全文获取类型
收费全文 | 13364篇 |
免费 | 704篇 |
国内免费 | 96篇 |
专业分类
耳鼻咽喉 | 88篇 |
儿科学 | 227篇 |
妇产科学 | 124篇 |
基础医学 | 2162篇 |
口腔科学 | 97篇 |
临床医学 | 1363篇 |
内科学 | 3017篇 |
皮肤病学 | 357篇 |
神经病学 | 1300篇 |
特种医学 | 523篇 |
外科学 | 2040篇 |
综合类 | 52篇 |
一般理论 | 2篇 |
预防医学 | 657篇 |
眼科学 | 215篇 |
药学 | 929篇 |
中国医学 | 40篇 |
肿瘤学 | 971篇 |
出版年
2023年 | 63篇 |
2022年 | 84篇 |
2021年 | 260篇 |
2020年 | 151篇 |
2019年 | 223篇 |
2018年 | 318篇 |
2017年 | 202篇 |
2016年 | 237篇 |
2015年 | 269篇 |
2014年 | 372篇 |
2013年 | 515篇 |
2012年 | 903篇 |
2011年 | 1023篇 |
2010年 | 605篇 |
2009年 | 536篇 |
2008年 | 872篇 |
2007年 | 1012篇 |
2006年 | 908篇 |
2005年 | 943篇 |
2004年 | 879篇 |
2003年 | 865篇 |
2002年 | 845篇 |
2001年 | 138篇 |
2000年 | 106篇 |
1999年 | 149篇 |
1998年 | 214篇 |
1997年 | 165篇 |
1996年 | 164篇 |
1995年 | 110篇 |
1994年 | 111篇 |
1993年 | 110篇 |
1992年 | 99篇 |
1991年 | 65篇 |
1990年 | 51篇 |
1989年 | 65篇 |
1988年 | 57篇 |
1987年 | 46篇 |
1986年 | 48篇 |
1985年 | 39篇 |
1984年 | 48篇 |
1983年 | 41篇 |
1982年 | 42篇 |
1981年 | 33篇 |
1980年 | 36篇 |
1979年 | 24篇 |
1978年 | 22篇 |
1977年 | 16篇 |
1976年 | 10篇 |
1975年 | 10篇 |
1974年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Chretien Marie Francoise; Lebouvier Brigitte; Denis Alain; Chappard Daniel 《Human reproduction (Oxford, England)》1998,13(10):2767-2771
A cytomorphometric analysis of superficial vaginal cells inwomen in three groups of different types of hormonal concentrationwas made. There were 15 women in each group. Group I was studiedduring a natural cycle, group II under oral contraceptive therapyand group III during an in-vitro fertilization (IVF) stimulationprotocol. Morphometric parameters were measured on an imageanalyser. The area, perimeter and several form factors weremeasured separately for nuclei and cytoplasm. The nucleus:cytoplasmicratio was also determined. The cytoplasmic area was significantlyreduced in group II and was associated with a statisticallysignificant reduction of the nuclear area. The nucleus:cytoplasmicratio appeared significantly increased in group II and reducedin group III. Low oestradiol impregnation obtained with an oralminidosed contraceptive interfered with vaginal cell maturation.High oestradiol concentrations obtained during IVF protocolsinduced marked nuclear pycnosis but did not induce supra-physiologicalcell enlargement. Maximal cell size is genetically regulatedaccording to Driesch's law of volume invariance and hormonalover-stimulation has no effect on cell size. The nucleus:cytoplasmicratio appears to be a powerful parameter reflecting the oppositeeffects of hormones on cell compartments. 相似文献
4.
5.
Alain Deschamps Steven B Backman Vera Novak Gilles Plourde Pierre Fiset Daniel Chartrand 《The Journal of pharmacology and experimental therapeutics》2002,300(1):112-117
Edrophonium, an anticholinesterase, exerts a biphasic effect on cardiovascular autonomic drive in humans (lower doses enhance; higher doses reduce). Twenty-five anesthetized, mechanically respired (10 breaths. min(-1), constant tidal volume) patients were given either saline (n = 10) or edrophonium (0.01-1.0 mg. kg(-1), n = 15) following surgery. ECG, radial arterial pressure, and respiratory rate were sampled at 250 Hz to obtain time series for consecutive R-R intervals (RRIs), and systolic (SBP) and diastolic blood pressure (DBP). A Wigner distribution was used for time frequency mapping of spectral powers at high (HFP, 0.15-0.5 Hz) and low (LFP, 0.0-0.05 Hz) frequency. Edrophonium produced a dose-dependent decrease in heart rate [baseline 66.8 +/- 1.9 (S.E.M.) beats per minute; maximum decrease to 55.8 +/- 1.4 beats per minute with 1.0 mg. kg(-1), P < 0.01]. HFP of the RRI increased at low doses (0.2-0.4 mg. kg(-1); maximum increase to 111.0 +/- 58.2% baseline; P < 0.01) but decreased (-49.5 +/- 35.5% baseline; P < 0.01) at higher (1.0 mg. kg(-1)) doses. Edrophonium had no effect on SBP and DBP. HFP of SBP decreased with increasing doses (maximal decrease to -26.2 +/- 7.5% baseline, P < 0.01, 1.0 mg. kg(-1)). LFP of SBP was also decreased (-46.3 +/- 10.9% baseline, P < 0.01, 1.0 mg. kg(-1)). Edrophonium may enhance (lower dose) or reduce (higher dose) cardiovascular autonomic drive in humans, as evidenced by the significant changes it evokes in HFP of the RRI (parasympathetic drive), and in the HFP and LFP of SBP (sympathetic drive). These observations may account for the modest autonomic side effects of edrophonium when this drug is used clinically. 相似文献
6.
Minerva Giménez y Ribotta Christelle Roudet Françoise Sandillon Alain Privat 《Brain research》1996,707(2):245
The synaptic connections established by grafted noradrenergic (NA) neurons into the lesioned adult rat spinal cord were analysed using immunocytochemistry at the electron microscopic level. An embryonic cell suspension of the locus coeruleus region from E-13 rat embryos was transplanted into the spinal cord following either: (1) spinal cord transection or (2), partial selective denervation by 6-hydroxy dopamine (6-OH DA). One month after grafting, the NA-neurons established, in the two models, an innervation pattern similar to that found in the intact spinal cord. In both models, the transplanted NA-immunoreactive neurons formed extensive synaptic contacts with dendrites, spines and perikarya. The proportion of axodendritic and axospinous contacts was inverse in the two models. The first model thus reproduced more closely the normal synaptic pattern prefering dendritic targets, which could correspond to a better integration of the graft. In the second model, a partially NA-denervated spinal cord, there existed a competition between residual intrinsic and grafted neuron-derived fibres, which presumably affects synaptogenesis. In conclusion, the present study illustrate the complexity of cell interations conducting to the formation of a specific circuitry. Recognition phenomenon are likely modulated by space constraints, which ultimately shape-up the geometry of synaptic contacts. 相似文献
7.
8.
Georgios Amoiridis Ludwig Gutmann Dennis E. Wilkins Raja Sawaya Alain Lagueny Roger Marthan Philippe Schuermans Philippe Le Collen Xavier Ferrer Jean Julien Reha Kuruoglu Shin J. Oh Brian Thompson A. Aggarwal L. Gutmann A. Gutierrez Okifumi Nakazato Russel Johnsen Philip Morling B. A. Kakulas 《Muscle & nerve》1994,17(2):245-253
9.
Alain Djacoba Tehindrazanarivelo Jean Marc Visy Marie-Germaine Bousser 《Cephalalgia : an international journal of headache》1992,12(5):318-320
We report two patients with ipsilateral attacks of cluster headache and chronic paroxysmal hemicrania. The first patient, a 33-year-old man, started having attacks of chronic cluster headache at the age of 27. At 33, they were replaced by typical attacks of ipsilateral chronic paroxysmal hemicrania which showed a dramatic improvement with indomethacin 150 mg daily. After two days of complete remission, cluster headache attacks reappeared and persisted until verapamil, 360 mg a day, was added to indomethacin. The second patient, a 45-year-old man, first developed attacks of episodic cluster headache at the age of 35. At 44, he experienced ipsilateral typical attacks of chronic paroxysmal hemicrania, and two months later attacks of cluster headache. Under verapamil 240 mg daily, attacks of cluster headache disappeared, but those of chronic paroxysmal hemicrania increased in frequency until indomethacin 150 mg daily was added. These observations suggest a close relationship but not a similarity between cluster headache and chronic paraoxysmal hemicrania, and show the practical therapeutic interest of maintaining this distinction. 相似文献
10.