全文获取类型
收费全文 | 126709篇 |
免费 | 7783篇 |
国内免费 | 863篇 |
专业分类
耳鼻咽喉 | 1550篇 |
儿科学 | 3606篇 |
妇产科学 | 2883篇 |
基础医学 | 16486篇 |
口腔科学 | 2752篇 |
临床医学 | 10772篇 |
内科学 | 28319篇 |
皮肤病学 | 2343篇 |
神经病学 | 11781篇 |
特种医学 | 5028篇 |
外国民族医学 | 24篇 |
外科学 | 19050篇 |
综合类 | 1855篇 |
一般理论 | 65篇 |
预防医学 | 7359篇 |
眼科学 | 1934篇 |
药学 | 9534篇 |
3篇 | |
中国医学 | 552篇 |
肿瘤学 | 9459篇 |
出版年
2023年 | 577篇 |
2022年 | 1304篇 |
2021年 | 2535篇 |
2020年 | 1612篇 |
2019年 | 2402篇 |
2018年 | 2983篇 |
2017年 | 2208篇 |
2016年 | 2278篇 |
2015年 | 2686篇 |
2014年 | 3688篇 |
2013年 | 5255篇 |
2012年 | 7241篇 |
2011年 | 7622篇 |
2010年 | 4746篇 |
2009年 | 4299篇 |
2008年 | 6665篇 |
2007年 | 6977篇 |
2006年 | 6631篇 |
2005年 | 6350篇 |
2004年 | 6478篇 |
2003年 | 6206篇 |
2002年 | 6075篇 |
2001年 | 3951篇 |
2000年 | 3804篇 |
1999年 | 3171篇 |
1998年 | 1488篇 |
1997年 | 1165篇 |
1996年 | 1009篇 |
1995年 | 990篇 |
1994年 | 850篇 |
1993年 | 825篇 |
1992年 | 1858篇 |
1991年 | 1854篇 |
1990年 | 1563篇 |
1989年 | 1505篇 |
1988年 | 1369篇 |
1987年 | 1229篇 |
1986年 | 1221篇 |
1985年 | 1095篇 |
1984年 | 844篇 |
1983年 | 775篇 |
1982年 | 523篇 |
1981年 | 457篇 |
1980年 | 413篇 |
1979年 | 599篇 |
1978年 | 449篇 |
1975年 | 451篇 |
1974年 | 500篇 |
1973年 | 479篇 |
1972年 | 436篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Total parenteral nutrition is now a broadly used method whose efficacy is confirmed, even if it is still not free from risk of complications. The Authors report their own clinical experience on 130 cases in the period 1981-1988. Complications were registered in 4.6% of the observed cases. They underline the problems relating to this subject. 相似文献
43.
F. Marino M. Cosentino F. De Ponti C. Giaroni L. Somaini R. Bombelli M. Ferrari A.J. Aasen S. Lecchini G. Frigo 《Autonomic & autacoid pharmacology》1997,17(6):365-372
1 The present study examined the role of muscarinic receptors in the modulation of noradrenaline (NA) release in the guinea-pig isolated distal colon. The spontaneous endogenous NA overflow assayed by HPLC-ED was taken as an index of NA release from enteric noradrenergic nerve terminals. 2 Physostigmine (10 μm ) significantly enhanced spontaneous endogenous NA overflow. Hyoscine (muscarinic antagonist), (R)-(-)-trihexyphenidyl and telenzepine (M1-selective antagonists), and 11[[2-[(diethylamino)methyl]-1-piperydil]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one (AF-DX 116, M2-selective antagonist) inhibited NA overflow in a concentration dependent manner, with the following EC50 values: 131.74 (18.19–953.96), 101.62 (58.83–175.60), 150 (60–330), 30 (5–170) nm , respectively. 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP, M1- and M3- selective antagonist) had no significant effect up to 100 μm . 3 The muscarinic agonist oxotremorine inhibited NA overflow in a concentration dependent manner, with an EC50 value of 0.67 (0.30–1.51) μm . The response to oxotremorine was inhibited by muscarinic antagonists with the following order of potency: hyoscine = (R)-(-)-trihexyphenidyl = telenzepine > 4-DAMP >> AF-DX 116. 4 In the presence of 3 μm tetrodotoxin (TTX), the effect of oxotremorine and 4-DAMP was unchanged, while hyoscine, (R)-(-)-trihexyphenidyl, telenzepine and AF-DX 116, instead of inhibiting, significantly enhanced NA overflow. 5 The present results indicate that, in the guinea-pig colon, endogenous acetylcholine sustains spontaneous NA release by activating muscarinic receptors possibly located on interneurones. In addition, inhibitory muscarinic receptors may exist on adrenergic terminals. 相似文献
44.
De Leo V; Morgante G; Lanzetta D; D'Antona D; Bertieri RS 《Human reproduction (Oxford, England)》1997,12(2):357-360
We report the results of administration of danazol after suspension of
gonadotrophin-releasing hormone analogue (GnRHa) therapy for uterine
myomas. A total of 21 women with uterine myomas was treated with 100 mg
danazol for 6 months after GnRHa therapy. Uterine volume and endocrine
status were monitored monthly by ultrasound and assay of plasma
gonadotrophins, oestradiol and progesterone. The results show a rebound of
uterine volume about 30% less than in controls at the end of danazol
therapy. Menstrual cyclicity returned after 65 +/- 3 days in 16 subjects
and five patients remained amenorrhoeic. Hormone assays confirmed renewed
ovarian function in the women whose menstrual periods returned. Bone
mineral content was substantially reduced during GnRHa treatment but
improved significantly during danazol therapy even in the women who
remained amenorrhoeic. These results show the utility of danazol in
prolonging the therapeutic effects of GnRHa. The mechanism by which danazol
inhibits rebound of uterine volume may be due to its antiprogesterone
effects on uterine myomas.
相似文献
45.
Hilda A. Perez Carmen Bracho Mirtha Romano Mercedes De la Rosa 《Parasitology research》1997,83(3):246-251
A monoclonal antibody raised by immunization of BALB/c mice with erythrocytic stages of Plasmodium vivax was shown to react with asexual erythrocytic stages of P. chabaudi. The cross-reactivity molecules are antigens of 200 and 148 kDa in P. vivax and of 190 and 70 kDa in P. chabaudi. Immunofluorescence studies of the erythrocytic stages of P. vivax and P. chabaudi indicated that expression of these antigens increased as the parasites' developed from the ring stage to the schizont stage.
In the mature trophozoites of P. chabaudi, immunoelectron microscopy revealed clusters of antigen distributed in the cytoplasm of the parasitized erythrocyte. In the
schizont, packets of antigen were found associated with the parasitophorous vacuole and the cytoplasm of the infected host
cell.
Received: 19 March 1996 / Accepted: 28 August 1996 相似文献
46.
47.
J. Hucke R. L. Campo F. De Bruyne A. Abou Freikha 《Archives of gynecology and obstetrics》1993,254(1-4):421-423
Ohne Zusammenfassung 相似文献
48.
49.
Tissues were obtained from 387 male pig fetuses ranging from 60 to 120 days of gestation. The relative wet mass and water content of the gubernaculum increased during and decreased after the period of testicular descent. The extracellular glycosaminoglycans (GAG) were assayed to determine whether these polyanionic macromolecules are responsible for the increased water content of the gubernaculum. The total GAG/wet tissue mass in the gubernaculum decreased during and increased after descent, while the total GAG/dry mass decreased during and after descent, indicating an accumulation of water during descent, with a loss of water and an increase in less hydrated tissue components after descent. The major GAG fraction in the gubernaculum was dermatan sulfate, but the percentage hyaluronate in the gubernaculum was two times higher than in striated muscle or umbilical cord, indicating that this GAG fraction may be responsible for the increased water content of the gubernaculum, which probably serves to dilate the inguinal canal and scrotum, thus facilitating descent. 相似文献
50.
J T Knuiman J G Hautvast K F Zwiauer K Widhalm M Desmet G De Backer R R Rahneva V S Petrova M Dahl J Viikari 《European journal of clinical nutrition》1988,42(10):847-855
We have measured systolic and diastolic blood pressure and excretions of sodium, potassium, calcium and magnesium in groups of about 50 8- and 9-year-old boys from 19 European centres using standardized methods for the measurement of blood pressure and collection of urine, and by carrying out all analyses in one laboratory. Weight, height, pulse rate and environmental temperature were also studied. Mean systolic blood pressure ranged from 91 to 105 mm Hg and diastolic blood pressure from 51 to 66 mm Hg. Mean 24-h excretion of sodium was between 91 and 146 mmol/d, that of potassium between 29 and 60 mmol/d, that of calcium between 1.5 and 2.6 mmol/d and that of magnesium between 2.7 and 4.2 mmol/d. Mean sodium excretion tended to be lower and potassium excretion tended to be higher in the boys from the north-western parts of Europe. Relations between either systolic or diastolic blood pressure and electrolyte excretions were generally weak or absent. Most remarkable is that only the association between mean diastolic blood pressure and 24-h magnesium excretion (partial regression coefficient (b +/- s.e., -5.04 +/- 2.08 mm Hg/mmol/d) was statistically significant after adjusting for differences in creatinine excretion and environmental temperature. Mean systolic blood pressure was not significantly related with any of the variables measured. The partial regression coefficient (b +/- s.e.) for diastolic blood pressure on weight was 0.186 +/- 0.062 mm Hg/kg, on height 0.165 +/- 0.056 mm Hg/cm, on pulse rate 0.364 +/- 0.100 mm Hg/beats per min and on outside temperature -0.25 +/- 0.07 mm Hg/degrees C. 相似文献