全文获取类型
收费全文 | 1696篇 |
免费 | 82篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 33篇 |
妇产科学 | 29篇 |
基础医学 | 263篇 |
口腔科学 | 15篇 |
临床医学 | 147篇 |
内科学 | 384篇 |
皮肤病学 | 12篇 |
神经病学 | 124篇 |
特种医学 | 116篇 |
外科学 | 253篇 |
综合类 | 8篇 |
一般理论 | 1篇 |
预防医学 | 109篇 |
眼科学 | 6篇 |
药学 | 143篇 |
肿瘤学 | 131篇 |
出版年
2023年 | 9篇 |
2022年 | 14篇 |
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 18篇 |
2018年 | 19篇 |
2017年 | 25篇 |
2016年 | 25篇 |
2015年 | 44篇 |
2014年 | 37篇 |
2013年 | 76篇 |
2012年 | 54篇 |
2011年 | 75篇 |
2010年 | 54篇 |
2009年 | 58篇 |
2008年 | 65篇 |
2007年 | 85篇 |
2006年 | 56篇 |
2005年 | 71篇 |
2004年 | 68篇 |
2003年 | 59篇 |
2002年 | 55篇 |
2001年 | 56篇 |
2000年 | 60篇 |
1999年 | 35篇 |
1998年 | 38篇 |
1997年 | 26篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1994年 | 24篇 |
1993年 | 26篇 |
1992年 | 21篇 |
1991年 | 18篇 |
1990年 | 23篇 |
1989年 | 26篇 |
1988年 | 31篇 |
1987年 | 29篇 |
1986年 | 21篇 |
1985年 | 26篇 |
1984年 | 17篇 |
1983年 | 24篇 |
1982年 | 11篇 |
1979年 | 17篇 |
1978年 | 8篇 |
1974年 | 14篇 |
1973年 | 11篇 |
1972年 | 8篇 |
1970年 | 8篇 |
1969年 | 9篇 |
1967年 | 8篇 |
排序方式: 共有1780条查询结果,搜索用时 15 毫秒
1.
2.
J Hildebrandt B D?ker 《Zeitschrift für die gesamte innere Medizin und ihre Grenzgebiete》1989,44(13):391-394
The interventional endoscopy and new knowledge about the spontaneous course of the cholelithiasis have obtained a far-reaching influence on the indication for operation and the surgical approach. Now as ever the adequate therapy of the symptomatic cholecystolithiasis consists in the early cholecystectomy. Since in the natural course the risk of lethality is small the operation for indication depending on the age and the risk factors given must be made cautiously. This in a still higher degree concerns the asymptomatic cholelithiasis in which at present no general indication for operation is regarded necessary. Due to the low lethality of circa 1% the endoscopic papillotomy has become the therapeutic method of choice in residual and recurrent calculi after cholecystectomy, but also in risk patients with cholecystocholedocholithiasis. The endoscopic papillotomy with stone extraction before the operation suggests a decrease of the operation lethality of 3 to 5% after cholecystectomy with revision of the choledochus. 相似文献
3.
Cholinergically induced bronchoconstriction is thought to be a major cause of bronchospasm during anesthesia. We used tracheally intubated rabbits (4-mm endotracheal tube) stimulated with methacholine to assess the efficacy of beta-adrenergic agonist and anticholinergic treatment in reversing the increases in respiratory system resistance. Four groups were compared: (a) inhaled metaproterenol, 20 puffs via metered dose inhaler (0.65 mg/puff); (b) inhaled ipratropium bromide, 20 puffs from a metered dose inhaler (18 micrograms/puff); (c) 2 mg of intravenous atropine; and (d) no treatment after methacholine challenge as a control group. Methacholine increased respiratory system resistance from 0.041 +/- 0.001 (mean +/- SEM) to 0.098 +/- 0.006 cm H2O.mL-1.s-1 (P < 0.001). Whereas beta-adrenergic agonist treatment was ineffective in ameliorating bronchoconstriction, inhaled ipratropium bromide and atropine were highly effective, causing an 86%-88% reversal in the methacholine-induced increase in respiratory system resistance. Both these agents were also effective in improving dynamic compliance. We conclude that inhaled ipratropium bromide is effective in treating cholinergic bronchospasm even when administered via a small endotracheal tube and that the beta-adrenergic agonist metaproterenol is ineffective in rabbits in the face of maximal cholinergic stimulation. 相似文献
4.
Prematurity Stereotyping by Mothers of Premature Infants 总被引:2,自引:1,他引:1
Previous research has experimentally documented a prematuritystereotype in college students and mothers of full-term infants.The present investigation extends the scope of earlier studiesto mothers of premature infants. Thirty-two mothers of prematureinfants viewed four videotapes of 9-month-old full-term infants,each labeled either full-term or premature and either male orfemale. When infants were labeled premature the mothers perceivedthem as littler, finer featured, weaker, more passive, and slowerthan infants labeled full-term. The mothers also perceived labeledboys as bigger than labeled girls. Differences in stereotypingbetween the mothers in this study and both mothers of full-terminfants and college students are identified and discussed. Resultssuggest that mothers of premature infants expect deficits inpremature infants' physical development but not in prematureinfants' mental or social development. The likely sources andpossible self-fulfilling nature of these biased perceptionsare considered 相似文献
5.
Steenbergen EJ; Verhagen OJ; van Leeuwen EF; van den Berg H; von dem Borne AE; van der Schoot CE 《Blood》1995,86(2):692-702
Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL. 相似文献
6.
7.
Paul K. Hildebrandt James D. Conroy Adam E. McKee M. B. A. Nyindo David L. Huxsoll 《Infection and immunity》1973,7(2):265-271
The ultrastructure of Ehrlichia canis was examined in both pulmonary mononuclear cells and in monocytes cultured from an infected dog. The cytoplasmic inclusions, or morulae, of E. canis consisted of a membrane-lined vacuole-containing elementary bodies which varied in size and number. The elementary bodies were bound by two trilamellar membranes. The organism shared morphological properties of both the genus Rickettsia and genus Chlamydia. 相似文献
8.
Fugger EF; Black SH; Keyvanfar K; Schulman JD 《Human reproduction (Oxford, England)》1998,13(9):2367-2370
The world's first deliveries of normal babies after use of flow cytometric
separated human sperm cells (MicroSort) for preconception gender selection
are reported. Offspring were of the desired female gender in 92.9% of the
pregnancies. Most of these pregnancies and births were achieved after
simple intrauterine insemination.
相似文献
9.
P C Arck M Rose K Hertwig E Hagen M Hildebrandt B F Klapp 《Human reproduction (Oxford, England)》2001,16(7):1505-1511
BACKGROUND: Stress is thought to be abortogenic and psycho-neuro-immunological pathways have been suggested to be involved in triggering miscarriages. From experiments in pregnant mice exposed to stress some insights into the underlying mechanisms have been gained, delineating immunological imbalances as a cause of pregnancy failure. In order to test the validity of the conclusions drawn from murine experiments and the role of stress in human pregnancy loss, the following study was performed. METHODS: We used an established perceived stress questionnaire and measured the stress score of women with a confirmed diagnosis of first trimester spontaneous abortion (n = 94). Decidual tissue was investigated by immunohistochemistry and in-situ hybridization to detect the presence and distribution of immunocompetent decidual cells [CD56(+) natural killer (NK) cells, CD8(+)and CD3(+) T cells, tryptase(+) mast cells (MCT(+)) and tumour necrosis factor (TNF)-alpha(+) cells]. The patient cohort was divided into women experiencing low or high levels of stress. RESULTS: In the decidua of women with high stress scores we observed significantly higher numbers of MCT(+), CD8(+) T cells and TNF-alpha(+) cells per mm(2) tissue (P < or = 0.05). No significant differences between individuals with lower or higher stress scores could be observed with respect to decidual CD56(+) NK and CD3(+) T cells. CONCLUSIONS: Using a questionnaire to score perceived stress in humans may be a valid approach to assess non-biased stress scores. Stress-triggered abortion in humans, identified by a questionnaire, can be linked to immunological imbalances. 相似文献
10.
Detecting pre-ovulatory luteinizing hormone surges in urine 总被引:2,自引:1,他引:2
Kesner JS; Knecht EA; Krieg EF Jr; Wilcox AJ; O'Connor JF 《Human reproduction (Oxford, England)》1998,13(1):15-21
The study objectives were to determine (i) if pre-ovulatory luteinizing
hormone (LH) surges, undetected in urine by two immunoradiometric assays
(IRMA), were detectable by an ultrasensitive immunofluorometric assay
(IFMA) and (ii) the influence of creatinine adjustment on the detection and
timing of the urinary LH surges. Daily urine specimens were contributed by
healthy 25-36 year old volunteers during 14 ovulatory menstrual cycles for
an epidemiological study conducted in 1983-1985. Specimens were selected as
having been previously assayed by two IRMA without consistently detecting
LH surges. These urine specimens were remeasured using an IFMA and adjusted
for creatinine concentration. IFMA measurements revealed unambiguous LH
surges in all cycles. Adjusting IRMA urinary LH values for creatinine
concentrations revealed previously undetected LH surges in four of eight
cycles. Creatinine adjustment also altered the timing of IRMA and IFMA LH
surges by 1-5 days. These results demonstrate an IFMA that detects pre-
ovulatory LH surges in unpreserved, frozen urine from cycles where such
surges were previously undetectable. Further, creatinine adjustment can
markedly affect detection and timing of the onset and peak of the urinary
LH surge. While our analysis suggests that this adjustment improves the
validity of the LH measure, this requires further investigation.
相似文献