全文获取类型
收费全文 | 2681篇 |
免费 | 181篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 79篇 |
妇产科学 | 37篇 |
基础医学 | 520篇 |
口腔科学 | 24篇 |
临床医学 | 221篇 |
内科学 | 618篇 |
皮肤病学 | 38篇 |
神经病学 | 269篇 |
特种医学 | 187篇 |
外科学 | 361篇 |
综合类 | 37篇 |
一般理论 | 1篇 |
预防医学 | 132篇 |
眼科学 | 11篇 |
药学 | 168篇 |
中国医学 | 1篇 |
肿瘤学 | 180篇 |
出版年
2022年 | 22篇 |
2021年 | 32篇 |
2020年 | 26篇 |
2019年 | 34篇 |
2018年 | 37篇 |
2017年 | 30篇 |
2016年 | 43篇 |
2015年 | 48篇 |
2014年 | 60篇 |
2013年 | 97篇 |
2012年 | 149篇 |
2011年 | 122篇 |
2010年 | 114篇 |
2009年 | 81篇 |
2008年 | 133篇 |
2007年 | 105篇 |
2006年 | 106篇 |
2005年 | 106篇 |
2004年 | 93篇 |
2003年 | 95篇 |
2002年 | 77篇 |
2001年 | 92篇 |
2000年 | 80篇 |
1999年 | 69篇 |
1998年 | 63篇 |
1997年 | 54篇 |
1996年 | 49篇 |
1995年 | 42篇 |
1994年 | 35篇 |
1993年 | 28篇 |
1992年 | 49篇 |
1991年 | 45篇 |
1990年 | 63篇 |
1989年 | 43篇 |
1988年 | 59篇 |
1987年 | 57篇 |
1986年 | 37篇 |
1985年 | 39篇 |
1984年 | 37篇 |
1983年 | 35篇 |
1982年 | 18篇 |
1981年 | 23篇 |
1980年 | 27篇 |
1979年 | 28篇 |
1978年 | 21篇 |
1977年 | 20篇 |
1976年 | 24篇 |
1975年 | 19篇 |
1972年 | 16篇 |
1971年 | 19篇 |
排序方式: 共有2895条查询结果,搜索用时 46 毫秒
31.
It is well recognized that the ability to cryopreserve unfertilizedhuman oocytes would make a significant contribution to infertilitytreatment. However, despite considerable interest, very fewsuccessful pregnancies have arisen from cryopreserved oocytesafter thawing, insemination and transfer of the subsequent embryo.The reasons for this lack of progress may well result from adearth of information on how the various biophysical changesduring a cryopreservation regimen affect human oocyte function.Recently, fundamental studies on the effects of cooling, membranepermeability, cryoprotectant addition and ice formation havebeen performed on human oocytes by a number of groups, and theseform the basis of the current review. It is likely that successfulhuman oocyte cryopreservation will only follow once these factorsare fully understood, but the existing base of knowledge shouldprovide a platform for further improvements in the techniquescurrently employed. 相似文献
32.
K. Kovacs E. Horvath B. Corenblum A. M. T. Sirek G. Penz C. Ezrin 《Virchows Archiv : an international journal of pathology》1975,366(2):113-123
Summary Morphologic studies of pituitary neoplasms removed by surgery from 36 human patients revealed 8 chromophobe adenomas which differed clearly from the remaining tumors. The cytoplasm of the adenoma cells failed to stain with PAS, aniline blue, aldehyde fuchsin, aldehyde thionin, orange G or light green, but positively stained granules were found by using erythrosine or carmoisine. Immunoperoxidase technique disclosed the presence of prolactin in the cytoplasm of some adenoma cells. The adenoma cells exhibited distinct ultrastructural features such as well developed rough surfaced endoplasmic reticulum with Nebenkern formation, prominence of Golgi apparatus, presence of misplaced exocytosis as well as pleomorphism of secretory granules with a considerable variation of size ranging from 130 to 500 nm in diameter. Thus, by electron microscopy the adenoma cells showed a close resemblance to prolactin cells of the non-tumorous pituitary glands except for the reduced size and number of secretory granules.These chromophobe adenomas are regarded as representing a distinct pathological entity clearly distinguishable from other forms of pituitary neoplasms. In view of the morphologic findings and the elevation of blood prolactin level (measured in 3 patients) the term, sparsely granulated prolactin producing pituitary adenoma, appears to be the most appropriate one to designate these tumors.The authors wish to thank Dr. H. Friesen for providing the anti-human prolactin and Dr. L. A. Sternberger for the peroxidase-anti-peroxidase complex. The excellent technical assistance of Mrs. Gezina Ilse and Miss Nancy Macphail and the valuable secretarial help of Mrs. Maureen Rowling are appreciated.The work was supported in part by MA-552 grant of the Medical Research Council of Canada and by the St. Michael's Hospital Research Society. 相似文献
33.
Charles Frèche Francisque Leynadier Friedrich Horak David Hide Fernando Duce Gracia Manfred Goos Claus Bachert Attila Horvath Eva Antosova Muriel Verrecchia Paul Ben Soussen 《Annals of allergy, asthma & immunology》2002,89(3):304-310
BACKGROUND: Mizolastine is a nonsedating H1 histamine receptor antagonist with additional antiallergic properties currently marketed in Europe for the treatment of seasonal and perennial allergic rhinitis (PAR) and urticaria. OBJECTIVE: This multicenter, randomized, double-blind, parallel-group study was conducted to evaluate the efficacy and safety of mizolastine in PAR compared with loratadine and placebo. METHODS: After a 1-week placebo run-in period, 428 adult PAR patients received placebo (146 of 428), mizolastine 10 mg (141 of 428), or loratadine 10 mg (141 of 428) once daily for 28 days. Symptoms were evaluated by patients and physicians using a total nasal score, evaluating itching, rhinorrhea, nasal blockade, and sneezing severity. RESULTS: Mizolastine treatment resulted in a significantly greater decrease in patient-rated total nasal score than placebo after 2 weeks (D14; -42%, P < 0.001) and at the end of the treatment period (-46%, P = 0.01), and significantly greater than that observed with loratadine at D14 (P = 0.031). No significant difference in change in total nasal score was observed between loratadine and placebo at 2- and 4-week visits. The global safety was satisfactory and the incidence of adverse events was similar in the three treatment groups. CONCLUSIONS: Mizolastine provides effective symptom relief in PAR together with a satisfactory safety profile. Improvement with mizolastine was significantly greater than placebo throughout the study despite a large placebo effect. Also mizolastine's effects were greater those observed with loratadine after 2 weeks of treatment. 相似文献
34.
Ochiai Y Golding LA Massiello AL Medvedev AL Horvath DJ Gerhart RL Chen JF Krogulecki AY Takagaki M Doi K Howard MW Fukamachi K 《ASAIO journal (American Society for Artificial Internal Organs : 1992)》2002,48(3):249-252
The Cleveland Clinic CorAide left ventricular assist system consists of a permanently implantable centrifugal pump in which the rotating assembly is completely suspended and noncontacting. A series of chronic animal in vivo studies were conducted to evaluate the biologic effects of CorAide circulatory support without the use of anticoagulation therapy. The CorAide pump was implanted in six calves (five calves for 21 to 32 days and one calf for 95 days). The first five calves received intravenous heparin during the early postoperative periods (2-7 days). Heparin administration was then discontinued and no other anticoagulant drugs were used for the duration of the experiments. The last calf did not receive any anticoagulant except for a bolus dose of heparin (200 U/kg) during surgery. Hemodynamics were stable in all six calves, with a mean pump flow of 5.6+/-1.2 L/min and mean arterial pressure of 100+/-4 mm Hg. The blood pump surfaces were clean of thrombus in all six calves. Significant findings at autopsy were limited to one case of renal infarction. There was no incidence of mechanical failure, bleeding, or device infection. The CorAide pump can be safely run with minimal or no anticoagulant therapy. 相似文献
35.
Ectopic pituitary adenoma (EPA) is rare and, to the authors’ knowledge, its association with peliosis has not yet been described.
The case of a 38-yr-old woman with clinical and biochemical evidence of Cushing’s syndrome is reported. Magnetic resonance
imaging (MRI) disclosed a normal pituitary and a separate mass in the sphenoid sinus. The surgically remove’s hyaline change
in the corticotrophs, indicating exposure to glucocorticoid excess. By histology, the mass in the sphenoid sinus was a congested,
chromophobic, partly basophilic, periodic acid-Schiff (PAS)-positive pituitary adenoma composed of pleomorphic, adrenocorticotropic
hormone (ACTH)-positive, corticotrophs. There was focal immunopositivity for MIB-1 and proliferating cell nuclear antigen
(PCNA). Electron microscopy confirmed the diagnosis of corticotroph adenoma. A striking finding, consistent with the diagnosis
of peliosis, was the presence of multiple large blood-filled spaces lacking an endothelial lining. The capillaries were dilated,
but often appeared empty and the fenestrated endothelium exhibited discontinuities. The cause of peliosis is obscure. It may
be that the venous outflow was impaired in this case leading to capillary dilation, congestion, hyperpermeability, rupture,
and accumulation of blood in extravascular spaces. 相似文献
36.
Deodhare SS Bilbao JM Kovacs K Horvath E Nomikos P Buchfelder M Reschke K Lehnert H 《Endocrine pathology》1999,10(3):237-241
We report a case of xanthomatous hypophysitis, a recently described entity of obscure etiology affecting the pituitary gland,
in a 43-yr-old women. Histologically it is characterized by infiltration of the anterior pituitary by foamy histiocytes which
are strongly immunoreactive for CD68 (histiocytic marker) and are immunonegative for S100 and CD1a. Electron microscopy revealed
histiocytes with abundant cytoplasmic lipid droplets and membrane bound vacuoles. Fragments of intact anterior pituitary with
preserved vascular and reticulin networks are seen. Xanthomatous hypophysitis resembles neoplasm on clinical and radiologic
grounds. 相似文献
37.
Albert Beckers Kalman Kovacs Eva Horvath Roger Abs Michel Reznik Achille Stevenaert 《Endocrine pathology》1991,2(3):123-131
Twenty-four acromegalic patients were treated with octreotide subcutaneously for periods of 3 to 6 weeks (group I, 12 cases)
or 6 months (group II, 12 cases) before transsphenoidal surgery. Radiological studies performed in 19 patients before and
at the end of this treatment period revealed no changes in 8 cases. In 8 other cases, a slight reduction in tumorsize was observed, and in 3 cases an important shrinkage was documented. At surgery, the adenomatous tissue appeared softer than
in nonpretreated patients, facilitating the operation. Pathological examination revealed widening of perivascular spaces with
accumulation of fibrous tissue and more crinophagy than in nonpretreated patients but failed to reveal morphologically pronounced
cell involution as observed in prolactin-producing adenomas treated with dopamine agonists. No significant difference in frequency
or extent of cellular changes was noted between the two groups. These morphological findings seem to be more consistent with
a functional inhibition of growth hormone release than with cellular alterations induced by octreotide. 相似文献
38.
Margaret T. Duncan Ruby Husain Hui-Min Chen Steven M. Horvath 《American journal of human biology》1995,7(3):329-337
The interaction of race and climatic adaptation on patterns of cardiovascular reactivity among young adult males was examined. Malay and Chinese subjects living in a tropical climate in the Orient and Caucasians living in a sub-tropical climate in North America were investigated. The cold pressor test with hand immersion in cold water was used as the stressor. Systolic and diastolic blood pressures, cardiac frequency, cardiac output, and stroke volume were measured. The results provided limited evidence for absence of differences in cardiac reactivity among racial groups and for greater vascular reactivity in the Caucasians. Cold immersion also elicited differential responses which could be partially attributed to differences in acclimatizations status. © 1995 Wiley-Liss, Inc. 相似文献
39.
Diane L. Spitler Steven M. Horvath Kando Kobayashi Jeames A. Wagner 《European journal of applied physiology》1980,43(2):157-166
Summary Twelve subjects completed a progressive treadmill test to maximal aerobic capacity while breathing air or a 79% helium — 21% oxygen gas mixture (HeO2). Metabolic and thermoregulatory responses to work while breathing the two mixtures were compared at rest, 30–40%, 60–70%, and 85–95% of maximal performance, and at maximal effort. Ventilation, ventilatory equivalent, and respiratory rates were increased and oxygen uptakes decreased by breathing HeO2 when the level of work exceeded 85–95% of maximum. Heat loss through the respiratory tract was greater breathing HeO2. The reduction in maximal oxygen uptake is probably due to a reduction in the oxygen cost of breathing a less dense gas. It was not related to a lower body temperature and probably not to O2 transport or circulatory limitation. HeO2 breathing had no effect on maximal mechanical work capacity.The nature and purpose of the study and the risks involved were explained verbally and given on a written form to each subject prior to his or her voluntary consent to participate. The protocol and procedures for this study have been approved by the Committee on Activities Involving Human Subjects, of the University of California, Santa Barbara, California, USA 相似文献
40.