全文获取类型
收费全文 | 1275129篇 |
免费 | 94109篇 |
国内免费 | 1984篇 |
专业分类
耳鼻咽喉 | 18185篇 |
儿科学 | 42257篇 |
妇产科学 | 37812篇 |
基础医学 | 186983篇 |
口腔科学 | 35380篇 |
临床医学 | 108102篇 |
内科学 | 251427篇 |
皮肤病学 | 26497篇 |
神经病学 | 99170篇 |
特种医学 | 49981篇 |
外国民族医学 | 366篇 |
外科学 | 197579篇 |
综合类 | 26513篇 |
现状与发展 | 1篇 |
一般理论 | 300篇 |
预防医学 | 92580篇 |
眼科学 | 29056篇 |
药学 | 97755篇 |
1篇 | |
中国医学 | 2496篇 |
肿瘤学 | 68781篇 |
出版年
2018年 | 11808篇 |
2015年 | 11610篇 |
2014年 | 15994篇 |
2013年 | 24343篇 |
2012年 | 33540篇 |
2011年 | 35935篇 |
2010年 | 21206篇 |
2009年 | 20013篇 |
2008年 | 34973篇 |
2007年 | 37940篇 |
2006年 | 38497篇 |
2005年 | 37791篇 |
2004年 | 36376篇 |
2003年 | 35366篇 |
2002年 | 34915篇 |
2001年 | 58093篇 |
2000年 | 59583篇 |
1999年 | 50687篇 |
1998年 | 14232篇 |
1997年 | 12809篇 |
1996年 | 13071篇 |
1995年 | 12345篇 |
1994年 | 11757篇 |
1993年 | 10860篇 |
1992年 | 40984篇 |
1991年 | 40358篇 |
1990年 | 39885篇 |
1989年 | 38706篇 |
1988年 | 36108篇 |
1987年 | 35349篇 |
1986年 | 33723篇 |
1985年 | 32134篇 |
1984年 | 23922篇 |
1983年 | 20818篇 |
1982年 | 12377篇 |
1981年 | 10927篇 |
1980年 | 10204篇 |
1979年 | 22635篇 |
1978年 | 15877篇 |
1977年 | 13729篇 |
1976年 | 12970篇 |
1975年 | 14201篇 |
1974年 | 16682篇 |
1973年 | 16076篇 |
1972年 | 15318篇 |
1971年 | 14229篇 |
1970年 | 13214篇 |
1969年 | 12731篇 |
1968年 | 11978篇 |
1967年 | 10478篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
991.
Controlled study of haloperidol, pimozide and placebo for the treatment of Gilles de la Tourette's syndrome 总被引:5,自引:0,他引:5
E Shapiro A K Shapiro G Fulop M Hubbard J Mandeli J Nordlie R A Phillips 《Archives of general psychiatry》1989,46(8):722-730
The results of this controlled study of the treatment of 57 patients with Gilles de la Tourette's syndrome suggested that both haloperidol and pimozide were more effective than placebo, but that haloperidol was slightly more effective than pimozide. Adverse effects occurred more frequently with haloperidol vs placebo than with pimozide vs placebo, but the frequency was not significantly different for haloperidol compared with pimozide. Clinically significant cardiac effects did not occur at a maximum dosage of 0.3 mg/kg or 20 mg/d for pimozide and 10 mg/d for haloperidol. However, the QTc interval was prolonged during pimozide treatment compared with that during haloperidol treatment, although the values for both medications were not in an abnormal range. 相似文献
992.
G Stüttgen 《Zeitschrift für Hautkrankheiten》1989,64(11):971-6, 979
We discuss the senescence of the skin considering both intrinsic aging and photoaging; special regard is paid to the various layers, the microcirculation, and the adnexa of the skin. In particular, the barrier function and microcirculation of the skin has been pointed out. 相似文献
993.
994.
J H Newcorn J M Halperin J M Healey J D O'Brien D M Pascualvaca L E Wolf A Morganstein V Sharma J G Young 《Journal of the American Academy of Child and Adolescent Psychiatry》1989,28(5):734-738
To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed. 相似文献
995.
D G Daniel K F Berman D R Weinberger 《The Journal of neuropsychiatry and clinical neurosciences》1989,1(4):377-384
A double-blind, placebo-controlled crossover study of the effects of apomorphine on regional cerebral blood flow (rCBF) during a prefrontal cortex activation task was undertaken to explore the role of dopamine on cortical function. The subjects were eight drug-free, chronically psychotic patients; six patients had schizophrenia. In each, apomorphine increased the relative prefrontal flow. The results suggest that enhanced prefrontal dopamine activity may reverse deficits in prefrontal cortex metabolism in schizophrenia. 相似文献
996.
Inhibition of the replication of hepatitis B virus by the carbocyclic analogue of 2''-deoxyguanosine. 总被引:10,自引:2,他引:8
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)
P M Price R Banerjee G Acs 《Proceedings of the National Academy of Sciences of the United States of America》1989,86(21):8541-8544
We report that treatment of 2.2.15, a human hepatoblastoma-derived cell line in which hepatitis B virus is actively replicating, with the carbocyclic analogue of 2'-deoxyguanosine [Shealy, Y. F., O'Dell, C. A., Shannon, W. M. & Arnett, G. (1984) J. Med. Chem. 27, 1416-1421] resulted in the nearly complete cessation of viral replication, as monitored by the absence of both intracellular episomal and secreted viral DNAs and by the absence of viral DNA polymerase activity. The drug was nontoxic in concentrations up to 200 times the minimum effective inhibitory concentration. 相似文献
997.
998.
Out of 24 patients with laryngeal papillomatosis 6 (5 female, 1 male) suffered from repeated relapses and underwent long-term treatment with alpha-IFN-therapy. Age at onset of the disease: 1 5/12-16 2/12 years. Duration of illness: 1-7 years, with several relapses were treated surgically and with laser-coagulation. Three out of 6 patients had a tracheal cannula and were cauterized by podophylline at 2-4 week intervals. IFN was given in dosages of 5-20 X 10(4) U/kg 2 or 3 times a week. IFN-dosage for each patient was determined using the induction kinetics of (2'-5')-oligo(A)synthetase (OAS) in the mononuclear cells of the circulating blood of patients with laryngeal papillomatosis. A continuous effect could be achieved by the dose of IFN determined in the described way always before OAS activity decreased to its initial level. All 6 patients responded favorably to the alpha-IFN-therapy. Two patients treated only with IFN showed remission without relapses. In 2 cases IFN was successfully used to prevent relapses after surgical treatment and laser-coagulation. In 2 patients with papillomatosis extending into the main bronchi the disease could only be brought to a standstill, i.e. it was not necessary to remove the papillomas. Two out of 3 patients with laryngeal papillomatosis could be decannulated. Long-term therapy following the above described principles is efficient and without significant side-effects. Three patients are in treatment for more than 3 10/12 years. 相似文献
999.
S Shuman E M Kane S G Morham 《Proceedings of the National Academy of Sciences of the United States of America》1989,86(24):9793-9797
Site-directed mutagenesis of the vaccinia virus gene encoding a type I DNA topoisomerase implicates Tyr-274 as the active-site residue that forms a covalent adduct with DNA during cycles of DNA-strand breakage and reunion. Replacement of Tyr-274 by phenylalanine results in loss of the ability of the enzyme to relax negatively supercoiled DNA as well as to form the covalent DNA-protein intermediate. Substitution of phenylalanine for tyrosine at nine other sites in the protein has no apparent effect on enzyme activity. Amino acid sequence alignment reveals Tyr-274 to be homologous to Tyr-727 and Tyr-771, respectively, of the type I topoisomerases from Saccharomyces cerevisiae and Saccharomyces pombe; Tyr-727 and Tyr-771 have been shown to represent the active-site tyrosines of those enzymes. Sequence comparison of the active-site regions defines a motif Ser-Lys-Xaa-Xaa-Tyr common to the viral and cellular type I topoisomerases, including the human enzyme. 相似文献
1000.
S. Tsagarakis Feng Ge L. H. Rees G. M. Besser A. Grossman 《Journal of neuroendocrinology》1989,1(2):129-133
While extensive evidence suggests that adrenoceptors play an important role in the control of growth hormone in the rat, there are few studies involving the direct measurement of growth hormone-releasing hormone (GHRH). We have therefore developed a radioimmunoassay for rat GHRH, and used it to investigate the modulation of GHRH release by noradrenaline from incubated rat hypothalamus in vitro. The GHRH radioimmunoassay had no significant cross-reactivity with other hypothalamic or GHRH-related peptides, and was sensitive to 4 pg/tube; intra- and interassay coefficients of variation were 6% and 12% respectively. Single incubated rat hypothalami produced a stable and readily measurable output of GHRH in successive 20 min incubations after an initial 60 min preincubation; the release of GHRH was increased in the presence of 56 mM KCI, but did not respond to KCI-depolarization when calcium was excluded from the medium. Stimulated GHRH release was identical to synthetic rat GHRH(1–43) on high-performance liquid chromatography and Sephadex G-75 chromatography.
Noradrenaline stimulated GHRH secretion in a dose-dependent manner in the concentration range 10−10 — 10−6 M, with a plateau in response at 10−7 M. Stimulation with noradrenaline 10−7 M was blocked by idazoxan 10−5 M and attenuated by thymoxamine 10−5 M, but was unaffected by timolol 10−5 M. Both the α2 -adrenoceptor agonist guanfacine, and the α1 -adrenoceptor agonist methoxamine, specifically stimulated GHRH secretion.
It is concluded that noradrenaline stimulates the release of GHRH at both α1 and α2 -adrenoceptors. 相似文献
Noradrenaline stimulated GHRH secretion in a dose-dependent manner in the concentration range 10
It is concluded that noradrenaline stimulates the release of GHRH at both α