全文获取类型
收费全文 | 2858篇 |
免费 | 228篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 179篇 |
妇产科学 | 57篇 |
基础医学 | 418篇 |
口腔科学 | 26篇 |
临床医学 | 224篇 |
内科学 | 522篇 |
皮肤病学 | 48篇 |
神经病学 | 164篇 |
特种医学 | 79篇 |
外国民族医学 | 1篇 |
外科学 | 407篇 |
综合类 | 163篇 |
一般理论 | 1篇 |
预防医学 | 205篇 |
眼科学 | 65篇 |
药学 | 244篇 |
中国医学 | 16篇 |
肿瘤学 | 266篇 |
出版年
2023年 | 16篇 |
2022年 | 49篇 |
2021年 | 65篇 |
2020年 | 34篇 |
2019年 | 57篇 |
2018年 | 59篇 |
2017年 | 47篇 |
2016年 | 71篇 |
2015年 | 73篇 |
2014年 | 91篇 |
2013年 | 116篇 |
2012年 | 157篇 |
2011年 | 179篇 |
2010年 | 88篇 |
2009年 | 99篇 |
2008年 | 137篇 |
2007年 | 154篇 |
2006年 | 161篇 |
2005年 | 131篇 |
2004年 | 137篇 |
2003年 | 113篇 |
2002年 | 96篇 |
2001年 | 69篇 |
2000年 | 75篇 |
1999年 | 72篇 |
1998年 | 26篇 |
1997年 | 20篇 |
1992年 | 32篇 |
1991年 | 46篇 |
1990年 | 45篇 |
1989年 | 28篇 |
1988年 | 28篇 |
1987年 | 31篇 |
1986年 | 29篇 |
1985年 | 30篇 |
1984年 | 18篇 |
1982年 | 15篇 |
1981年 | 19篇 |
1980年 | 17篇 |
1979年 | 31篇 |
1978年 | 24篇 |
1977年 | 23篇 |
1976年 | 16篇 |
1975年 | 22篇 |
1974年 | 22篇 |
1973年 | 27篇 |
1972年 | 23篇 |
1971年 | 25篇 |
1970年 | 17篇 |
1969年 | 19篇 |
排序方式: 共有3110条查询结果,搜索用时 15 毫秒
1.
Metabolic abnormalities of gastrointestinal mucosa in celiac disease: An in vitro proton nuclear magnetic resonance spectroscopy study 下载免费PDF全文
2.
I. Fishtik C.A. Callaghan J.D. Fehribach R. Datta 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》2005,576(1):57-63
The reaction route (RR) graph approach recently developed by us for complex, non-linear kinetic mechanisms is applied to the hydrogen oxidation and evolution reactions. A corresponding RR graph is constructed and translated into an equivalent electrical circuit network by associating each elementary step with a characteristic resistance for the steady-state case and considering the overall reaction as a power source. It is further shown that the steady-state kinetics of the reaction can be investigated employing the conventional methods of the electrical network theory. Using a set of rate constants for the hydrogen evolution reaction (her) in alkaline solutions from the literature, the dominant RRs are identified and simplified mechanisms and kinetics derived. 相似文献
3.
4.
5.
6.
A. Datta R. David S. Glennie D. Scott E. Cernuda-Morollon R. I. Lechler A. J. Ridley F. M. Marelli-Berg 《American journal of transplantation》2006,6(12):2871-2883
The best-characterized mechanism of the action of immunosuppressive drugs is to prevent T-cell clonal expansion, thus containing the magnitude of the ensuing immune response. As T-cell recruitment to the inflammatory site is another key step in the development of T-cell-mediated inflammation, we analyzed and compared the effects of two commonly used immunosuppressants, cyclosporin A (CsA) and the rapamycin-related compound SDZ-RAD, on the motility of human CD4+ T cells. We show that CsA, but not SDZ-RAD, inhibits T-cell transendothelial migration in vitro. CsA selectively impaired chemokine-induced T-cell chemotaxis while integrin-mediated migration was unaffected. The inhibition of T-cell chemotaxis correlated with reduced AKT/PKB but not ERK activation following exposure to the chemokine CXCL-12/SDF-1. In addition, CsA, but not SDZ-RAD, prevents some T-cell receptor-mediated effects on T-cell motility. Finally, we show that CsA, but not SDZ-RAD inhibits tissue infiltration by T cells in vivo. Our data suggest a prominent antiinflammatory role for CsA in T-cell-mediated tissue damage, by inhibiting T-cell trafficking into tissues in addition to containing clonal expansion. 相似文献
7.
8.
9.
Osteoclastic inhibition: an action of nitric oxide not mediated by cyclic GMP. 总被引:18,自引:3,他引:15 下载免费PDF全文
I MacIntyre M Zaidi A S Alam H K Datta B S Moonga P S Lidbury M Hecker J R Vane 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(7):2936-2940
The osteoclast is unique in its ability to resorb bone, and excessive osteoclastic activity has been implicated in osteoporosis, Paget disease of bone, rheumatoid arthritis, and the growth of metastases in bone. The activity of this cell is controlled by the main circulating inhibitor, calcitonin, in association with locally produced modulators. We show that nitric oxide (NO) may be an important member of the latter group. NO is produced by the vascular endothelium and nervous system and is involved in both neurotransmission and the regulation of blood pressure. However, our results show that the autocoid is also a potent inhibitor of osteoclast function. NO (30 microM) produced a decrease to approximately 50% of the original osteoclast spread area. Similar effects were also produced by 3-morpholinosydnonimine or sodium nitroprusside, reagents that spontaneously release NO. These shape changes were associated with a reduction of bone resorption after a 24-hr incubation of isolated osteoclasts on devitalized bone slices. NO is thought to act by stimulating guanylate cyclase, with a consequent increase in cyclic GMP, but a different mode of action is likely in the osteoclast since dibutyryl or 8-bromo cyclic GMP have no effect. It should be noted that calcitonin can produce similar changes in shape and activity but is associated with an increase in osteoclast intracellular calcium and cessation of membrane movement; neither of these is produced by NO, suggesting that its mode of action is different. The abundance of NO-producing endothelial cells in bone marrow and their proximity to osteoclasts suggests that marrow endothelial cells may play a physiological role in the regulation of osteoclastic activity. 相似文献
10.
Shyamal K Das Tapas K Banerjee Atanu Biswas Trishit Roy Deepak K Raut Arijit Chaudhuri Abhijit Hazra 《Movement disorders》2007,22(14):2031-2036
An epidemiological study on dystonia has not been reported from India. As part of a major study to find out the prevalence of major neurological disorders in the large urban city of Kolkata, Eastern India, we planned to determine the prevalence of primary dystonia. The study design was a cross-sectional study of a sample population obtained through stratified random selection and conducted in a two-stage procedure of screening by a nonprofessional team followed by confirmation of screened positive cases by the study neurologist. A total population of 52,377 was screened, and 29 subjects with dystonia were diagnosed. Out of them 23 subjects had primary dystonias [crude prevalence rate (CPR), 43.91/100,000; 95% confidence interval (CI), 28.41-64.81; age-standardized rates to world standard population, 49.06 (95% CI,31.74-72.41)] and all cases were focal type and predominantly of limb dystonia variety. Mean onset of dystonias were earlier in women (43.5 years) as compared to men (46.6 years). Thus our study on primary dystonia shows higher prevalence when compared with that of many studies globally, predominantly of focal type, earlier onset among women, and more cases of limb dystonias when compared with more prominent blepharospasm and cervical dystonias in western reports. 相似文献