全文获取类型
收费全文 | 29495篇 |
免费 | 4689篇 |
国内免费 | 263篇 |
专业分类
耳鼻咽喉 | 925篇 |
儿科学 | 977篇 |
妇产科学 | 761篇 |
基础医学 | 2935篇 |
口腔科学 | 904篇 |
临床医学 | 4003篇 |
内科学 | 5955篇 |
皮肤病学 | 854篇 |
神经病学 | 2833篇 |
特种医学 | 1255篇 |
外科学 | 5363篇 |
综合类 | 538篇 |
现状与发展 | 2篇 |
一般理论 | 9篇 |
预防医学 | 2773篇 |
眼科学 | 628篇 |
药学 | 1592篇 |
中国医学 | 24篇 |
肿瘤学 | 2116篇 |
出版年
2023年 | 568篇 |
2022年 | 271篇 |
2021年 | 576篇 |
2020年 | 900篇 |
2019年 | 493篇 |
2018年 | 994篇 |
2017年 | 888篇 |
2016年 | 1057篇 |
2015年 | 1000篇 |
2014年 | 1375篇 |
2013年 | 1673篇 |
2012年 | 1119篇 |
2011年 | 1083篇 |
2010年 | 1151篇 |
2009年 | 1289篇 |
2008年 | 1145篇 |
2007年 | 1012篇 |
2006年 | 1142篇 |
2005年 | 892篇 |
2004年 | 825篇 |
2003年 | 745篇 |
2002年 | 755篇 |
2001年 | 797篇 |
2000年 | 760篇 |
1999年 | 699篇 |
1998年 | 504篇 |
1997年 | 464篇 |
1996年 | 532篇 |
1995年 | 492篇 |
1994年 | 359篇 |
1993年 | 340篇 |
1992年 | 578篇 |
1991年 | 556篇 |
1990年 | 491篇 |
1989年 | 565篇 |
1988年 | 527篇 |
1987年 | 415篇 |
1986年 | 443篇 |
1985年 | 477篇 |
1984年 | 353篇 |
1983年 | 285篇 |
1982年 | 235篇 |
1981年 | 213篇 |
1979年 | 240篇 |
1978年 | 233篇 |
1977年 | 247篇 |
1976年 | 203篇 |
1975年 | 208篇 |
1973年 | 202篇 |
1972年 | 200篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
S E Starkstein R G Robinson M L Berthier R M Parikh T R Price 《Archives of neurology》1988,45(7):725-730
Patients with computed tomographic scan-verified unilateral lesions in the basal ganglia or thalamus were examined for the presence of poststroke mood disorders. Patients with left-sided basal ganglia lesions (mainly in the head of the caudate nucleus) showed a significantly higher frequency and severity of depression, as compared with patients with right-sided basal ganglia or thalamic (left- or right-sided) lesions. Results suggest that damage to biogenic amine pathways and/or frontocaudate projections may play an important role in the modulation of mood. 相似文献
72.
Abnormalities of copper in Gilles de la Tourette syndrome 总被引:1,自引:0,他引:1
The Gilles de la Tourette syndrome is a disorder whose etiology and pathogenesis are little understood. The number of biochemical abnormalities described in this disorder is minimal. Ten of a total of 80 patients were found to have an abnormally low serum copper. A report is presented on two patients who consented to further detailed investigation and in whom copper radioisotope studies were carried out. Both exhibited abnormalities of copper handling, in that we observed an abnormally fast disappearance of copper from the plasma and an abnormally slow uptake by the liver. The rates of intestinal absorption and urinary excretion were normal. We did not identify an abnormal site of sequestration of the metal in the body. 相似文献
73.
Over the past 20 years there has not only been a substantialincrease in indicators of alcoholrelated harm, but also an increasein professional and public awareness of alcohol problems andthe need to prevent them. Sadly, however, much of this awarenessof the need for prevention has resulted in little more thanrather desultory calls for more education. From my pointof view it is time to shift further some of the emphasesin the debate aboust alcohol, education and action. 相似文献
74.
A J Robinson 《The Anatomical record》1987,217(1):1-7
The spatial distribution of twitch and tonic fibres in a snake muscle one myofibre thick (ventral costocutaneous) has been investigated. It was found that small groups of like fibres were favoured at the expense of larger groups when compared with sequences generated by a computer in which fibres were distributed randomly. The number of times that like fibres occurred next to one another was used as another measure of their spatial distribution. The number of adjacencies of like fibres was less than the expected number of adjacencies determined both by random sequences and by probability theory. The expected number of adjacencies determined by means of random sequences and a priori probability theory were almost identical. This dispersion of like fibres may reflect processes that occur during muscle development and may have functional implications. 相似文献
75.
76.
The pathologist's examination of the "lumpectomy"--the pathologists' view of surgical margins. 总被引:1,自引:0,他引:1
Despite the widespread conservative management of breast cancer, the pathologists' examination of these specimens is far from uniform. Pathologists sample margins differently, and even disagree on what constitutes a positive margin. This variability in the pathologic examination of the lumpectomy creates tremendous problems in analyzing the existing literature on the importance of positive margins. Herein is a discussion of the available data on the significance of margin assessment. We furthermore suggest a practical approach to examining margins with an emphasis on a functional orientation of the specimen with respect to the nipple. Only by adopting a uniform system of margin assessment can we begin to critically evaluate the importance of positive margins in segmental resections of the breast. 相似文献
77.
Dr. A. Belluzzi MD C. Brignola MD M. Campieri MD E. P. Camporesi BS P. Gionchetti MD F. Rizzello MD C. Belloli MD G. De Simone MD S. Boschi MD M. Miglioli MD L. Barbara MD 《Digestive diseases and sciences》1994,39(12):2589-2594
Fish oil has been recently proposed as a possible effective treatment in inflammatory bowel disease (IBD); however, a lot of annoying side effects (ie, belching, halitosis, diarrhea, etc) affect patient compliance. We carried out a study of patient tolerance in a group of Crohn's disease (CD) patients with a new fish oil derivative consisting of 500-mg capsules of eicosapentaenoic-docosahexaenoic (EPA 40%-DHA 20%), a free fatty acid mixture (Purepa), and we also evaluated its incorporation into phospholipids, both in plasma and in red cell membranes. Five groups of 10 CD patients in remission received nine Purepa capsules daily in four different preparations (A: uncoated, B: coated, pH 5.5; C: coated, pH 5.5, 60 min time release; D: coated, pH 6.9) and 12 × 1-g capsules daily of a triglyceride preparation (Max-EPA, EPA 18%-DHA 10%), respectively. We coated three of the four Purepa preparations in order to delay the release of contents in an attempt to minimize the side effects. After six weeks of treatment, the group taking Purepa capsules, coated, pH 5.5, 60 min time release (group C) showed the best incorporation of EPA and DHA in red blood cell phospholipid membranes (EPA from 0.2 to 4.4%, DHA from 3.7 to 6.3%), and no side effects were registered, whereas in all other groups side effects were experienced in 50% or more of subjects. This new preparation will make it possible to treat patients for long periods. 相似文献
78.
The lighting environment where the baby born prematurely is placed is different from that experienced in utero. As early exposure to light may affect the immature visual system we have attempted to quantify the neonatal ocular light dose. Lighting surveys performed in 7 neonatal units (NNUs) suggested that mean unit illuminance was 470 lux (range 192-890 lux) and intensive care areas within the NNU were significantly brighter than their corresponding low dependency nurseries. The spectral power distribution of fluorescent lights in NNUs was weighted towards the blue end of the spectrum. Datalogging studies demonstrated that between about 30% and 98% of environmental light was incident on the eyelid, which acts as a predominantly red-pass filter, permitting 21% transmission at 700 nm with less than or equal to 5% transmission at 580 nm. Eye-lid opening frequency was quantified: 45% less than or equal to 26 weeks gestational age and decreasing to 7% at 28 weeks gestational age. The onset of the pupillary reflex to light was between 30 and 34 weeks postmenstrual age, the mean diameter was 3.46 mm before this event and 3.02 mm afterwards. Retinal irradiance values calculated from these data show that it is a function of postmenstrual age. Further studies are required to determine its effect on the immature visual system. 相似文献
79.
M. L. Strong BS RPh L. J. Schaaf PhD M. C. Pankaskie PhD D. H. Robinson PhD 《Journal of clinical pharmacy and therapeutics》1994,19(6):361-369
Published reports regarding the stability of morphine are at variance, especially in syringes used in patient-controlled analgesia (PCA) devices. In addition to the effects of container type and vehicle, reasons for this variation include the effect of excipients temperature and light during storage. Furthermore, the literature varies regarding the mechanisms of decomposition for morphine. To our knowledge, the stability of meperidine (pethidine) stored in plastic syringes has not been reported. The purposes of this study were to investigate the stability of morphine sulphate (1 and 5 mg/ml) and meperidine hydrochloride (5 and 10 mg/ml) in plastic syringes for use in PCA devices for a duration of 12 weeks, and evaluate the influence of light (240 foot-candies), temperature (-20, 4 and 23d?C), diluent (5% dextrose or normal saline), and drug concentration on the stability of these narcotic analgesics. Samples were taken bi-weekly for solutions protected from light and weekly for solutions exposed to light. Morphine sulphate and meperidine hydrochloride concentrations were quantified using independent, stability-indicating, high performance liquid chromatographic assays. The within-day and between-day coefficients of variation for these assays were 4% over each of the concentration ranges studied. Under the conditions of this study, it is proposed that although decomposition of morphine to its main product, pseudomorphine, can be interpreted using first-order kinetics, consecutive (to form the N-oxide) and parallel mechanisms (to form apomorphine) exist. Morphine solutions were more stable in normal saline than in 5% dextrose. SheIf-life data indicate that morphine is stable for at least 6 weeks when protected from light. Exposure to light accelerates morphine decomposition two to six-fold depending on the concentration, and the shelf-life is reduced to about 1 week in some instances. Meperidine solutions in both vehicles under all conditions had shelf-lives of at least 12 weeks. No effects of light were detected and no changes in solution colour were observed. This study illustrates that patients using PCA devices must be advised about shelf-lives as well as correct storage conditions to protect solutions of these drugs from environmental factors that may alter shelf-lives. Pharmacists should also note that other formulation factors such as: antioxidants, preservations, buffers, impurities, and the source and quality of containers, may significantly alter the shelf-lives of these drugs. 相似文献
80.