全文获取类型
收费全文 | 22035篇 |
免费 | 1947篇 |
国内免费 | 86篇 |
专业分类
耳鼻咽喉 | 241篇 |
儿科学 | 728篇 |
妇产科学 | 422篇 |
基础医学 | 3042篇 |
口腔科学 | 355篇 |
临床医学 | 2416篇 |
内科学 | 4411篇 |
皮肤病学 | 332篇 |
神经病学 | 1943篇 |
特种医学 | 788篇 |
外国民族医学 | 3篇 |
外科学 | 2738篇 |
综合类 | 502篇 |
一般理论 | 14篇 |
预防医学 | 2256篇 |
眼科学 | 736篇 |
药学 | 1631篇 |
1篇 | |
中国医学 | 31篇 |
肿瘤学 | 1478篇 |
出版年
2022年 | 147篇 |
2021年 | 326篇 |
2020年 | 246篇 |
2019年 | 367篇 |
2018年 | 393篇 |
2017年 | 305篇 |
2016年 | 360篇 |
2015年 | 422篇 |
2014年 | 590篇 |
2013年 | 855篇 |
2012年 | 1232篇 |
2011年 | 1326篇 |
2010年 | 667篇 |
2009年 | 728篇 |
2008年 | 1106篇 |
2007年 | 1279篇 |
2006年 | 1188篇 |
2005年 | 1216篇 |
2004年 | 1167篇 |
2003年 | 1004篇 |
2002年 | 1000篇 |
2001年 | 469篇 |
2000年 | 487篇 |
1999年 | 504篇 |
1998年 | 371篇 |
1997年 | 299篇 |
1996年 | 284篇 |
1995年 | 250篇 |
1994年 | 209篇 |
1993年 | 192篇 |
1992年 | 323篇 |
1991年 | 318篇 |
1990年 | 308篇 |
1989年 | 317篇 |
1988年 | 285篇 |
1987年 | 272篇 |
1986年 | 289篇 |
1985年 | 251篇 |
1984年 | 217篇 |
1983年 | 170篇 |
1982年 | 166篇 |
1981年 | 131篇 |
1980年 | 132篇 |
1979年 | 195篇 |
1978年 | 148篇 |
1977年 | 120篇 |
1976年 | 106篇 |
1975年 | 102篇 |
1974年 | 115篇 |
1973年 | 134篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
O W Woltersdorf H Schwam J B Bicking S L Brown S J deSolms D R Fishman S L Graham P D Gautheron J M Hoffman R D Larson 《Journal of medicinal chemistry》1989,32(11):2486-2492
A series of O-acyl derivatives of 6-hydroxybenzothiazole-2-sulfonamide (4, L-643,799) was prepared and the potential utility of each series member as a topically active inhibitor of ocular carbonic anhydrase was determined. In vitro studies showed these esters to be substrates for ocular esterases which liberate 4 during corneal translocation. The most interesting series member, 2-sulfamoyl-6-benzothiazolyl 2,2-dimethylpropionate (22, L-645,151), acting as a prodrug form of 4, was found to enhance delivery through the isolated albino rabbit cornea by 40-fold when compared to the parent phenol 4. Studies in rabbits revealed that 22 is a potent topically active ocular hypotensive carbonic anhydrase inhibitor. 相似文献
92.
Pippa Storey Fred J Frigo R Scott Hinks Bryan J Mock Bruce D Collick Nicole Baker Jonathan Marmurek Simon J Graham 《Magnetic resonance in medicine》2007,57(3):614-619
Partial k-space sampling is frequently used in single-shot diffusion-weighted echo-planar imaging (DW-EPI) to reduce the TE and thereby improve the SNR. However, it increases the sensitivity of the technique to bulk rotational motion, which introduces a phase gradient across the tissue that shifts the echo in k-space. If the echo is displaced into the high spatial frequencies, conventional homodyne reconstruction fails, causing intensity oscillations across the image. Zero-padding, on the other hand, compromises the image resolution and may cause truncation artifacts. We present an adaptive version of the homodyne algorithm that detects the location of the echo in k-space and adjusts the center and width of the homodyne filters accordingly. The adaptive algorithm produces artifact-free images when the echo is shifted into the high positive k-space range, and reduces to the standard homodyne algorithm in the absence of bulk motion. 相似文献
93.
Scott M. Graham M.D. Garth H. Ballantyne M.D. Irvin M. Modlin M.D. 《The American journal of gastroenterology》1987,82(1):82-85
This is the first case report of the preoperative diagnosis of a gastric epithelioid leiomyosarcoma by percutaneous needle biopsy. Preoperative diagnosis facilitated curative surgical resection. Patients may present without symptoms or may report symptoms of peptic ulcer disease or gastrointestinal bleeding. Upper gastrointestinal series is the most useful radiological tool for detecting these lesions. Ultrasound and CT play a useful role in documenting the origin of these large masses, as well as their spread. Endoscopy is being used with increasing frequency, but because these are submucosal lesions diagnosis cannot easily be made through the endoscope. Pathologically, these tumors can be subdivided histologically into a benign epithelioid leiomyoma and two varieties of malignant epithelioid leiomyosarcoma. Prognosis correlates with histological features. Complete surgical resection is the treatment of choice. Chemotherapy or radiotherapy have no proven efficacy in treating epithelioid leiomyosarcoma. Unlike most other gastric malignancies, a favorable prognosis follows successful resection. 相似文献
94.
Summary— Experiments were designed to determine whether or not indapamide, an antihypertensive agent with vasodilator properties, inhibits endothelium-dependent contractions. Rings of aortae with and without endothelium from spontaneously hypertensive rats (SHR) were suspended in conventional organ chambers for the measurement of isometric force. Acetylcholine and adenosine diphosphate-β-S in the presence of a nitric oxide synthase inhibitor, caused endothelium-dependent contractions, which were inhibited by indapamide. The compound (10−4 M) also slightly reduced the contractions of rings without endothelium evoked by U-46,619, which activates thromboxane-endoperoxide receptors. These results demonstrate that indapamide inhibits endothelium-dependent contractions in the SHR aorta, and suggest that the inhibition is due, at least in part, to the action of the drug on the hypertensive vascular smooth muscle. 相似文献
95.
96.
Martin A. Graham David R. Newell Brenda J. Foster A. Hilary Calvert 《Cancer chemotherapy and pharmacology》1989,23(1):8-14
Summary CI-941 is a new synthetic DNA-binding agent selected for phase I clinical evaluation. The drug has broad-spectrum antitumour activity against a number of murine tumours and, in contrast to doxorubicin, is unlikely to induce cardiotoxicity by a free-radical-mediated mechanism. In this study the toxicity and pharmacokinetics of CI-941 were studied in the mouse to enable the implementation of a pharmacokinetically guided dose-escalation strategy in patients. Following a single i.v. bolus injection in mice, CI-941 induced dose-dependent leukopenia. The white blood cell counts were suppressed on day 3 by 18%, 50% and 65% of control, at doses of 10, 15 and 20 mg/kg CI-941, respectively. Other toxicities such as weight loss, alopecia, diarrhoea and convulsions were observed at doses >20 mg/kg. Lethality studies in female Balb-c mice resulted in an LD10 value of 20 mg/kg (95% confidence limits; range, 19–21 mg/kg) and an LD50 value of 22 mg/kg (95% confidence limits; range, 21–23 mg/kg). The pharmacokinetics of CI-941 were studied at four dose levels from 1/10 of the LD10 to the LD10 (20 mg/kg). The drug was rapidly cleared from the plasma (250–400 ml/min per kg) at a rate approaching the cardiac output of mice, displaying triphasic plasma pharmacokinetics. The area under the plasma CI-941 concentration vs time curve (AUC) was linear with respect to the dose, up to and including 15 mg/kg (AUC=110 M x min at 15 mg/kg), but became non-linear at 20 mg/kg (AUC=277 M x min). Despite 80%–84% plasma protein binding, CI-941 was rapidly and extensively distributed into tissues, especially the kidney. Following i.v. bolus injections at doses of 1.5 and 15 mg/kg, elimination of the parent compound by urinary excretion accounted for 12%–18% of the delivered dose. A phase-I starting dose (based on that equivalent to 1/10 of the LD10 in the mouse) of 5 mg/m2 CI-941 is recommended for single administration schedules. In addition, a pharmacokinetically guided dose-escalation strategy, based on achieving a target AUC of 110 M x min, is proposed. 相似文献
97.
Richard O. Shillaker Graham M. Bell John T. Hodgson Michael D. J. Padgham 《Archives of toxicology》1989,63(4):283-288
Current European Community (Annex V) guidelines recommend the use of 20 test animals in the guinea pig maximisation test for skin sensitisation. The suitability, for classification and labelling purposes, of reducing the number of test animals has been examined by analysing the results of 40 studies submitted to the Health and Safety Executive, and by the use of a mathematical model. Our results suggest that in most cases an experiment with ten test animals can be used to determine satisfactorily whether a substance should be labelled with the risk phrase may cause sensitisation by skin contact. However, serious consideration should be given to the need for additional investigation if two or three of the ten test animals show a sensitisation response. The highest nonirritant concentration of a substance should be used at challenge. Clearer guidance in Annex V on evaluating challenge responses would be beneficial. 相似文献
98.
The origins of the projections of the superior colliculus to the dorsal lateral geniculate nucleus and to the pulvinar in Dutch-belted rabbits were investigated using horseradish peroxidase (HRP) methods. Following injections of HRP in the dorsal lateral geniculate nucleus, retrogradely labeled neurons were found in the upper two-thirds of the stratum griseum superficiale of the ipsilateral superior colliculus. Most of the labeled somata were spindle-shaped, and their major axes tended to be perpendicular to the surface of the superior colliculus. In contrast, following injections of the pulvinar, labeled neurons were found in the lower third of the ipsilateral stratum griseum superficiale. In these cases, the labeled somata were larger than those labeled following dorsal lateral geniculate injections and were multipolar in shape. 相似文献
99.
Psychophysiology is just as closely related to internal medicine as it is to psychiatry. “Psychological variable” has two distinct meanings: a) an external sensory stimulus, or b) an organismic state described in psychological language. “Psychological” and “Physical” are names of two different languages. There is no such thing as a non-physical illness. Asking whether emotions cause diseases, or diseases cause emotions, leads to many difficulties and is unprofitable. It is far more useful to ask about stimulus-response relationships. There are more kinds of specificity relations in psychophysiology and psychosomatic medicine than are usually recognized, and the usual specificity statements in psychosomatic medicine are not concerned with I-R or S-R specificity. There are many problems in medicine which psychophysiology could help to solve. 相似文献
100.