全文获取类型
收费全文 | 110168篇 |
免费 | 6218篇 |
国内免费 | 658篇 |
专业分类
耳鼻咽喉 | 1075篇 |
儿科学 | 3548篇 |
妇产科学 | 2583篇 |
基础医学 | 15783篇 |
口腔科学 | 3998篇 |
临床医学 | 9934篇 |
内科学 | 24790篇 |
皮肤病学 | 2779篇 |
神经病学 | 10726篇 |
特种医学 | 2559篇 |
外国民族医学 | 1篇 |
外科学 | 10057篇 |
综合类 | 405篇 |
一般理论 | 48篇 |
预防医学 | 10956篇 |
眼科学 | 1778篇 |
药学 | 7730篇 |
中国医学 | 431篇 |
肿瘤学 | 7863篇 |
出版年
2024年 | 120篇 |
2023年 | 1052篇 |
2022年 | 2250篇 |
2021年 | 3720篇 |
2020年 | 2329篇 |
2019年 | 3135篇 |
2018年 | 3604篇 |
2017年 | 2744篇 |
2016年 | 3168篇 |
2015年 | 3493篇 |
2014年 | 4614篇 |
2013年 | 6007篇 |
2012年 | 9140篇 |
2011年 | 9496篇 |
2010年 | 5191篇 |
2009年 | 4363篇 |
2008年 | 7551篇 |
2007年 | 7550篇 |
2006年 | 6948篇 |
2005年 | 6505篇 |
2004年 | 5820篇 |
2003年 | 5200篇 |
2002年 | 4686篇 |
2001年 | 663篇 |
2000年 | 488篇 |
1999年 | 685篇 |
1998年 | 813篇 |
1997年 | 671篇 |
1996年 | 572篇 |
1995年 | 467篇 |
1994年 | 441篇 |
1993年 | 357篇 |
1992年 | 349篇 |
1991年 | 252篇 |
1990年 | 229篇 |
1989年 | 217篇 |
1988年 | 191篇 |
1987年 | 160篇 |
1986年 | 185篇 |
1985年 | 124篇 |
1984年 | 145篇 |
1983年 | 134篇 |
1982年 | 166篇 |
1981年 | 116篇 |
1980年 | 132篇 |
1979年 | 86篇 |
1978年 | 90篇 |
1977年 | 77篇 |
1976年 | 64篇 |
1974年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Paolo Cossu Rocca Matteo Brunelli Stefano Gobbo Albino Eccher Emma Bragantini Maria M Mina Vincenzo Ficarra Filiberto Zattoni Alberto Zamò Maurizio Pea Aldo Scarpa Marco Chilosi Fabio Menestrina Franco Bonetti John N Eble Guido Martignoni 《Modern pathology》2007,20(7):722-728
S100A1 is a calcium-binding protein, which has been recently found in renal cell neoplasms. We evaluated the diagnostic utility of immunohistochemical detection of S100A1 in 164 renal cell neoplasms. Forty-one clear cell, 32 papillary, and 51 chromophobe renal cell carcinomas, and 40 oncocytomas, 164 samples of normal renal parenchyma adjacent to the tumors and 13 fetal kidneys were analyzed. The levels of S100A1 mRNA detected by quantitative RT-PCR analysis of frozen tissues from seven clear cell, five papillary, and six chromophobe renal cell carcinomas, four oncocytomas, and nine samples of normal renal tissues adjacent to neoplasms were compared with the immunohistochemical detection of protein expression. Clear cell and papillary renal cell carcinomas showed positive reactions for S100A1 in 30 out of 41 tumors (73%) and in 30 out of 32 (94%) tumors, respectively. Thirty-seven renal oncocytomas out of 40 (93%) were positive for S100A1, whereas 48 of 51 (94%) chromophobe renal cell carcinomas were negative. S100A1 protein was detected in all samples of unaffected and fetal kidneys. S100A1 mRNA was detected by RT-PCR in all normal kidneys and renal cell neoplasms, although at very different levels. Statistical analyses comparing the different expression of S100A1 in clear cell and chromophobe renal cell carcinomas observed by immunohistochemical and RT-PCR methods showed significant values (P<0.001), such as when comparing by both techniques the different levels of S100A1 expression in chromophobe renal cell carcinomas and oncocytomas (P<0.001). Our study shows that S100A1 protein is expressed in oncocytomas, clear cell and papillary renal cell carcinomas but not in chromophobe renal cell carcinomas. Its immunodetection is potentially useful for the differential diagnosis between chromophobe renal cell carcinoma and oncocytoma. Further, S100A1 protein expression is constantly detected in the normal parenchyma of the adult and fetal kidney. 相似文献
62.
63.
Micha? Ciurzyński Piotr Bienias Agnieszka Szewczyk Barbara Lichodziejewska Maria B?aszczyk Danuta Liszewska-Pfejfer Piotr Pruszczyk 《Medical science monitor》2007,13(10):CS124-CS127
BACKGROUND: Systemic sclerosis (SSc) is a connective tissue disorder of unknown etiology characterized by fibrosis of the skin and visceral organs, in which the heart is frequently (40-70% of patients) and severely involved. Pulmonary hypertension affects 10-15% of patients with SSc and is one of the most important complications adversely influencing their survival. CASE REPORT: The case report presents a 59-year-old male patient with advanced systemic sclerosis whose initial examination revealed pulmonary hypertension, rhythm and atrioventricular conduction disturbances, and elevated level of NT-proBNP. After six months the patient deteriorated; an increase in NT-proBNP level and progression of pulmonary hypertension were observed. CONCLUSIONS: The described case is followed by a discussion of cardiovascular involvement in systemic sclerosis and emphasizes that heart involvement in SSc may have very serious clinical implications. 相似文献
64.
Maria Grazia Daidone Rosella Silvestrini Nadia Zaffaroni Egle Grignolio Fabio Landoni 《Investigational new drugs》1987,5(3):245-250
An in vitro assay, which evaluates drug effect on 3H-thymidine incorporation, was used to investigate the absolute and relative activities of cisplatin (DDP), carboplatin (CBDCA) and iproplatin (CHIP) on 317 specimens from untreated tumors, including breast and ovarian cancers and malignant melanomas. Similar activities were generally observed for DDP and CHIP, whereas CBDCA exhibited a lower, although not significantly different cytotoxicity on breast and ovarian cancers. The relative activities of Platinum analogues were analyzed on 239 two-way drug sensitivity comparisons. The overall agreement rates ranged from 80.2 to 83.9% for the different comparisons. High coresistance, from 61.1 to 93.8%, was observed for all the comparisons, regardless of the tumor type. Cosensitivity rates were poor for breast and ovarian cancers, from 0 to 37.5%, whereas for melanomas an association in sensitivity was observed in 80% of the cases. 相似文献
65.
66.
Paavo Riekkinen Jr. Jouni Sirvi Pekka Jkl Maria Mazurkiewicz Antti Valjakka Minna Riekkinen Paavo Riekkinen 《Brain research bulletin》1991,27(2):287-289
Quisqualic acid NBM lesions had no effect on water maze performance, but slightly impaired passive avoidance acquisition. GammavinylGABA treatment alone had no effect on the passive avoidance and water maze performance, but aggravated acquisition deficit in rats subjected to NBM lesioning. However, gammavinylGABA-treated NBM-lesioned rats reached control level of performance. 相似文献
67.
R. Gamzu L. Yogev PhD A. Botchan A. Amit J. B. Lessing D. Lichtenberg G. Paz and H. Yavetz 《Andrologia》1997,29(1):17-21
Summary. The study was conducted to evaluate the diverse effect and clinical significance of TEST yolk buffer treatment on sperm samples of 128 infertile men. Sperm samples were incubated with TEST yolk buffer and control medium (Ham's F-10) at room temperature for 2 h. The hemizona indices (mean ± SE) of the TEST yolk buffer and medium-treated sperm samples were 29 ± 2.3% and 22 ± 1.6%, respectively. Inspection of the individual response of each sperm sample to TEST yolk buffer revealed that 63 samples (49%) improved (double the interassay variation = 28%) their binding to zona pellucida, 36 (28%) remained unchanged, whereas the binding capacity of 29 samples (23%) decreased. Furthermore, TEST yolk buffer treatment of 24 samples (19%) resulted in an increased binding beyond the hemizona index threshold set up at 23%. This level was previously shown to be the cut-off point between fertile and infertile sperm samples. It was concluded that when applied to an unselected group of infertile men, TEST yolk buffer significantly increased sperm binding capacity to the zona pellucida. However, only 19% of the sperm samples showed improvement with clinical significance. The other sperm samples may have improved, remained unchanged or even deteriorated independently on basic sperm variables. Thus, the effect of TEST yolk buffer treatment on sperm binding should be tested prior to its clinical use to avoid possible damage to certain sperm samples. 相似文献
68.
Marina Quartu Maria Pina Serra Annalisa Manca Paolo Follesa Rossano Ambu Marina Del Fiacco 《International journal of developmental neuroscience》2003,21(6):309-320
The immunohistochemical occurrence of the high affinity neurotrophin (NT) receptors trkA, trkB, and trkC is shown in the pre-term newborn, infant, and adult human post-mortem cerebellum. Immunoreactive neuronal perikarya and processes were observed in all specimens examined, where they appeared unevenly distributed in the cerebellar cortical layers and deep nuclei, and showed regional differences among cerebellar lobules and folia. The trk receptor-antibodies, tested by Western blot on human cerebellum homogenates, revealed multiple immunoreactive bands for trkA and single bands for trkB and trkC. The results obtained show the tissue localization of the trk receptor-like immunoreactivity in the human cerebellum from prenatal to adult age. The analysis for codistribution of the receptors with the relevant ligand and among the receptors in discrete cortical and deep nuclei tissue fields shows a wide variety of conditions, from a good similarity in terms of type and density of labeled structures, to a lack of correspondence, and suggests the possibility of colocalization of trk receptors with the relevant neurotrophin and among them in the cerebellar cortex. These results sustain the concept that the neurotrophin trophic system participates in the development, differentiation, and maintenance of the human cerebellar connectivity and support the possibility of a multifactorial trophic support for the neurotrophins through target-derived and local mechanisms. 相似文献
69.
Serafim N. Nanas John N. Nanas Christos E. Charitos Alexandros Gougoulakis Konstantinos Makaritsis John Chatzigeorgiou Kiriaki Moussoutzani Maria I. Anastasiou-Nana Spyridon D. Moulopoulos 《World journal of surgery》1997,21(3):318-322
p
< 0.001), the tension time index (712 ± 381 versus 1333 ± 694,
p
< 0.01), and the double product (5629 ± 2574 versus 7440 ± 3294,
p
< 0.01) were significantly lower during assistance with the PACD than with the CBP. It was concluded that PACD is at least
as effective as CBP for restoring hemodynamic status during acute experimental cardiogenic shock. Moreover, the PACD unloads
the left ventricle more effectively than CBP, making it suitable for left ventricular mechanical support in cases with reversible
myocardial damage. 相似文献
70.
Spindler A; Paz S; Berman A; Lucero E; Contino N; enalba A; Tirado S; Santana M; Zeballos A 《Nephrology, dialysis, transplantation》1997,12(1):128-132
Purpose. The objective of this study was to determine
the relationship between muscular strength and bone mineral density (BMD)
in patients undergoing regular haemodialysis. Methods.
The BMD was measured in the lumbar spine (L2L4) and in the proximal femur
(femoral neck and trochanter) with dual-energy X-ray absorptiometry (DEXA
(Lunar DPX). Muscular strength of the extensors, flexors and abductors
muscles of the femur (proximal muscles) and extensors muscles of the back
was measured with an isometric cynamometer. Thirty patients, 15 women with
a mean age of 33.7 years (18-43) and 15 men with a mean age of 15.5 years
(18-65) were included in the study. Results. There was
a positive and significant correlation between the BMD of the femoral neck
and muscular strength of the flexors (r=0.490, P<0.005), the
extensors (r=0.658, P<0.01) and the abductors muscles of the femur
(r=0.671, P <0.0008), as well as between the muscular strength of
the flexors (r=0.413, P <0.02) and extensors muscles of the femur
(r=0.433, P <0.01) with BMD of the trochanter. There was no
correlation between the muscular strength of the back extensor muscles and
the BMD of the lumbar spine (r=-0.119, P NS). There was no correlation
between the BMD and the number of years of haemodialysis therapy (r=-0.032,
P NS), the patient's age (r=-159, P NS), or the value of serum PTH
(r=0.369, P NS) respectively. However, there was a significant correlation
between the BMD of the femoral neck with muscular strength (r=0.602, P
<0.05). Conclusion. This study reveals the
close relationship that exists between muscular strength of the proximal
muscles and the BMD of proximal femur in patients undergoing haemodialysis. 相似文献