全文获取类型
收费全文 | 1351篇 |
免费 | 149篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 99篇 |
妇产科学 | 28篇 |
基础医学 | 146篇 |
口腔科学 | 43篇 |
临床医学 | 241篇 |
内科学 | 316篇 |
皮肤病学 | 27篇 |
神经病学 | 191篇 |
特种医学 | 48篇 |
外科学 | 155篇 |
综合类 | 25篇 |
预防医学 | 55篇 |
眼科学 | 11篇 |
药学 | 47篇 |
中国医学 | 5篇 |
肿瘤学 | 65篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 9篇 |
2021年 | 20篇 |
2020年 | 16篇 |
2019年 | 23篇 |
2018年 | 37篇 |
2017年 | 36篇 |
2016年 | 38篇 |
2015年 | 40篇 |
2014年 | 41篇 |
2013年 | 74篇 |
2012年 | 70篇 |
2011年 | 88篇 |
2010年 | 62篇 |
2009年 | 76篇 |
2008年 | 58篇 |
2007年 | 66篇 |
2006年 | 61篇 |
2005年 | 58篇 |
2004年 | 53篇 |
2003年 | 39篇 |
2002年 | 49篇 |
2001年 | 29篇 |
2000年 | 23篇 |
1999年 | 40篇 |
1998年 | 28篇 |
1997年 | 41篇 |
1996年 | 44篇 |
1995年 | 33篇 |
1994年 | 25篇 |
1993年 | 25篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 17篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 19篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1974年 | 4篇 |
1931年 | 1篇 |
排序方式: 共有1508条查询结果,搜索用时 31 毫秒
1.
2.
AM Manganoni† C Farisoglio† G Tucci† F Facchetti‡ PG Calzavara Pinton† 《Journal of the European Academy of Dermatology and Venereology》2007,21(10):1333-1336
BACKGROUND: Development of more than one primary melanoma in a patient is a relatively uncommon but well-recognized phenomenon. Its frequency has ranged from 1.2% to 8.2% in several series. This subgroup of patients with multiple primary lesions has not been characterized sufficiently. We report the experience of the Melanoma Unit of University Hospital Spedali Civili of Brescia, Italy. METHOD: Study subjects were drawn from 1240 patients with histologically confirmed melanoma, including melanoma in situ. From this group, multiple melanomas developed in 47 patients (3.79%). Every one of our patients has been taught to perform self-examination of the skin to detect suspicious pigmented lesions. RESULTS: Of the 47 patients described in this study, 38 had two primary melanomas, 7 had three melanomas and 2 had 5 and 10 melanomas, respectively. Mean age at first diagnosis was 46.2 years. The majority of subsequent melanomas (74.5%) were removed within 5 years of the initial operation. Synchronous lesions were found in 10 patients. In male patients, the lesion appeared most frequently on the trunk; in female patients, melanoma appeared mostly on the lower extremities. The second primary melanomas developed in the same anatomic region from the first in 53.2% of our patients. The proportion of in situ to invasive melanomas was greater for the second melanomas compared with the first melanomas. Regarding invasive melanomas, the mean thickness of the first melanomas was 1.31 mm compared with 0.66 mm for the second ones. Dividing patients into two groups, of more and less than 50, it is highlighted that in older patients synchronous lesions appear more frequently (36.4% vs. 8.0%); the median time interval between sequential melanomas is longer (84 vs. 63.7 months); and the ratio between the primary and secondary melanoma mean thickness is lower (1.21 : 1.08 vs. 1.43 : 0.63 mm). CONCLUSIONS: The study confirms that second primary melanoma is usually thinner than the first lesion, and it is more common in the same region of the body as the initial melanoma. The highest risk for a second melanoma is during the first 5 years, but a much longer time interval of 28 years is possible. Continued medical follow-up with complete skin examinations seems prudent, but it is very important to promote self-skin evaluation in patients to detect not only metastases but also subsequent primary melanomas in their earliest phases. 相似文献
3.
Tortoriello DV; McGovern PG; Colon JM; Loughlin J; Santoro N 《Human reproduction (Oxford, England)》1998,13(11):3005-3008
We report an instance of critical ovarian hyperstimulation syndrome in a
highly responsive in-vitro fertilization patient despite the preventive
measure of a 4 day 'coast' interval during which no gonadotrophins were
administered while gonadotrophin-releasing hormone agonist therapy
continued until serum oestradiol concentrations fell below 3000 pg/ml.
相似文献
4.
5.
Hashimoto's thyroiditis, autoimmune adrenalitis, pernicious anaemia, and diabetes mellitus are all recognised associations with Down's syndrome. In addition chronic active hepatitis (CAH) resulting from chronic hepatitis B antigenaemia is known to occur in these patients, but an association of autoimmune CAH and Down's syndrome has not previously been described. We report a case in which Down's syndrome was associated with autoimmune CAH, Hashimoto's thyroiditis, and alopecia areata. 相似文献
6.
7.
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
8.
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
9.
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
10.
Rapid diagnosis of rotavirus gastroenteritis by a commercial latex agglutination test. 总被引:1,自引:6,他引:1
The Rotalex test, a commercial latex agglutination test for rotavirus, was compared with direct electron microscopy (EM) and the Rotazyme test I, a commercial enzyme immunoassay, for detection of rotavirus in stools of children and neonates. For initial stool specimens from 265 children (less than 3 years old) with diarrhea, the Rotalex test had a sensitivity of 81.7% and specificity of 99.5% compared with EM results. Positive and negative predictive values were 98 and 94.9%, respectively. The Rotalex test was slightly more sensitive and specific than the Rotazyme test. When daily stool specimens from patients with rotavirus gastroenteritis were examined, the sensitivity of the Rotalex test varied depending on the time of stool collection relative to the onset of symptoms. Sensitivity was 100 (20/20), 96 (23/24), and 54% (7/13) during 1 to 4, 5 to 7, and 8 to 18 days, respectively, after the onset of symptoms. The sensitivity of the Rotazyme test varied similarly with days from onset. We also examined 214 EM-negative stool specimens from asymptomatic newborns. False positivity by the Rotalex test was only 3.3% (7/214) compared with 4.2% (9/215) for the Rotazyme test. The Rotalex test was as sensitive and specific as EM for detection of rotavirus during the acute stage of illness and much faster and cheaper than EM or the Rotazyme test. The test appears to be suitable for routine use in small hospitals, emergency wards, or even the physician's office for rapid diagnosis of rotavirus gastroenteritis. 相似文献