全文获取类型
收费全文 | 19062篇 |
免费 | 818篇 |
国内免费 | 142篇 |
专业分类
耳鼻咽喉 | 224篇 |
儿科学 | 282篇 |
妇产科学 | 260篇 |
基础医学 | 2238篇 |
口腔科学 | 445篇 |
临床医学 | 1257篇 |
内科学 | 5306篇 |
皮肤病学 | 372篇 |
神经病学 | 1636篇 |
特种医学 | 630篇 |
外科学 | 3049篇 |
综合类 | 83篇 |
一般理论 | 4篇 |
预防医学 | 573篇 |
眼科学 | 417篇 |
药学 | 1224篇 |
中国医学 | 46篇 |
肿瘤学 | 1976篇 |
出版年
2023年 | 123篇 |
2022年 | 246篇 |
2021年 | 395篇 |
2020年 | 209篇 |
2019年 | 291篇 |
2018年 | 372篇 |
2017年 | 306篇 |
2016年 | 352篇 |
2015年 | 395篇 |
2014年 | 463篇 |
2013年 | 553篇 |
2012年 | 994篇 |
2011年 | 1067篇 |
2010年 | 685篇 |
2009年 | 574篇 |
2008年 | 978篇 |
2007年 | 1072篇 |
2006年 | 1066篇 |
2005年 | 1065篇 |
2004年 | 1090篇 |
2003年 | 1048篇 |
2002年 | 1047篇 |
2001年 | 486篇 |
2000年 | 409篇 |
1999年 | 443篇 |
1998年 | 266篇 |
1997年 | 202篇 |
1996年 | 190篇 |
1995年 | 152篇 |
1994年 | 133篇 |
1993年 | 148篇 |
1992年 | 317篇 |
1991年 | 253篇 |
1990年 | 216篇 |
1989年 | 243篇 |
1988年 | 215篇 |
1987年 | 237篇 |
1986年 | 206篇 |
1985年 | 192篇 |
1984年 | 149篇 |
1983年 | 119篇 |
1982年 | 60篇 |
1979年 | 119篇 |
1978年 | 64篇 |
1975年 | 62篇 |
1974年 | 68篇 |
1973年 | 60篇 |
1970年 | 73篇 |
1968年 | 66篇 |
1967年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Kazumichi Yamada Satoshi Goto Taro Oyama Makoto Yoshikawa Shinji Nagahiro Yukitaka Ushio 《Acta neuropathologica》1995,89(2):172-177
The present study concerns the vulnerability of striatal interneurons immunopositive for the Ca2+-binding protein calretinin to ischemic neuronal injury. An immunohistochemical study was carried out on the striata of rats which had undergone transient middle cerebral artery occlusion. Two weeks after the ischemia, there was a marked reduction in the number of calretinin-positive neurons in the ipsilateral ischemic lesion, although the striatal interneurons positive for parvalbumin, which are a neuronal population distinct from the calretinin-immunoreactive cells in the striatum, were spared in the insulted areas. The present data indicate that the striatal calretinin-positive neurons are less resistant to transient ischemia, suggesting that there may exist vulnerability differences among the striatal interneurons in ischemia-induced neuronal injury. 相似文献
23.
Tsuyoshi Takeda Hiroyuki Ishida Yukio Horiuchi Yasushi Nakao Yutaka Yabe 《Journal of orthopaedic science》1997,2(6):372-377
We examined radiographs of the elbows of the pitching arms of 79 professional baseball pitchers (mean age, 25.1 years; mean
duration of professional career, 4.7 years) and noted the frequency and size of spurs, bone fragments, and intra-articular
loose bodies according to site. The influence of duration of professional baseball career on these osteoarthritic changes
was also investigated. The olecranon tip was the most frequent site of spurs (62/79; 78.5%), and fragmentation of the spur
was detected in 17 joints. The frequency of spurs was also high at the medial margin of the olecranon, the tip of the coronoid
process, the medial margin of the sigmoid notch, the medial margin of the trochlea and the olecranon fossa. In 38 subjects,
spurs were observed at the distal portion of the radial notch of the ulna. However, few pitchers had osteoarthritic changes
in the humeral capitellum or radial head. Intra-articular loose bodies were detected in 4 of 79 joints (5.1%), and bone fragments
were present below the medial humeral epicondyle in 25 of 79 joints (31.6%). Osteoarthritic changes in the elbow joint appeared
to be attributable mainly to traction stress and impingement associated with extension and valgus strain. Significant osteoarthritic
changes were often found in professional pitchers whose careers exceeded 5 years. 相似文献
24.
Kodama Hideya; Fukuda Jun; Karube Hiroko; Matsui Toshihiko; Shimizu Yasushi; Tanaka Toshinobu 《Human reproduction (Oxford, England)》1995,10(8):1962-1967
This study was aimed at assessing the outcome of in-vitro fertilization(IVF) and embryo transfer in patients with polycystic ovariansyndrome (PCOS). The results of IVF and embryo transfer in PCOSpatients (PCOS group, 78 cycles of 26 patients) were comparedwith those of a control group (423 cycles in 202 patients withoutmale factor; age and ovarian stimulation protocol were matched).Although the pregnancy rate per transfer was not different inthe two groups of patients (25 versus 34%, PCOS versus controlgroup), the PCOS group had a significantly lower pregnancy rateper follicle aspiration (19 versus 31%, P < 0.05). A notableresult was a significantly higher incidence of embryo transfercancellations in the PCOS group (22 versus 8%, P < 0.01),which resulted from unpredictable failure of either oocyte recoveryor fertilization. The incidence of unexplained complete failureof fertilization was significantly higher in the PCOS group(18 versus 5%, P < 0.01). These results may reflect a reducedquality of the oocytes in the PCOS group, and there was a subgroupof PCOS patients who repeatedly produced poor results of treatment.Although the ovarian stimulation regimen best suited to PCOSpatients remains to be determined, special care should be takenduring ovarian stimulation, especially when the PCOS patientshad experienced unexplained failure of oocyte recovery or fertilizationin the previous treatment cycle(s). 相似文献
25.
26.
T Nishiyama A Hirasaki Y Odaka K Seto I Goto 《Masui. The Japanese journal of anesthesiology》1990,39(2):230-236
We compared midazolam 0.2 mg.kg-1 and fentanyl 50 micrograms with thiamylal 4 mg.kg-1 for rapid sequence induction. We could use midazolam safely in patients with bronchial asthma or drug allergy. There was no difference in time from the beginning of induction to intubation between midazolam treated group and thiamylal treated group. Changes in systolic as well as diastolic blood pressure and heart rate during 2 hours from intubation were smaller in midazolam treated group than in thiamylal treated group. In midazolam treated group, no arrhythmias were observed at the time of intubation. We could reduce the amount of anesthetics in midazolam treated group during 2 hours from intubation. From the results mentioned above, we conclude that midazolam is a useful agent for rapid sequence induction. 相似文献
27.
Hiroyuki Yamamoto Fumio Itoh Akinori Senota Yasushi Adachi Mitsuru Yoshimoto Takao Endoh Yuji Hinoda Akira Yachi Kohzoh Imai 《Journal of clinical laboratory analysis》1995,9(5):297-301
The matrix metalloproteinase matrilysin (MMP-7) is a member of the matrix metallo-proteinase gene family, which is believed to play an important role in tumor invasion and metastasis. We have previously found that matrilysin mRNA is specifically expressed in colorectal cancers and adenomas and that its message is localized in the tumor cells themselves. We examined the effects of activated Ki-ras oncogene on the expression of matrilysin in colon cancer cells. We showed that both mRNA and the enzymatic activity of matrilysin were induced by the introduction of activated Ki-ras into SW1417 colon cancer cells. To understand the mechanisms regulating this induction, we analyzed alterations of AP-1 activity induced by activated Ki-ras, using the chloramphenicol acetyltransferase assay. AP-1 activity in SW1417 cells expressing activated Ki-ras was higher than that in control cells. The gel-shift assay also showed higher levels of AP-1 binding protein in SW1417 cells expressing activated Ki-ras than those in control cells. Our results suggest that activated Ki-ras may play a role in inducing expression of matrilysin through an AP-1-dependent pathway in colon cancer cells. 相似文献
28.
Vasoconstrictor response of large cerebral arteries of cats to endothelin, an endothelium-derived vasoactive peptide 总被引:6,自引:0,他引:6
A Saito R Shiba S Kimura M Yanagisawa K Goto T Masaki 《European journal of pharmacology》1989,162(2):353-358
Endothelin, a 21-amino acid peptide produced by vascular endothelial cells, caused a sustained constriction of isolated large cerebral arteries of cats in a dose-dependent manner. The increased tone of the tissue did not return to the resting level after repeated washings. No vasodilator response was evoked by endothelin in the presence of an active tone. The contractile response of cerebral arteries was not inhibited by rubbing of the endothelium, cold storage denervation or indomethacin. In contrast, nicardipine or diltiazem antagonized the endothelin-induced contraction non-competitively. No contraction was evoked by endothelin in a Ca2+-free solution while the addition of Ca2+ ions in the presence of endothelin in a Ca2+-free solution caused a sustained contraction. Ca2+-induced contraction in the Ca2+-free solution containing endothelin was also inhibited by nicardipine. Therefore, endothelin causes a direct contraction of the smooth muscles of cat cerebral arteries, probably by activating the influx of Ca2+ ions through L-type Ca2+ channels of smooth muscles. 相似文献
29.
30.
Hironori Nakagami Yasushi Kikuchi Tomohiro Katsuya Ryuichi Morishita Hiroshi Akasaka Shigeyuki Saitoh Hiromi Rakugi Yasufumi Kaneda Kazuaki Shimamoto Toshio Ogihara 《Hypertension research》2007,30(12):1239-1246
We examined a gene polymorphism of a novel Z-disc-related protein, myospryn (cardiomyopathy-associated 5). We focused on one haplotype block associated with a tag single nucleotide polymorphism (SNP) that covered 16 of 27 coding SNPs with linkage disequilibrium (minor allele frequency 0.413). Screening a myospryn polymorphism (K2906N) in a general health check-up of a rural Japanese population revealed an association with cardiac diseases (p=0.0082). In further analysis of the interaction between K2906N and cardiac function in patients, K2906N was associated with the anteroseptal wall thickness of the left ventricle in a recessive model (p=0.0324) and with the ratio of the peak velocity of the early diastolic filling wave to the peak velocity of atrial filling (A/E) (p=0.0278). In an association study based on left ventricular wall thickness, we found a significant difference in the K2906N genotype between controls and patients with cardiac hypertrophy. These results suggest that the K2906N polymorphism could be clinically associated with left ventricular hypertrophy and diastolic dysfunction independent of known parameters. Although the precise mechanism underlying this association remains to be elucidated, treatment with angiotensin II induced an increase in heart myospryn mRNA level in vitro and in vivo. Our results suggest that the polymorphism of myospryn is associated with left ventricular hypertrophy, and an association between a Z-disc protein and cardiac adaptation in response to pressure overload. 相似文献