全文获取类型
收费全文 | 28674篇 |
免费 | 2245篇 |
国内免费 | 84篇 |
专业分类
耳鼻咽喉 | 221篇 |
儿科学 | 922篇 |
妇产科学 | 629篇 |
基础医学 | 4295篇 |
口腔科学 | 637篇 |
临床医学 | 2695篇 |
内科学 | 6349篇 |
皮肤病学 | 726篇 |
神经病学 | 2411篇 |
特种医学 | 953篇 |
外国民族医学 | 1篇 |
外科学 | 3881篇 |
综合类 | 300篇 |
一般理论 | 24篇 |
预防医学 | 2424篇 |
眼科学 | 785篇 |
药学 | 1667篇 |
中国医学 | 12篇 |
肿瘤学 | 2071篇 |
出版年
2022年 | 253篇 |
2021年 | 489篇 |
2020年 | 237篇 |
2019年 | 416篇 |
2018年 | 534篇 |
2017年 | 357篇 |
2016年 | 402篇 |
2015年 | 455篇 |
2014年 | 616篇 |
2013年 | 944篇 |
2012年 | 1417篇 |
2011年 | 1466篇 |
2010年 | 807篇 |
2009年 | 749篇 |
2008年 | 1357篇 |
2007年 | 1420篇 |
2006年 | 1332篇 |
2005年 | 1441篇 |
2004年 | 1272篇 |
2003年 | 1216篇 |
2002年 | 1234篇 |
2001年 | 748篇 |
2000年 | 849篇 |
1999年 | 708篇 |
1998年 | 359篇 |
1997年 | 312篇 |
1996年 | 254篇 |
1995年 | 283篇 |
1994年 | 245篇 |
1993年 | 253篇 |
1992年 | 588篇 |
1991年 | 601篇 |
1990年 | 520篇 |
1989年 | 529篇 |
1988年 | 484篇 |
1987年 | 497篇 |
1986年 | 455篇 |
1985年 | 438篇 |
1984年 | 419篇 |
1983年 | 295篇 |
1982年 | 217篇 |
1981年 | 208篇 |
1980年 | 238篇 |
1979年 | 291篇 |
1978年 | 245篇 |
1977年 | 199篇 |
1976年 | 197篇 |
1975年 | 189篇 |
1974年 | 235篇 |
1973年 | 223篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
E Schwartz 《Occupational and environmental medicine》1988,45(4):234-238
A proportionate mortality ratio (PMR) analysis of 1071 deaths in pulp and paper mill workers in New Hampshire during 1975-85 showed an increase in cancers of the digestive tract and lymphopoietic tissues. A similar analysis of deaths for 452 timber cutters and loggers failed to show excess PMRs for cancers of these sites. Despite methodological constraints, these results suggest that one or more of the exposures experienced by pulp and paper mill workers may pose a significant carcinogenic risk. More definitive epidemiological studies are required to determine particular high risk processes or specific aetiological agents. 相似文献
13.
14.
Factors affecting fusion rate in adult spondylolisthesis 总被引:8,自引:0,他引:8
The authors examined factors affecting fusion rate in the surgical treatment of 89 consecutive adult patients with spondylolisthesis. Two factors significantly improved fusion rate: combined anterior and posterior fusion and rigid postoperative immobilization in the cast. In 65 patients with isthmic spondylolisthesis, the fusion rate was raised from 70% when posterior fusion alone was used to 88% when combined anterior and posterior fusion was used. In 20 patients with degenerative spondylolisthesis, frequent use of combined anterior and posterior fusion contributed to a high overall fusion rate of 95%. Among patients with isthmic spondylolisthesis, postoperative cast immobilization resulted in a higher fusion rate of 90% compared with a fusion rate of 63% obtained after brace immobilization. 相似文献
15.
16.
Perceptual asymmetry on a series of four specially constructed dichotic word tests was found to change as a function of the emotional quality of the words in the tests (P = 0.05). This was most pronounced in the case of positively valued words which produced an increase in asymmetry consistent with facilitated left-hemisphere function (P less than 0.004). Changes in asymmetry with emotion differed as a function of personality characteristics of the subjects, with repressors and high anxious subjects showing an increase with emotion while true low anxious subjects showed a decrease (P less than 0.02). Personality groups also differed in asymmetry on an emotionally neutral test (P less than 0.04) and in changes in asymmetry over time independent of emotion (P less than 0.001). These data suggest that emotion mediated activation of the left hemisphere may facilitate information processing within that hemisphere. Moreover, they indicate that dichotic listening tests may provide a non-invasive and inexpensive method for assessing emotion mediated changes in brain state that are clinically relevant. 相似文献
17.
18.
Cloning and characterization of Ca(2+)-dependent and Ca(2+)-independent PKCs expressed in Aplysia sensory cells 总被引:2,自引:0,他引:2
K E Kruger W S Sossin T C Sacktor P J Bergold S Beushausen J H Schwartz 《The Journal of neuroscience》1991,11(8):2303-2313
We isolated cDNA clones from an Aplysia sensory-cell library encoding two isoforms of protein kinase C (PKC). Several isozyme-specific regions are conserved in the Aplysia kinases, notably the variable regions V5 in the Ca(2+)-dependent PKC (Apl I) and V1 in the Ca(2+)-independent PKC (Apl II). Neuronal proteins with the properties expected of these two isoforms can be identified with antibodies raised against peptides synthesized from the amino acid sequences deduced from the clones. Sacktor and Schwartz (1990) measured the proportion of kinase activity that can be translocated to membrane in Aplysia sensory neurons and ganglia by stimuli that produce the presynaptic facilitation underlying behavioral sensitization. Much less Apl I and Apl II are translocated, suggesting that still other isoforms of PKC exist in these cells. 相似文献
19.
Ann G Schwartz Geoffrey M Prysak Valerie Murphy Fulvio Lonardo Harvey Pass Jan Schwartz Sam Brooks 《Clinical cancer research》2005,11(20):7280-7287
PURPOSE: A role for estrogens in determining lung cancer risk and prognosis is suggested by reported sex differences in susceptibility and survival. Archival lung tissue was evaluated for the presence of nuclear estrogen receptor (ER)-alpha and ER-beta and the relationship between ER status, subject characteristics, and survival. EXPERIMENTAL DESIGN: Paraffin-embedded lung tumor samples were obtained from 214 women and 64 men from two population-based, case-control studies as were 10 normal lung autopsy samples from patients without cancer. Nuclear ER-alpha and ER-beta expression was determined by immunohistochemistry. Logistic regression was used to identify factors associated with ER positivity and Cox proportional hazards models were used to measure survival differences by ER status. RESULTS: Neither tumor (0 of 94) nor normal (0 of 10) lung tissue stained positive for ER-alpha. Nuclear ER-beta positivity was present in 61% of tumor tissue samples (170 of 278; 70.3% in men and 58.3% in women) and 20% of normal tissue samples (2 of 10; P = 0.01). In multivariate analyses, females were 46% less likely to have ER-beta-positive tumors than males (odds ratio, 0.54; 95% confidence interval, 0.27-1.08). This relationship was stronger and statistically significant in adenocarcinomas (odds ratio, 0.40; 95% confidence interval, 0.18-0.89). Women with ER-beta-positive tumors had a nonsignificant 73% (P = 0.1) increase in mortality, whereas men with ER-beta-positive tumors had a significant 55% (P = 0.04) reduction in mortality compared with those with ER-beta-negative tumors. CONCLUSIONS: This study suggests differential expression by sex and influence on survival in men of nuclear ER-beta in lung cancer, particularly in adenocarcinomas. 相似文献
20.