全文获取类型
收费全文 | 1329537篇 |
免费 | 99219篇 |
国内免费 | 5471篇 |
专业分类
耳鼻咽喉 | 18716篇 |
儿科学 | 42913篇 |
妇产科学 | 38260篇 |
基础医学 | 193296篇 |
口腔科学 | 36217篇 |
临床医学 | 114692篇 |
内科学 | 260218篇 |
皮肤病学 | 27164篇 |
神经病学 | 102216篇 |
特种医学 | 52484篇 |
外国民族医学 | 385篇 |
外科学 | 203327篇 |
综合类 | 35345篇 |
现状与发展 | 15篇 |
一般理论 | 307篇 |
预防医学 | 96051篇 |
眼科学 | 30398篇 |
药学 | 103543篇 |
52篇 | |
中国医学 | 5324篇 |
肿瘤学 | 73304篇 |
出版年
2018年 | 13631篇 |
2017年 | 10592篇 |
2016年 | 11856篇 |
2015年 | 14216篇 |
2014年 | 19107篇 |
2013年 | 27424篇 |
2012年 | 37941篇 |
2011年 | 40626篇 |
2010年 | 24585篇 |
2009年 | 22614篇 |
2008年 | 38107篇 |
2007年 | 41052篇 |
2006年 | 41311篇 |
2005年 | 40540篇 |
2004年 | 38383篇 |
2003年 | 37454篇 |
2002年 | 36673篇 |
2001年 | 59351篇 |
2000年 | 60562篇 |
1999年 | 51607篇 |
1998年 | 14793篇 |
1997年 | 13357篇 |
1996年 | 13439篇 |
1995年 | 12772篇 |
1994年 | 12060篇 |
1993年 | 11041篇 |
1992年 | 41245篇 |
1991年 | 40539篇 |
1990年 | 40042篇 |
1989年 | 38865篇 |
1988年 | 36215篇 |
1987年 | 35464篇 |
1986年 | 33821篇 |
1985年 | 32190篇 |
1984年 | 23958篇 |
1983年 | 20833篇 |
1982年 | 12400篇 |
1981年 | 10942篇 |
1979年 | 22650篇 |
1978年 | 15882篇 |
1977年 | 13737篇 |
1976年 | 12975篇 |
1975年 | 14203篇 |
1974年 | 16688篇 |
1973年 | 16087篇 |
1972年 | 15326篇 |
1971年 | 14232篇 |
1970年 | 13216篇 |
1969年 | 12743篇 |
1968年 | 11980篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
As deficiencies of the cholinergic and non-adrenergic non-cholinergic innervation of the gastrointestinal tract have been described in diabetic rats, we studied the simultaneous release of, and muscular response to, acetylcholine, vasoactive intestinal polypeptide and adenosine-5'-triphosphate in isolated preparations of gastric fundus from control and 8-week streptozotocin-treated diabetic rats. Muscular responses were measured in longitudinal muscle strips prepared from one half of the gastric fundus and release was studied in the other half. The contractile response to acetylcholine and electrical field stimulation was not different in control and diabetic rats. In the presence of atropine, and when tone was increased with prostaglandin F2 alpha, electrical field stimulation, vasoactive intestinal polypeptide and adenosine-5'-triphosphate induced relaxation with a similar response in control and diabetic rats. The basal release of acetylcholine, vasoactive intestinal polypeptide and adenosine-5'-triphosphate was not significantly different in control and diabetic rats. Electrical field stimulation significantly increased the release of the three substances and this increase was tetrodotoxin-sensitive. While the stimulation-induced increase of acetylcholine and vasoactive intestinal polypeptide was not different in control and in diabetic rats, the stimulation-induced release of adenosine-5'-triphosphate increased 3-fold in diabetic compared to control gastric fundus. Desensitization to alpha,beta-methylene adenosine-5'-triphosphate reduced the relaxant response to adenosine-5'-triphosphate and to electrical field stimulation, suggesting a role of adenosine-5'-triphosphate in non-adrenergic non-cholinergic neurotransmission of rat gastric fundus. The reduction of the non-adrenergic non-cholinergic relaxation by alpha,beta-methylene adenosine-5'-triphosphate was greater in diabetic tissues. This, with the increase in stimulation-induced adenosine-5'-triphosphate release, suggests that the purinergic component of the vagal non-adrenergic non-cholinergic response of the stomach may be increased in diabetics. 相似文献
992.
A young patient had an auriculo-ventricular block and a distal myopathy with muscle biopsy findings suggestive of inclusion body myositis. What was most unusual was the presence of numerous sarcoplasmic bodies identified as desmin by electron microscopy and immunocytochemistry. The nosological situation of this condition is discussed. 相似文献
993.
Increased lymphocyte beta-adrenergic receptor density in progressive multiple sclerosis is specific for the CD8+, CD28- suppressor cell. 总被引:1,自引:0,他引:1
Beta-adrenergic receptor density on T cells from healthy humans is greatest on suppressor cells (CD8+, CD28-) and the effect of catecholamines, secreted by the sympathetic nervous system, predominates on this subset. The sympathetic skin response, a measure of sympathetic nervous system function, is absent in most patients with chronic progressive multiple sclerosis (MS). We measured beta-adrenergic receptor density on suppressor cells, cytotoxic cells, and monocytes from patients with chronic progressive MS and healthy control subjects. Control receptor density on suppressor cells was 2.8 +/- 0.3 fmol/10(6) cells versus a density of 5.1 +/- 0.7 fmol/10(6) cells for patients. Cytotoxic cell (CD8+, CD28+) receptor density was 1.4 +/- 0.4 fmol/10(6) cells in control subjects and 0.9 +/- 0.3 fmol/10(6) cells in the patients. Monocytes displayed beta-adrenergic receptor densities of 2.6 +/- 0.4 fmol/10(6) cells in normal individuals and 2.7 +/- 0.4 fmol/10(6) cells in the patient group. CD8 lymphocyte beta-adrenergic receptor densities in patients with relapsing-remitting and those with stable MS were not different from control values, yet were significantly less than the values for patients with chronic progressive MS. We find that mononuclear cells from healthy control subjects and patients with chronic progressive MS proliferate in response to 200 units/ml of recombinant human interleukin-2 (IL-2) similarly. However, IL-2 treatment increased beta-adrenergic receptor density on normal mononuclear cells, but failed to increase it on mononuclear cells from patients with chronic progressive MS.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
994.
R J Barrnett J P Docherty G M Frommelt 《Journal of the American Academy of Child and Adolescent Psychiatry》1991,30(1):1-14
Reports on individual nonbehavioral child and adolescent psychotherapy since 1963 are reviewed. Inclusion criteria required some minimal contrasting group. Forty-three studies were assessed for basic methodological adequacy and main findings. The authors conclude that summary impressions from this body of literature cannot be made due to the magnitude of the flaws in basic psychotherapy research methodology. Suggestions are made regarding the future of child and adolescent psychotherapy research. 相似文献
995.
996.
Bipolar disorder is a serious mental illness affecting a large number of Americans. While lithium, the treatment of choice for this disorder, is usually effective, a substantial number of individuals with bipolar disorder are not helped by lithium or are intolerant to its side effects. Consequently, investigators are searching for alternative drugs in order to treat lithium-resistant patients. Although a number of alternative drug treatments have been discussed in the literature, only the anticonvulsants carbamazepine and valproate appear to warrant serious consideration at this time. Future research will further define their roles as antimanic agents. 相似文献
997.
998.
999.
G I Rumiantsev T M Khodykina V I Arkhangel'ski? L N Nesterenko 《Gigiena truda i professional'nye zabolevaniia》1991,(6):19-22
In the processing of the waste products of phosphorus containing fertilizer production, several major health-related factors were identified depending on the industrial site's peculiarities: unfavourable microclimate conditions (both cold and heat), relative temperature differences, noise and vibration caused by the equipment, semi-product's, additives' and finished product's dusts, fluorine- and phosphorus-containing substances' affects and poor illumination. The proposed data were used for health-related improvements in the occupational conditions. 相似文献
1000.
NTS fallout-induced multiple myeloma in Utah. 总被引:1,自引:0,他引:1