全文获取类型
收费全文 | 6438篇 |
免费 | 385篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 244篇 |
妇产科学 | 65篇 |
基础医学 | 1125篇 |
口腔科学 | 280篇 |
临床医学 | 556篇 |
内科学 | 972篇 |
皮肤病学 | 237篇 |
神经病学 | 709篇 |
特种医学 | 264篇 |
外科学 | 807篇 |
综合类 | 35篇 |
一般理论 | 2篇 |
预防医学 | 247篇 |
眼科学 | 288篇 |
药学 | 464篇 |
中国医学 | 9篇 |
肿瘤学 | 480篇 |
出版年
2023年 | 17篇 |
2022年 | 50篇 |
2021年 | 89篇 |
2020年 | 83篇 |
2019年 | 67篇 |
2018年 | 107篇 |
2017年 | 96篇 |
2016年 | 133篇 |
2015年 | 176篇 |
2014年 | 191篇 |
2013年 | 243篇 |
2012年 | 366篇 |
2011年 | 368篇 |
2010年 | 255篇 |
2009年 | 255篇 |
2008年 | 465篇 |
2007年 | 396篇 |
2006年 | 411篇 |
2005年 | 414篇 |
2004年 | 463篇 |
2003年 | 420篇 |
2002年 | 385篇 |
2001年 | 111篇 |
2000年 | 94篇 |
1999年 | 101篇 |
1998年 | 100篇 |
1997年 | 93篇 |
1996年 | 75篇 |
1995年 | 52篇 |
1994年 | 42篇 |
1993年 | 44篇 |
1992年 | 35篇 |
1991年 | 32篇 |
1990年 | 31篇 |
1989年 | 50篇 |
1988年 | 34篇 |
1987年 | 29篇 |
1986年 | 22篇 |
1985年 | 25篇 |
1984年 | 17篇 |
1983年 | 14篇 |
1982年 | 23篇 |
1981年 | 15篇 |
1980年 | 16篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 18篇 |
1974年 | 13篇 |
1973年 | 16篇 |
1972年 | 18篇 |
排序方式: 共有6844条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
16.
Helmut Seidel Barbara Harazin Kristina Pavlas Christine Sroka Jörg Richter Ralph Blüthner Udo Erdmann Jan Grzesik Barbara Hinz Reinhard Rothe 《International archives of occupational and environmental health》1988,61(1-2):95-106
Summary This study was carried out in order: (1) to examine the effects of isolated and combined prolonged exposures to noise and whole-body vibration on hearing, vision and subjectively experienced strain, and (2) to check the combined effects with repeated exposures. Six male subjects were exposed twice to noise (N) at 92 dBA, whole-body vibration (V) in the Z-axis at 4 Hz and 1.0 ms–2 rms, and noise and vibration (NV) for 90 min with each condition. Temporary threshold shifts of hearing (TTS) and their integrals (ITTS) were measured at 4, 6, 10, and 12 kHz. Visual acuity was examined by means of a very sensitive test. Cross-modality matching (CMM) of the handgrip force was used to judge the subjectively experienced strain. NV induced a clear tendency of higher TTS and ITTS than N, with several significant differences most pronounced at 10 kHz. With repeated exposures, the effect of NV decreased, while the reactions to N and V remained unchanged. The individual reactions to NV differed. The influence of the duration of exposures on vision depended on the condition; N caused time-dependent changes, whereas V did not. CMM-data increased with the duration of the exposure during V and NV. N was generally judged to be more straining than V; NV caused higher strain than V during the first 30 min of exposure only. Correlations between different effects suggest certain links between them. Additionally, less motivation — daily obtained by a questionnaire — often correlated with higher ITTS during N and NV. The results also illustrate the combined effects on the individual susceptibility, repetition of exposure, the kind of response, and, possibly, the actual psychic state.Abbreviations CMM
cross-modality matching
- MVC
maximum voluntary contraction force
- N
exposure condition: noise level 92dBA, no whole-body vibration
- NV
exposure condition: combined exposure to noise with a level of 92 dBA and wholebody vibration with 4 Hz, 1 ms–2 rms
- V
exposure condition: whole-body vibration with 4 Hz, 1 ms–2 rms
- TTS
temporary threshold shift
- ITTS
integral of temporary threshold shift
- WBV
whole-body vibration in the common sense
This work was done in the Temporary International Research Team on Combined Effects of Noise and Vibration of the Council of Mutual Economic Assistance of the Socialist Countries. The authors gratefully acknowledge the help and assistance of L.-M. Brumm, Y. Bening, M. Godau, G. Weber, and R. Vizcaino. 相似文献
17.
von Willebrand factor mutation enhancing interaction with platelets in patients with normal multimeric structure. 总被引:7,自引:0,他引:7
下载免费PDF全文
![点击此处可从《The Journal of clinical investigation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
L Holmberg J A Dent R Schneppenheim U Budde J Ware Z M Ruggeri 《The Journal of clinical investigation》1993,91(5):2169-2177
Variant von Willebrand disease designated as type I New York or type Malmö is characterized by enhanced ristocetin-induced platelet agglutination with normal von Willebrand factor multimeric distribution in plasma. We have studied four such patients belonging to three unrelated families and found in all of them a unique cytosine-to-thymine transition changing the codon for Pro503 (CCG) to Leu (CTG). In three patients the mutant allele also had a silent mutation in the codon for Ser500 (TCG-->TCA). Both nucleotide changes are present in the von Willebrand factor pseudogene; however, the characterization of distinctive markers where the gene and pseudogene differ, as well as the examination of amplified cDNA derived from platelet mRNA, confirmed that the abnormality occurs in the von Willebrand factor gene of the patients. Moreover, recombinant expression of the isolated glycoprotein Ib-binding domain of von Willebrand factor provided direct evidence that the Pro503-->Leu mutation is responsible for enhanced platelet reactivity to lower ristocetin concentrations. These results define a new structural element affecting the affinity of von Willebrand factor for glycoprotein Ib and establish the molecular basis of a variant form of von Willebrand disease. 相似文献
18.
An extrachromosomal nucleic acid element was detected in high-molecular-weight DNA preparations formBabesia equi merozoites. This extrachromosomal element was shown to be DNA rather than RNA and had an apparent fragment size of about 9 kilobasepairs (kb). Hybridization experiments using purified 9-kb DNA as a probe revealed sequence homologies with extrachromosomal DNA from two otherBabesia species. 相似文献
19.
Effect of change of fecal bile acid excretion achieved by operative procedures on 1,2-dimethylhydrazine-induced colon cancer in rats 总被引:5,自引:0,他引:5
Dr. Krisztina Morvay M.D. Károly Szentléleki M.D. Géza Török M.D. Alan Pintér M.D. Mátyás Börzsönyi M.D. Reinhard Nawroth DSc 《Diseases of the colon and rectum》1989,32(10):860-863
The effect of bile on the development of 1,2-dimethylhydrazine (DMH)-induced colon cancer was studied in male Wistar rats. Experimental operative models were created, in which in Group 1, the half intestinal tract, the ileum, and the right side of colon were released from bile. In Group 2, both sides of the colon contained bile. The sham operated animals formed Group 3. These techniques changed the concentration of bile acid in different parts of the colon, and the daily total fecal bile acid excretion as well. After DMH treatment, the relationship between these changes of bile acid level and the development of colon cancer was studied. Significantly more tumors than in the control group were found if the daily total bile acid level and the bile acid concentration in the left side of the colon were increased. Our findings show an unambiguous connection between the fecal bile acid level and the incidence of DMH-induced colon cancer. 相似文献
20.