplemented male NOD-SCID mice at the subrenal capsule graft site permitting high tumor take rates. After five serial transplantations, the tumor tissues were grafted into mouse prostates. Resulting tumors and suspected metastatic lesions were subjected to histopathological and immunohistochemical analysis. Samples of metastatic tissue were regrafted in mouse anterior prostates and their growth and spread examined, leading to isolation from lymph nodes of a metastatic subline, PCa1-met. Orthotopic grafting of PCa1-met tissue in 47 hosts led in all cases to metastases to multiple organs (lymph nodes, lung, liver, kidney, spleen and, notably, bone). Histopathological analysis showed strong similarity between orthotopic grafts and their metastases. The latter were of human origin as indicated by immunostaining using antibodies against human mitochondria, androgen receptor, prostate-specific antigen and Ki-67. Spectral karyotyping showed few chromosomal alterations in the PCa1-met subline. This study indicates that transplantable subrenal capsule xenografts of human prostate cancer tissue in NOD-SCID mice can, as distinct from primary cancer tissue, be successfully grown in the orthotopic site. Orthotopic xenografts of the transplantable tumor lines and metastatic sublines can be used for studying various aspects of metastatic prostate cancer, including metastasis to bone. 相似文献
9.
Dystrophin and utrophin influence fiber type composition and post-synaptic membrane structure 总被引:5,自引:0,他引:5
Rafael JA Townsend ER Squire SE Potter AC Chamberlain JS Davies KE 《Human molecular genetics》2000,9(9):1357-1367
The X-linked muscle wasting disease Duchenne muscular dystrophy is caused by the lack of dystrophin in muscle. Protein structure predictions, patient mutations, in vitro binding studies and transgenic and knockout mice suggest that dystrophin plays a mechanical role in skeletal muscle, linking the subsarcolemmal cytoskeleton with the extracellular matrix through its direct interaction with the dystrophin-associated protein complex (DAPC). Although a signaling role for dystrophin has been postulated, definitive data have been lacking. To identify potential non-mechanical roles of dystrophin, we tested the ability of various truncated dystrophin transgenes to prevent any of the skeletal muscle abnormalities associated with the double knockout mouse deficient for both dystrophin and the dystrophin-related protein utrophin. We show that restoration of the DAPC with Dp71 does not prevent the structural abnormalities of the post-synaptic membrane or the abnormal oxidative properties of utrophin/dystrophin-deficient muscle. In marked contrast, a dystrophin protein lacking the cysteine-rich domain, which is unable to prevent dystrophy in the mdx mouse, is able to ameliorate these abnormalities in utrophin/dystrophin-deficient mice. These experiments provide the first direct evidence that in addition to a mechanical role and relocalization of the DAPC, dystrophin and utrophin are able to alter both structural and biochemical properties of skeletal muscle. In addition, these mice provide unique insights into skeletal muscle fiber type composition. 相似文献
10.
Comparative histochemistry of a flatfish fin muscle and of other vertebrate muscles used for ultrastructural studies 总被引:3,自引:0,他引:3
Naomi Chayen Alan Freundlich John M. Squire 《Journal of muscle research and cell motility》1987,8(4):358-371
Summary Because of the high degree of filament order in the myofibrils of fish skeletal muscles, and the resulting usefulness of such preparations (particularly flatfish fin muscles) in structural studies of muscular contraction, the fibre type composition of plaice fin muscle has been determined by conventional histochemical tests. As controls, and for comparison, fibre type distributions have also been studied in several other vertebrate skeletal muscles which are widely used for ultrastructural and mechanical studies. In view of the importance of single fibres in such studies and because much of the published information on fibre types is rather difficult to collate, we summarize here the fibre compositions of several muscles; comparable enzyme tests have been carried out on cryostat sections of rabbit psoas muscle, frog sartorius and semitendinosus muscles and plaice fin muscles. On this basis all four muscles are composed of more than one fibre type. We confirm that frog sartorius muscle is mainly a random mixture of two fast fibre types and show that there is also a third group of fibres which are small, metabolically rich and dark under acid m-ATPase tests. We confirm that the semitendinosus is composed of three fibre types, in three non-exclusive, concentric regions and that rabbit psoas muscle contains a mixture of at least three fibre types.The principal new findings of this work are that plaice fin muscle can be divided into four regions, some of which are composed of more than one fibre type, on the basis of its histochemical reactions. This division into regions changes seasonally. The system of classification devised by Dubowitz & Brooke (1973) for mammalian muscle, and which can be applied approximately to frog muscle, can also be applied to the fibres of plaice fin muscle provided that the test for lactate dehydrogenase is carried out in the presence of polyvinyl alcohol. These fibres do not easily fit the division into red, white and intermediate types normally used for fish myotomal muscles.Since none of these muscles is homogeneous, their complex nature must be borne in mind if they are to be used satisfactorily in structural and mechanical studies of muscular contraction involving the use of single fibres. 相似文献