全文获取类型
收费全文 | 22285篇 |
免费 | 2088篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 235篇 |
儿科学 | 842篇 |
妇产科学 | 510篇 |
基础医学 | 2889篇 |
口腔科学 | 484篇 |
临床医学 | 2478篇 |
内科学 | 4534篇 |
皮肤病学 | 170篇 |
神经病学 | 2159篇 |
特种医学 | 758篇 |
外科学 | 3106篇 |
综合类 | 388篇 |
一般理论 | 12篇 |
预防医学 | 2467篇 |
眼科学 | 460篇 |
药学 | 1512篇 |
中国医学 | 26篇 |
肿瘤学 | 1386篇 |
出版年
2022年 | 141篇 |
2021年 | 344篇 |
2020年 | 203篇 |
2019年 | 399篇 |
2018年 | 390篇 |
2017年 | 264篇 |
2016年 | 320篇 |
2015年 | 342篇 |
2014年 | 584篇 |
2013年 | 877篇 |
2012年 | 1212篇 |
2011年 | 1226篇 |
2010年 | 682篇 |
2009年 | 604篇 |
2008年 | 1138篇 |
2007年 | 1230篇 |
2006年 | 1163篇 |
2005年 | 1132篇 |
2004年 | 1105篇 |
2003年 | 1079篇 |
2002年 | 1067篇 |
2001年 | 491篇 |
2000年 | 511篇 |
1999年 | 458篇 |
1998年 | 265篇 |
1997年 | 224篇 |
1996年 | 232篇 |
1995年 | 231篇 |
1994年 | 220篇 |
1993年 | 214篇 |
1992年 | 374篇 |
1991年 | 306篇 |
1990年 | 335篇 |
1989年 | 340篇 |
1988年 | 277篇 |
1987年 | 286篇 |
1986年 | 308篇 |
1985年 | 282篇 |
1984年 | 252篇 |
1983年 | 238篇 |
1982年 | 186篇 |
1981年 | 199篇 |
1980年 | 153篇 |
1979年 | 219篇 |
1978年 | 185篇 |
1976年 | 148篇 |
1975年 | 143篇 |
1974年 | 154篇 |
1973年 | 148篇 |
1972年 | 130篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Russell L. Deter 《Journal of clinical ultrasound : JCU》1986,14(6):420-420
12.
13.
14.
Fluconazole resistance in AIDS patients. 总被引:14,自引:0,他引:14
15.
Terry Joe Sprinkle Julia F. Agee Russell B. Tippins C. Richard Chamberlain Guy B. Faguet George H. DeVries 《Brain research》1987,426(2):349-357
Monoclonal antibodies against human and bovine 2′:3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) were generated by fusing FOX-NY myeloma cells with spleen cells from RBF/Dn mice previously immunized with the purified brain antigens. The enzyme isolated from bovine brain was quite basic, with an isoelectric point of 9.71 and both the bovine and human enzymes consisted of a closely spaced doublet at approximately 44 and 46 kDa on SDS-PAGE. Six monoclonals were identified as strongly recognizing the enzyme on both ELISA plates and on immunoblots of whole brain protein. Four monoclonals very weakly cross-reacted with guinea pig myelin basic protein. In contrast with two previous reports, some of our monoclonal antibodies did immunostain 2 or 3 protein bands in peripheral nerve, two bands closely corresponding to those immunostained in central nervous system (CNS) myelin, the Wolfgram protein fraction and in acetone powders of whole brain. Each of the 6 monoclonals reacting strongly on immunoblots recognized the enzyme in from 2 to 5 of the species examined (human, bovine, rat, mouse and rabbit). In addition, all 6 monoclonals that immunostained the enzyme in whole brain, myelin and Wolfgram protein immunoblots recognized both CNP1 (44 kDa) and CNP2 (46 kDa). The two closely spaced protein bands observed on SDS-PAGE and previously stained on immunoblots of CNS CNPase using polyvalent rabbit anti-bovine CNPase antisera, and now different monoclonal antibodies, appear to be immunologically related and to contain highly conserved sequences. 相似文献
16.
17.
S V Kamat B Iwaskewycz E J Beckman A J Russell 《Proceedings of the National Academy of Sciences of the United States of America》1993,90(7):2940-2944
Supercritical fluids are a unique class of nonaqueous media in which biocatalytic reactions can occur. The physical properties of supercritical fluids, which include gas-like diffusivities and liquid-like densities, can be predictably controlled with changing pressure. This paper describes how adjustment of pressure, with the subsequent predictable changes of the dielectric constant and Hildebrand solubility parameter for fluoroform, ethane, sulfur hexafluoride, and propane, can be used to manipulate the activity of lipase in the transesterification of methylmethacrylate with 2-ethyl-1-hexanol. Of particular interest is that the dielectric constant of supercritical fluoroform can be tuned from approximately 1 to 8, merely by increasing pressure from 850 to 4000 psi (from 5.9 to 28 MPa). The possibility now exists to predictably alter both the selectivity and the activity of a biocatalyst merely by changing pressure. 相似文献
18.
D H Russell N E Zorn A R Buckley P D Crowe M D Sauro E M Hadden R V Farese H E Laird 《European journal of pharmacology》1990,188(2-3):139-152
Prolactin (PRL) and other trophic factors rapidly activate a nuclear pool(s) of protein kinase C (nPKC) in purified splenocyte nuclei. The PRL also enhanced [2-3H]glycerol incorporation into nuclear mono- and triacylglycerol. An assay was devised which not only probed the ability of the hormone to activate protein kinase C (PKC) but also demonstrated the presence of nuclear substrates. Using this methodology, a biphasic concentration-response curve to PRL was observed. Heterologous species of PRL and various growth factors also activated nPKC. The PRL-induced nPKC stimulation was antagonized by various immunomodulators, G protein-coupling inhibitors, PKC inhibitors, a calmodulin inhibitor, and a peripheral benzodiazepine agonist and antagonist. A monoclonal antibody to PKC, anti-rat PRL antiserum and a monoclonal anti-rat PRL receptor antibody antagonized PRL-induced PKC-dependent nuclear phosphorylation, further implicating nPKC and a PRL receptor-mediated activation process. Nuclear PKC may be a major target for trophic regulation in response to both positive and negative growth signals. 相似文献
19.
L B Russell J E Sisk 《International journal of technology assessment in health care》1988,4(2):269-286
This paper reviews the evolution of U.S. policy toward medical technology in areas such as cost containment, regulation of devices and drugs, and third party reimbursement. In addition the authors chronicle the diffusion of major medical technologies, procedures, and organizational innovations in the United States. Finally, the article provides tentative observations on the effect of recent policy changes and concludes with some recommendations for the future. 相似文献
20.