全文获取类型
收费全文 | 6131篇 |
免费 | 577篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 97篇 |
儿科学 | 314篇 |
妇产科学 | 185篇 |
基础医学 | 935篇 |
口腔科学 | 95篇 |
临床医学 | 942篇 |
内科学 | 1253篇 |
皮肤病学 | 78篇 |
神经病学 | 350篇 |
特种医学 | 426篇 |
外国民族医学 | 2篇 |
外科学 | 586篇 |
综合类 | 99篇 |
一般理论 | 12篇 |
预防医学 | 599篇 |
眼科学 | 53篇 |
药学 | 372篇 |
中国医学 | 8篇 |
肿瘤学 | 319篇 |
出版年
2021年 | 91篇 |
2020年 | 50篇 |
2019年 | 79篇 |
2018年 | 115篇 |
2017年 | 72篇 |
2016年 | 101篇 |
2015年 | 107篇 |
2014年 | 116篇 |
2013年 | 151篇 |
2012年 | 225篇 |
2011年 | 241篇 |
2010年 | 156篇 |
2009年 | 165篇 |
2008年 | 276篇 |
2007年 | 238篇 |
2006年 | 223篇 |
2005年 | 203篇 |
2004年 | 228篇 |
2003年 | 212篇 |
2002年 | 196篇 |
2001年 | 194篇 |
2000年 | 219篇 |
1999年 | 159篇 |
1998年 | 131篇 |
1997年 | 106篇 |
1996年 | 115篇 |
1995年 | 105篇 |
1994年 | 98篇 |
1993年 | 100篇 |
1992年 | 155篇 |
1991年 | 138篇 |
1990年 | 140篇 |
1989年 | 166篇 |
1988年 | 143篇 |
1987年 | 139篇 |
1986年 | 137篇 |
1985年 | 136篇 |
1984年 | 82篇 |
1983年 | 72篇 |
1982年 | 64篇 |
1981年 | 60篇 |
1980年 | 45篇 |
1979年 | 69篇 |
1978年 | 62篇 |
1977年 | 68篇 |
1976年 | 54篇 |
1975年 | 53篇 |
1974年 | 66篇 |
1973年 | 44篇 |
1970年 | 41篇 |
排序方式: 共有6725条查询结果,搜索用时 343 毫秒
31.
Does altered biomechanics cause marrow edema? 总被引:21,自引:0,他引:21
32.
33.
J M Benson A F Eidson R L Hanson R F Henderson C H Hobbs 《Journal of applied toxicology : JAT》1989,9(4):219-222
Quantification of nickel in animal soft tissue is of toxicological interest. A digestion method applying the use of microwave ovens for irradiating samples in Teflon digesters was developed. An acid mixture containing nitric acid (16 M, 1.0 ml g-1 tissue), hydrochloric acid (6 M, 0.5 ml g-1 tissue) and H2O2 (30%, 1.0 ml g-1 tissue) and irradiation at 600 W for 5 min were required for complete dissolution of tissue matrices and nickel compounds. Analyses of Ni in National Bureau of Standards Reference Material 1566 oyster tissue gave 0.87 +/- 0.24 micrograms g 1(mean +/- SD, n = 5), which was in agreement with the NBS certified value of 1.03 +/- 0.19 micrograms g-1. Recoveries of 1-300 micrograms Ni added as nickel sulfate (highly soluble), nickel subsulfide (moderately soluble in biological fluids and acid) or nickel oxide (green high-temperature oxide, low solubility in biological fluids and acid) to lung, liver, lymph node and kidney were quantitative, except in the case of nickel sulfate added to kidney, where recovery was less than quantitative for 1-10 micrograms Ni. The method appears effective for digestion of a variety of tissues requiring Ni analyses. 相似文献
34.
P W Lepinski T S Thielke D M Collins A Hanson 《American journal of hospital pharmacy》1986,43(11):2771-2779
Unit dose and traditional drug distribution systems were compared in a 352-bed long-term-care facility by analyzing nursing time, medication-error rate, medication costs, and waste. Time spent by nurses in preparing, administering, charting, and other tasks associated with medications was measured with a stop-watch on four different nursing units during six-week periods before and after the nursing home began using unit dose drug distribution. Medication-error rate before and after implementation of the unit dose system was determined by patient profile audits and medication inventories. Medication costs consisted of patient billing costs (acquisition cost plus fee) and cost of medications destroyed. The unit dose system required a projected 1507.2 hours less nursing time per year. Mean medication-error rates were 8.53% and 0.97% for the traditional and unit dose systems, respectively. Potential annual savings because of decreased medication waste with the unit dose system were $2238.72. The net increase in cost for the unit dose system was estimated at $615.05 per year, or approximately $1.75 per patient. The unit dose system appears safer and more time-efficient than the traditional system, although its costs are higher. 相似文献
35.
Discrepancies in bioassay and chromatography determinations explained by metabolism of itraconazole to hydroxyitraconazole: studies of interpatient variations in concentrations. 总被引:4,自引:3,他引:1
下载免费PDF全文
![点击此处可从《Antimicrobial agents and chemotherapy》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J S Hostetler J Heykants K V Clemons R Woestenborghs L H Hanson D A Stevens 《Antimicrobial agents and chemotherapy》1993,37(10):2224-2227
Pharmacologic studies of itraconazole (IZ), a triazole antifungal, indicated unexplained differences between bioassay and chromatographic determinations and large variations in steady-state blood concentrations. We show that concentrations of a hydroxylated metabolite, hydroxyitraconazole (HIZ), are approximately twofold higher than IZ over a range of concentrations. Though HIZ and IZ appear equipotent against selected pathogens, HIZ is two to three times more active against a commonly used bioassay fungus but minimally affects IZ activity. Hence, HIZ probably contributes importantly to the therapeutic activity attributed to IZ and contributes approximately four to six times the activity of IZ in bioassays, explaining discrepancies observed between assay methods. 相似文献
36.
37.
Carol Smillie B.N. B.Ed. M.S.C. Katherine Coffin B.A. ME.D. Kathryn Porter B.A. Brenda Ryan B.A. M.B.A. 《Journal of community health》1988,13(3):156-170
The International Conference on Primary Health Care, meeting in Alma-Ata, in the Soviet Union, September 12, 1978, expressed the need for urgent action by all governments, all health and development workers and the world community, to protect and promote the health of all people of the world. The world was caught by the phrase which emerged from this conference, Health For All by the Year 2000 and many have examined the articles of the Alma-Ata declaration and tried to implement them in their corner of the world. This paper describes a community-based smoking-cessation program which was implemented in the province of Nova Scotia, Canada, during the years 1980–1984. Primary to this project was the belief that people have the right and the duty to participate individually and collectively in planning and implementing their health care. This paper describes one community's effort in putting this belief into practice.Carol Smillie, B.N. BE.d. M.S.c. is an Assistant Professor at the School of Nursing, Dalhousie University, Halifax, Nova Scotia, Canada B3H 3J5, Katherine Coffin, BA, MEd is the Program Officer, Nova Scotia Office, Health Promotion Directorate Health and Welfare Canada, 5251 Duke Street, Halifax, Nova Scotia. Canada B3J 1P3. Kathryn Porter, B.A. (Gen)., is the Information and Education Coordinator, Nova Scotia Division Canadian Cancer Society. Brenda Ryan, B.A., M.B.A. is Program Evaluation Analysist, Nova Scotia Department of Health, 6088 Hollis Street, Halifax. Nova Scotia, Canada. This Project was funded by Health and Welfare Canada, Nova Scotia Department of Health, Nova Scotia Division Canadian Cancer Society, Requests for reprints should be addressed to: Professor Carol Smillie. 相似文献
38.
MIM/BEG4, a Sonic hedgehog-responsive gene that potentiates Gli-dependent transcription 总被引:7,自引:0,他引:7
Callahan CA Ofstad T Horng L Wang JK Zhen HH Coulombe PA Oro AE 《Genes & development》2004,18(22):2724-2729
39.
As part of the characterization of the host reactivity to the venom ofBothrops asper, we investigated the inflammatory responses in the mouse footpad model. The subcutaneously injected venom induced a rapid increase of serum IL-6 concentration, which peaked between 3 and 6 h and returned to normal values at 12 h. In contrast, serum TNF- and IL-1 were not detectable at any time point studied. A myotoxic phospholipase A2 isoform purified from this venom, myotoxin II, was also able to induce a systemic IL-6 release when injected into the footpad. Both venom and myotoxin induced local edema and a leukocyte infiltrate accumulating in the muscle and subdermal tissue within 6 h. The infiltrate consisted predominantly of neutrophils at 6 and 24 h, but at later times, mononuclear cells also appeared. The edema, leukocyte infiltration, and IL-6 responses did not depend on the hemorrhagic activity of venom, since all three effects were seen after injection of (1) preneutralized venom, devoid of hemorrhagic activity, and (2) purified myotoxin II. Circulating platelet numbers were significantly decreased 30 min after venom injection and returned to normal after 12 h. The venom also induced a rapid inversion in the ratio of neutrophils to lymphocytes in peripheral blood, which did not normalize until 12 h later. The present observations suggest that venom, besides its cytotoxic properties, induces early hematologic and immunologic alterations. These findings may be of relevance in future treatment modalities. 相似文献
40.
Hanley KA Manlucu LR Gilmore LE Blaney JE Hanson CT Murphy BR Whitehead SS 《Virology》2003,312(1):222-232
An acceptable live-attenuated dengue virus vaccine candidate should have low potential for transmission by mosquitoes. We have identified and characterized a mutation in dengue virus type 4 (DEN4) that decreases the ability of the virus to infect mosquitoes. A panel of 1248 mutagenized virus clones generated previously by chemical mutagenesis was screened for decreased replication in mosquito C6/36 cells but efficient replication in simian Vero cells. One virus met these criteria and contained a single coding mutation: a C-to-U mutation at nucleotide 7129 resulting in a Pro-to-Leu change in amino acid 101 of the nonstructural 4B gene (NS4B P101L). This mutation results in decreased replication in C6/36 cells relative to wild-type DEN4, decreased infectivity for mosquitoes, enhanced replication in Vero and human HuH-7 cells, and enhanced replication in SCID mice implanted with HuH-7 cells (SCID-HuH-7 mice). A recombinant DEN4 virus (rDEN4) bearing this mutation exhibited the same set of phenotypes. Addition of the NS4B P101L mutation to rDEN4 bearing a 30 nucleotide deletion (Delta30) decreased the ability of the double-mutant virus to infect mosquitoes but increased its ability to replicate in SCID-HuH-7 mice. Although the NS4B P101L mutation decreases infectivity of DEN4 for mosquitoes, its ability to enhance replication in SCID-HuH-7 mice suggests that it might not be advantageous to include this specific mutation in an rDEN4 vaccine. The opposing effects of the NS4B P101L mutation in mosquito and vertebrate systems suggest that the NS4B protein is involved in maintaining the balance between efficient replication in the mosquito vector and the human host. 相似文献