全文获取类型
收费全文 | 4640篇 |
免费 | 398篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 142篇 |
妇产科学 | 81篇 |
基础医学 | 652篇 |
口腔科学 | 35篇 |
临床医学 | 461篇 |
内科学 | 1028篇 |
皮肤病学 | 51篇 |
神经病学 | 411篇 |
特种医学 | 112篇 |
外科学 | 764篇 |
综合类 | 44篇 |
一般理论 | 14篇 |
预防医学 | 424篇 |
眼科学 | 50篇 |
药学 | 335篇 |
中国医学 | 3篇 |
肿瘤学 | 424篇 |
出版年
2023年 | 27篇 |
2022年 | 58篇 |
2021年 | 106篇 |
2020年 | 79篇 |
2019年 | 102篇 |
2018年 | 116篇 |
2017年 | 92篇 |
2016年 | 91篇 |
2015年 | 117篇 |
2014年 | 144篇 |
2013年 | 206篇 |
2012年 | 339篇 |
2011年 | 326篇 |
2010年 | 194篇 |
2009年 | 166篇 |
2008年 | 255篇 |
2007年 | 282篇 |
2006年 | 228篇 |
2005年 | 206篇 |
2004年 | 215篇 |
2003年 | 192篇 |
2002年 | 193篇 |
2001年 | 82篇 |
2000年 | 91篇 |
1999年 | 83篇 |
1998年 | 38篇 |
1997年 | 26篇 |
1996年 | 23篇 |
1992年 | 61篇 |
1991年 | 50篇 |
1990年 | 55篇 |
1989年 | 67篇 |
1988年 | 36篇 |
1987年 | 51篇 |
1986年 | 42篇 |
1985年 | 44篇 |
1984年 | 37篇 |
1983年 | 35篇 |
1982年 | 25篇 |
1981年 | 27篇 |
1980年 | 21篇 |
1979年 | 41篇 |
1978年 | 37篇 |
1977年 | 28篇 |
1975年 | 35篇 |
1974年 | 21篇 |
1973年 | 21篇 |
1971年 | 27篇 |
1970年 | 23篇 |
1969年 | 21篇 |
排序方式: 共有5058条查询结果,搜索用时 15 毫秒
101.
102.
Gagnaire Béatrice Bado-Nilles Anne Betoulle Stéphane Amara Rachid Camilleri Virginie Cavalié Isabelle Chadili Edith Delahaut Laurence Kerambrun Elodie Orjollet Daniel Palluel Olivier Sanchez Wilfried 《Ecotoxicology (London, England)》2015,24(1):215-231
Ecotoxicology - To characterize environmental risks linked to former uranium mines in the Limousin region of France, a study was conducted on fish health effects from uranium releases. Two private... 相似文献
103.
Pierre Ollitrault MD MSc Laure Champ-Rigot MD PhD Virginie Ferchaud MD MSc Arnaud Pellissier MD Olivier Coffin MD Paul Milliez MD PhD 《Journal of cardiovascular electrophysiology》2021,32(2):545-546
The IntellaMap OrionTM (Boston Scientific) is a 64-electrode basket catheter allowing for ultrahigh-density mapping of complex cardiac arrhythmias. We report the case of a basket catheter vascular entrapment, requiring surgical removal. 相似文献
104.
105.
Virginie Bernier Monique Lagacé Daniel G Bichet Michel Bouvier 《Trends in Endocrinology and Metabolism》2004,15(5):222-228
Increasing numbers of inherited diseases are found to result from mutations that lead to misfolded proteins. In many cases, the changes in conformation are relatively modest and the function of the protein would not be predicted to be affected. Yet, these proteins are recognized as "misfolded" and degraded prematurely. Recently, small molecules known as chemical and pharmacological chaperones were found to stabilize such mutant proteins and facilitate their trafficking to their site of action. Here, we review the recent published evidence suggesting that pharmacological chaperones represent promising avenues for the treatment of endocrine and metabolic diseases such as hyperinsulinemic hypoglycemia, hypogonadotropic hypogonadism and nephrogenic diabetes insipidus, and might become a general therapeutic strategy for the treatment of conformational diseases. 相似文献
106.
An increase in cytosolic free calcium (Cai) has been shown to occur early during ischemia in perfused rat, ferret, and rabbit hearts. It has been proposed that this increase in Cai may occur as a result of exchange of Nai for Cao, which occurs as a result of an increase in Nai arising from exchange of Nao for H+i. The latter exchange is stimulated by the intracellular acidification that occurs during ischemia. To test this hypothesis, we examined Cai, Nai, ATP, and pHi during ischemia in rats in the presence and absence of 1 mM amiloride, a Na-H exchange inhibitor. Cai was measured using 19F nuclear magnetic resonance (NMR) of 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetra-acetic acid (5F-BAPTA)-loaded rat hearts. Nai was measured using 23Na NMR, and the shift reagent 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetramethylenephosph onate (Tm[DOTP]-5) was used to separate Nai and Nao. ATP and pH were determined from 31P NMR measurements. During 20 minutes of ischemia, amiloride did not significantly alter the ATP decline but did significantly attenuate the rise in Nai and Cai. After 20 minutes of ischemia, time-averaged Cai was 1.0 +/- 0.2 microM (mean +/- SEM) in amiloride-treated hearts compared with 2.3 +/- 0.9 microM in nontreated hearts. After 20 minutes of ischemia, Nai in the untreated heart was threefold greater than control, whereas in the amiloride-treated heart, Nai was not significantly different from control. These data are consistent with the involvement of Na-Ca exchange in the rise in Cai during ischemia.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
107.
The fat component of the meal is the major stimulant of the gastrocolonic response. The aim of this study was to characterize the mechanism of the gastrocolonic response after eating fat in healthy human volunteers. A bipolar clip electrode recorded spike activity (SP) from the distal colon. An immediate increase in colonic spike activity occurred after eating a fat meal (18.0 +/- 3.0 SP/30 min) (p less than 0.02). Spike activity remained elevated for 90 min after eating the fat meal (18.6 +/- 2.7 SP/30 min) (p less than 0.01). The intravenous infusion of naloxone or atropine inhibited the fat-induced increase in colonic motility. Cholecystokinin is a candidate mediator of the fat-stimulated gastrocolonic response. The intravenous infusion of the octapeptide of cholecystokinin (20 ng/kg . h) stimulated an increase in distal colonic spike activity (16.0 +/- 3.7 SP/30 min) (p less than 0.025). Intravenous atropine did not affect stimulation of colonic motility by the octapeptide of cholecystokinin. Continuous infusion of naloxone, however, did inhibit stimulation of colonic spike activity by the octapeptide of cholecystokinin. There was no cross-reactivity between opiate or muscarinic receptors. These data suggest (a) fat stimulation of the gastro-colonic response required a muscarinic and opiate receptor, and (b) octapeptide of cholecystokinin can stimulate colonic motility, but it is not the major mediator of the gastrocolonic response. 相似文献
108.
Total effective vascular compliance, hemodynamic parameters, cardiopulmonary (CPBV) and total blood volumes (TBV) were determined in 31 men, including nine normotensive controls and 22 permanent essential hypertensive patients. The effective compliance was calculated from the changes in central venous pressure recorded simultaneously with the changes in blood volume obtained after a rapid dextran infusion. In hypertensives, compliance was significantly reduced (1.55 +/- 0.6 vs 2.25 +/- 0.11 ml./mm. Hg/Kg. in controls) (P less than 0.001) and negatively correlated with blood pressure (P less than 0.01), cardiac index (P less than 0.01), and the CPBV/TBV ratio (P less than 0.01). These results suggest that venous compliance contributes to the control of cardiac output in essential hypertension. 相似文献
109.
BACKGROUND: Increased pulse pressure and arterial stiffness are identified as predictors of cardiovascular risk in older hypertensive populations, particularly that of myocardial infarction. Because increased pulse pressure involves an increase in systolic (SBP) and a decrease in diastolic blood pressure (DBP), and because the former promotes cardiac hypertrophy and the latter alters coronary perfusion, a drug regimen reducing pulse pressure and decreasing arterial stiffness might further reduce cardiovascular risk. Under conventional treatment, normalization of DBP (< or = 90 mmHg) is not consistently associated with normalization of SBP (< or = 140 mmHg). THERAPEUTIC DESIGNS: In individuals older than 50 years, the goal of antihypertensive treatment should be, not only to decrease mean blood pressure (to less than 100 mmHg), but also to decrease pulse pressure (to less than 50 mmHg). Using appropriate pharmacological tools, trials should test whether an active decrease in arterial stiffness might produce an attenuation of the age-related increase in SBP and decrease in DBP, thus delaying the age-related increase in pulse pressure and decreasing further cardiovascular risk. This procedure requires concomitant non-invasive evaluations of aortic stiffness. CONCLUSION: The studies that are required in hypertension should use two different approaches: novel titrations of conventional drugs to achieve a decrease in either SBP or pulse pressure, and development of new drugs acting selectively on the large artery wall, to facilitate the conduct of subsequent controlled trials. 相似文献
110.
Inhibition of protein synthesis in rabbit reticulocyte lysates by double-stranded RNA and oxidized glutathione: indirect mode of action on polypeptide chain initiation. 总被引:9,自引:14,他引:9
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M J Clemens B Safer W C Merrick W F Anderson I M London 《Proceedings of the National Academy of Sciences of the United States of America》1975,72(4):1286-1290
In the presence of added double-stranded RNA or oxidized glutathione, protein synthesis in heminsupplemented reticulocyte lysates declines abruptly after 8-12 min of incubation at 30 degrees. The kinetics of amino-acid incorporation are very similar to those seen when lysates incorporation are very similar to those seen when lysates are incubated in the absence of added hemin. The inhibitory effects of double-stranded RNA (dsRNA) and oxidized glutathione (GSSG) are partially overcome by a homogeneous initiation factor, IF-MP, which also stimulates protein synthesis in hemin-deficient lysates. This factor is involved in the binding of Met-tRNAfmet to 40S ribosomal subunits during protein chain initiation. However, neither dsRNA alone nor GSSG alone significantly inhibits formation of [40S subunit-Met-tRNAf] complexes induced in reticulocyte lysates by dsRNA or GSSG involves one or more components present in the lysates but absent from the fractionated in vitro system. Such components may be related to the translational inhibitor that is active in hemin-deficient lysates. 相似文献