全文获取类型
收费全文 | 1595篇 |
免费 | 117篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 72篇 |
妇产科学 | 61篇 |
基础医学 | 164篇 |
口腔科学 | 40篇 |
临床医学 | 204篇 |
内科学 | 318篇 |
皮肤病学 | 47篇 |
神经病学 | 50篇 |
特种医学 | 65篇 |
外科学 | 248篇 |
综合类 | 135篇 |
一般理论 | 1篇 |
预防医学 | 118篇 |
眼科学 | 32篇 |
药学 | 89篇 |
肿瘤学 | 52篇 |
出版年
2023年 | 12篇 |
2018年 | 18篇 |
2017年 | 12篇 |
2016年 | 11篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 28篇 |
2011年 | 12篇 |
2010年 | 28篇 |
2009年 | 44篇 |
2008年 | 16篇 |
2007年 | 15篇 |
2006年 | 13篇 |
2005年 | 16篇 |
2004年 | 10篇 |
2000年 | 8篇 |
1999年 | 23篇 |
1998年 | 33篇 |
1997年 | 48篇 |
1996年 | 63篇 |
1995年 | 49篇 |
1994年 | 29篇 |
1993年 | 39篇 |
1992年 | 24篇 |
1991年 | 13篇 |
1990年 | 16篇 |
1989年 | 27篇 |
1988年 | 23篇 |
1987年 | 25篇 |
1986年 | 20篇 |
1985年 | 18篇 |
1984年 | 19篇 |
1983年 | 10篇 |
1982年 | 16篇 |
1981年 | 11篇 |
1980年 | 21篇 |
1979年 | 10篇 |
1978年 | 14篇 |
1977年 | 8篇 |
1976年 | 13篇 |
1963年 | 9篇 |
1959年 | 75篇 |
1958年 | 126篇 |
1957年 | 133篇 |
1956年 | 108篇 |
1955年 | 97篇 |
1954年 | 86篇 |
1949年 | 40篇 |
1948年 | 73篇 |
1947年 | 8篇 |
排序方式: 共有1715条查询结果,搜索用时 15 毫秒
21.
Battaglia C; Artini PG; Giulini S; Salvatori M; Maxia N; Petraglia F; Volpe A 《Human reproduction (Oxford, England)》1997,12(11):2477-2482
The objective of this study was to evaluate the Doppler flow variations
which occur following the use of different protocols of ovarian stimulation
in an IVF programme, and to investigate the thromboxane production by
cultured endometrial cells and its influence on embryo implantation. A
total of 60 patients underwent three different ovarian stimulation
protocols: long gonadotrophin-releasing hormone agonist (GnRH-a), short
GnRH-a and no GnRH-a. Transvaginal ultrasonography and colour Doppler
analysis were performed before and during the treatment. On the day that
the Doppler examination took place, luteinizing hormone, follicle
stimulating hormone, plasma oestradiol and thromboxane concentrations were
assayed. On the day of oocyte retrieval, endometrial cells were collected
and cultured, and their thromboxane production evaluated. No significant
differences in hormonal, ultrasonographic or Doppler parameters were
observed between the three groups. Ten out of 56 patients who had a
successful embryo transfer became pregnant. In the group of pregnant women
the pulsatility index values of both uterine and spiral arteries was lower
than in non-pregnant patients, and was associated with significantly lower
thromboxane concentrations from cultured endometrial cells. It is concluded
that thromboxane plays a role in embryo implantation, and that Doppler flow
analysis of uterine and spiral arteries in infertile patients may be
important in the management of ovarian stimulation.
相似文献
22.
A longitudinal study of maternal serum inhibin-A, inhibin-B, activin-A, activin-AB, pro-alphaC and follistatin during pregnancy 总被引:6,自引:1,他引:6
Fowler PA; Evans LW; Groome NP; Templeton A; Knight PG 《Human reproduction (Oxford, England)》1998,13(12):3530-3536
Maternal serum concentrations of inhibin-A, inhibin-B, activin-A,
activin-AB, pro-alphaC-related inhibin forms, total follistatin, steroids
and gonadotrophins were measured longitudinally in six normal singleton
pregnancies. Maternal venous blood was collected randomly during a
spontaneous follicular phase prior to donor insemination, at 5, 7, 9, 11,
16, 20, 24, 28, 32 and 36 weeks after the first missed menses and in the
early puerperium. Steroid and gonadotrophin profiles conformed to previous
reports. While at week 5 of gestation inhibin-A, activin-A and follistatin
concentrations were similar to those at the follicular phase, all three
increased progressively (P < 0.001) to maximal concentrations in week
36: approximately 48-fold (3740 +/- 1349 ng inhibin-A/ml), approximately
22-fold (6109 +/- 1443 ng activin-A/ml) and approximately 10-fold (3563 +/-
418 ng follistatin/ml) higher. Pro- alphaC concentrations reached a maximum
in weeks 5 (approximately 5- fold, P < 0.001) and 36 (1027 +/- 174
pg/ml, P < 0.01). Inhibin-B (71 +/- 23 pg/ml prior to pregnancy) was
undetectable (<12 pg/ml) between week 5-16 of gestation but increased
slightly in the third trimester (26 +/- 7 pg/ml in week 36). Activin-AB was
undetectable throughout pregnancy. Post-partum concentrations of inhibin-A
(41 +/- 12 ng/ml), inhibin-B (<12 pg/ml), activin-A (950 +/- 149 pg/ml),
pro-alphaC (128 +/- 22 pg/ml) and follistatin (990 +/- 79 ng/ml) were
substantially lower than at week 36 of gestation. The activin-A:follistatin
ratio increased from 0.5 in week 5 to 1.8 in week 36, suggesting that more
free activin-A is available in the maternal circulation during late
pregnancy.
相似文献
23.
24.
Catt SL; Sakkas D; Bizzaro D; Bianchi PG; Maxwell WM; Evans G 《Molecular human reproduction》1997,3(9):821-825
Controlling the sex of offspring by the separation of X and Y
chromosome-bearing spermatozoa using flow cytometry has been reported as a
clinical technique aiding prevention of X-linked diseases. Although this
technique has resulted in several hundred normal births in animals and at
least one human birth, there is still concern over its genetic safety due
to the involvement of two potentially mutagenic agents: UV light and the
fluorochrome dye, Hoechst 33342 (H33342). Human spermatozoa, particularly
those considered abnormal, may be more likely to suffer DNA damage
following exposure to mutagenic agents, compared with other mammalian
species. The stability of normal fresh and decondensed human spermatozoa
were examined after exposure to a range of levels of UV and H33342
staining, using an assay that detects endogenous nicks in the DNA of
spermatozoa. The stability of abnormal and normal, fresh and frozen-thawed
human spermatozoa was examined following UV laser, H33342 staining and flow
cytometry treatments utilizing the same assay. There was an increase in the
presence of endogenous nicks when spermatozoa were decondensed compared
with fresh spermatozoa. There was no increase in the incidence of nicks in
any group of spermatozoa after UV and fluorochrome exposure compared with
controls without exposure.
相似文献
25.
A cytochrome P-450 gene family mapped to human chromosome 19 总被引:1,自引:19,他引:1
I. R. PHILLIPS † E. A. SHEPHARD† S. POVEY M. B. DAVIS G. KELSEY M. MONTEIRO L. F. WEST J. COWELL 《Annals of human genetics》1985,49(4):267-274
We have recently isolated a cloned cDNA coding for a cytochrome P-450 of human liver microsomal membranes, which corresponds to a major phenobarbital-inducible cytochrome P-450 of rat liver. This human cytochrome P-450 is encoded by a member of a multigene family. DNA extracted from a panel of 12 independent human-rodent somatic cell hybrids was analysed by Southern blot hybridization with the cloned cDNA. The results indicate that all components of this cytochrome P-450 gene family are located on chromosome 19. Evidence from hybrids derived from an individual carrying a balanced translocation suggests a regional localization of 19p13.2→qter. Analysis of human metaphase chromosomes by in situ hybridization localizes this cytochrome P-450 gene family further to the long arm of chromosome 19 in the region q13.1→qter. We propose the designation P450PB for this locus. 相似文献
26.
Iolo Madoc-Jones PhD MSc BA Hons CQSW Sarah Wadd PhD MSc BSc Lawrie Elliott PhD MA PG Cert Anne Whittaker PhD BSc Post Grad Dip RNMH RMN Laura Adnum PhD MSc BSc Ciara Close PhD MSc BSc Jennifer Seddon PhD MSc BSc Maureen Dutton Michelle McCann MA CQSW Fiona Wilson BA 《Health & social care in the community》2021,29(2):344-352
Cognitive Impairment (CI) screening is recommended for those engaged in harmful levels of alcohol use. However, there is a lack of evidence on implementation. This paper explores the barriers and facilitators to CI screening experienced across a service specifically for older drinkers. The findings draw on data gathered as part of an evaluation of a multilevel programme to reduce alcohol-related harm in adults aged 50 and over in five demonstration areas across the United Kingdom. It is based on qualitative interviews and focus groups with 14 service providers and 22 service users. Findings are presented thematically under the section headings: acceptability of screening, interpretation and making sense of screening and treatment options. It is suggested that engagement with CI screening is most likely when its fit with agency culture and its purpose is clear; where service providers have the technical skills to administer and discuss the results of screening with service users; and where those undertaking screening have had the opportunity to reflect on their own experience of being screened. Engagement with CI screening is also most likely where specific intervention pathways and engagement practices can be accessed to respond to assessed need. 相似文献
27.
28.
Pathways to care for alcohol use disorders 总被引:1,自引:0,他引:1
29.
WILKINSON S. M.; SMITH A. G.; DAVIS M. J.; MATTEY D. L.; DAWES P. T. 《Rheumatology (Oxford, England)》1993,32(9):798-803
Cutaneous toxicity from drugs used to treat RA is a major perceivedproblem. Over a 2-yr period we have prospectively reviewed 114patients with a suspected adverse cutaneous reaction to anti-rheumaticdrugs. In 71 (62%), the rash was thought to be unrelated todrug therapy. This group included 10 in whom the rash had resolvedbefore review (usually < 1 week), 38 with a rash relatedto their rheumatoid disease and 23 with eruptions unrelatedto either drugs or arthritis. Fortythree (38%) patients hadrashes thought to be related to their drug therapy. Gold therapy(both oral and intramuscular) was implicated most frequently(31 patients). However, the majority of these (23) had a pityriasiform/discoideczematous eruption that responded to potent topical steroidsoccasionally with a reduction in gold dosage. In this sample it was possible to continue drug therapy in 82%of patients with what were initially thought to be cutane ousadverse drug reactions. Careful evaluation should allow a majorityof patients to continue drug therapy from which they are oftengaining benefit. KEY WORDS: Rheumatoid arthritis, Cutaneous drug toxicity, Vasculitis, Capillaritis, Pruritus, Asteatotic eczema, Pityriasis rosea, Discoid eczema, Pemphigus, Alopecia 相似文献
30.
REEL JERRY R.; TYL ROCHELLE W.; LAWTON A. DAVIS; LAMB JAMES C. IV 《Toxicological sciences》1992,18(4):609-615
Sulfamethazine (SMZ) was evaluated for reproductive toxicityin Swiss CD-1 mice using a continuous breeding protocol. SMZwas administered in the diet at 0, 0.25, 0.5, or 1% (w/w), whichrepresented an average daily intake of 0, 313, 625, or 1250mg SMZ/kg/day, respectively. Exposure of F0 male and femalemice to 1% SMZ for 126 days resulted in a significant decreasein the mean number of live pups per litter and the number oflitters produced (task 2); the percentage pups born alive to1% SMZ females showed a nonsignificant decrease versus controlfemales. The effects on fertility were rapid to onset (1 to4 weeks) and cumulative in nature. F0 male and female body weightswere slightly depressed from 3 weeks to the end of the study.The crossover mating trial (task 3) revealed that the adverseeffect on ferility involved both treated partners in that littersize decreased when either 1% SMZ males were bred to controlfemales or 1% SMZ females were mated with control males. Afterapproximately 155 days of exposure of F0 mice to 1% SMZ, theterminal body weight of 1% SMZ females was significantly decreasedand that of 1% SMZ males showed a nonsignificant decrease. Inaddition, the liver weight to body weight ratio of the maleswas increased. Further, the prostate and seminal vesicle weightto body weight ratios were decreased in 1% SMZ males relativeto control males. No treatment-related gross or histopathologicallesions were noted for the pituitary or reproductive organsof either sex. Sperm assessment indicated no significant differencein the epididymal sperm concentration or percentage motile orabnormal sperm. In conclusion, SMZ was found to be a reproductivetoxicant in the male and female Swiss CD-1 mouse, albeit atrelatively high dietary intake (1250 mg/kg/day), and in thepresence of mild systemic toxicity. 相似文献