全文获取类型
收费全文 | 11497篇 |
免费 | 610篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 88篇 |
儿科学 | 212篇 |
妇产科学 | 190篇 |
基础医学 | 1949篇 |
口腔科学 | 240篇 |
临床医学 | 1037篇 |
内科学 | 2263篇 |
皮肤病学 | 241篇 |
神经病学 | 1358篇 |
特种医学 | 569篇 |
外科学 | 1921篇 |
综合类 | 50篇 |
一般理论 | 2篇 |
预防医学 | 362篇 |
眼科学 | 211篇 |
药学 | 735篇 |
中国医学 | 25篇 |
肿瘤学 | 706篇 |
出版年
2023年 | 71篇 |
2022年 | 97篇 |
2021年 | 224篇 |
2020年 | 134篇 |
2019年 | 184篇 |
2018年 | 208篇 |
2017年 | 189篇 |
2016年 | 234篇 |
2015年 | 291篇 |
2014年 | 368篇 |
2013年 | 471篇 |
2012年 | 720篇 |
2011年 | 743篇 |
2010年 | 441篇 |
2009年 | 439篇 |
2008年 | 690篇 |
2007年 | 716篇 |
2006年 | 669篇 |
2005年 | 670篇 |
2004年 | 625篇 |
2003年 | 595篇 |
2002年 | 570篇 |
2001年 | 101篇 |
2000年 | 78篇 |
1999年 | 83篇 |
1998年 | 128篇 |
1997年 | 106篇 |
1996年 | 78篇 |
1995年 | 80篇 |
1994年 | 77篇 |
1993年 | 64篇 |
1992年 | 57篇 |
1991年 | 41篇 |
1990年 | 39篇 |
1989年 | 42篇 |
1988年 | 34篇 |
1937年 | 33篇 |
1936年 | 34篇 |
1935年 | 34篇 |
1933年 | 47篇 |
1932年 | 75篇 |
1931年 | 35篇 |
1930年 | 45篇 |
1929年 | 35篇 |
1928年 | 61篇 |
1927年 | 57篇 |
1926年 | 38篇 |
1925年 | 33篇 |
1924年 | 43篇 |
1922年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
81.
Hans-Martin Becker MD Jairo Ramirez MD Vincent Echave MD Georg Heberer MD 《Annals of vascular surgery》1986,1(2):196-200
From July 1979 to December 1985 we observed 51 patients with traumatic lesions of the descending thoracic aorta. Twenty-nine had acute ruptures, mostly accompanied by multiple injuries, and 27 had to be operated upon immediately. Twenty-two patients (19 males, 3 females) had chronic traumatic aneurysms of the descending thoracic aorta (more than six weeks after trauma). Mean age at the time of trauma was 24 years. Mean age at time of surgery was 36.5 years. Twelve patients were symptomatic. All were treated surgically. At surgery, complete aortic disruption was found in 15 patients and partial rupture in seven. We did not use aortic shunting of any kind, only aortic cross-clamping. Hypertension was controlled by intravenous drug infusion. The ruptured aortic segment was replaced in all cases by prosthetic Dacron graft. There were no operative deaths. One patient (age 77) died 11 weeks after surgery from multiple organ failure. One case of postoperative paraplegia was observed. This patient recovered almost completely from his neurological deficit. 相似文献
82.
Kerstin Kempf Martin Rhling Winfried Banzer Klaus Michael Braumann Martin Halle David McCarthy Hans Georg Predel Isabelle Schenkenberger Susanne Tan Hermann Toplak Aloys Berg Stephan Martin 《Nutrients》2021,13(5)
Lifestyle interventions, including meal replacement, are effective in the prevention and treatment of type-2-diabetes and obesity. Since insulin is the key weight regulator, we hypothesised that the addition of meal replacement to a lifestyle intervention reduces insulin levels more effectively than lifestyle intervention alone. In the international multicentre randomised controlled ACOORH (Almased Concept against Overweight and Obesity and Related Health Risk) trial, overweight or obese persons who meet the criteria for metabolic syndrome (n = 463) were randomised into two groups. Both groups received nutritional advice focusing on carbohydrate restriction and the use of telemonitoring devices. The intervention group substituted all three main meals per day in week 1, two meals per day in weeks 2–4, and one meal per day in weeks 5–26 with a protein-rich, low-glycaemic meal replacement. Data were collected at baseline and after 1, 3, 6 and 12 months. All datasets providing insulin data (n = 446) were included in this predefined subanalysis. Significantly higher reductions in insulin (−3.3 ± 8.7 µU/mL vs. −1.6 ± 9.8 µU/mL), weight (−6.1 ± 5.2 kg vs. −3.2 ± 4.6 kg), and inflammation markers were observed in the intervention group. Insulin reduction correlated with weight reduction and the highest amount of weight loss (−7.6 ± 4.9 kg) was observed in those participants with an insulin decrease > 2 µU/mL. These results underline the potential for meal replacement-based lifestyle interventions in diabetes prevention, and measurement of insulin levels may serve as an indicator for adherence to carbohydrate restriction. 相似文献
83.
Ezgi Dogan-Sander Roland Mergl Anja Willenberg Ronny Baber Kerstin Wirkner Steffi G. Riedel-Heller Susanne Rhr Frank M. Schmidt Georg Schomerus Christian Sander 《Nutrients》2021,13(6)
Depression and vitamin D deficiency are major public health problems. The existing literature indicates the complex relationship between depression and vitamin D. The purpose of this study was to examine whether this relationship is moderated or mediated by inflammation. A community sample (n = 7162) from the LIFE-Adult-Study was investigated, for whom depressive symptoms were assessed via the German version of CES-D scale and serum 25-hydroxyvitamin D (25(OH)D) levels and inflammatory markers (IL-6 and CRP levels, WBC count) were quantified. Mediation analyses were performed using Hayes’ PROCESS macro and regression analyses were conducted to test moderation effects. There was a significant negative correlation between CES-D and 25(OH)D, and positive associations between inflammatory markers and CES-D scores. Only WBC partially mediated the association between 25(OH)D levels and depressive symptoms both in a simple mediation model (ab: −0.0042) and a model including covariates (ab: −0.0011). None of the inflammatory markers showed a moderation effect on the association between 25(OH)D levels and depressive symptoms. This present work highlighted the complex relationship between vitamin D, depressive symptoms and inflammation. Future studies are needed to examine the effect of vitamin D supplementation on inflammation and depressive symptomatology for causality assessment. 相似文献
84.
85.
Holger Mietz Maria Severin Georg Arnold Bernd Kirchhof Günter K. Krieglstein 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》1997,235(2):87-91
Background: Fibrous histiocytomas of the corneoscleral limbus are rare tumors. We present an additional case and review the treatment approaches in the literature. So far, only light and electron microscopic studies have been performed. We used immunohistochemical stains to further characterize the cellular composition. Methods: The excised lesion was routinely fixed and processed for light microscopy and immunohistochemical studies. For comparison, three dermal fibrous histiocytomas were also examined and processed similarly. Results: The corneolimbal tumor was mainly composed of fibroblasts and histiocytes with a large amount of interstitial collagen, arranged in a storiform pattern. Immunohistochemical stains were positive for histiocytes, fibroblasts, and a marker for mesenchymal cells. The staining pattern of the dermal lesions was similar. Conclusion: Fibrous histiocytomas of the corneolimbal region are morphologically benign, slowly growing and infiltrative tumors. Complete resection, especially of the deep margin, is suggested. The immunohistochemical staining pattern is similar to that of dermal fibrous histiocytomas, which behave in a benign manner. 相似文献
86.
Joseli Lannes-Vieira Jochen Gehrmann Georg W. Kreutzberg Hartmut Wekerle 《Acta neuropathologica》1994,87(5):435-442
We have investigated the T cell receptor (TCR) repertoire in the inflammatory infiltrates of T line-transferred experimental autoimmune encephalomyelitis (EAE) of the Lewis rats. Using a panel of TCR V-specific monoclonal antibodies (mAbs) and immunocytochemistry, we studied the nature of the T cells entering the central nervous system (CNS) after transfer of either myelin basic protein (MBP)-reactive, or MBP-reactive but non-encephalitogenic T cell lines. All the MBP-specific T cell lines predominantely used the V8.2 TCR chain. T cell lines specific for the tuberculin purified protein derivative (PPD), using TCR V genes different from V8.2, served as controls. We first studied the time course of T cells entering the CNS. In all recipient rats, small, but significant numbers of -TCR-expressing infiltrate cells appeared in the CNS within the first 24 h after T cell transfer. In animals injected with either type of MBP-reactive T cells, the early infiltrate cells were preferentially located within the parenchyma of the spinal cord, while in PPD T lineinjected rats, the lymphocytes were mostly found in the meninges. TCR V gene usage was examined on the peak of clinical disease. Six days after T cell transfer, the TCR repertoire used by infiltrating lymphocytes in general seemed to be highly diverse. None of the V isotypes examined (i.e. V8.2, V8.5 or V10) was used by a major population of the -TCR-positive T cells. A more detailed, quantitative analysis of individual infiltrate compartments revealed, however, a preferential accumulation of V8.2-positive T cells within the parenchyma. In contrast, perivascular infiltrating cells used V genes randomly. Our results confirm first that activated T lymphocytes enter the brain rapidly irrespective of their antigen specificity. Second, the data show that most of the perivascular infiltrate T cells in the acute EAE lesion are host-derived, recruited presumably from the recirculating T cell pool, while the encephalitogenic, V8.2-positive T cells preferentially persist within the parenchyma.Abbreviations
EAE
experimental autoimmune encephalomyelitis
-
MBP
myelin basic protein
-
TCL
T cell line
Supported by the Brazilian Research Council (CNPq) 相似文献
87.
Modulation of electrically evoked [3H]-noradrenaline release from cultured chick sympathetic neurons
Clemens Allgaier Angelika Schobert Manuela Belledin Rolf Jackisch Georg Hertting 《Naunyn-Schmiedeberg's archives of pharmacology》1994,350(3):258-266
In the present study we attempted a comprehensive characterization of modulation of noradrenaline release from chick sympathetic neurons. To this purpose sympathetic neurons derived from chick lumbosacral paravertebral ganglia and kept in culture for 7 days were loaded with 0.05 mol/l [3H]-noradrenaline and subjected to electrical field stimulation (36 pulses/3 Hz). Since the released transmitter was partially recaptured, superfusion was usually performed in the presence of (+)-oxaprotiline, an inhibitor of noradrenaline re-uptake. [3H]-Noradrenaline was released in a manner which was dependent on extracellular Ca2+ and sensitive to tetrodotoxin (TTX). -Conotoxin (-CTX; 100 nmol/l) abolished [3H]-noradrenaline release indicating that influx through -CTX-sensitive Ca2+-channels was essential for transmitter release. 1,4-dihydro-2,6-dimethyl-5-nitro4-[2-(trifluoromethyl)-phenyl]-3-pyridine carboxylic acid methyl ester ((±)Bay K 8644) and 4-(4-benzofurazanyl)-1,4-dihydro-2,6-dimethyl-3-nitro-5-pyridinecarboxylic acid isopropyl ester ((±)-202-791), agonists at L-type voltage sensitive Ca2+-channels (VSCCs), increased noradrenaline release and induced, in addition, an overflow of tritium which was Ca2+-dependent and prevented by the presence of TTX. The L-type VSCC antagonists (–)-202-791 and (+)-4-(4-benzofurazanyl)-1,4-dihydro2,6-dimethyl-3,5-pyridinedicar boxylic acid methyl, isopropyl ester ((+)-PN 200–110) diminished [3H]-noradrenaline release. These data suggest that L-type VSCCs, probably located on the cell body of the neuron, play an additional role in modulation of release. The full 2-adrenoceptor agonists 5-bromo-6-(2-imidazolin-2-ylamino)-quinoxaline ( UK-14,304) and noradrenaline significantly inhibited noradrenaline release, whereas clonidine, a partial a2-agonist, produced only a slight inhibition even at 10 mol/l. The facilitation of noradrenaline release observed in the presence of the 2-adrenoceptor antagonist rauwolscine was very low in comparison to that obtained with brain slices and isolated smooth muscle tissues. These results corroborate the observation that noradrenaline release from chick sympathetic neurons is regulated by an 2-adrenoceptor which needs further subtype characterization. The experiments were mostly performed at 25°C, since a rise in temperature to 37°C increased the resting outflow, but not the evoked overflow of tritium, approximately 4-fold. In the presence of pargyline to block monoamine oxidase, however, the temperature-dependent enhancement was diminshed and the release showed properties comparable to those observed at 25°C (with respect to TTX-sensitivity, Ca2+ dependence and modulation via 2-adrenoceptors). In addition to the 2-adrenoceptors, we detected inhibitory -adrenoceptors, opioid and receptors, and P2 purinoceptors as well as facilitatory prostaglandin (PG) E receptors. No indication was found for a functional relevance of 5-hydroxytryptamine (5-HT), opioid , PGD, adenosine A1 or glutamate receptors. In conclusion, electrically evoked noradrenaline release from cultured chick sympathetic neurons shows the properties of action-potential-induced transmitter release and is bidirectionally regulated by various substances. Therefore, sympathetic neurons in culture offer the possibility to investigate directly the mechanisms bringing about receptor-coupled modulation of transmitter release.Abbreviations ATP
adenosine 5-triphosphate
- Bay K 8644
1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)-phenyl]-3-pyridine carboxylic acid methyl ester
- DAGO
(d-Ala2,N-methyl-Phe4,Gly-ol5)-enkephalin
- DPDPE
(d-Pen 2,5)-enkephalin
- 5-HT
5-hydroxytryptamine
- -CTX
-conotoxin
- KRBB
modified Krebs-Ringer bicarbonate buffer
- NMDA
N-methyl-d-aspartic acid
- PG
prostaglandin
- PN 200-110
4-(4-benzofurazanyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxy lic acid methyl, isopropyl ester
- R-PIA
R(–)-N6-(2-phenyl-isopropyl)-adenosine
- TTX
tetrodotoxin
- U-50,488H
trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzene acetamide
- UK-14,304
5-bromo-6-(2-imidazolin-2-ylamino)-quinoxaline
- VSCC
voltage sensitive Ca2+-channel
- 202-791
4-(4-benzofurazanyl)-1,4-dihydro-2,6-dimethyl-3-nitro-5-pyridinecarboxylic acid isopropyl ester
Correspondence to: C. Allgaier at the above address 相似文献
88.
Heinz Werner Seifert Georg Klingmüller Klaus Tschubel 《Archives of dermatological research》1978,261(2):163-173
Zusammenfassung Bei einem 47 jährigen Patienten entwickelten sich am rechten Bein mehrere rasch wachsende Tumoren von distal nach proximal. Histologisch und elektronenmikroskopisch zeigten die Tumorzellen morphologische Besonderheiten, die für ihre histiocytäre Provenienz sprechen. Auffallend war die große Anzahl polymorpher cytoplasmatischer Membranstrukturen und großer Vacuolen, die massenhaft kleine Vesikel enthielten. Diese Strukturen werden als transformierte multivesiculäre Körper gedeutet; ihre Entstehung vollzieht sich im Rahmen einer bizarr übersteigerten Membranaktivierung einer malignen Zellrasse. Bemerkenswert ist die rasche und völlige Remission durch Radiotherapie.
Auszugsweise vorgetragen beim 4th European Meeting on Electron Microscopy Applied on Cutaneous Pathology, Heidelberg, 6. und 7. Mai 1977: Multivesicular Vacuolization in Malignant Histiocytoma. 相似文献
Multivesicular vacuolization in malignant histiocytoma of the skin
Summary A 47-year-old patient developed several rapidly growing tumours in his right leg. Histologic and electron microscopic examination revealed morphological characteristics suggesting the histiocytic origin of the tumour cells. An important finding was the striking number of pleomorphic membraneous inclusions and large vacuoles containing numerous small vesicles. These cytoplasmic inclusions are interpreted as transformed multivesicular bodies. Their formation may be an expression of an increased and bizarre membraneous activity of a malignant cell race. Radiotherapy resulted in a remarkably rapid and complete remission.
Auszugsweise vorgetragen beim 4th European Meeting on Electron Microscopy Applied on Cutaneous Pathology, Heidelberg, 6. und 7. Mai 1977: Multivesicular Vacuolization in Malignant Histiocytoma. 相似文献
89.
Christoph Keβler Heinrich Bleckmann Georg Kleintges 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》1991,229(5):487-491
The concentration of the metabolite of the beta-blocker metipranolol was determined in the aqueous humour of 89 cataract patients. At 1, 2 or 5 h before surgery, they received one drop (30 l) of a 0.1 % or 0.3% solution of the drug. At 1, 2 or 5 h after the application of 0.1 % metipranolol eye drops, desacetylmetipranolol concentrations of 624.55, 235.29 and 88.02 ng/ ml, respectively, were measured. At the same intervals after the instillation of 0.3% metipranolol eye drops, the respective values of 1289.20, 1120.88 and 327.36 ng/ ml were found. The metabolite concentration in the eye drops and the values measured show no consistent correlation.Offprint requests to: H. Bleckmann 相似文献
90.
Georg Bauer Susanne Kahl Iva Singh Sawhney Petra Hfler Ralph Gerspach Bertfried Matz 《International journal of cancer. Journal international du cancer》1992,51(5):754-760
Studies on the mechanisms of transformation of mammalian cells by herpes simplex virus (HSV) in vitro have been prevented so far by the extremely low transformation frequencies obtained in monolayer culture. Here we present a transformation system that relies on the direct seeding in soft agar of infected single cells, thus avoiding negative interactions between normal and transformed cells. We took advantage of HSV-I temperature-sensitive mutants at the UL9 locus, which codes for a DNA-binding protein necessary for viral DNA replication. At the non-permissive temperature, viral DNA synthesis and late gene expression are prevented. Viral gene expression is restricted to immediate early and early genes. Induction of transformation was highly efficient in our one-step transformation system. It depended on intact viral particles and viral DNA. Immediate early and/or early viral gene expression was sufficient to induce transformation. Colonies were stably transformed and did not show any rescue of viable virus after temperature downshift and co-cultivation with susceptible cells. Transformed cells maintained the transformed state in the absence of viral DNA. Our data therefore support the "hit-and-run" hypothesis for the transforming effect of HSV. 相似文献