全文获取类型
收费全文 | 1337426篇 |
免费 | 100340篇 |
国内免费 | 4288篇 |
专业分类
耳鼻咽喉 | 16811篇 |
儿科学 | 43644篇 |
妇产科学 | 36438篇 |
基础医学 | 198049篇 |
口腔科学 | 35965篇 |
临床医学 | 129715篇 |
内科学 | 258824篇 |
皮肤病学 | 26401篇 |
神经病学 | 112073篇 |
特种医学 | 48217篇 |
外国民族医学 | 368篇 |
外科学 | 184342篇 |
综合类 | 28776篇 |
现状与发展 | 1篇 |
一般理论 | 460篇 |
预防医学 | 114429篇 |
眼科学 | 28985篇 |
药学 | 98915篇 |
6篇 | |
中国医学 | 3169篇 |
肿瘤学 | 76466篇 |
出版年
2021年 | 10959篇 |
2019年 | 11680篇 |
2018年 | 16368篇 |
2017年 | 12316篇 |
2016年 | 13292篇 |
2015年 | 15260篇 |
2014年 | 20868篇 |
2013年 | 32152篇 |
2012年 | 44374篇 |
2011年 | 47025篇 |
2010年 | 27156篇 |
2009年 | 24990篇 |
2008年 | 42842篇 |
2007年 | 45187篇 |
2006年 | 45280篇 |
2005年 | 43712篇 |
2004年 | 41669篇 |
2003年 | 39592篇 |
2002年 | 38381篇 |
2001年 | 60886篇 |
2000年 | 62569篇 |
1999年 | 52333篇 |
1998年 | 14600篇 |
1997年 | 13286篇 |
1996年 | 13134篇 |
1995年 | 12466篇 |
1994年 | 11642篇 |
1993年 | 10932篇 |
1992年 | 41602篇 |
1991年 | 40787篇 |
1990年 | 39474篇 |
1989年 | 37385篇 |
1988年 | 34612篇 |
1987年 | 33713篇 |
1986年 | 32170篇 |
1985年 | 30661篇 |
1984年 | 23046篇 |
1983年 | 19606篇 |
1982年 | 11766篇 |
1979年 | 20820篇 |
1978年 | 14825篇 |
1977年 | 12076篇 |
1976年 | 11880篇 |
1975年 | 12116篇 |
1974年 | 14808篇 |
1973年 | 14476篇 |
1972年 | 13369篇 |
1971年 | 12419篇 |
1970年 | 11486篇 |
1969年 | 10412篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
The proliferative T-lymphocyte response to streptokinase 总被引:1,自引:0,他引:1
Purified streptokinase was found to initiate a proliferative T-lymphocyte response. The response was characterized by dose-response and kinetics investigations. Streptokinase did not initiate any response when tested on T lymphocytes from newborns, thus indicating that the proliferative T-lymphocyte response to streptokinase in vitro is an antigen stimulated activation of T lymphocytes from individuals previously sensitized in vivo. Of healthy individuals, 40% (16 out of 40 tested) showed a significant proliferative response to streptokinase. Methylprednisolone, cyclosporin A, theophyllamine and verapamil all inhibited the streptokinase-stimulated proliferative T-lymphocyte responses in a dose-dependent manner. 相似文献
962.
Localization of epileptogenic foci using a simple reference-subtraction montage to document small interchannel time differences 总被引:1,自引:0,他引:1
P Jayakar M S Duchowny T J Resnick L A Alvarez 《Journal of clinical neurophysiology》1991,8(2):212-215
We present a modified EEG montage that detects small interchannel time differences and assists in localizing the epileptogenic focus. Regions with apparently synchronous epileptic discharges are displayed simultaneously in referential and subtraction derivations. The subtraction derivation is a bipolar configuration of two regions of interest that are not necessarily adjacent. The referential derivation reveals the polarity, voltage, and morphology of the two discharges, and the subtraction derivation detects asynchrony; the combined reference-subtraction derivation thus indicates the region that is activated first. 相似文献
963.
Compared with results obtained in locally anesthetized, paralyzed rats, the dissociative anesthetic ketamine did not alter either the number of spontaneously active striatal neurons or the basal firing rate of striatal neurons; 90% of these cells exhibited the type I striatal neuron waveform. Chloral hydrate anesthesia suppressed both the occurrence and the firing rate of spontaneously active type I cells, but did not alter the activity of type II striatal neurons. Cortical stimulation preferentially activated type II cells in paralyzed rats and in chloral hydrate-anesthetized rats. Thus, under dissociative anesthesia it is possible to study spontaneously active type I striatal neurons. However, a method of activation such as cortical stimulation is necessary to study type II striatal neurons. 相似文献
964.
Stuttering and tetanic syndrome 总被引:1,自引:0,他引:1
965.
D Schiffer L Autilio-Gambetti A Chiò P Gambetti M T Giordana F Gullotta A Migheli M C Vigliani 《Journal of neuropathology and experimental neurology》1991,50(4):463-473
Several neurodegenerative diseases, including motor neuron disease (MND), are characterized by formation of abnormal cytoskeleton-derived inclusions which contain ubiquitin (Ubq). We have studied the distribution of Ubq in 26 cases of MND with light and electron microscopic immunocytochemistry. Ubiquitin-positive inclusions were found in neurons of anterior horns in most cases of amyotrophic lateral sclerosis (ALS) but were not present in other forms of MND. Ubiquitin immunoreactivity was observed in 10-15 nm intraneuronal filaments, which were not stained by antibodies to neurofilaments, and on dense bodies of dystrophic neurites throughout the neuropil of anterior horns and pyramidal tracts. Data analysis showed a trend toward lower percentage of Ubq-positive neurons in cases with longer duration of illness or lower number of neurons. A high percentage of Ubq-positive inclusions occurred in cases with an aggressive clinical course, suggesting that ubiquitination takes place at early stages of the disease. 相似文献
966.
967.
Although many monoclonal antibodies have been made in human colon cancer, none of them are from the Chinese species. Recently, a colon cancer cell line CC-M2 established from a Chinese patient has been completely characterized and used as immunogen to produce monoclonal antibodies. Monoclonal antibodies were produced by standard hybridoma technique. The fusion rate was 95.8%. An isotype IgG1 of high proliferation named as Sam-2 was used in this study. The titers were measured around 10(4). Further studies on MoAb Sam-2 through indirect immunofluorescent and immunoperoxidase tests revealed its good specificity and sensitivity in colorectal cancer tissue. In CEA study, the result indicated that Sam-2 may react on a non-CEA related antigen. For further clinical application, the antigen was identified as a glycoprotein by chemical resistant test. In preliminary studies using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting techniques, Sam-2 could recognize two closed antigens or a dimer antigen with molecular weight 25.2 and 27 Kd respectively. 相似文献
968.
969.
Approximately one quarter of a series of 45 schizophrenic and schizoaffective patients with operationally diagnosed episodes of postpsychotic depression were also found to have anxiety symptoms consistent with the panic-attack syndrome. The incidence of such attacks was distributed across all demographic groups. Heuristic and treatment implications of this observation are considered. 相似文献
970.
Carnitine, valproate, and toxicity 总被引:1,自引:0,他引:1
D L Coulter 《Journal of child neurology》1991,6(1):7-14
Carnitine is an important nutrient that is present in the diet (particularly in meat and dairy products) and is synthesized from dietary amino acids. It functions to assist long-chain fatty acid metabolism and to regulate the ratio of free coenzyme A to acylcoenzyme A in the mitochondrion. Carnitine deficiency occurs in primary inborn errors of metabolism, in nutritional deficiency, and in various other disorders including antiepileptic drug therapy. Valproate therapy is often associated with decreased carnitine levels and occasionally with true carnitine deficiency. Some experimental and clinical evidence links valproate-induced carnitine deficiency with hepatotoxicity, but this evidence is limited and inconclusive. Carnitine supplementation has been useful in some studies, but these data are also limited. Young children with neurologic disabilities taking multiple antiepileptic drugs may have the greatest risk for carnitine deficiency. Measurement of carnitine levels appears warranted in these patients and in patients with symptoms and signs of possible carnitine deficiency. 相似文献