全文获取类型
收费全文 | 2378654篇 |
免费 | 195370篇 |
国内免费 | 4214篇 |
专业分类
耳鼻咽喉 | 34273篇 |
儿科学 | 72851篇 |
妇产科学 | 63013篇 |
基础医学 | 335319篇 |
口腔科学 | 67590篇 |
临床医学 | 216083篇 |
内科学 | 469425篇 |
皮肤病学 | 47975篇 |
神经病学 | 201148篇 |
特种医学 | 96152篇 |
外国民族医学 | 886篇 |
外科学 | 360954篇 |
综合类 | 56326篇 |
现状与发展 | 1篇 |
一般理论 | 981篇 |
预防医学 | 191080篇 |
眼科学 | 55494篇 |
药学 | 177726篇 |
4篇 | |
中国医学 | 4367篇 |
肿瘤学 | 126590篇 |
出版年
2018年 | 24294篇 |
2016年 | 20642篇 |
2015年 | 23342篇 |
2014年 | 33612篇 |
2013年 | 51002篇 |
2012年 | 68946篇 |
2011年 | 72507篇 |
2010年 | 42602篇 |
2009年 | 40970篇 |
2008年 | 68923篇 |
2007年 | 73292篇 |
2006年 | 74224篇 |
2005年 | 72191篇 |
2004年 | 69525篇 |
2003年 | 67182篇 |
2002年 | 66429篇 |
2001年 | 112579篇 |
2000年 | 116638篇 |
1999年 | 98421篇 |
1998年 | 27919篇 |
1997年 | 25573篇 |
1996年 | 25493篇 |
1995年 | 24641篇 |
1994年 | 23197篇 |
1993年 | 21589篇 |
1992年 | 79456篇 |
1991年 | 76493篇 |
1990年 | 73632篇 |
1989年 | 70914篇 |
1988年 | 65896篇 |
1987年 | 64857篇 |
1986年 | 61382篇 |
1985年 | 58464篇 |
1984年 | 44276篇 |
1983年 | 37700篇 |
1982年 | 22910篇 |
1981年 | 20355篇 |
1980年 | 19058篇 |
1979年 | 41323篇 |
1978年 | 29016篇 |
1977年 | 24376篇 |
1976年 | 22855篇 |
1975年 | 23982篇 |
1974年 | 29660篇 |
1973年 | 28069篇 |
1972年 | 26245篇 |
1971年 | 24166篇 |
1970年 | 22765篇 |
1969年 | 21107篇 |
1968年 | 19152篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
D Mari? J Velji? J Ranin B D Jankovi? 《The International journal of neuroscience》1991,59(1-3):135-142
There is a large body of evidence for the role of thymosin peptides in immunogenesis and immunity. In this paper we report on the influence of prothymosin alpha 1 (ProT-alpha 1), a hormone-like peptide derived from the calf thymus, on humoral and cellular immune reactions in the rat. Young adults received intraperitoneal injections of ProT-alpha 1 in the periods before and after immunization with cellular and soluble antigens. ProT-alpha-treatment produced a dose-dependent increase of both humoral and cell-mediated immune responses. The thymus weight increased but not that of spleen. Treatment of nonimmunized rats with this polypeptide significantly elevated the number of CD4+ and decreased the number of CD8+ cells in the peripheral blood. The results suggest a potent immunostimulatory activity of ProT-alpha 1 and imply direct action of this polypeptide on T lymphocytes. 相似文献
992.
993.
994.
D S Rao R Antonelli K R Kane J E Kuhn C Hetnal 《Henry Ford Hospital medical journal》1991,39(1):41-44
Coexistent primary hyperparathyroidism and monoclonal gammopathy, although rare, has been reported previously by a number of investigators. We report four patients with such an occurrence who were seen between 1976 and 1988. Another patient with primary hyperparathyroidism also had multiple myeloma and was in remission for 12 years. These patients represent approximately 1% of the 386 patients with primary hyperparathyroidism seen during the same 12-year period. Although several mechanisms have been proposed to explain this concurrence, we believe it is the result of a chance occurrence. A review of the literature, an estimate of the chance occurrence of coincidental monoclonal gammopathy, benign or malignant, in patients with primary hyperparathyroidism, and some practical implications of this interesting coexistence are presented. 相似文献
995.
E J Garland D H Smith 《Journal of the American Academy of Child and Adolescent Psychiatry》1991,30(4):553-555
Concurrent acute onset of night terrors, somnambulism, and spontaneous daytime panic attacks meeting the criteria for panic disorder is reported in a 10-year-old boy with a family history of panic disorder. Both the parasomnias and the panic disorder were fully responsive to therapeutic doses of imipramine. A second case of night terrors and infrequent full symptom panic attacks is noted in another 10-year-old boy whose mother has panic disorder with agoraphobia. The clinical resemblance and reported differences between night terrors and panic attacks are described. The absence of previous reports of this comorbidity is notable. It is hypothesized that night terror disorder and panic disorder involve a similar constitutional vulnerability to dysregulation of brainstem altering systems. 相似文献
996.
We conducted a randomized, double-blind, crossover trial of two anticholinergic agents--trihexyphenidyl and tridihexethyl chloride (a quaternary anticholinergic that does not cross the blood-brain barrier)--in patients with acquired nystagmus and measured visual acuity and nystagmus before and at the end of 1 month on each medication. Of the 10 patients admitted to the study, only five completed trials of both drugs due to intolerance of medication or intercurrent illness. Of six patients who completed the trial of trihexyphenidyl, only one showed improvement. Of six patients who completed a trial of tridihexethyl chloride, four showed improvement. We conclude that (1) trihexyphenidyl is not a reliable treatment for acquired nystagmus, although occasional patients may benefit; (2) anticholinergic agents may suppress nystagmus by peripheral rather than central mechanisms; and (3) the side effects of anticholinergic agents limit their effectiveness in the treatment of nystagmus. 相似文献
997.
998.
N A Zakhari M I Walash M S Rizk S S Toubar C J Brooks W J Cole 《Journal of pharmaceutical and biomedical analysis》1991,9(9):705-709
A simple gas chromatographic procedure has been developed for the determination of methyltestosterone in bulk powders and in tablets. Two new silyl ether derivatives of methyltestosterone have been prepared using dimethylethylsilylimidazole (DMESI) and dimethylisopropylsilylimidazole (DMiPSI). The method is accurate and selective for methyltestosterone within the concentration range 0.1-1.5 micrograms microliters-1. 相似文献
999.
G Hochhaus H Derendorf H M?llmann J Barth 《Journal of pharmaceutical and biomedical analysis》1991,9(9):761-767
A combined LC/RIA procedure is described for the selective determination of dexamethasone (DEX) and its prodrug dexamethasone-21-isonicotinate (DIN) in plasma. The low affinity of the employed dexamethasone antiserum for DIN (cross-reactivity less than 0.5%) allowed the direct determination of DEX in plasma extracts. For the determination of DIN, both substances of interest were separated by LC, the DIN containing fraction was collected, hydrolysed and the generated DEX was consequently assayed by radioimmunoassay. The assay detection limits were 0.1 ng ml-1 for DEX and 0.75 ng ml-1 for DIN. For both substances, inter- and intra-day variabilities (RSDs) were 6 and 12%, respectively. 相似文献
1000.